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ipwnyou3
03-10-2008, 11:10 PM
I was wondering, i have a 01 330i. I was looking to supercharge it, or turbo it? I dont know, let me know please. which will make me more power? or what would my car like more? and if you pick one, let me know what kind, and price? please, thanks.

BMW_Matt
04-20-2008, 07:51 PM
i know this is a old post but ur gonna have to supercharge it. You will probably need a custom turbo because i don't think they make them.

Synaps3
04-21-2008, 02:53 AM
I thought there was a post on bimmerforums or semething about an E46 turbo in the last year.

Theres definitely been a kit made. Still could be hard to get though.

EUROTEK///M3
05-06-2008, 09:38 PM
turbo

swing0r
06-10-2008, 01:38 PM
turbocharge without a doubt. Only reason to supercharge is if you don't have enough money, or they dont manufacture aftermarket turbo's for your car, in which case you'd have to get custom ones made ... again its gonna be about the money.

e30e
06-10-2008, 01:46 PM
turbocharge without a doubt. Only reason to supercharge is if you don't have enough money, or they dont manufacture aftermarket turbo's for your car, in which case you'd have to get custom ones made ... again its gonna be about the money.

If your going boost on any n/a car its always about money. For e36's specifically you can get the St. II supercharger for 3-4k less than stage II turbo and make very close to similiar power. Along with a less intense installation which means it'll cost you less to install. It depends on climate and driving style too, supercharging a car in Arizona makes so much more sense than a turbo since you don't tend to have build boost like you do in a turbo. Both get hot, but its too damn hot for turbo's when your constantly building boost and its 120+ outside.

franka
07-22-2008, 11:53 AM
Do you want a good daily driver with hp all over the rpm range and instant response or are you willing to sacrifice good low end torque and instant throttle response for a little more higher hp figure in the 6-7000 rpm range ? That is always the question.

First is a twin screw or a modern roots blower. The second is a turbo.

BMW_Matt
07-28-2008, 06:56 PM
get the supercharger. Get a twin screw from ess tuning @ 8 psi. You will need to find a custom turbo for your car because the inline 6 is difficult to get pipes ran from both sides.

Edev
07-29-2008, 01:40 AM
also is it an auto or a 5 speed? cause ive heard a few auto trannys cant hold its ground with that much extra hp. someone correct me if im wrong??

BIMMERUSAM5
08-04-2008, 07:38 AM
turbocharge without a doubt. Only reason to supercharge is if you don't have enough money, or they dont manufacture aftermarket turbo's for your car, in which case you'd have to get custom ones made ... again its gonna be about the money.

+1
If you wan't more power and more boost go with a turbo.

kingbadman
09-20-2008, 11:41 PM
turboo for shore. i have owned both supercharged applications and turboed ones and find a turbo so much more fun and alot easier to add to or up grade if you have bigger plans for it in the future. a supercharger in my opinion would be more expensive. but depends how much of the work you are planning to do yourself.

krenar
09-20-2008, 11:54 PM
i go for turbo big turbo:lmao:

franka
09-22-2008, 07:22 AM
A turbo will be much harder to tune than a SCr because the turbos rpms are up and down and all over. Turbo rpms have no fixed relation to engine rpms and that is a major source of problems. Trying to match the injector's shot volumes and ignition timing and relief valves with the engine rpms and varying throttle demands and varying turbo speeds is a nightmare. Tuning a turbo set up to run clean and smooth is difficult. It takes much more time than to tune a SCr

A Roots or a Twin Screw's rpm always matches the engine's rpms at a fixed ratio. More rpms and the SCr pumps more volume to force feed the engine's displacement. A SCr is always in synch with the motor. This simple fact makes tuning much easier.

Turbos have lag, even the best set ups have lag. Lag, lag and then the turbo starts to catch up with the engine and starts to make some boost for power. Its a slow process when compared to a driven SCr

A screw type SCr like a Roots or a Twin Screw, has NO lag, you get full boost immediately, as fast as you can open the throttle, mili-seconds not 2 or 3 full seconds.

But this is not true for a Centrifugal SCr, it too needs rpms to build boost much like a turbo. A Dinan SCr and the VF SCr are centrifugal types. They build boost like a turbo, with rpms. Boost at low rpm is quite small and can not be increased.

For street use a Roots or a Twin Screw SCr, only they can deliver full boost instantly and at low rpms and all the way up to the engine's rpm limit. That is why the new Corvette and the Ford GT40 LeMans has a Roots SCr and not a turbo.

A turbo, on the same motor, will make more net hp at the top end because there is no screw to spin, but it is a poor choice for street use. Turbo exhaust ducting has to be made to fit in a cramped space and the red hot ducts and turbo add more heat to an already hot engine compartment.

I could go on in more detail but I will not spend my time on this subject when you can Google it and get all the info you ever would want.

Corey Milne
09-30-2008, 10:13 PM
A turbo will be much harder to tune than a SCr because the turbos rpms are up and down and all over. Turbo rpms have no fixed relation to engine rpms and that is a major source of problems. Trying to match the injector's shot volumes and ignition timing and relief valves with the engine rpms and varying throttle demands and varying turbo speeds is a nightmare. Tuning a turbo set up to run clean and smooth is difficult. It takes much more time than to tune a SCr

A Roots or a Twin Screw's rpm always matches the engine's rpms at a fixed ratio. More rpms and the SCr pumps more volume to force feed the engine's displacement. A SCr is always in synch with the motor. This simple fact makes tuning much easier.

Turbos have lag, even the best set ups have lag. Lag, lag and then the turbo starts to catch up with the engine and starts to make some boost for power. Its a slow process when compared to a driven SCr

A screw type SCr like a Roots or a Twin Screw, has NO lag, you get full boost immediately, as fast as you can open the throttle, mili-seconds not 2 or 3 full seconds.

But this is not true for a Centrifugal SCr, it too needs rpms to build boost much like a turbo. A Dinan SCr and the VF SCr are centrifugal types. They build boost like a turbo, with rpms. Boost at low rpm is quite small and can not be increased.

For street use a Roots or a Twin Screw SCr, only they can deliver full boost instantly and at low rpms and all the way up to the engine's rpm limit. That is why the new Corvette and the Ford GT40 LeMans has a Roots SCr and not a turbo.

A turbo, on the same motor, will make more net hp at the top end because there is no screw to spin, but it is a poor choice for street use. Turbo exhaust ducting has to be made to fit in a cramped space and the red hot ducts and turbo add more heat to an already hot engine compartment.

I could go on in more detail but I will not spend my time on this subject when you can Google it and get all the info you ever would want.

+1, for a street car a supercharger is far more practical.

boofsmb
09-30-2008, 11:12 PM
turbo and you should be able to get kits for your model more easily then alot of other bmw models who have added the turbo to theirs

ipwnyou3
10-20-2008, 02:37 PM
thanks alot guys im going with a supercharger, cas all im gonna be driving is on the streets. thank you.

franka
10-21-2008, 06:36 AM
thanks alot guys im going with a supercharger, cas all im gonna be driving is on the streets. thank you.

A perfect choice for street use.

robb01
10-24-2008, 11:17 AM
I would have gone with turbo charge :rolleyes:

franka
10-24-2008, 11:28 AM
I would have gone with turbo charge :rolleyes:

Why? Because its cool or your friend has one?

Black-Out
11-01-2008, 08:12 AM
A turbo will be much harder to tune than a SCr because the turbos rpms are up and down and all over. Turbo rpms have no fixed relation to engine rpms and that is a major source of problems. Trying to match the injector's shot volumes and ignition timing and relief valves with the engine rpms and varying throttle demands and varying turbo speeds is a nightmare. Tuning a turbo set up to run clean and smooth is difficult. It takes much more time than to tune a SCr

A Roots or a Twin Screw's rpm always matches the engine's rpms at a fixed ratio. More rpms and the SCr pumps more volume to force feed the engine's displacement. A SCr is always in synch with the motor. This simple fact makes tuning much easier.

Turbos have lag, even the best set ups have lag. Lag, lag and then the turbo starts to catch up with the engine and starts to make some boost for power. Its a slow process when compared to a driven SCr

A screw type SCr like a Roots or a Twin Screw, has NO lag, you get full boost immediately, as fast as you can open the throttle, mili-seconds not 2 or 3 full seconds.

But this is not true for a Centrifugal SCr, it too needs rpms to build boost much like a turbo. A Dinan SCr and the VF SCr are centrifugal types. They build boost like a turbo, with rpms. Boost at low rpm is quite small and can not be increased.

For street use a Roots or a Twin Screw SCr, only they can deliver full boost instantly and at low rpms and all the way up to the engine's rpm limit. That is why the new Corvette and the Ford GT40 LeMans has a Roots SCr and not a turbo.

A turbo, on the same motor, will make more net hp at the top end because there is no screw to spin, but it is a poor choice for street use. Turbo exhaust ducting has to be made to fit in a cramped space and the red hot ducts and turbo add more heat to an already hot engine compartment.

I could go on in more detail but I will not spend my time on this subject when you can Google it and get all the info you ever would want.


Common misconceptions in turbocharging....Although easier to install superchargers have thier own list of dis-advantages especialy when the charger of choice is the roots blower or twin screw, such as heat control with in the charge air. Roots blowers until recently were never intercooled because there was no way to fit a heat exchanger between the blower and the intake manifold which forces one to run either really low boost pressures, really low compression, really low ignition timing or all three, all of which degrade the cars true potential to make horsepower and torque. The after coolers made for twinscrew and roots blowers are rediculously expensive because they require elaborate cast manifold adapters to allow for the coolers to be mounted and routed to the throttle body, or replace the intake manifold completely.

There's also the paracitic drag associated with supercharging over turbocharging which, on a decent sized roots blower or twin screw, can produce enough drag to require 50 or more horsepower to turn the engine at idle........enough to cause non linear throttle responce from off idle transitions to accelerate.

Then there is the amount of boost available when you get on the throttle. You may have instant boost responce yes, but it's NOT the full boost potential of the supercharger. Because it's tied to the crank pulley full boost isn't reached untill redline which is what the pulley is tuned for.....maximum RPM boost pressure so you can't overboost the engine. Turbos on the other hand provide maximum boost anytime it's called upon beyond boost thresh hold which depends on turbo selection. This makes them trickier to handle on a race track but much more fun on the street.

Turbo chargers are far more fuel efficient than any supercharger period, as they do not drag off the engine before they are needed and require fuel enrichment from the time the engine is started to the time the engine is redlined. Turbos only need enrichment when the engine is boosting if you are at 10% load going down the highway at 70mph your supercharger requires fuel enrichment because it makes boost in a situation that doesn't require boost. A turbo charger lets the engine handle cruise conditions and only comes on when load demand exceeds the engines current speed allowing you to cruise and still have milage like stock if you can control your urges.

Then there is the noise roots style blowers and twin screw blowers generate when they're producing thier boost pressure...if you've never heard one of these things then you should get a ride in either a Mustang Cobra or F150 Lightning or a Chevy Cobalt SS or Saturn Ion RedLine to get an idea as to wether you could cope with the high pitched whine the blower produces (often loud enough to hear over everything including the a/c and your radio at the same time)
These things are extreamly loud and don't stop making noise untill you lift off the throttle even under light loads. It's really cool at first but it can become highly annoying in my oppinion and this is coming from a guy who loves all types of boosted cars.
Turbos are much more quite during operation and way more pleasant to hear under high load operation


Tuning for your BMW will more than likely be handled by a qualified individual so this is not something a customer should have to concern themselves with but at anyrate,tuning a boosted car is tuning a boosted car. It makes no difference the choice of the power adder be a turbo or a supercharger or nitrous oxide for that matter.... they all are not easy to tune because of the amount of knowledge required to pick up on pre-ignition and lean run conditions which if tuned improperly all set-ups will generate, so this is just plain wrong. I work at a shop as a technician where we tune boosted cars on a dyno daily and I can assure you that even tuning an N/A engine can be tricky if you don't know what to look for on a particular set up.


Turbo chargers are almost lag free if you choose the correct sized turbo for the power level you want to achive along with a good ball bearing CHRA which in some cases can produce boost as low as 2200 rpm (Porsche 996 Twin Turbo produced 60 percent of it boost pressure at this engine speed using variable air nozzle turbine technolgy) which can make a properly tuned set up feel like a larger engine rather than a turbo one...Don't believe me? drive a 335i they feel seamless in power delivery

And lastly Chevrolet did infact turbocharge the Blue Devil concept (ZR-1) Corvette first......and they proceeded to burn the car down because of a lack of precaution taken to prevent residual heat from the turbocharges' piping from catching flamable items on fire.
The set up worked fine...the engineers did not. The results of which were rather than going outside of the norm they opted to the do the cheaper form of forced induction to hold down production costs to meet the $100,000 goal they set for the car to be sold for.

Sorry to take up so much space but because the technology behind forced induction systems has changed so much over the years Turbos are a superior form of forced induction to the supercharger....they require more time and money to get the end result yes, but they are more effiecient and when properly sized will produce more power and nearly the same flat torque responce as any supercharger. Believe me when I tell you there is a reason that the only two European car companies to use a supercharger in the last 20 years for mass production was Mercedes-Benz and Volkswagen in the Golf Ralley G-60, Polo G-40 and Corrado G-60......Everyone else used a turbo charger including BMW with the new 335i, and when VW switched to the Turbo look at the result. The all mighty Bugatti Veyron EB-16.4 was born with a 1001 hp engine that produces 900+ lbs-ft of torque and it poduces it using 4 turbochargers with variable air nozzle turbine technology.
Just incase you all didn't know VW designed that engine......

A lot of what was posted above was true at one time long ago before the advent of digitaly operated, microprocessor controlled, programable management systems but not anymore,and with turbo manufacturers doing thier fluid dynamics homework, and brushing up on thier aero dynamics knowledge the turbocharger has never performed better!!

In short........Turbocharge it ....when you mash on the throttle, you'll thank me....
Good luck with it!

franka
11-03-2008, 08:00 AM
Turbo boost is not instantaneous and its not free.

1) What has changed with turbos so that they no longer have lag? What specifically has eliminated lag? What is the technical development that has eliminated all turbo lag? There is none.

2) The vast amount of miles driven are driven between 1400 rpms and 2400 rpms. If you have a twin screw or a roots and you jump on the gas pedal you have immediate, full boost. Instantaneous boost. As fast as you can move your foot.

Not so with a turbo. A downshift and a few seconds or more are required to get the turbo up to speed. Its called lag and it will always be there and it will always have a response time that is greater than a screw.

3) The exhaust that drives a turbo is not exactly free. A turbo requires pressure in the exhaust system to drive it, back pressure. That back pressure prevents the cylinder from completely emptying of all exhaust. After the turbo has been spun up high the boost pressure in the intake tract will help to scavenge the exhaust but not for free. Contrary to beliefs there is a cost to run a turbo. Turbo boost is not free, it comes with a certain amount of loss or cost depending on how you look at it. A turbo always requires back pressure to function.

Turbos are great for top end power because they do not have as much drag on the engine as a screw at full rpms. But for instant boost you can't beat a screw compressor. Instant torque down low and higher up, exactly when and where you need it on the street.

franka
11-03-2008, 08:59 AM
As an example only, lets say the twin screw puts out the same volume as the engine's displacement. Lets say that is 300 cu inches per revolution of the engine and the blower. For simplicity I assume both are pumping the same volume and both are turning the same rpms. Other examples with different volume of engine and blower and different rpms each but locked together in any combination will still yield the same results which is that as rpms go up so does the blower's as per their fixed ratios.

At low rpms or high rpms the screw will always be putting out proportionally the same exact volume as the engine which is full volume at any and all speeds.

Engine pumped volume at 1000 rpms = 300 cuin/rev x 1000 = 300,000

Blower pumped volume at 1000 rpms = 300 cuin/rev x 1000 = 300,000

The numbers can be changed but the result will always show that the engine and the blower's pumped volumes are proportionally in lock step with each other at ALL rpms. If one goes up the other goes up and does so proportionally.

The blower being tied to the engine's crank is not a disadvantage, as you state, it is an advantage. Being locked together is good, not bad.

The blower's pumped volume is always in a fixed relation to the engine's pumped volume.

This is a critical point to the understanding of screw compressors and why they are good for the street.

chucksrt
11-04-2008, 06:32 PM
Hey,

I'm new to BMW, I just bought a 540i6sp love it!!!! I have to +1 the turbo!!! I have driven many different cars with both set ups and The turbocharged cars did have all of the benefits mentioned by black out. The turbo is the point of backpressure but there is no back pressure required beyond that point, What very little flow you do loose via the turbine is nothing compared to the loss of power due to the addition of another accessory that's belt driven. Turbo lag is not much of a factor, VNT turbos are nice but are prone to blade failure due to the constant flexing they are able to do. a well setup turbo system has limited lag and on a engine that is N/A from the factory it is even less of a concern being that they are generally running higher compression and have slightly higher torque which assist it's low end performance and make the lag less noticed. There are a ton of reasons I love turbocharged cars over supercharged cars but to each their own. It seems that either way you decide to go for a bmw it will be expensive!!! If you can do any of the fab work yourself then turbo may even be cheaper then a S/C. I am going to be picking up an extra E39 4.4 engine and designing a turbo system for it, Time and wife permitting? nice to be on this forum and see so much love being put into these cars!!!
Chuck

franka
11-05-2008, 06:06 AM
The turbo is the point of backpressure but there is no back pressure required beyond that point, VNT turbos are nice but are prone to blade failure due to the constant flexing they are able to do.

Hi Chuck, you have it a bit wrong on 2 points.

Back pressure exists from the exhaust valve, even from inside the cylinder, all the way to the turbo. The higher the back pressure the faster the turbo spins.

Turbo blade failure is not due to blade flexing, but if it was it would be due to the back pressure since there is nothing else it could be from.

Blade failure is due to the high centrifugal forces it sees, over and over again, at very high temperatures and very high rpms like 180,000 rpms and more. And to make the enviroment even more hostile centrifugal force is proportional to the square of the rpm.

Black-Out
11-09-2008, 01:37 AM
[QUOTE=franka;3673288]Turbo boost is not instantaneous and its not free.

1) What has changed with turbos so that they no longer have lag? What specifically has eliminated lag? What is the technical development that has eliminated all turbo lag? There is none.

2) The vast amount of miles driven are driven between 1400 rpms and 2400 rpms. If you have a twin screw or a roots and you jump on the gas pedal you have immediate, full boost. Instantaneous boost. As fast as you can move your foot.

Not so with a turbo. A downshift and a few seconds or more are required to get the turbo up to speed. Its called lag and it will always be there and it will always have a response time that is greater than a screw.

3) The exhaust that drives a turbo is not exactly free. A turbo requires pressure in the exhaust system to drive it, back pressure. That back pressure prevents the cylinder from completely emptying of all exhaust. After the turbo has been spun up high the boost pressure in the intake tract will help to scavenge the exhaust but not for free. Contrary to beliefs there is a cost to run a turbo. Turbo boost is not free, it comes with a certain amount of loss or cost depending on how you look at it. A turbo always requires back pressure to function.

Turbos are great for top end power because they do not have as much drag on the engine as a screw at full rpms. But for instant boost you can't beat a screw compressor. Instant torque down low and higher up, exactly when and where you need it on the street.



:confused: Okay.......

As I already stated above correctly sized turbochargers with ball bearing CHRA's is just one of several developments in turbocharging that have taken the lag out of the responce time required to spool a turbo, another is ceramic turbines used to lighten the assemblies which give a lower moment of inertia,crucial if you want responce. Ceramic is much lighter than the old style inconel steel exhaust wheels from the old days which are in part responcible for your lag that you are reffering to. Variable air nozzle turbine hot sides ,which despite what was posted about the reliability, have proven themselves in mass production since VW and Porsche have been using them for quite some time in mass production (since 99') . Turbine wheel design and flow have been changed to allow for high flow, low back pressure, (ever hear of clipping the exhaust wheel?) and a number of compressor housing modifications have been made from inlet shape, to pressure wave cancellation technology which helps smooth out airflow prior to it's contact with the actual compressor wheel itself (look at the Garrett GT-K series ballistic ball bearing turbochargers). You are incorrect in your first statement and need to do more research, you will find I'm right on this one.

Regaurdless on what you may feel when you get on the throttle, if you monitor a boost gauge on any supercharged engine you will see that from your low 2400rpm engine speed a supercharger does not infact provide full boost it provides a percentage of full boost till maximum engine speed is reached and at that point it provides it's full boost. I have seen this dozens of times from the F150 lightining we have at the shop during dyno tuning. Boost starts off at a given point,usually about 12psi and then reaches a peak at high rpm, about 15psi (it has to, it's tied to the crank pulley) The physical fact that they are mechanicly linked, and that more air is brought into the supercharger and compressed the faster it spins supports this alone,otherwise you wouldn't make any boost pressure above a certain engine speed due to VE, especialy on a car equiped with VANOS or Double VANOS.....your boost pressure would instead go down as engine speed increased and your power delivery would fall off at high rpm meaning the Supercharger would NOT be moving the volume the engine needs at high rpm to supply the flat torque and increase in horsepower everyone wants from a boosted engine.

That means that the supercharger has to start low and peak high if the airflow for a given power out put is to be achieved....period....this is just simple physics at work that can NOT be argued....Turbochargers on the other hand,that are properly chosen will supply the maximum pressure from the point of boost threshold to the point of redline if the system is properly set up and the power requirement is not outrageous. The turbo that comes to mind is the Garret GT28RS. It can provide enough airflow to support 400rwhp and would spool on any BMW inline six from around 2400 rpm on up, lightning fast, with tractor like torque.

If you downshift in any turbo equipped car you will also find that it spools that much quicker because of the fact that you have moved the engine speed into a spot where the port velocity and thermal influx within the exhaust gasses are higher.....a HUGE benefit for any turbo system be it sized properly or not.......This is just one reason why the hot housings are made of cast iron...to scavenge every bit of heat that they can to help yield responce effieciency as well as stregnth, but on a properly set up turbo system this would only yield maximum power delivery and a massive surge in torque ALMOST INSTANTANEOUSLY.....there is no waiting for a few seconds when VE and turbo size match each other.

Superchargers also have a neat little hardley talked about downside called shiftlag ,which occurs on the upshifts when engine speed is down and supercharger parasitic drag is high. This hampers the smooth resumption of boost pressure when the throttle is re-applied and high load demand is desired. Then there is resumption of boost delivery at a pressure lower than maximum (remember the slower the engine turns the less boost you make and the harder the engine has to work to produce the engine speed required to get the pressure up.) This yields ramping in power delivery where you get some power then you feel it ramp up as your engine speed builds progressively. A properly sized turbo won't ramp nearly as bad as a supercharger will, because it gets to it's maximum pressure WAY faster.

Turbos don't require back pressure, although the hot side is responcible for a small amount which the engine doesn't mind seeing as per the scavenging effect at low rpm (idle to 2800rpm) which you speak of.
N/A engines REQUIRE BACK PRESSURE at low rpm to the point at which the cam starts to help deliver high rpm horsepower period.This is to produce the pressure waves that help evacuate the combustion chamber to make way for a fresh charge of air at below atmosphere (vacume) which is why long tube headers and x pipes work so well to produce low end power on large displacement V8's. A turbocharger doesn't need anything but heat,and port velocity to do it's job, which doesn't require back pressure at all...

We are simply talking about the turbo and supercharger themselfs....there is also another HUGE reason the turbo's efficiency has become so much better over the years and thats engine management. The advent of completely microprocessor controlled, transistorized coil on plug ignition systems, combined with the piezo-electric knock sensor and the ability for the computer to hold many fuel and ignition tables in a multi axis grid means the ability to run a turbocharger on engines with much higher static compression without detonation......(the avaerage turbo engined car manufactured beyond 1990 is proof of this, with C/R going from a lowly 7.5-7.8:1 to 8.0 to 9.0:1 depending on which car company you speak of.
I can list many examples if anyone wants me to.

The mere fact that more compression can be run with out detonation while turbocharging is enough to explain the reasoning behind why the turbos reduction in lag is so great but this alone doesn't cut it. There is also the shaping of the combustion chambers, and cylinder head ports as well as the fire rings on head gaskets made from multi layer steel, which reduce leaks and benifit squish/quench to help produce the extra turbulance needed to mix the air/fuel mixture even further, and if that isn't enough there is always fact that modern engines are designed to flow air more efficiently without boost which means they are more reponsive to boost pressure when turbocharged or supercharged.

Then there is the advent of the microprocessor controlled electronic boost control, which in some cases is built right into the engine management itself. These controllers will block the signal to the waste gate, which allows the turbo to reach full boost before the waste gate is even opened, preventing bleed off which slows down the turbochargers ability to produce boost pressure and comes off as lag. The result is that even an improperly sized turbo within a certain amount can be made to spool well and a properly sized turbo to spool lighting quick. This is probably the single largest improvement to the turbochargers operation which, you believe does not exist, as well as the other improvements to the turbo itself that you failed to acknowledge. Old school pnuematic only waste gate systems tend to open before they reach the set pressure, not after, which means some exhaust energy is lost and wasted out of the dump tube by-passing the turbine and slowing responce to full turbine speed. Why do you think people used to adjust their waste gate control rods tighter on built in waste gate systems, or switch out springs on the remote mount waste gates?
It's mainly to keep that from happening before they reach the boost level selected...the side effect of which is more boost and boost spikes. There is a reason all turbo systems now a days have a low pressure wastegate actuator (5psi typically) and a computer controlled solenoid to allow for higher boost pressure (around 9psi to 20psi depending on manufacturer)

I never implied that the turbo is instantaneous and free and doesn't have it's negatives, just that they are far fewer now than they have ever been, making it a better choice IMHO. That said if you haven't experianced a drive behind the wheel of a proper turbo system vs a supercharger then I see why you think the way you do, but from experiance and this is from driving many cars with both systems...I've seen far more people switch to good turbo systems than I've seen go from a turbo system to a supercharger, and thats for the street..I won't even get into racing........

This and my last post were not to offend just to educate...and the info I'm giving here isn't B.S. it's solid if you don't believe me then pick up Maximum Boost, written by Corky Bell...I've met the guy in person and have discussed thermodynamic principles, along with the pros and cons of turbocharging and supercharging. He's an engineer by trade I trust he would not have gotten this far if he didn't know a thing or two about what he does for a living, which is design and build forced induction kits for the automobile.:thumbup:

Although new to this list I am also no rookie, I've been working on cars professionally for 10yrs now and working on cars liesurely for 19yrs, from old school big block Chevy's to working for Roger Beasley Porsche as a repair technician before going out on my own yrs ago. If I don't know it, I find out about it or contact someone who does, so please don't take my confidence as a slap in the face. I just deal with forced induction on a daily basis because thats what our shops customers come to us for so I'm hardly a stranger to it.
Cheers

Black-Out
11-09-2008, 03:43 AM
As an example only, lets say the twin screw puts out the same volume as the engine's displacement. Lets say that is 300 cu inches per revolution of the engine and the blower. For simplicity I assume both are pumping the same volume and both are turning the same rpms. Other examples with different volume of engine and blower and different rpms each but locked together in any combination will still yield the same results which is that as rpms go up so does the blower's as per their fixed ratios.


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**Obviously.....I have already stated this so this point is moot, but go on....**


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At low rpms or high rpms the screw will always be putting out proportionally the same exact volume as the engine which is full volume at any and all speeds.


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***This is not true ,because you have not taken into concideration the effect that thermo efficiency has on air that is being compressed along with the required shaft speed a blower has to have to put out a specific amount of air flow at a given pressure...with this calculation your intake manifold would have to be 300cu in displacement just so it wouldn't blow apart at idle due to pressure alone, which is more than I could say about the engine itself.(you cant move 300cu inches of air per crankshaft reveloution through anything smaller than 300cu without producing massive amounts of pressure which would show up as parasitic drag). This is why most superchargers are smaller than the engines they are attatched to, and then overdriven to produce the pressure and flow they require to make the desired horsepower output. This is where heat also comes into play.
As flow requirements (blower size) go up so do parasitic drag and horsepower required just to turn the supercharger at idle....which is also one reason why the pulley sizes change to accomodate flow at a given engine speed, which again effects heat infusion into the charge air. This alone just to make boost and surplus air flow to get to, and beyond boost thresh hold. This needs to be exacted in terms of CFM of air flow,and not cubic inch displacement which tells nothing of the story of effieciency when the supercharger is turning at crankshaft speed and heat soak begains to take place on this 300cu engine. The mathmatical equation for your justification is no where near this simple but okay...... ***


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Engine pumped volume at 1000 rpms = 300 cuin/rev x 1000 = 300,000

Blower pumped volume at 1000 rpms = 300 cuin/rev x 1000 = 300,000

The numbers can be changed but the result will always show that the engine and the blower's pumped volumes are proportionally in lock step with each other at ALL rpms. If one goes up the other goes up and does so proportionally.


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***And again this is common knowlege which is why I stated earlier that if you apply the throttle at low rpms a supercharger will create more boost as the engine speed increases , a turbo doesn't need physical engine speed to produce this effect only a load change to effect heat and port velocity to increase shaft speed and effect boost pressure.....
A supercharger can not possibly produce the exact volume that the engine displaces at that speed because the idea behind supercharging is to produce more airflow than the engine displaces up to a certain point at a given speed. Meaning somewhere between 2500rpm and redline (typically) a supercharger will exceed the engines displacement which is why it produces boost and they are called this by name....POSITIVE DISPLACEMENT SUPERCHARGERS. On a good day theoretically speaking the 2500rpm point would represent the cross over from parasitic drag to boost or more easily put boost thresh hold. This tells us two things....a supercharger has to be A: wound up to see the benefits of it's use and, B: it displaces far less volume than the physical engine size.
A good example is the fact that GM uses an eaton M62 on thier 4 cylinder models (62 cubic inches) and a blower that diplaces a mere 2.3liters per engine reveloution on the 6+ liter v8 engine in the ZR-1. Remember it takes 2-3 reveloutions per engine reveloution to produce the desired effect.***


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The blower being tied to the engine's crank is not a disadvantage, as you state, it is an advantage. Being locked together is good, not bad.



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***To each his own but I dis-agree here.....Turn on your a/c and then accelerate through traffic....If you don't think it requires more throttle to get your car to react to it's input the same way if it were off,then your mistaken....same thing with a supercharger.... until the engine overcomes the forces the supercharger exerts on it and produces boost pressure. This is the effect overdriving a supercharger has on an engine to produce part throttle boost pressure or boost pressure from a low rpm. It is called parasitic drag which can be equivicated to turbo lag. Boost threshold occurs with a supercharger just like it does with a turbocharger so ignoring this fact only makes it seem like desperation to prove a point, not proof of a superchargers operation and it's effect on the internal combustion engine......***

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The blower's pumped volume is always in a fixed relation to the engine's pumped volume.



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This fact isn't argued upon......
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This is a critical point to the understanding of screw compressors and why they are good for the street.


:confused::confused::confused:
I would check your math on this one because it's not possible for an automotive supercharger to do this in one reveloution, nor is it a good idea to partake in theoretical semantics using a 1:1 drive ratio for a device that is typicaly undersized and overdriven to produce it's positive displacement effect.......It's not uncommon for a blower to have to be driven 2-3 times it's engine speed just to produce good enough flow to make pressure at all, let alone at part throttle and thats with a properly sized unit for your theoretical engine...... If this was the case most blowers would have a pulley the same size as the crank shaft they were attached to, and the engine would have difficulty idling due to the compressive forces produced in one supercharger revoloution.
This is just not adequate in terms for searching for scientific justification to support your views. I would definately get some hard info and then repost the proper formulas needed to calculate what you really want to prove, which is the low speed airflow advantage a supercharger has over turbocharging,But with what you have provided me with I do not remain convinced that a supercharger is the better performing choice. A less expensive choice, maybe, but not a better one.
The fact is turbos aren't slow and lethargic unless your running to the top end like you make them out to be, which is why the turbo system is growing to become the most saught after in the main stream performance aftermarket. Far more companies are making turbo kits because they no longer have the hang-ups they used to be known for from relaibility to responce and effieciency to NVH (Noise Vibration and Harshness) they are just plain better...but hey,thats my oppinion, again to each his own.......:soapbox:

franka
01-03-2009, 03:55 PM
Turbos have lag despite ball bearings, ceramic vanes, trap doors, etc, etc.

Lag is not as bad as days gone by but it is still there. There are methods to get around lag like injecting fuel into the exh manifold when shifting to keep the revs up but they are all band aids that are external to the turbo.

A twin screw is a true compressor. Ambient air pressure in and boosted pressure out. It doesn't matter if the engine is at 1,000 rpms or 4,000 rpms. In all cases the TS's output is boosted.

Turbos, TS, Roots, Centrifugal they all have their own unique features and capablities.

Black-Out
01-07-2009, 08:25 PM
I understand what your saying how ever I never said that turbos didn't have lag.....:rolleyes: I just said it wasn't crippling to the turbo systems performance on the street like you suggest.
And I am sorry but there isn't a supercharger on earth that's going to give you enough flow to reach boost thresh hold at 1000rpm's so saying there is, just isn't accurate, neither device can flow that much air that quickly.

No one tuner injects fuel into the exhaust manifold for spool up, they simply increase injector pulse width and retard timing to heat up the exhaust gasses to maintain turbine speed between shifts.......(Anti-lag, a common feature in most well designed stand alone management systems and hardly what I would call a band aid) But this is used mainly for motor sport application, the percentage of people whom use this on the street are extreamly low and have cars usually fitted with turbochargers that have monsterous compressors (60mm and up)

Speaking of band-aids.....why would you suggest that technological advances made in turbocharging are mere band-aids? That would be like me suggesting that the built in by pass valve on some twin screw superchargers are band aids for the parasitic drag they reduce when boost isn't needed. Or that the 4 bladed helical cut impellars on the newer roots blower are band aids for poor flow and compressor inefficiency.....That just doesn't make sence, they are all improving the basis of the origional concept and doing so improves the efficiency of both devices. Just as turbos still have lag superchargers still have parasitic drag both devices will never eliminate their negatives they can only make them less obvious, the turbo just has more space to show improvement because it has many more sizes to choose from and combinations to exploit.

Do you realize compound turbocharging (a large turbo feeding a smaller turbo which feeds the engine and is commonly used on diesels) can produce boost pressures beyond boost thresh hold as low as 1800rpm? They have to because a diesel engine can't rev much beyond 4000rpm. Compound turbocharging and twincharging (using both a supercharger and a conciderably large turbocharger) are just a couple of examples of how forced induction used on diesels has had a profound effect on the way turbocharging is used on gasoline vehicles now. Both systems can be applied to gasoline engines and neither concept is considered a band-aid by the automotive community.

All have their own capabilities true, each shines in a different area of the performance realm it just depends on how much efficiency plays into your power requirements, and the intention on the use of said car. The larger the turbo the larger the lag obviously but, with that said, the larger the supercharger the higher the drag..... if 400hp is your goal it can be achieved without the lag commonly associated with that kind of power output. That's just how far the game has come in the last 20 years.:thumbup:

franka
01-08-2009, 06:42 AM
A twin screw compress the air before it leaves the SC. Every turn of the TS compresses the air. That is why it is called a positive displacement SC.

RPMs are not a factor. They are in a turbo but not in a TS.

http://www.whipplesuperchargers.com/content.asp?PageID=67

Black-Out
01-08-2009, 08:10 PM
A twin screw compress the air before it leaves the SC. Every turn of the TS compresses the air. That is why it is called a positive displacement SC.

RPMs are not a factor. They are in a turbo but not in a TS.

http://www.whipplesuperchargers.com/content.asp?PageID=67

Thats not true:thumbdwn:.......again, its common knowledge that a supercharger compresses the air before it leaves the charger but this has nothing to do with the flow requirements to reach and go beyond boost thresh hold on any given engine........pressure and volume are not linear with one another.

As pressure goes up, volume goes down. This is fact. The volume of air displaced at 1000 rpm on any supercharger will not be anywhere near enough to create boost as you suggested it, due to the blowers physical displacement, which is usually only 1/3 the engines total capacity (I believe I already stated this.) Even on a turbo charger when the compressor reaches the edge of it's efficiency you will not gain any power from simply "turning up the boost" as the compressor will not flow anymore air with out heating it up causing a decrease in air density from the increases in charge air temp, thats why people fit larger turbos and even superchargers to gain horsepower. The gains in power can usually be seen even at a stock boost levels because the flow rate increases at the same pressure ratio, and charge air temp goes down.

Because of the superchargers volume difference in respect to the engine, there is no way to produce the amount of volume required to exceed the engine displacement at such a low rpm (1000) no matter how much compression occurs with in your twin screw.....By the way that is also why parasitic drag is such an issue with twin screw compressors and roots type blowers.

As I have stated before this drag can be equivicated to turbo lag, which is why superchargers of this type provide their responce the way they do. 2400rpm is where you usually "feel" the blower begain to work.......As stated in previous posts, a stock Porsche 911 (996/997) twin turbos you can actually get that same feeling between 2200 and 2500 rpm depending on weather or not the car is an X-50 package with larger turbos........the point is a turbocharger chosen properly with a reasonable maximum power output will respond just as quickly as a twin screw or roots blower and out do a centrifugal supercharger, hands down.

Not to sound like an ass, but are you reading the details within my posts? cause we're actually starting to go in circles here.:dunno:

I almost feel like I'm playing a game of chess......It's your move chief.........lol.....


By the way I see this as nothing more than a friendly debate so please tell me if I'm irritating you or pissing you off, I'm not here to troll or aggrivate people......:thumbup:

franka
01-09-2009, 07:56 AM
Dah..you spin the blower faster than the engine. Not 1:1 as you said giving only 1/3 the volume you claim. And if that is not enuff you go to a larger blower. That is so elementry. (splg?)

After reading the Whipple link you should be able to understand that it is a "positive displacement" blower and what that means. It is not variable displacement like a turbo or a Roots. Not all blowers compress the air before they leave the blower.

I'm not going to keep arguing with someone that doesn't understand this simple fact.

Knock yourself out now.

Black-Out
01-09-2009, 09:42 PM
:nono::nono: Well this would be great if I was the one who didn't understand, but I do, it's you who doesn't grasp it......If you care to read any of your own post you would find that YOU were the one whom suggested the 1:1 ratio and not me......I corrected you on it as I've done the remaining parts of this thread.

Originally Posted by franka View Post
As an example only, lets say the twin screw puts out the same volume as the engine's displacement. Lets say that is 300 cu inches per revolution of the engine and the blower. For simplicity I assume both are pumping the same volume and both are turning the same rpms. Other examples with different volume of engine and blower and different rpms each but locked together in any combination will still yield the same results which is that as rpms go up so does the blower's as per their fixed ratios.




Ring a bell? how about this........





At low rpms or high rpms the screw will always be putting out proportionally the same exact volume as the engine which is full volume at any and all speeds.
Engine pumped volume at 1000 rpms = 300 cuin/rev x 1000 = 300,000

Blower pumped volume at 1000 rpms = 300 cuin/rev x 1000 = 300,000

The numbers can be changed but the result will always show that the engine and the blower's pumped volumes are proportionally in lock step with each other at ALL rpms. If one goes up the other goes up and does so proportionally.





Or how about this one.......






Originally Posted by franka View Post
A turbo will be much harder to tune than a SCr because the turbos rpms are up and down and all over. Turbo rpms have no fixed relation to engine rpms and that is a major source of problems. Trying to match the injector's shot volumes and ignition timing and relief valves with the engine rpms and varying throttle demands and varying turbo speeds is a nightmare. Tuning a turbo set up to run clean and smooth is difficult. It takes much more time than to tune a SCr

A Roots or a Twin Screw's rpm always matches the engine's rpms at a fixed ratio. More rpms and the SCr pumps more volume to force feed the engine's displacement. A SCr is always in synch with the motor. This simple fact makes tuning much easier.

Turbos have lag, even the best set ups have lag. Lag, lag and then the turbo starts to catch up with the engine and starts to make some boost for power. Its a slow process when compared to a driven SCr

A screw type SCr like a Roots or a Twin Screw, has NO lag, you get full boost immediately, as fast as you can open the throttle, mili-seconds not 2 or 3 full seconds.

But this is not true for a Centrifugal SCr, it too needs rpms to build boost much like a turbo. A Dinan SCr and the VF SCr are centrifugal types. They build boost like a turbo, with rpms. Boost at low rpm is quite small and can not be increased.

For street use a Roots or a Twin Screw SCr, only they can deliver full boost instantly and at low rpms and all the way up to the engine's rpm limit. That is why the new Corvette and the Ford GT40 LeMans has a Roots SCr and not a turbo.

A turbo, on the same motor, will make more net hp at the top end because there is no screw to spin, but it is a poor choice for street use.

I could go on in more detail but I will not spend my time on this subject when you can Google it and get all the info you ever would want.




That wasn't me, all that mess up there is yours......you seem to be the one who needs a link to explain the simple facts......I have plenty of literature on forced induction involving turbocharger and superchargers.

:confused: Care to tell me I wrote and edited anymore of YOUR posts?




I already know that not all blowers compress the air before they leave the charger, I said Roots blowers and twin screws DO, and centrifugal blowers DON'T....Please don't try to take parts of my post and make it sound like I don't know what I'm talking about, I view that as....... well........rather pathetic. :gay:

There friend, I have knocked myself out......Next time high light your link so I can notice it and maybe I'll check it out, but I have enough info already, you don't seem to.
Feel free to review your post as well as mine thoroughly, so that you may post intelligently before claiming someone said what you implied to be fact first.

I know what I said I can go back and pull it all up,then confirm the information.......but you are not reading your own past statements, and then passing them off on me. Is it because you made a mistake and are trying to save face? If I make a mistake and someone proves it to me, I'll at least acknowledge it and give credit to the one who is correct.....Can't say as much for you unfortunately.

If you want to call your self right on this topic, then by all means be my guest, but being correct takes a lot more then suggesting theoretical operation or scenarios which have absoloutely no scientific calculations to support your desired out come.

There......... now you can knock yourself out.......I'm more than done trying to explain simple technological advances in forced induction to a brick wall, stuck in the dark ages.
Enjoy!
:madrazz:

franka
01-16-2009, 01:06 PM
Black-Out (and other turbo fans)

1) You must have a lot of emotion tied up in being right, to spend the amount of time you have to go back to my prior post and bring them up to post. You have more invested than me.

2) I stand by my posts, all of them.

3) I can see that I failed to present my thoughts in a manner that all can easily see and understand. So I will try it one more time.

4) When I say one engine rev I mean two full revs beacuse it is a 4 cycle engine. Or 720 degrees.

When I said 1:1 what I meant was that whatever the pressurized engine could take in in volume and pressure in one revolution (one cycle) that the TS would be sized to produce that much. That was my error, I failed to explain it in more detail and more clearly. My fault but it doesn't change some facts.

I will make up some hypothetical numbers to illustrate the point. This is all hypothetical so please don't jump on the numbers here and claim the engine or the TS can not produce this or that.

If you have an engine that can injest 300 cubic inches at a pressure of 10 psi in one revolution then one could size the TS itself (the size of the blower) and the speed of the TS to deliver 300 cubes at 10 psi. in a fixed manner. So we have the TS delivering what the engine can injest in one revolution. That is what I should have said. That is what I meant. Now recalling that a TS is a positive dispacement supercharger we know that whatever the engine rpms are, that the TS will be pumping the volume and pressure to match what the engine is injesting. A positive displacent blower compresses the air internally, none of it wasted or escapes around the sides.

Now the important point is that at whatever the engine rpms are, 1000 rpms or 4000 rpms the blower will be pumping the volume and pressure that the engine can injest. So at 1000 rpm or 4000 rpm the engine will respond immediately.

A turbo can't do that at 1000 rpms because it is not a positive displacement SC. The turbo needs rpms to make power. The turbo is great at top end but it can't match the TS on the low end. That is why a TS is the best for a daily driver. Instant torque. Look up Whipple again and you will see that that is what they are saying. There are more TSs than Whipple. Try twin screw in Google

Like I said in one of my prior posts, because the TS is tied directly to rpm it will be easier to tune than the turbo. The turbo will require more maps of engine load, rpms, high and low speed, etc than the TS.

I'm not bashing turbos, they great for max power, top end power but they will never be able to beat a TS at low and medium rpms. They will not have the grunt. That is all I need to say.

I will respond to resonable, factual posts but not emotional or insulting ones.

franka
01-19-2009, 08:11 AM
[QUOTE=Black-Out;3826288]:

I already know that not all blowers compress the air before they leave the charger, I said Roots blowers and twin screws DO, and centrifugal blowers DON'T....Please don't try to take parts of my post and make it sound like I don't know what I'm talking about,[ QUOTE]



You are mistaken, the Roots, contrary to your claim above, is not a positive displacement compressor. It has rotors like a TS but functions as a large fan. It carries the intake air around the two sides of its case and discharges into the manifold with out compressing the air. It just moves the air.

A TS is a positive displacement compressor. The air is goes in between the rotors and is compressed in the SC and then released into the manifold.

The airflow in a TS is not the same as a Roots, even though the two look similiar. The TS takes the air in and it goes into the center of rotors and is compressed as the space between the rotors gets smaller and smaller.

Summary...

Root's air goes around the two outer sides of the rotors and against the body of the SCr case, without it being compressed at the exit.

The TS's air goes into the center of the rotors and is compressed before it exits.

Both look very similiar but operate in a very different manner.

Black-Out
01-22-2009, 09:20 AM
Black-Out (and other turbo fans)

1) You must have a lot of emotion tied up in being right, to spend the amount of time you have to go back to my prior post and bring them up to post. You have more invested than me.

2) I stand by my posts, all of them.

3) I can see that I failed to present my thoughts in a manner that all can easily see and understand. So I will try it one more time.

4) When I say one engine rev I mean two full revs beacuse it is a 4 cycle engine. Or 720 degrees.

When I said 1:1 what I meant was that whatever the pressurized engine could take in in volume and pressure in one revolution (one cycle) that the TS would be sized to produce that much. That was my error, I failed to explain it in more detail and more clearly. My fault but it doesn't change some facts.

I will make up some hypothetical numbers to illustrate the point. This is all hypothetical so please don't jump on the numbers here and claim the engine or the TS can not produce this or that.

If you have an engine that can injest 300 cubic inches at a pressure of 10 psi in one revolution then one could size the TS itself (the size of the blower) and the speed of the TS to deliver 300 cubes at 10 psi. in a fixed manner. So we have the TS delivering what the engine can injest in one revolution. That is what I should have said. That is what I meant. Now recalling that a TS is a positive dispacement supercharger we know that whatever the engine rpms are, that the TS will be pumping the volume and pressure to match what the engine is injesting. A positive displacent blower compresses the air internally, none of it wasted or escapes around the sides.

Now the important point is that at whatever the engine rpms are, 1000 rpms or 4000 rpms the blower will be pumping the volume and pressure that the engine can injest. So at 1000 rpm or 4000 rpm the engine will respond immediately.

A turbo can't do that at 1000 rpms because it is not a positive displacement SC. The turbo needs rpms to make power. The turbo is great at top end but it can't match the TS on the low end. That is why a TS is the best for a daily driver. Instant torque. Look up Whipple again and you will see that that is what they are saying. There are more TSs than Whipple. Try twin screw in Google

Like I said in one of my prior posts, because the TS is tied directly to rpm it will be easier to tune than the turbo. The turbo will require more maps of engine load, rpms, high and low speed, etc than the TS.

I'm not bashing turbos, they great for max power, top end power but they will never be able to beat a TS at low and medium rpms. They will not have the grunt. That is all I need to say.

I will respond to resonable, factual posts but not emotional or insulting ones.



Now that reply makes MUCH MUCH more sence, and had you gone through the explanation that way this would have been much different. Now in going back and looking again your correct in the assesment of the roots blower it isn't a positive displacement device....but do you know what is?

The turbocharger......It seems that the turbocharger and the centrifugal supercharger both compress air in the cold housings before forcing it down the throat of the engine. (Positive displacement by definition) Oddly enough I didn't remember this fact so I looked it up in a third source after looking through my books...(Wikipedia) and found supporting information on this fact.

More imediate responce is the effect of a supercharger but not without the drag associated with its operation and that still does not change the fact that a properly set up turbo system will rival a supercharger on the street and then some.

You still won't really address any of the facts I've stated on such cars named that have low speed high responce turbo systems that rival the supercharger on the street so I will name a few....
Cars by comparison that are equipped with a turbo system that responds comparitavely are

1: Porsche 911 turbo-485hp engine responds as low as 2400rpm
2: Porsche 911 GT-2 540hp near same responce as above
3: Ford Falcon XR6
4: BMW 335i (or any twin turbo BMW for that matter)
5: Mazda RX-7 Twin Turbo
6: Toyota Supra Twin Turbo
7: Porsche 959
8: Bugatti Veyron EB 16.4
9: Bugatti EB 110
10: Mercedes Benz ......pick any one of their turbcharged cars I'm sure you will find they deliver power so smoothly you'll think it's a big N/A engine not a turbocharged one.
11: Nissan Skyline GT-R

That's just eleven examples....I'm not saying I can't be wrong obviously, I've been that before as have you. But I will say that the idea that turbos don't produce power at low rpms has been long since a dead issue with forced induction...anymore manufacturers use supercharging over turbocharging as a cheap means of boosting output, and doing it in the close confines in certain engine compartments, than they do for producing power outputs at low engine speeds.

I appoligise for being snappy in my last post, but I don't care for it when someone puts words in to my mouth. That's what I felt like you did, that's why my responce was what it was.

Go for a ride and see what I mean cause I've beeen in both supercharged and turbo cars and I'm telling you the difference is almost non existent........don't take my word for it try one out.

Shunn
03-15-2009, 11:46 AM
you tune cars on a daily basis but didn't know/forgot that turbocharger's compress the air via the turbine in the cold side? :eek:

franka
03-16-2009, 01:57 PM
you tune cars on a daily basis but didn't know/forgot that turbocharger's compress the air via the turbine in the cold side? :eek:

Makes one wonder about that.....:dunno:

Shunn
03-17-2009, 01:10 AM
I'm not back either of you two up. i was just questioning it. maybe he -works- at a tuning shop but isn't the one doing the tuning :dunno:

both setups are good. both have their pros and cons but if someone decides to get a supercharger then consider forking out the dough for a twin screw or roots type.. as a centrifugal blower at a low setting(8psi for example) wont even start making boost until after 4K rpm XD

CR67
05-14-2009, 08:52 AM
:banghead: Reading that post wore me out! Think I'll go take a nap now.
I've read the whole turbo/SC debate on a number of different forums over the years and the one thing I've found consistant is that turbo guys love their turbos and SC guys love their superchargers. Their are pros and cons to both and it really boils down to how much money you want to spend as they'll both give you some nice HP gains.

franka
05-18-2009, 07:20 AM
Its the area below the hp and/or torque curve that matters. A roots or twin screw will have more area under the curve than a turbo.

For comparison I'm stating same rated max boost pressure and same max boost volume.

San Diego E36
05-29-2009, 12:22 PM
I would do a turbo system that has a small turbo so it would be funner, supercharge if I was hitting the track a lot, and big turbo if I drag raced a lot.

franka
05-29-2009, 12:36 PM
Thanks for the insight.

RX7 FC Guy
09-10-2009, 09:08 PM
turbos are the better choice for power. they have next to no lag. as long as there set up properly there is no real down side except for creating alot of heat in your engine bay. you can always set it up like STS and put the turbo where your muffler is and eliminate that problem all together.

superchargers cause parasitic loss on the engine at idle and do choke out if you romp on them from idle.

I am also a Tech and deal with both often.

franka
09-15-2009, 06:07 AM
[QUOTE=CR67;4181372 the one thing I've found consistant is that turbo guys love their turbos and SC guys love their superchargers. Their are pros and cons to both and it really boils down to how much money you want to spend as they'll both give you some nice HP gains.[/QUOTE]


The younger and less experienced guys go "turbo" because they hear of them much more frequently, some auto mfgrs offer them, turbos can make a big hp number at max revs and that is what catches their attention, there is all the turbo tech on Hondas and the other imports that they grew up with and the word turbo sounds cooler to them than Roots or Twin Screw or Centrifugal.

It takes some effort to learn about the 3 other ways to SCrg and the pros and cons of each. Many reading this can not tell you what the differece is between a TS and a Roots.

Ya know what I mean?

franka
09-15-2009, 06:12 AM
[QUOTE=RX7 FC Guy;4508544]turbos are the better choice for power. they have next to no lag. as long as there set up properly there is no real down side except for creating alot of heat in your engine bay. you can always set it up like STS and put the turbo where your muffler is and eliminate that problem all together. superchargers cause parasitic loss on the engine at idle and do choke out if you romp on them from idle. QUOTE]



Turbos have lag lag and lag. Wishing or saying no more lag is just factually incorrect. BMW haas gone to two smaller turbos on the 335 to decrease lag but still not eliminating it.

JasonSC540ia
10-13-2009, 06:54 PM
A twin screw compress the air before it leaves the SC. Every turn of the TS compresses the air. That is why it is called a positive displacement SC.

RPMs are not a factor. They are in a turbo but not in a TS.

http://www.whipplesuperchargers.com/content.asp?PageID=67

Franka

Dead wrong. A superchager is an external compression device, and a turbo in an internal compression device. The air exiting a "roots" style or screw style SC is not compressed. It is simply moving larges amounts of air that cause it to back up in the intake system...by that it gets compressed (thats why there "aftercoolers" are in the intake manifold). The air leaving a turbo compressor or a centrifugal superchager (vortech, Paxton, ect.) the air is compressed already.

You sound like a very intelligent guy with maybe an engineering degree of some sort, but it sounds like you lack the "hands on" experience.

Black-out is 100% correct in everything he has posted...suggest you listen to him.

jhstealth
11-11-2009, 10:10 PM
i say supercharge because its allot easier to get and cheaper generally.

franka
11-19-2009, 05:54 PM
[QUOTE=JasonSC540ia;4597565] A superchager is an external compression device, and a turbo in an internal compression device. The air exiting a "roots" style or screw style SC is not compressed. It is simply moving larges amounts of air that cause it to back up in the intake system...by that it gets compressed (thats why there "aftercoolers" are in the intake manifold). The air leaving a turbo compressor or a centrifugal superchager (vortech, Paxton, ect.) the air is compressed already.QUOTE]

External compression, what the hell is an external compression device? Please show me one. Your comments are so far off the wall that I have to think you are just posting to get a rise out of me

Your above several posts are about 15% correct and 85% wrong and I'm not going to argue it. If you want to know the facts just google for them. Try 'twin screw compressor'. For those looking for real, correct and the truth please check the below links and have a good time reading all about SCs.



http://www.eurosporthighperformance.com/supercharger.html

http://www.simpsonmotorsport.co.uk/default.asp?id=147&pid=70&name=BMW%20530%20Twin%20Screw&page=Projects

http://www.bimmerforums.co.uk/forum/f81/superchargers-how-they-work-what-types-there-are-t84/

JasonSC540ia
11-20-2009, 11:29 PM
External compression, what the hell is an external compression device? Please show me one. Your comments are so far off the wall that I have to think you are just posting to get a rise out of me

Your above several posts are about 15% correct and 85% wrong and I'm not going to argue it. If you want to know the facts just google for them. Try 'twin screw compressor'. For those looking for real, correct and the truth please check the below links and have a good time reading all about SCs.


Calm down...dont get your panties in a twist. I already explained to you what an external compression device is. A "roots" style or screw type supercharger do not compress air. There just large air pumps that move massive amounts of air, but do not compress it. A turbo compressor or centifigel compressors are internal compression. Meaning, by slinging the air outward and forceing it through the gap in the compressor housing forces the air to compress.

One of the reasons why screw type and roots SC give instant boost is because the boost starts in the cylinder and moves back towards the manifold. And the reason you have "lag" from a turbo is because you have to wait for the already compressed air to come from the turbo's compressor housing, into the manifold, and then into the cylinder.

Iv been a jet engine machanic rebuiling/testing axial flow and centifigal compressors for the past 19 years. Iv been building custom turbos for my applications since I had my first car at 16. I dont need to google anything.....maybe you should stop googling.

Everytime I see people quoteing "facts" they saw on the internet about forced induction, I try to help them out and point them in the right direction, because I know most people dont have the experiences that I have.

I suggest you stop giving people false info, and spend more time in your garage..."doing". Better yet, just stick with upgrading head lights, tail lights, and such. Leave the serious stuff for people who know before you melt a piston (do you need me to explain to you what a piston does?) Like I said before...you lack the hands on, and it shows.

Black-out knows what hes talking about with forced induction. Its plainly obvious why he stop replying to you....because you dont.

PDP///M
12-31-2009, 11:12 AM
Hey franka, you said superchargers make more low rpm power than a turbo. Sorry but have you ever seen two dyno sheets of two same cars, same peak boost, one with a supercharger, and one with a properly sized turbo? Which car do you believe has more hp and torque under the curve? Its not the supercharger. And i have one on my current car. When the turbo is spooled, e.g. At 2500rpm, you can have full boost from that point till redline. Which car has more power under the curve?

franka
12-31-2009, 12:49 PM
http://www.whipplesuperchargers.com/content.asp?PageID=79

Read it all

franka
12-31-2009, 01:02 PM
If more power is what you crave…Whipple Superchargers has the solution…heart-stopping acceleration, complete bolt-on packages, emissions legal supercharger kits that boost power up to 60%. By utilizing the Whipple Twin Screw Supercharger, we provide the largest effective power gains, while maintaining safe, trouble-free operation. The Whipple Charger gives you the unique combination of maximum power at low rpm’s for incredible drive-ability while still providing ultra high efficiency for top-end horsepower. Just squeeze the throttle and the engine responds immediately, from idle to redline. the thrill ride never stops!

The results are breathtaking…0-60 times drop dramatically, up to 60% power increases throughout the operating range, incredible throttle response, emission compliance and virtually maintenance-free. How is this possible? It’s the integration of the Whipple Twin Screw Supercharger and Whipple's superior engineering that makes it all possible.

Over the past fifteen years, Whipple Superchargers has risen above the competition to become the true supercharging leaders with proven performance, reliability, customer service and quality. Other companies claim to be leaders with incredible power levels, but the results speak for themselves.

WHAT SEPERATES WHIPPLE FROM THE COMPETITION


Positive displacement twin screw design has the highest efficiency of all superchargers including roots and centrifugal
Higher efficiency means more power at all rpm levels
Unique Whipple twin screw design provides the largest power gains across entire rpm range
Similar screw compressor design as the Ford GT supercar
Same screw compressor technology that Mercedes has utilized on all their latest vehicles including the 600hp McLaren SLR, E55AMG, S55, CL55, SLK32 and SL55
Dyno proven to produce more horsepower and torque than any other supercharger throughout the entire rpm range.
21st century fuel injection that has more processing power than the factory computer resulting in incredible drive-ability
Whipple designed air-bypass system for unsurpassed fuel economy
Commitment to quality and excellence
Astounding customer support from our well trained, performance enthusiast personnel
Nobody can compare to the OEM packaging and quality of parts Whipple provides
50 state emission compatibility
Unmistakable industry leading fit and finish
100% complete systems ready for an easy installation and trouble free operation
Systems consistently produce very low levels of noise, commonly undetectable
True technological leader in supercharger industry
SUPERIOR ENGINEERING

:thumbup:

franka
12-31-2009, 01:19 PM
OEM manufactures utilize positive displacement superchargers due to their incredible throttle response and drive-ability of a big cubic inch motor. When building a system for the consumers, you must provide a very broad power ban with a high peak horsepower level, only the screw compressor can give you this. This is due to the high adiabatic (up to 80%) and volumetric efficiency levels (up to 99.9%). The Whipple screw compressor is the latest generation, durable and dependable performance-enhancing item ever designed for either low boost or high boost levels. Available in a complete unit or a “rotor assembly” for builders own housings.


The screw compressor is by far the best supercharger available today; it’s the only supercharger to provide a positive displacement design for maximum low-end torque as well as high efficiency for maximum top-end horsepower. No other supercharger in the world can offer the same unique benefits. Centrifugals and turbos have tremendous lag time during shift points, on-off throttle and off the line boost. Roots-type superchargers have been proven to not be very efficient, especially at higher boost levels. Whipple Superchargers has a variety of screw compressors for all types of applications, anywhere from a 100 cubic inch compressor to the 510 cubic inch compressor. Whipple also has a wide assortment of drive lengths, pulley combinations and bypass valves for all types of applications.

PDP///M
01-04-2010, 12:07 PM
i thought we were talking about bmw applications. can't get a whipple for a bmw unless custom.

franka
01-06-2010, 04:01 PM
So much for turbos.

And so much for ...Black Out and JasonSC540

PDP///M
01-07-2010, 06:51 AM
there are plenty companies that sell bolt on turbo kits for bmw.

QuoteWarz Insurance
01-07-2010, 10:01 AM
Yes, there are a lot of different companies that sell bolt-on turbo kits. It is just a matter of finding the right kit that will fit within your budget and power goals. Yes, the supercharger kit will offer a little more grunt off the line, but there is nothing like when you turbo hits boost and you are pinned in your seat.

franka
01-07-2010, 12:32 PM
but there is nothing like when you turbo hits boost and you are pinned in your seat.

exactly...'when your turbo hits boost' .... and how long is that?

JasonSC540ia
01-14-2010, 03:32 AM
So much for turbos.

And so much for ...Black Out and JasonSC540

Dude...are you running any kind of forced induction...right now?

Here is a video clip of a turbo car I built some years ago. This was 25psi on a very large turbo (Frankenstein level 4 minus 10 degree turbine wheel clip). Notice how fast second gear is finished. Notice the gear changes, and how there is zero lag in between.

Point out the lag Fanka.

http://s849.photobucket.com/albums/ab53/JasonSC540ia/?action=view&current=launch.flv

franka
01-14-2010, 04:17 AM
Nice clip, good job, but its just a few seconds in time. It doesn't begin to show the difference btw a screw and a turbo.

Congrats to your work.

PDP///M
01-15-2010, 06:54 AM
So franka you didnt answer the question at hand. Do you own or have you ever owned a f/i vehicle? If the answer is yes, i'd like to see pictures. Thanks

franka
01-15-2010, 01:35 PM
No

JasonSC540ia
01-17-2010, 01:13 PM
Thanks for the compliment Fanka. I was'nt expecting that.

Your right. the video clip is kinda short. We were borrowing a camera from a friend and could'nt figure out how to make longer videos (old cam that only shot about 10 seconds worth). Still you can get an idea of how little lag there is. And that was with a bushing turbo...not ball bearing. The ball bearing turbos are insane with the response they have.

If I had the funds, I would make a custom twin turbo kit for my 540 and ditch the Vortech. Its just you would have to do a ****load of pluming do to lack of space. You'd have to mount the turbos way back underneath the car.....$$$$.

My SC 540 has ****loads of torque right off idle. However, it really lacks the midrange punch/top end that my turbo cars had. Dont get me wrong...it still hauls ass (it will pass 120 like nothing and keep going).

franka
01-17-2010, 05:52 PM
I have ideas of how to mount and duct a twin screw SC onto a 540, thru an intercooler and into the stock intake manifold.

But I and many others do not know how to tune it, using the standard 540 ECU. :dunno:

JasonSC540ia
01-17-2010, 07:40 PM
If your gonna go that far (or twin turbo), I would suggest going with a Mega squirt or similiar stand alone computer. Im sure there is a way to hach the factory ECU but I would think it would be more trouble then its worth. If you have the $$ you can always go with a Motech computer. Iv assisted in tuning one before and you can adjust fuel and ignition curves right down to each rpm (1440, 1441, 1442 ect). Very nice.:thumbup:

franka
01-18-2010, 04:08 AM
Doesn't a separate Mega Squirt, or any separate system, kill most of the electrical and electronic BMW functions and capabilities?

:dunno:

JasonSC540ia
01-18-2010, 08:22 AM
Yep!:thumbup: Thats the great thing about it. Although, we...(99 and above) might have a problem with that and getting our drive by wire throttles to work. I would think you could switch to a 97-98 TB and be good.

In my mind, all that BMW BS with the oil level sensor and coolent level, is for rich people that buy the cars in the first place, and dont know 1 thing about how a car/engine works.

CE light cuz my gas cap is'nt on tight. Come on...im really.:rofl:

franka
01-18-2010, 03:40 PM
You have a point there. What good is that info on a car that was chopped up (heavily modified in a good way)?

JasonSC540ia
01-19-2010, 04:58 PM
I know it is possiable...Iv seen it done(Sema show Vegas). However, Im not far enough into my project to be that deep in wiring diagrams yet. I would like to maintain the stock interior 100%. I want to tastefully hide all gauges/computers in the glove box. The trick would be haveing no caution/warning lights and all factory gauges funtioning.:eek:

QuoteWarz Insurance
01-20-2010, 10:30 AM
It is kind of hard to explain, but the turbo will kick it a certain RPM depending on your set up. There are so many factors like turbo size, engine size, exhaust size, etc. You need to find the proper set up and that will come from doing research and setting goals for what you want out of the car. It might be a pure daily driven street car or a road racer maybe.

franka
01-20-2010, 04:11 PM
It is kind of hard to explain, but the turbo will kick it a certain RPM depending on your set up. There are so many factors like turbo size, engine size, exhaust size, etc. You need to find the proper set up and that will come from doing research and setting goals for what you want out of the car. It might be a pure daily driven street car or a road racer maybe.


Excuse me please, but what are you talking about?

JasonSC540ia
01-20-2010, 08:28 PM
Franka

All he is saying is you have to set a horse power goal.

Example : "I want 500hp @ the wheels and still be a daily driver."

Turbo/SC selection is very critical. Bigger is not always better. It has to be precise. You have to learn to read compressor maps. He's just saying you cant bolt any ol' parts on and hope to reach your goals.

You said you had a plan for mounting 2 SC, and still maintaining the stock manifold. I would really like to hear about your ideas. Dont get me wrong...Im not mocking you. I'am truly interested in hearing about that idea. I love $hit like that.:thumbup:

franka
01-21-2010, 04:23 AM
You said you had a plan for mounting 2 SC, and still maintaining the stock manifold. I would really like to hear about your ideas. Dont get me wrong...Im not mocking you. I'am truly interested in hearing about that idea. I love $hit like that.:thumbup:


Me too, I enjoy that. No time to write this morning B4 work. I'll catch you after work today.

Above you wrote "2 SC", is that short for twin screw?

JasonSC540ia
01-21-2010, 08:11 PM
Me too, I enjoy that. No time to write this morning B4 work. I'll catch you after work today.

Above you wrote "2 SC", is that short for twin screw?

No...I meant 2 superchargers. I thought you said you had a plan for 2 twin screw superchargers on a stock manifold. Thats why I wanted to hear your plan, because it sounded so outragous.

Maybe Im mistaken.

Id still like to hear your plan...even if its 1 roots/screw SC hooked up to a stock mani.

franka
01-22-2010, 03:46 AM
Its one twin screw pumping into an intercooler and then into the stock intake manifold.

Details to follow. Its pretty straight forward.

franka
01-24-2010, 05:50 PM
Here are some rough plans to run a Twin Screw Supercharger in a 540. :D

So looking at the engine hood up, the right side is the driver side. Move the power steering unit and the oil filter and anything else that is there and relocate them. That is where the TS SCr goes.

Fabricate a mounting plate for the TS out of aluminum plate about 3/4" thick or more if required. Simple if you have access to the right tools. Then fab some steel brkts to mount the plate and TS off of the engine such that the pulley on the front of the SCr is inline with all the other pulley's.

The mounting plate would allow the TS to huff and puff and blow down (vertical) into ducting that would connect to a 90 degree duct at the bottom that then runs horizontal and forward to connect up with the intercooler's intake that is also low and on the same side.

The intercooler runs across the front of the car as usual and then discharges as high as possible into a horizontal duct that connects to the OEM intake ducting, leading to the intake manifold.

The OEM intake manifold is not designed for pressure, however I have been studying a loose one that I bought off of here. Its a rigid and strong pc that will hold at least 1.0 atm and maybe 2.0 atm, althought 1.0 is more than enough.

Paxton, Dinan and other superchargers are usually mounted in this same space. :thumbup:

JasonSC540ia
01-26-2010, 06:17 PM
Intersting

I just dont see the space being there to mount it. Also, fabing that bracket would be no easy task. Ofcourse anything is possiable with enough time and money.

I think it would be easier, and more cost effective to just mount a large turbo (T3 25g) back in the same place as the factory resagnator. 25g compressors have been known to support over 600whp. This turbo is only $450 new (see link below). Oil lines and a pump to move the oil back to the engine $200. Intercooler, exhaust, and inlet piping with fittings...maybe another $400-$500. Figure another $500 for an HKS additional injector controller and injectors and lines (run two 550cc-720cc). You could do the whole set-up for less then $2k

How much is just the supercharger you want to mount?

http://cgi.ebay.com/ebaymotors/OBX-Street-Power-Turbo-Charger-T3-25G-DSM-HONDA-500HP_W0QQcmdZViewItemQQhashZitem56392bbadfQQitemZ 370326354655QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAc cessories

franka
01-27-2010, 05:28 AM
[QUOTE=JasonSC540ia;4882590]
How much is just the supercharger you want to mount?
QUOTE]



I haven't a clue of the price since I have no plans to pursue installing a TS, or any SCr.

The mounting plate I mentioned would be an easy pc to machine from aluminum plate (0.75" or 1.0")using a common Bridgeport milling machine. No tricks or code to write, all manual. A decent machinest could cut it in half a day or less, including set-ups.

JasonSC540ia
01-28-2010, 06:04 PM
I guess what Im trying to ask is; What would the brake-down cost wise be?

franka
01-29-2010, 03:52 AM
If you are asking me about costs you are out of luck because, like I said, I don't know. :dunno:

Regarding the space, there is a lot of vertical room to the hood. The sound insulating material in the hood makes the vertical space appear to be less than it actually is. Check it out and see for yourself.

QuoteWarz Insurance
02-01-2010, 10:27 PM
Fabing a kit like this is never as easy as it looks. It will end up costing you a lot more time and money in the long run then just getting a production kit.

franka
02-02-2010, 04:09 AM
Fabing a kit like this is never as easy as it looks. It will end up costing you a lot more time and money in the long run then just getting a production kit.


In general I have to agree, of course.

But for me specifically.....I'm not building a thing. Never was intending to and I'm not now.