Bimmerfest - BMW Forums

Bimmerfest - BMW Forums (
-   E34 (1989 - 1995) (
-   -   Known E34 Upgrades and Common E34 Myths (

Monsignor 03-07-2011 08:48 PM

Known E34 Upgrades and Common E34 Myths
I will start with Upgrades in this first installment, and then move on to Common myths (i.e. off the shelf engine additives) as my contribution in a series that BMW_LVR, robertobaggio20, and myself will be writing for general knowledge and reference.
There are many upgrades used on E34s that are BMW OEM from other models such as the M3. But others are completely mythical.

We'll start with the 540i AFM (Air Flow Meter) upgrade: MYTH! Many E30 owners like to put in the "24V upgrade" which would be M50 or S50 motors because they came stock with M20s (12V motors). It was conjured up in this realm of 24V engine swaps that a 540i AFM would allow for more air flow, equating to more power, because they bolt up to the M50 intakes and are from a bigger engine, 4.4L. It is thought that the AFM would tell the engine to take in more air, as if it were for a V8. This is false. The AFM doesn't tell the ECU how much air to take (1st off it cant do that) but rather it tells the ECU how much is being taken in by the engine. It's simply telling the ECU "Hey man, the engine is taking in this much air, please compensate with fuel." A receding cylinder can take in a certain amount of air through an open valve, and can only be adjusting by leaving the valves open further and/or longer (cams) or forced induction. A K&N air filter will allow for more air in your engine, this is a recommended upgrade by yours truly. I love mine and it is easily serviced, and lasts forever. Putting a 540 AFM on a 525 has the same effect as 540 wheels on a 525, confirmed by sources at Turner Motorsports.

Next up, Headers! M50 engines come with cast iron manifolds, where S50 or S52 engines come with tubular steel manifolds. Some generalized differences are design and material. Starting with material, cast iron, is bulky, heavy, and rough (inside and out), and steel is lighter and smoother, and easily formed so as to make an efficient shape. Design differs from manifold to header as well. Manifolds are like a dumping ground that the exhaust port spills into that is then poured through a single exit. Headers are a separate exhaust path for each cylinder exhaust port and are then eased into each other for a much better flow and less back-pressure, which equates to more power. Because M50 and S50/52 share the same block and configuration, these bolt right up. When installing your new headers, be sure to replace gaskets, because there will be more airflow and old gaskets will only get worse and they're ~$25 (c'mon). The S50 headers bolt right up without any modification. S52 headers, require some light modification. Because the S52 headers are from OBDII vehicles, they have secondary vacuum lines at the manifold side, and O2 ports close to the cat-side flange. The O2 holes are easily plugged with M18 oil drain plugs from a 1985 Land Cruiser, found at any hardware store. The vacuum lines may have a plate welded over them, or with an OEM Plates that bolts over it.

On to the Cams! As most of you know, I've been working on this project, locating and acquiring parts and ordering pieces. I'm well versed in this topic with an abundant amount or research and knowledge. There are many how-to's on installing them on many different forums, don't be intimidated. S50 and S52 cams will be the ones to find. They offer virtually identical power gains, confirmed by, again, sources at Turner Motorsports. They offer more duration and lift than stock which equates to more power. Cam specs can be read, simply put by their duration and lift. The lobes of the camshafts are what determine these specs and are what cause the differences between each other. The DURATION of the cam tells us how long a valve is open for. Having a valve open longer equates to more air flow meaning more power. On on the exhaust side, it means it can relieve more pressure and rid your cylinder of exhaust gasses more efficiently. The LIFT of the cam lobe tells how far a valve can open. this is the same principle of how long it is open. The further it opens, the more air, the more power; the same is true for the exhaust side. The more duration and lift a cam has, it is said to be more aggressive or "hotter". They are difficult to come by however. S52s are easier to find but they require the cam trays to match as well because of their square core design. They bolt up to the stock VANOS unit and sprockets. They are seating in the stock bearing caps. One thing to keep in mind though is that non-VANOS cams can only be used in non-VANOS cars, single VANOS cams is only VANOS car, and dual VANOS cam in only dual VANOS cars.
Things like valve cover gasket and VANOS bits should be replaced, but that will be discussed by BMW_LVR.

Ram Air Intake is the most efficient and easy to produce modification on your car. This, however, is not for everybody. If you remove the backing of the driver side headlights, you will find that the air box intake hole lines up rather nicely to the high beam light. You can go to Home Depot, Loews or any other large hardware store to pick up a couple that will fit from the high beam hole to the intake box. Removing the High beam and, at speeds, you will have air, directly and unobstructedly forced directly through the filter. This will allow for a greater amount of airflow into your engine rather than around the high beam bulb. Some drawbacks to this though, many people don't like the lopsided look of having only one high beam, or they don't like a hole in the middle of their grille, or they are worried about debris and water getting in. The former two are your own prerogative but the latter can be addressed. Putting some sort of fine filter over the end of the tube by the light's empty space will keep out large debris (rocks, sticks, stones, branches, boulders, trees, low-flying birds, small children) from your air box. The filter will be able to block out the water effectively, save for a torrential downpour. People have used women's stocking cut and fitted over the end of this tube as a filter, as a point of reference.

Performance Software can be used to improve the hand you're dealt. The software is a small chip that clips into your ecu. It is a very simple DIY, especially with these instructions. The chip is like a small floppy disc that the ECU looks to to find answers to situations. The chip contains an increased rev limiter, usually ~500 revs higher, and removes the top speed governor. In addition to these perks, it holds air fuel mappings, so as to get the most power from your engine given the stock setup. It will add more fuel to better compensate for air flow at certain revs, equating to up to 10-15 horsepower/torques gained.

Lowering Springs
Lowering springs are a nice upgrade both for visual and functional applications. They work by compressing at different rates than stock springs, or by having fewer coils in the same height spring. They will lower your car anywhere from $300. Springs should be complimented by shocks and struts to improve upon spring functions, and strut mount longevity.

Sport Shocks and Struts
Sport shocks and struts are good compliments for lowering or sport springs. The springs will be holding the same weight lower with less room for wheel travel, creating a stiffer ride. the Sport shocks and struts will compensate for the limited wheel travel by having shorter damping rates and rebound rates. Damping is how fast the shock cylinder will compress into the absorber, this differs between shocks due to the pressure inside. The more pressure inside the shock, the less damping it will have, and create a firm ride because of less wheel travel. Low damping rates also lead to high rebound, which is how fast the the shock will expand, pushing the tire to the road. Lower pressure shocks will have a softer rider, because they compress faster and deeper, but are slower to release and expand. The sportier the ride, the less damping and more rebound you'd want. Bilsteins seem to be the most common for our precious chariots. When installing springs and struts/shocks, it is highly recommended to change the mounts also. Meyle HD mounts are popular but even an OEM would do just fine.

Sway Bars
As far as OEM sway bars go, they do their job of keeping a comfortable daily-driven ride, just fine. An upgrade that would be on the affordable end, Would be OEM E34 M5 sway bars. they are the thickest made from factory. A thicker sway bar, makes for less torsion in the bar, which equates to a stiffer chassis, a better handling car, and helps to reduce understeer, by holding the car straight through a corner. On the aftermarket end, adjustable sway bars, like Racing Dynamic bars, are relatively expensive, but they are even thicker than M5 OEM bars. the offer three different holes on the end for the bottom of the end-link to bolt into. Each hole on the sway bar will adjust how much or how little the chassis is stiffened. These are a must for an weekend racer.

E34 540i/E32 740i/L
For all of you non-540 owners, you'll like this. You can upgrade to 540 brakes!! The brakes have the same diameter, but are thicker. They allow for faster stopping power, and fit onto your OEM MacPherson assembly, and fit inside your wheels. They bolt on exactly like when you do a regular brake job. You can find these off of parts cars, or junk yards, all you need are the calipers and the brake carriers. You can take the rotors and pads if they are in good shape but that's a last resort. Try to get replacement rotors and pads, obviously for the 540i. Aftermarket rotors and pads for performance may also be bought, make sure they fit your calipers and hubs though, they are also up to you for research.

Steel Braided Brake Lines
Steel braided brake lines were not offered OEM so you wont find them in any junk yard or parts car. they replace your brake lines by the calipers. There are no disadvantages to to these lines, only gains to be had. Our luxo-liners come with rubber lines, which, over time, can become worn from use. Every single time you hit the brakes, pressure builds up in the lines and causes them to weaken ever so slightly. They will eventually bulge which, in the long-run, decreases brake performance. This weakening in the rubber, also helps to contribute to brake-fade, which is an Achilles heel to all racers. Steel braided lines do not deal with this flexing, weakening, or bulging. They remain constant and can hold much more pressure than stock lines can. they are unaffected by heat, and will give you constant and linear performance. They are about $120 for the whole set (reliable sets have been found on ebay for as low as $60). They are an excellent upgrade for any one of us, racer or daily-driver.

Stil Adding Daily!!!

BMR_LVR 03-08-2011 05:06 AM

Great write up. I will be covering the valve cover issue, but really don't know enough to discuss any vanos work/maintenance. I was thinking it was a non-maintenance item. However, if in the course of replacing the cams it is prudent to replace vanos parts, then please feel free to address that on my thread and I will add it up in the top part under engine work.


luckydog 03-08-2011 07:06 AM

I think there is a divide on aftermarket air filters. They are more work if using oil as a trap. The particle s may be larger coming into the intake system ,resulting in build up on MAF sensor and throttle body, resulting in possible early oil contamination.. Could i say ,I think the engineered air box and paper filter is cleaner and overall just fine.Yes Im sure others will work and they look cool too.:).

Monsignor 03-08-2011 07:42 AM


Originally Posted by luckydog (Post 5901792)
I think there is a divide on aftermarket air filters.I think They are more work if using oil as a trap. The particle s may be larger coming into the intake system ,resulting in more build up on MAF sensor,throttle body, and possible early oil contamination.. Could i say ,I think the engineered air box and fine paper filter is cleaner and over all just fine.Yes, I do think the others will work and they look cool too.:)

I have a K&N drop-in filter, for two years now, its great, IMHO

Sent from Joe's iPhone using BimmerApp

wisbimmer20 03-08-2011 07:59 AM


robertobaggio20 03-08-2011 09:36 AM

A contribution : using a fuel pressure regulator meant for the the immediately lower capacity in your engine class (i.e. using a 520s fpr in a 525) will improve fuel economy by 10% or higher without any noticeable fall in low and high end performance. The engine will not start any differently either. IOW, if someone did the swop while you were not looking, you wouldn't notice the difference at all after you got back into your car and drove off. For the m20 engine, the 525 uses a 3.0 bar fpr while the 520 uses a 2.5 bar one. For the m50 cars, the 525 uses a 3.5 bar fpr while the 520 uses a 3.0 bar one.

Another contribution : using a heat shield to cover the starter does not significantly affect its lifespan.

jhayregz 03-08-2011 11:57 AM

man..m20's dont have many options for HP upgrades :(

Monsignor 03-08-2011 12:01 PM


Originally Posted by jhayregz (Post 5902512)
man..m20's dont have many options for HP upgrades :(

M50 head/intake manifold.
'Nuff said

Sent from Joe's iPhone using BimmerApp

AndrewZ 03-08-2011 12:04 PM

I see good potential in this thread. I'm making it a sticky.

Please continue to add as much info possible about e34's. :thumbup:

Monsignor 03-08-2011 12:27 PM


Originally Posted by LuvThatSam (Post 5902527)
I see good potential in this thread. I'm making it a sticky.

Please continue to add as much info possible about e34's. :thumbup:


Sent from Joe's iPhone using BimmerApp

gmnmsclM540i 03-08-2011 04:31 PM

didnt see much info on the M60b30

Monsignor 03-08-2011 04:34 PM

nonsense poopy pants! the very first one!
if i had one i'd know more, but i need to do some research on the others and fill in some gaps

robertobaggio20 03-08-2011 05:08 PM


Originally Posted by 95 E34 (Post 5902522)
M50 head/intake manifold.
'Nuff said

Sent from Joe's iPhone using BimmerApp

Are you suggesting sir that an m50 head and intake manifold can be stuck on top of an m20 block?

Would this apply to an m50 head with a vanos unit?

Will the exhaust headers (apologies, exhaust manifold) be a direct fit?

Would the wiring harness have to be changed? How about the water pump, alternator, oil filter housing....i suppose all of that will have to go too.

Will a new ecu be required ?

How much would one gain from all of this?

I long to drink deeply from the fountain of knowledge that flows through you sir this is so interesting.

Monsignor 03-08-2011 07:12 PM

I was being facetious. It would be a ludicrously difficult job seeing as it is a 24V head instead of a 12V. It also has the VANOS system. Timing is different. Exhaust will bolt right up. The VANOS swap would be the most difficult part. I have to be entirely honest with you i have no idea about the water pump and all the other jazz in relation to swapping a head.
It would just be easier to get an M30 or M50 or M60 IMHO. Much much easier to simply pull the motor and throw in a new one. I don't know much about M20 and M30 upgrades yet.

jhayregz 03-08-2011 07:33 PM


Originally Posted by 95 E34 (Post 5902522)
M50 head/intake manifold.
'Nuff said

Sent from Joe's iPhone using BimmerApp

reading up on that through other forums. looks like its better to just do a swap.
but being RHD. might be a bit costlier..

just some links i found on it

Monsignor 03-08-2011 10:42 PM


Originally Posted by gmnmsclM540i (Post 5903113)
didnt see much info on the M60b30

The M60s are as good as it gets out of the box. The connecting rods are already forged, the cams are as aggressive as you can get without valve float, but its ok. Intake and exhaust are non-restrictive. you could chip it and get headers and whatnot for sound and marginal air flow.

robertobaggio20 03-09-2011 01:13 AM

Padre, was reading through your master post. Would like you to add something important to the section on performance chips. There are performance chips which can remove the EWS 1 and 2 system on an ecu. While this means a reduction in security, at this point, no one would bother to steal such an old car, there are cheaper and better car alarms systems available, the obc has a password access option without which the engine will not be allowed to crank, and removing the ews1 saves alot of trouble in terms of swopping ecus etc (of course that means that the chip has to transferred to the new ecu so not entirely fuss-free). If you verify this to be true, I would be most obliged if you ammend your post accordingly.

robertobaggio20 03-09-2011 07:56 AM

Hi Padre, most people think that unlocking doors requires the complicated procedure in the bentley manual. I found another method recently and am submitting it to you for inclusion in your main post. The full details are found here :

" There's another MUCH simpler way of unlocking your car. This method was discovered purely by a combination of frustration and coincidence by a friend of mine who also owns an E34.

First, unlock the boot.
Second, unlock the driver's door normally. No need to hold up handles etc.
Third, if #2 doesn't work, then try this on the passenger door, after first unlocking your boot.

That's all !!! Its so ridiculously easy compared to the bentley method geez !! I couldn't believe it, considering how i'd struggled with it on more than one ocassion in the past. "

robertobaggio20 03-10-2011 03:16 AM

Other common myths :

1. voltage stabilisers. These do zero for performance, throttle response and fuel economy.
2. Battery desulfators : these do not extend battery life in any way.
3. Sprint boosters : for e-throttle cars, this would only artificially enhance the throttle signal to the ecu, which is no different than stepping on the accelerator a little harder.
4. Vortex/venturi air intake cones = the wonderful turbulent air does zero for the car's power and fuel economy, and most of these things serve as obstructions to air flow. True air turbulence takes place as the air flows over the intake valves into the combustion chamber, and nowhere else.
5. Sports air filters = although they flow more air and dirt than stock filters, these filters do not allow in enough dirt to damage the engine during normal operations, as their detractors love to claim all the time ===> this is the myth. However, they usually have a smaller surface area than stock filters, and thus need to be cleaned more regularly. They do not require immersion in proprietory oil, however - just normal water rinsing followed by a 30 minute soak in a tub of water and concentrated laundry detergent, followed by another wash and rinse, is all that's required.

Padre, I realise these are more generalised issues but i hope you'll include it as our e34 owners also regularly fall victim to stuff like this. Thanks.

wisbimmer20 03-10-2011 01:03 PM

I have a KN filter and I always thought the 'recharging' oil was to help entrap more particles than simply just rinsing it off

Monsignor 03-10-2011 02:31 PM

the oil is permeable. It doesnt seal the filter. You must be careful to use the recommended amount so it catches dust and fine particles that can be passed through. If you drown it then it's the equivalent of waterlocking your motor.

Monsignor 03-10-2011 06:22 PM

Updated with Suspension and Brakes!

BMR_LVR 03-10-2011 06:44 PM

Nice !!!!

Nice !!!

Oh, BTW, did I say .... Nice !!!


PS: I hope to add more to my post soon. Maybe I can get it stickied too :dunno:

Monsignor 03-10-2011 06:49 PM

gotta be honest Steve. Your write-up in awesome. I should definitely be stickied. Would you like me to message a moderator?

robertobaggio20 03-10-2011 07:19 PM

Hi Padre. How are you going to write up the section on common myths in Part 2? Will you be starting a new thread? May I suggest that you append your op with a section called Common Myths, right at the end after everything involving the E34 specifically? Then as the hive mind posts contributions in, it will make the weighty task of collating, filtering and updating the information easier.

At the end of your OP, i propose that you consider rounding off with a section on important threads. There, you can link Steve's thread. It will thus become indirectly sticky. Steve sir in your post as well it would be a good idea to link back to the Padre's thread with the appropriate heading. Thus, a person who comes upon one good thread, who, with sufficient time and food resources, will be able to sit for hours and essentially read through 80-90% of all the quality posts about the E34.

I feel that thread linkage is important because frequently, the back and forth nature of discussions is as valuable as the final conclusions. This thread linkage can also be a simple way to invoke full details for complicated procedures such as preloading, which would take too long to cover in brief writeups that are mean to be printed out and kept as a modern reference alongside the owner's manual.


All times are GMT -7. The time now is 10:44 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms