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Z4 Mvangelist
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Discussion Starter · #1 · (Edited)
As most of you know by now I have been running ESS's N/A software on my MC for a month and a half. I am VERY pleased with the results. Prior to ESS I had BMS Stage 2 exhaust and RPI's intake scoop as my only power mods. Now I have BMS Stage 3 exhaust and RPI's intake scoop along with ESS's software.

First, let me explain the difference between BMS's Stage 2 and Stage 3 exhausts. The Stage 2 (the only one currently for sale) is a cat-back exhaust based around two Magnaflow mufflers and tips with custom application-specific x-pipe, tubing, hangars and tip arrangement. As you can see from dyno graph #2, BMS's Stage 2 does not provide a peak gain over stock, but adds significant power through the whole RPM range. The Stage 3 exhaust replaces the US secondary cats with custom straight pipes and a resonator. I tested it back when we were developing the BMS exhaust and while it created more significant low and mid-range gains (see dyno graph #3) the top end fell off for reasons that made no physical sense. If anything, a more open exhaust should show power losses at lower RPM, but gains at higher RPM :dunno: I theorized that the DME was sensing exhaust flow outside of acceptable values and was shutting things down. The Stage 3 was abandoned as BMS has no budget to write their own software.

After a while of running Stage 2 with RPI's wonderful intake scoop on the street and tracks, ESS's N/A software appeared on the market. After talking with AJ (ESS's software engineer) at Bimmerfest earlier this year I was convinced that they knew their craft and could be trusted to support their customers. I thought it would be a good test of my theory to get ESS's software and see if it "magically" unlocked the potential of the Stage 3 exhaust. And it DID :clap:

Compare the top end of dyno graphs #3 and #6 and you'll see how ESS's software kept the DME from shutting down the power.


On the track the huge increase in low-end torque is very noticeable (see dyno graph #6). One of the few problems with the S54 is that it is a fairly peaky engine. As sometimes happens on the track, in situations in which you have to exit a turn at relatively low revs (say 4k RPM or so), my current setup will leave a stock Z4 MC for dead. My last time at Willow it was 114F, and I had no SES lights, limp mode issues, or overheating. Caymans, a few other Porches, a C6 Z06 and an RPI-equipped M6 all overheated. My car ran just like stock, only faster - which is how ROM3N described ESS's philosophy (very much like Dinan's). I was pacing off a modded 996 GT3, and to my surprise my Z4 MC (with my 270lb butt in it) kept up with it on the straights! Even on the very long and fast front straight at Willow the GT3 pulled only about 1/2 a car length.

Prior to ESS's software I was seeing a top speed on Willow's front straight of about 125mph. After ESS's software I was seeing over 130mph.

When the car was stock it was impractical to accelerate in 6th gear from below 70mph to pass cars on the freeway. Now it's easy to pass from as low as 60mph!

When the car was stock I couldn't cruise in 6th gear at 40mph like I can in my Dinan S2 M5, because the S54 would bog on even a slight uphill. After ESS software and BMS exhaust I can!

Another advantage of my setup vs stock is that I no longer have to wind my S54 out to 7800rpm to reach max power. Since maximum HP is now achieved at only 7150rpm, I can shift at 7700rpm and still be making much more power than stock through each gear! This saves wear on the engine over time while making me more power :bow:

My mileage has also improved a bit. I lost MPG when I switch to R-comp tires, due to their increased rolling resistance. Now with ESS's software installed I am back to my stock mileage! This claim is based on my casual observation of highway driving on commonly driven routes, relative to my MPG on the same routes when stock. I have an MPG test route that factors out elevation change, but I haven't had a chance to run my MC on it yet because I corded my tires at Willow and am waiting for replacements. As soon as I get them on the car I'll test MPG more accurately.

The following are corrected to flywheel power from the posted dyno graphs using the stock run as a baseline.
Stock
HP peak: 330 HP
TQ peak: 262 ft-lb

With BMS Stage 2 exhaust and RPI scoop.

HP peak: 335 HP
TQ peak: 289 ft-lb
Biggest HP gain (from stock): +33 HP
Biggest TQ gain (from stock): +41 ft-lb

With BMS Stage 3 exhaust, RPI scoop and ESS N/A software.
HP peak: 339 HP
TQ peak: 283 ft-lb
Biggest HP gain (from stock): +24 HP
Biggest TQ gain (from stock): +57 ft-lb

In case you were wondering, I would expect the difference between BMS Stage 2+RPI+ESS and BMS Stage 3+RPI+ESS to be very slight. Based on my observation and testing I would estimate that the Stage 2 exhaust would make a little more top-end power but not quite as much on the low/mid-range as the Stage 3. With either system you and your car will benefit :thumbup:

The BMS Stage 2 exhaust retails for about $1600, the RPI scoop for $125 and the ESS software for $800. That's only $2525 for a LOT more fully-usable power for your Z4 M.

If you guys have any questions, fire away!

p.s. BMS's Stage 3 exhaust is not officially for sale, but if you really want it I'm sure Chris can make that happen.
 

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S54=Living on the Edge
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The torque gains and mid/low end gains are great. I definitely feel the S54/Z4M can use more low end/mid range esp on some of the turns on the track where a higher gear puts you below the power band and a lower gear puts you so close to redline that you have to shift up fairly quickly- neither lead to improved times, at least for me.

That being said, can you explain the HP dip between 7200 and 7600 rpms on the stock curve? Looks like the RPI scoop gets rid of it as does the BMS stage 2 exhaust ... lack of enough intake air causing a timing retard?

Also, what dyno it this on? The numbers look very low as I was expecting a stock S54 Z4M to put out around 275-280 whp ...
 

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Z4 Mvangelist
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Discussion Starter · #4 ·
I guess I'll use this as an opportunity to educate myself on how exhaust systems work...

What does "The Stage 3 exhaust replaces the US secondary cats with custom straight pipes and a resonator." mean? What parts is this replacing, and what do the new parts look like?
On US E46 M3s and Z4 Ms there are 4 cats. Two are in the headers and are hooked up to O2 sensors. Two more cats are downstream of the headers and simply serve to clean up anything missed by the primary cats. In Europe they only have two cats, downstream of the headers, hooked up to O2 sensors.

The Z4 M exhaust consists of three sections (not counting the headers): The mufflers, the x-pipe and the secondary cats. Most exhaust systems for the Z4 M replace only the mufflers. This is good for weight savings, and good for sound. BMS's Stage 2 system replaces the BMW mufflers and x-pipe with more efficient mufflers and x-pipe. This is also good for weight and sound, and better for performance. The Stage 3 system replaces the same two sections as the Stage 2, but also replaces the secondary cat section with a custom section consisting of straight pipes and a resonator (basically a very open muffler). The resonator is important to keep the sound volume from skyrocketing, which happens when you replace cats with straight pipes alone.

Here are a couple pics of the prototype 3rd section. They were taken during initial fitting, so its far from finished in the pics. I don't have pics of the stock cats, but you can stick you head under your car if you want to see them. They are pretty much in the same location as the new resonator.




Here it is finished:


A little further down, showing the Stage 2 x-pipe and mufflers:


The torque gains and mid/low end gains are great. I definitely feel the S54/Z4M can use more low end/mid range esp on some of the turns on the track where a higher gear puts you below the power band and a lower gear puts you so close to redline that you have to shift up fairly quickly- neither lead to improved times, at least for me.
-That's exactly the problem I noticed. In such a situation, you're usually better off going with the higher gear, even though it feels slower.

That being said, can you explain the HP dip between 7200 and 7600 rpms on the stock curve? Looks like the RPI scoop gets rid of it as does the BMS stage 2 exhaust ... lack of enough intake air causing a timing retard?
-I don't know the precise cause, but it is consistent across all my old dyno runs, at both Autowave and RPI. It's not AFR by itself, because I have access to that data. Could be timing, could be an inefficiency caused by the cam profile in combination with the intake/exhaust that BMW designers felt was worth some other benefit :dunno: Apparently the RPI scoop helps a little, but not as much as ESS's software. I know one of the things ESS does that other software companies don't generally do is reprogramming the Vanos in conjunction with timing and fuel maps, etc.

Also, what dyno it this on? The numbers look very low as I was expecting a stock S54 Z4M to put out around 275-280 whp ...
-Yeah, sort of forgot to mention that :eek:uch: All the runs were done on Dyno Dynamics dynos. Prior to knowing RPI I would get my dynos done at Autowave, now I only use RPI because they are more precise in inputting variables such as ambient temperature and humidity (etc.) and have smaller variations in consecutive runs. This is not to say that RPI can get more power to show up (the opposite, if anything), but they can more consistently test for the small variations created by most products. I have tested the Stage 2 exhaust with no other mods at both facilities under nearly identical conditions, and used this to calibrate a correction factor between the two. I then plotted, point by point, each HP and TQ curve in Adobe Illustrator. I tried to keep the spacing of points as even as possible, but in some cases this would be misleading (it could flatten sudden, significant rise or dip) so I added points to some curves to increase accuracy.

p.s. I didn't artificially flatten the ESS dyno run - it really IS that smooth :thumbup:
 

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///M
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On US E46 M3s and Z4 Ms there are 4 cats. Two are in the headers and are hooked up to O2 sensors. Two more cats are downstream of the headers and simply serve to clean up anything missed by the primary cats. In Europe they only have two cats, downstream of the headers, hooked up to O2 sensors.

The Z4 M exhaust consists of three sections (not counting the headers): The mufflers, the x-pipe and the secondary cats. Most exhaust systems for the Z4 M replace only the mufflers. This is good for weight savings, and good for sound. BMS's Stage 2 system replaces the BMW mufflers and x-pipe with more efficient mufflers and x-pipe. This is also good for weight and sound, and better for performance. The Stage 3 system replaces the same two sections as the Stage 2, but also replaces the secondary cat section with a custom section consisting of straight pipes and a resonator (basically a very open muffler). The resonator is important to keep the sound volume from skyrocketing, which happens when you replace cats with straight pipes alone.

Here are a couple pics of the prototype 3rd section. They were taken during initial fitting, so its far from finished in the pics. I don't have pics of the stock cats, but you can stick you head under your car if you want to see them. They are pretty much in the same location as the new resonator.
Thanks man. I now know more than I did a few minutes ago :thumbup:
 

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S54=Living on the Edge
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-That's exactly the problem I noticed. In such a situation, you're usually better off going with the higher gear, even though it feels slower.
That's what I end up doing ... using the higher gear. More torque in the low/mid range would def increase the exit speeds and straight line speeds as a result and hence quicker laps.

-I don't know the precise cause, but it is consistent across all my old dyno runs, at both Autowave and RPI. It's not AFR by itself, because I have access to that data. Could be timing, could be an inefficiency caused by the cam profile in combination with the intake/exhaust that BMW designers felt was worth some other benefit :dunno: Apparently the RPI scoop helps a little, but not as much as ESS's software. I know one of the things ESS does that other software companies don't generally do is reprogramming the Vanos in conjunction with timing and fuel maps, etc.
Now that I look at the plots again, the RPI scoop and BMS Stg2 do a nice job of flattening the power between 7000 and 8000 rpms. All others seem to start dropping the power past 7600, but still much better than stock.

-Yeah, sort of forgot to mention that :eek:uch: All the runs were done on Dyno Dynamics dynos.
.................
p.s. I didn't artificially flatten the ESS dyno run - it really IS that smooth :thumbup:
That explains a lot ... Dyno Dynamics report much lower numbers compared to a Dynojet. The ESS software looks like the way to go for NA tuning.

I will be bringing my Z4MC to a local Dynojet on Monday so we'll see how it does with the RPI scoop and K&N panel filter. Anything I should be aware of when dyno'ng this car besides turning off DSC and using 3rd gear?
 

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Z4 Mvangelist
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Discussion Starter · #9 ·
I will be bringing my Z4MC to a local Dynojet on Monday so we'll see how it does with the RPI scoop and K&N panel filter. Anything I should be aware of when dyno'ng this car besides turning off DSC and using 3rd gear?
-The gear shouldn't matter, as long as they input the ratio is correctly. On drum-type dynos (like Dynojet) the ratio may have an effect on the drum's inertia that wouldn't exist on the light-drum dynos like a Dyno Dynamics. But I don't know enough to comment further.

You really should remove the RPI scoop and filter and run a stock baseline run. Without it you will not have conclusive results. It should be easy enough to do a few baseline runs and then reinstall it and do more runs.

You MUST do several runs. And they should update the ambient temperature, barometric pressure and humidity no less than every 5 minutes. The biggest fan they can provide would be good. Nothing the average shop has sufficiently simulates real driving airflow, but the more the better. This helps the DME stay mellow as there are certain temperature combinations that can trigger a partial "shutdown". Make SURE that they feed the temperature probe in through the scoop so that it's in the area of the air filter. This ensures that the probe reads what actually enters the engine.

Don't forget to turn off the radio, A/C and lights!

Most of the e46 M3s I've seen don't have a set of secondary cats FYI. Maybe the very late MY ones but I know up to 04 they don't.
-I didn't know that. Very interesting :thumbup:

Thanks for the great info. Hope I get a chance to meet up and check out the results one of these days!
-MFest?
 

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Do you have any AFR numbers?

Do you have a run of the ESS software by itself without the exhaust installed?

How much power does the Scoop and ESS add without the exhaust?

Looks like the exhaust needs the software to get the full benefit.

Does the exhaust weigh less or more than stock? By how much?
 

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Do you have any AFR numbers?

Do you have a run of the ESS software by itself without the exhaust installed?

How much power does the Scoop and ESS add without the exhaust?

Looks like the exhaust needs the software to get the full benefit.

Does the exhaust weigh less or more than stock? By how much?
+1

I'm interested as well.
 

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Discussion Starter · #12 ·
Do you have any AFR numbers?
-I have the AFR numbers from the tailpipe, but those are not true AFR as they are post-cat. If you want proper AFR you must weld in a bung to accept the sensor in the headers prior to the cats. Even then, unless you make a small manifold, you will get AFR from only one cylinder.

Do you have a run of the ESS software by itself without the exhaust installed?
-Nope. I didn't want to go through the expense/hassle of swapping exhausts and paying for double dyno runs.

How much power does the Scoop and ESS add without the exhaust?
-See above. I can estimate though, as I've tested my car with and without the RPI scoop by itself. Conservatively I'd say between 10-15HP at peak, with additional benefits in the rest of the RPM curve - but not to the same extent as with proper exhaust. See dyno graph #4 and just use my pre-RPI run as a baseline, then add a little power and considerable smoothness from ESS.

Now you ask, and rightly so, where do you see RPI making that kind of power? Well, not here. Why? Because the stock dyno graph I posted is the best run my MC has EVER recorded - on either dyno. When we dyno'd my car at RPI the first time - baselined it with only BMS Stage 2 exhaust, then added the scoop only and did more runs - we gained 12.5hp (flywheel) from the scoop alone! I prefer to show the worst-case scenario, not the best-case, which is why I posted the strongest stock run as a baseline. Even if it makes the mod gains look smaller.

Looks like the exhaust needs the software to get the full benefit.
-Of course. No exhaust is optimized to the stock DME programming except the stock exhaust. I was very impressed that BMS's exhaust actually made any power prior to software, let alone as much as 13hp and 35ft-lb (at the flywheel) from stock. With ESS the gains are higher, but more importantly they are more consistently higher.

Does the exhaust weigh less or more than stock? By how much?
-21lbs from stock, I believe.
 

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Doesn't RPI now have software for the z4m? I wonder how that software would compare to ESS with scoop and stage 2.... Also this is a new twist: how about an intake system ie gruppeM? Yes we know they all lose power on stock software but wonder how that would change with aftermarket software.
 

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Discussion Starter · #14 ·
Doesn't RPI now have software for the z4m? I wonder how that software would compare to ESS with scoop and stage 2.... Also this is a new twist: how about an intake system ie gruppeM? Yes we know they all lose power on stock software but wonder how that would change with aftermarket software.
-RPI's (actually Powerchip's) software is no doubt better than ESS's with just the RPI scoop, because it was optimized for that one mod. But it's not a complete rewrite of BMW's adaptive code, so if you add other mods with Powerchip you may make things worse.

Regarding an intake system (Gruppe M or Injen come to mind), I really don't know if they would benefit from ESS's software as no one's tested them. But I would expect there to be some additional gains from the software - particularly from Injen's. I saw their dyno plots last year, and while they were gaining 20hp in the midrange, it flattened out at peak RPM just like the BMS exhaust. This could be a byproduct of the intake's design, or it could be the DME intervening. We won't know until someone steps up and tests them. See if you can find the Injen intake's dyno plot. It's somewhere on Bimmerforums.
 

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-RPI's (actually Powerchip's) software is no doubt better than ESS's with just the RPI scoop, because it was optimized for that one mod. But it's not a complete rewrite of BMW's adaptive code, so if you add other mods with Powerchip you may make things worse.

Regarding an intake system (Gruppe M or Injen come to mind), I really don't know if they would benefit from ESS's software as no one's tested them. But I would expect there to be some additional gains from the software - particularly from Injen's. I saw their dyno plots last year, and while they were gaining 20hp in the midrange, it flattened out at peak RPM just like the BMS exhaust. This could be a byproduct of the intake's design, or it could be the DME intervening. We won't know until someone steps up and tests them. See if you can find the Injen intake's dyno plot. It's somewhere on Bimmerforums.
Your in one of the best positions do to since at this point all you would need to do is install the intake. Be nice if you could get a hold of one for dyno testing with your current set up. With RPI there is an assumption the ESS would be better with the scoop and exhaust but there is no hard data to prove otherwise.
 

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Discussion Starter · #16 ·
Your in one of the best positions do to since at this point all you would need to do is install the intake. Be nice if you could get a hold of one for dyno testing with your current set up. With RPI there is an assumption the ESS would be better with the scoop and exhaust but there is no hard data to prove otherwise.
-True, but I don't feel like spending the money/time to buy and dyno and intake I'm not going to use since I'm eying the CFR500 kit.
 

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S54=Living on the Edge
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I'm eying the CFR500 kit.
Sweet ... I cannot wait for you to get the SC kit. I want to see the car being beaten the p*ss out of on road courses to get a feel for reliability of the car with the added power. I had a blower on my GTI and had a few issues on track and it took about 4-6 events and various small mods to work around them- its inevitable.:thumbup:
 

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///M
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Your in one of the best positions do to since at this point all you would need to do is install the intake. Be nice if you could get a hold of one for dyno testing with your current set up. With RPI there is an assumption the ESS would be better with the scoop and exhaust but there is no hard data to prove otherwise.
DO AS I SAY!:whip::rofl:
 

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Discussion Starter · #19 ·
Sweet ... I cannot wait for you to get the SC kit. I want to see the car being beaten the p*ss out of on road courses to get a feel for reliability of the car with the added power. I had a blower on my GTI and had a few issues on track and it took about 4-6 events and various small mods to work around them- its inevitable.:thumbup:
-ESS tracks the hell out of their cars before releasing any product, but they don't get 115F heat over in Germany very often. If it can survive a hot summer day at Cal Speedway or Willow without overheating I'd truly be impressed. Time will tell.
 
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