When the opportunity to begin Project M3 knocked on my door four years ago I knew I wanted to start with a 1995 3.0-liter. I was willing to give up a little displacement in favor of having the OBD-I computer pre-1996 cars had. OBD-I made it easy to swap chips and get power gains out of popular and easy-install upgrades for the M3 such as chip upgrades and Euro-spec HFM (hot film mass, aka "air-mass sensor") conversions, getting these cars closer to 230 whp. The ultimate, normally-aspirated upgrade for a street '95 M3 was the Schrick cam kit I tested on Project M3 a few years ago, which by itself took the car to 240 whp with no exhaust modifications (ec 01/02).
At the time, none of this stuff was available for the S52 (3.2-liter) OBD-II engine. Not only that, but to keep air velocity at a maximum BMW supplied these cars with a more choked down intake manifold-good for low- and mid-range torque but bad for top-end power and straight-line acceleration. For people that wanted more power out of a normally-aspirated E36 M3, the OBD-I 3.0-liter was the car to get. But thanks to Eurosport High Performance (EHP), those dark days are over.
Based out of Salt Lake City and working closely with BMW chip tuning expert Jim Conforti, EHP's Josh McMurray released the OBD-II cam kit for '96-99 E36 M3s, which not only uses the same cams and Euro HFM I tested, it also adapts the OBD-I intake manifold to the 3.2-liter motor without throwing a fault code. The kit also comes with EHP's Shark Injector device, which simply plugs into your OBD-II port in the engine bay and loads the corresponding software in a matter of seconds. No need to remove the ECU, let alone experience the multi-day downtime from sending it in for recalibration. But it will only work on the first car it's used on, so forget about helping your friends out with freebee software.
We borrowed the same '99 M3 used in our exhaust shootout (ec 01/03) but only after I converted it completely back to stock. Testing took place on a Dynojet 224LX, a load-based dynamometer, at the House of Power in Huntington Beach, Calif. Owned by Josh Rickards, House of Power was also hired for installation since Rickards has plenty of experience with E36 M3s. Rather than perform one simple test comparing stock numbers to the cam kit, we broke the test up in several stages to show the power gains between EHP's different power stages.
With 150k miles on the odometer and an estimated 13k miles of track use, this '99 M3 has seen a lot of action in recent years with track junky and BMW CCA instructor Jonathan Lawson behind the wheel. But after a 208 whp baseline, the car proved healthy enough still. Note, since this is a load-based dynamometer, some will argue the power figures may be slightly conservative when compared to the much more widely used Dynojet 248C inertial dynamometer. In order to keep testing variances to a minimum, three runs were made for each upgrade with the cylinder head temperature at 190F and the intake air temperature at 95F, as monitored by Rickards' scanner tool. Air/fuel ratios registered between 12.0-12.5 from 5000 rpm.
Our first upgrade was EHP's stage-one power upgrade. A separate Shark Injector was sent specifically for this setup so as to not over-richen the mixture with the Shark Injector meant for the cam kit. With a register of 218 whp, this simple, 15-minute upgrade was good for 13.9 hp at 5750 rpm and 13.2 lb-ft of torque at 5050 rpm. Slightly leaner, the air/fuel ranged from 12.5-13.1 from 5000rpm-on.
Because of the car's choked down intake manifold there is a serious drop in power after 6500 rpm, which is where any stage-one-equipped M3 should be shifted from second gear onwards. At 7000 rpm this car is only making 189 whp.
So what would happen if we were to successfully adapt an OBD-I manifold? What we like to call EHP's stage-two power upgrade does simply that-it exchanges the OBD-II intake manifold for an OBD-I manifold that can be found on any stock '92-95 325i or '95 M3. EHP made this possible with its CNC OBD-I adapter bracket, which adapts the OBD-II idle air control motor and vacuum lines. The install isn't as simple as it may seem, but luckily EHP's easy-to-read CD-ROM instructions were easy to follow, keeping this portion of the install to three hours.
When finished, this upgrade proved well worth it. Without changing the stage-one software, the power soared to 233 whp-the most power I've ever seen out of the stock HFM. Because EHP hasn't developed specific software for running the intake manifold with its stage-one intake kit, it does not recommend this particular setup-despite the fact that several of its customers reportedly drive their M3s this way. I think EHP just wants to be able to fine-tune a lone intake manifold upgrade first. But we found the idle was still good and the air/fuel ratios were a leaner 12.5-13.2 from 5000 rpm-still fine for a normally-aspirated car.
The gains don't come without a small price paid in low-end performance, however. A power loss started at 2500 rpm and continued to 4600 rpm, with a peak loss of 17.4 hp and 23.3 lb-ft at 3930 rpm. But the window in which it happens is fairly small and will only be noticed while driving around town or powering out of turns in too high a gear (in that case, shame on you). In a drag race the losses would be insignificant, as all you'd have to do is launch at any engine speed greater than 4000 rpm. It's evident BMW chose the OBD-II manifold to make the car feel quicker at low speeds and at a stab of the throttle. But where the OBD-II intake manifold really drops off in torque-at 5000 rpm-is where the OBD-I manifold shines, maintaining it much better through redline. And it's this range that makes the car significantly faster in a straight line for the simple fact that the engine is now getting much more work done over time. In other words, horsepower-32 whp more at 7000 rpm to be exact.
Eurosport High Performance will sell you a new intake manifold for $497 or a refurbished unit for $275. The company encourages its customers, however, to source their own (I've seen several for around a couple hundred bucks online). For the cost of a used intake manifold and the $375 CNC-machined bracket and included bolts, gaskets and a fuel rail cover, I'd say this is more really good bang for your buck. Taking a used manifold into account, total parts cost to this point would be approximately a grand. For a jump from 208 whp to a relatively untuned 233 whp, I'd say that isn't bad at all.
Our hopes for surpassing the 240 whp mark rested on the shoulders of EHP's Schrick 264/256 degree cam kit, which also brings the larger Euro-spec HFM into play. For a job like this you will definitely need a mechanic that knows his or her way around BMW's Vanos system because of the cams. Rickards was our guy and he got it done in an additional six hours.
Upon initial startup we were blessed with no check engine lights or hesitations, but the sound of bigger lobe cams was audibly apparent under the hood. The car was driven for several miles, dynoed, driven again for a week, and then dynoed again just to check for any adaptation. No significant change was found between the two dyno days, but with nearly 243 whp the car felt fantastic in the upper rev range, particularly in a third-to-fourth gear shift at redline (with a 34 whp gain in peak power, it had better).
Our last upgrade had nothing to do with EHP's power upgrades, but I felt a cat-back exhaust system needed to be thrown into the equation regardless. After all, most E36 M3s owners ditch the stock cat-back in favor of an aftermarket one anyway. UUC's new RSC36 features Corsa Performance's RSC (Reflective Sound Cancellation) technology designed to give a moderate, deep sound at idle and a roaring wail at full-throttle. Believe me, it does just that, and it's even a little louder at wide-open throttle than its original System U, which won our exhaust E36 exhaust shootout (ec 01/03). It sounds great, but I don't recommend a good rip next to your local police officer.
Power-wise, like all other E36 cat backs we've ever tested, there were very small peak power gains at the lesser power level with EHP's stage-one intake system, which we anticipated on this car. In our exhaust shootout we didn't even see a gain by taking out the M3's stock cat-back altogether. At that power level, nearly all aftermarket cat-back systems we tested were found to be good for a 1-2 whp gain in peak power and a 3-6 whp in the midrange on the OBD-II M3.
Now that this 3.2-liter engine was flowing significantly more air, I felt we might see a significant gain with the UUC RSC36. And we did. After an easy 20-minute install the car was brought back to its dyno-testing temperatures and run again. Power continued to climb, finally reaching a healthy 246 whp. With a $900 price tag it may not be the best power bang for the buck when compared to intake systems, and exhausts never will be. But you will experience an aggressive-and almost scary-sounding exhaust, a 20-pound weight savings and a few free ponies to boot.
Peak power gains for this entire installment over stock are overshadowed by the fact that you can only compare power changes up to 6330 rpm due to the stock ECU's rpm cut. Still, a peak gain of 38.5 hp at 6330 rpm and 33.1 lb-ft at 5840 rpm should paint a nice picture, even with the 6 hp and 8 lb-ft loss at 3800 rpm.
To put the differences into perspective I'll compare the cam kit to another stage that also sees 7000 rpm. Those of you shifting your Eurosport High Performance stage-one-equipped (or equivalent intake/software upgrade) 3.2-liter M3s at 7000 rpm-unaware of the power drop between 6500 and 7000 rpm-will appreciate what I'm about to say the most. Sure, there is a loss of a handful of horses from 2600 to 4200 rpm, but from 5850 rpm to redline EHP's OBD-II cam kit with a cat-back exhaust had peak power gains ranging from 25-49 horsepower over its proven stage-one intake system, with a peak gain of 49.4 hp at 7000 rpm. Now that is a serious power gain!
Author's Note: Eurosport High Performance's available cam kit for the OBD-I 1995 M3 will show slightly lesser gains but with no losses due to no change in the intake manifold. A thorough test can be seen in the January 2002 issue.
Seat Of The PantsCar owner and BMW CCA instructor Jonathan Lawson had a chance to track test the performance of the OBD-II cam kit back-to-back with his previous stage-one intake kit from EHP. I'll let him explain in his own words:
"At Buttonwillow, with the central California chapter of the BMW CCA, the weekend provided a lot of good testing. On the straights, S54-powered E46 M3s and M Coupes used to be able to easily walk away. This time, however, it wasn't that noticeable and my car actually caught up to several E46 M3s on the front straight. When coming off the final turn onto the front straight behind other E36 M3s, the car would be about an equal pulling distance behind for the first 1/4 of the straight but would catch up to or pass them once in the upper-rpm power band. In the higher revs, the nature of the car is transformed, pulling much harder than with just an intake, software and exhaust.
"I'm very comfortable at Buttonwillow and we were running a very fun configuration (#13 counter-clockwise). With this car in the past, there were turns where I could comfortably have my foot on the firewall without worries of overpowering the 235/40-17 Toyo RA-1s. Now, even with 255/40-17 RA-1s all around, I had to exhibit a bit more patience with the throttle. Going into the grapevine and cotton corners in third gear required a much more progressive input of throttle in order to keep the tires from breaking loose.
"During street cruising there's a slight loss in low-end torque but not enough to really complain about. On the track and in hard acceleration, however, the EHP OBD-II cam kit really shines. Where the power used to start falling off a little-beyond 5000 rpm-that's where the fun really starts now, and it never feels like it's running out of breath. With stock gearing it feels great, but I have a feeling that a 3.46 rear end (stock is 3.23) would help keep it right in the meaty part of the powerband a bit better without sacrificing any useable top end, and it would probably still keep freeway cruising bearable." Sounds like an interesting test, Jonathan! Stay tuned.