Project E46 M3: Part 2 – Cat-back Exhaust and Pulleys

Project E46 M3 sitting pretty on lightweight D-Force wheels and BFG Rival tires.  We’ll discuss these, along with our new brakes and tires, in detail, and include real-world testing, later in Part 6.

Project E46 M3: Part 2 – Cat-back Exhaust and Pulleys

Better sounds, Less Weight and More Power

by Pablo Mazlumian

After a six-month hiatus, Project E46 BMW M3 is back and on a roll.  We’ve been busy testing new parts, and we’re excited to share the results.

To recap, in Part 1 we dyno-tested the car on Modified by KC’s Dynojet 424x.  Power started at an unusually healthy 290whp baseline, and ended at 304whp with a fluids flush and new spark plugs, as well as a new intake and software upload.

May I interject here for a second?  I’m compelled to edify the S54 motor because it is simply a magnificent piece of machinery.  When the 3.2-liter E36 M3—which is still a great car—came out in 1996, Americans liked the torque.  When the 3.2-liter E46 M3 followed in 2000, some perceived it as lacking torque.  It is this misinterpretation that urges me to clarify why the S54 engine’s torque output is such a remarkable achievement.

To illustrate the point above, I’ve included torque curves of stock E36, E46 and E90 M3s.  Keep in mind that both the E36 and E46 were 3.2-liter inline-six engines, but with the infinite cam adjustment from the dual VANOS, slightly larger displacement (3151cc versus 3246cc for the E36 and E46, respectively) and a freer flowing cylinder head fed through individual throttle bodies, the E46’s S54 engine’s performance is closer to that of the current E92 M3’s S65 4.0-liter V8 than it is to the US-spec E36 M3’s 3.2-liter S52.

The improvement above shows over 40 lb-ft down low and 60 lb-ft up top over the E36 M3, which equates to over 75whp in the high revs.  Compared to the V8, which is factory-rated by 33 more lb-ft than the E46 (295 lb-ft vs 262 lb-ft for the E92 and E46, respectively), the E46 is only down 13 lb-ft at peak, at least in this comparison.

Comparing horsepower tells an even better story of how the M3’s line up.  While the V8 is clearly the fastest when zipping through the gears, it’s impressive to see just how close the E46’s S54 3.2-liter is in performance to the S65 V8 4.0-liter until 6500rpm, when the S65 really starts to flex its 8-pack with even higher revs.  The E36, by comparison, looks like it left an aftermarket supercharger in the trunk.

This isn’t an attempt to knock the E36 M3 by any means.  I love them and, like Jonathan Lawson–the author of own Project E36 M3 series–have owned four, myself.  But the S54 3.2-liter is just on another performance page.  In fact, the wheel horsepower power level is more akin to that of the same-year Porsche 996 Carrera, which has 3.6 liters and an assumed lower loss in power to the wheels.

With that background info shared, let’s get back to Project E46 M3. This engine is great and we cleared 300whp in Part 1.  But over the next two parts we’re back with a quest for even more power.

We’ll start by testing a cat-back exhaust system by Corsa…

…and finish with a power pulley kit from VAC Motorsport.  All testing and installations will be performed once again with our friends at Modified by KC.  MKC has, and always will be, instrumental with all of the technical articles we do in the Kansas City area.

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