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As we did in Part 1, using our previously supplied handheld flashloader, we emailed the graph and file to Randy at Epic Motorsports, who immediately turned it around with an adjustment to increase our benefit from the headers. While some of this included further tweaks to the fuel and ignition maps, he also fixed things up so we wouldn’t have a check-engine light, or a need for the rear 02 sensors anymore.
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Randy Mueller, owner of Epic Motorpsorts, also races an E46 M3… | … only his car is propelled by an S65 4.0-liter V8 from an E92 M3, making up to 410 whp (way to rain on my 100whp/liter parade, Randy). Even more impressive, Randy got this setup to work with a factory S54 ECU! |
With the Epic Stage 2 tune, the gains we'd hoped for are realized. In fact, we’ve hit our 100 whp-per-liter goal!
Randy’s tune alone helped improve performance by 10whp at 7500 RPM, and netted a 3 lb-ft average gain from 3500-4500 RPM. Our peak torque is now up to 256.7 lb-ft at 4300 RPM. This is impressive, showing once again BMW’s ingenuity with the S54 motor, because a car with this high of a specific output—much like a road race car with six cylinders or less—will usually toss low-end torque out the window.
It’s great that Project M3 makes 100whp/liter, but what about the torque? Actually, ask yourself how many 3.2-liter non-boosted engines are out there twisting with this much force? To put this question into perspective, it’s my experience to see this kind of peak torque only on larger (and even newer) engines, like the 3.8-liter 997.1 Porsche Carrera or, better yet, the 4.0-liter V8 BMW M3!
Yes, we’re comparing to cars with stock cats in place but we’re also talking mild and maintenance-free, bolt-on upgrades to a much smaller engine here, making it worth noting. Besides, the cat-less headers didn’t necessarily raise Project E46 M3’s torque where it peaks (the area we're using to compare). With just a fluids flush our M3 in stock form made 252 lb-ft.
Having tested Bavarian Autosport’s high performance ignition coils (right) on a previous BMW E36 M3, we were excited to test a set for the E46 M3.
Because of how simply they fit, Bavarian Autosport's high performance ignition coils are a good replacement for failing coils. 
