It took four months to get the hardware to spec, a little bit longer to come up with the software, a task that Active Autowerke performs internally. Importantly, the new code will be flashed directly to the ECU. Once the big hope for cramming software tuning through increasingly complex factory code, the ubiquitous piggyback units have fallen back out of favor. The next generation of BMW software will supposedly monitor for these types of add-ons and send any perceived offenders slithering home in limp mode. ECU flashing, for those who can unravel the code, is back on the table as the only truly viable option.
Hugh welcomes the challenge. "If we're going to tune like the factory, we go through the ECU," he says. "Eventually, the piggybacks won't be able to do what the ECU will. It will separate the men from the boys for sure."
As with previous Active Autowerke supercharger systems, this one will be offered in two flavors: Level 1 and Level 2. The first will boost engine output by some 37-38 percent, about 570 hp. The second adds more aggressive boost, fueling, and a methanol/water injection system for total output of 638 hp and 460 lb-ft of torque, mathematically corrected for a reading at the crank. Max torque is up more than 50 percent over stock with increased output in front of the peak, or "beneath the curve" as they say. After peak, torque tends to simply level off in a relatively straight line as boost increases, the boost essentially "propping up" the torque curve.
Still, Hugh says: "This engine is about revs and horsepower. You have to keep it buzzing to see the true benefit. This supercharger is perfectly matched to its power characteristics. This thing pulls very strong right up to the 8400-rpm limit; it almost feels like it needs a higher one. The power curve looks like a staircase."
In addition to the blower setup, the prototype car wears standard Active Autowerke "Signature" series hardware, including a short-shift assembly to tighten gear selection, and a full exhaust from the headers back.
Running gear is comprised of a set of 19-inch BBS CH wheels shod with Michelin PS2 rubber. The chassis crouches over this rolling stock courtesy of another Active-recommended treatment, KW Variant 3 coilovers. These use electronic sending units in the front and rear to essentially simulate the electronically adjustable EDC sensors from the OEM dampers. They offer a wider range of manual suspension adjustment--14-way compression damping, "infinitely adjustable" rebound, and individual height adjustment. The suspension will be shortly upgraded to a KW Clubsport package for further on-track thrashing.
Depending on the time of day and your location in the city, Miami can be one of the more frustrating places on Earth to drive. At length you reach the water and make a crawl up the virtual parking lot that is Ocean Drive. You probably couldn't get any further from the M3's natural alpine habitat, but if you want to be seen (or heard), this is the place to be.
You goose the throttle; the exhaust report shivers off caf windows lining the seething beachfront sidewalk. Heads whip around; a coffee cup shatters against the pavement.
Yeah, the Active prototype'll do that too.
Active Autowerke E90 M3
supercharged prototype
* Layout
Longitudinal front engine, rear-wheel drive
* Engine
4.0-liter V8, dohc, 32-valve. Active Autowerke prototype intercooled supercharger kit and software, AA Signature exhaust
* Transmission
Six-speed manual, AA short shift kit
* Suspension
KW Clubsport coilovers
* Brakes
Factory assemblies
* Wheels and Tires
BBS CH, 9.5x19 (f), 10x19 (r)Michelin Pilot Sport 2, 255/30 (f), 275/30 (r)
* Exterior
Active Autowerke Signature badge
*Performance*
Peak Power: 638 hpPeak Torque: 460 lb-ft*AA data, corrected for crank