Mike, Fred and Karl Hughes, the brains behind Active's turbocharged success, are probably unaware the BMWs they tune possess these capabilities, but I know differently. In the safety of my office, I can tell a story about a moment that had me whiter than the spaces between these words, about how I launched an M3 like the space shuttle and survived re-entry. Just a stone's throw from Homestead Raceway, where the thick air is punctuated by the sound of high-strung Indy cars, lies a gridwork of pavement spanning the entire length of lower Florida. Indigenous locals and farm workers use these ribbons of asphalt almost exclusively as transport to and from their Fleetwood double-wides. Sort of a southern, cracker autobahn, if you will. I brought the Active crew here to see just how fast its new breed of OBD-II M3 turbos is--if they run as well as Active literature states.
It throws out these numbers: 398 bhp @ 8.5 psi, 400 lb-ft of twist @ 4250 rpm, 0 to 60 in 4.6 sec. and 12.79-sec. quarter miles. Those sorts of statements are rarely repeatable, at least in the real world.
Seated behind the wheel of Active's Black M3 turbo, I found an open stretch, pointed the wheels straight ahead and mashed the throttle. The next few seconds happened with such frightening brevity they resembled a movie on fast-forward. First gear took a gentle touch--too much gas broke the tires loose and slammed the tach into the rev limiter. Second gear took equal finesse--if the rear tires weren't 100-percent planted (and they weren't), the turbo's torque breaks them loose and the rear end gets big-time squirrelly. Third gear and the Active M3 was hell-bent on breaching 100 mph--and the tremendous power was almost laughable, in a deranged "oh-my-god-I'm-gonna-die-but-I-can't-stop-myself" kind of way. Fourth and the speedometer read 130 mph, showing no intention of slowing down. Suddenly, the road I was on became more interesting--barely perceptible undulations became ramps pointed straight toward heaven. At 135 mph the M3 got light as it crested a hill and then very heavy as it went down the backside and then up another hill.
And then it happened: I was airborne.
There was an eerie moment of silence and a brief eternity as I pondered what was going to happen next, what it was going to cost, what my headstone would read. It ended as the rear wheels spun wildly, making a sickening "ZZZZIIIIIIIIIIINNG," and all I could see were treetops and sky. I jumped the next dip entirely, Evil Knievil-style, and landed precisely on the next hill. A few sparks and tire smoke hailed my landing, and I managed to bring the M3 to a stop, pull over and throw up (too much Cuban food).
From what I can discern from my test flight, the biggest problem Active turbos face is finding enough room to wring them out. I suggest we pave all of Texas and designate it an Active M3 turbo playground--these cars could certainly use the space.
I've known about Active for 6 years, about the same amount of time since the release of its first generation of turbocharged BMWs. They were brutally fast and remain a benchmark car for me in terms of outright, ballsy power. Active's more recent notoriety came from its remarkable performance during the One Lap of America, where a highly modified 318ti featuring an Active turbocharged M3 engine took third place overall, just behind a Lambo SV and the vicious Mosler Raptor (see ec, 12-99).
Debate rages over which is better, turbocharging or supercharging, and while both certainly have their distinct advantages, nothing quite compares to the brutal acceleration of an Active turbo...nothing. The g-forces these cars generate is so euphoria inducing, I found myself coming to a dead stop and re-launching every half mile or so. As recorded on a G-Tech performance computer, 100 mph comes up in a scant 10.4 sec., and, despite a slipping clutch, I was able to get low 13s in the 1/4-mile.
What's especially noteworthy is the way all this torque is delivered--not an all-or-nothing blast like the early Porsche 930 but in a smooth, linear rush, punctuated by the cymbal-like crash of the wastegate. Packing almost as much punch as the vaunted M5, you begin to wonder about things like aerodynamics and downforce, how much torque the driveshaft can take before it snaps, speed ratings on tires, the strength of the wheels and, always, the brakes. Do I have enough brakes?
Active's first generation of force-fed M3s were based on 3.0-liter cars with OBD-I technology, a system good tuners found very workable. It all changed with the advent of the 3.2-liter M3s equipped with OBD-II, a system so sensitive it threatened to "close the hood" on all OBD-II cars.
Unfortunately, less than 5,000 3.0 M3s came stateside between 1994-96, so Active would retrofit later-model cars with OBD-I gear. The process included swapping the fuel rail, wiring harness and ECU, knock sensors and all other engine sensors with older bits. It worked great, produced huge gains and was very tuneable, but the supply was limited. The trick was working within the needle's eye of OBD-II, a bit of magic Karl Hughes discovered after years of work.
"I did it, mon," said Karl, an automotive engineer with a pronounced Jamaican accent. "We control everything within the Siemen's computer."
That seems to be a recurrent theme in today's tuning circles--working within the factory's code, an especially daunting task given the sensitive air-mass system utilized by many European brands. In any case, Active had done its homework, and the proof played out in these blazingly fast M3s.
Active turbo systems have a lot going for them...literally. The kit is very comprehensive, containing pretty much everything the M3 owner needs to punish the competition.
"The Active OBD-II turbo system was designed to be a simple bolt-on," explained Fred Hughes. "There are no options in this package...we carefully matched all the components to deliver the advertised output. If you want this type of power, want it safe and reliable, this is everything you will need."
From a hardware standpoint, Active's new OBD-II turbo systems are fundamentally the same as its previous generation--no new ground cut here. Why fix something when it's not broken? The turbo itself is a fairly large, older Mitsubishi TD06 hybrid with an external HKS wastegate linked to Active's own exhaust manifold and turbo downpipe. Mandrel-bent plumbing is augmented with high-temp silicone hoses and aircraft-quality stainless-steel fasteners throughout. Active's intake is fed with sizable 3.0-in. piping and a low-restriction ECIS air-filter system; the fuel system is largely stock save for high-flow injectors. Unlike the previous AA kit that relied on a compression-reducing head-spacer, the OBD-II system retains its stock 10.5:1 ratio. Running between 7.5 and 8.5 psi raises the equivalent compresion ratio to 16.6:1, which raises a host of concerns like spark, fuel, knock, heat, etc. This is where Karl's programming magic comes into play (a properly matched turbo and good head design doesn't hurt, either), keeping things happy and healthy. Despite my purposely lugging the car, it never pinged or knocked--not once! It was a pleasant surprise, because virtually every tuned 1.8t VW/Audi I have driven has displayed some degree of detonation.
Active uses a Mustang chassis dyno, a loaded unit that allows it to target specific areas in the rpm range rather than simply measuring outright horsepower such as with an inertial-type Dynojet. Just for grins, Active threw an M5 on the Mustang dyno--it spun the big wheels to some 300 bhp. After computing parasitic driveline losses, the M5 was making an even 400 bhp. Active tested a different M5, and it recorded just 5 hp more. "We compared the graphs, and we ended up very close to the M5...a little shy on torque, but pretty good nonetheless," said Mike.
Active includes a huge, front-mounted intercooler with the OBD-II kit, an absolute necessity to cool the charge air. An electronic boost controller, boost gauge and turbo timer is also included. Oh, yeah--without Active's heavy-duty clutch/flywheel pack, this whole exercise would go up in smoke. Active harnesses all this grunt with a hi-po clutch kit comprised of a super-duty pressure plate, composite disk and a release (throw-out) bearing. Active's aluminum flywheel replaces the factory's dual-mass unit and weighs 12 lb versus the stock unit's 26 lb, which results in quicker spool-up. The unit is CAD designed and CNC machined. The increase in pedal effort is minimal--that's good. On the other hand, its clamping force still lacks sufficient grip to effectively harness the huge amount of twist--after a half dozen launches, it felt greasy.
Like I said before, the power these cars make is addictive--many of Active's customers come back for another fix. "If they say it's not fast enough, I tell them not to drive it for a week," said Karl. "They get used to so much power, and their perspective gets skewed. Sure, we can give them more, but that involves major engine work, transmission considerations, brakes, etc."
Still, a few insist they need more--no wonder Florida is home to some of the world's fastest BMWs.
If you can't tell by the tone of this story, I'm a fan of Active's work. It's a family-owned and -operated business with good values and a burning desire to build lightning-quick BMWs. It is only logical then that European Car obtain an M3 of its own, turbocharge it and terrorize the streets of L.A. I'm not kidding.
Stay tuned.
Active Autowerke Specifications:
Silver 1997 M3
Active OBD-II turbo, 7-9 psi
400 bhp @ 7200 rpm
AA clutch and flywheel
AA stainless-steel exhaust
AA short-shift kit
Koni dampers
H&R springs
RD strut brace
LTW X-brace
Racing Hart wheels: 8.5x18 in.
Toyo Proxes radials, f/r: 225/40ZR18, 235/40ZR-18
AA cross-drilled rotors
LTW front splitter
Owner: Vince Garey
Black 1997 M3
Active OBD-II turbo, 7.5 psi
375 hp @ 7200 rpm
AA clutch and flywheel
AA stainless-steel exhaust
AA short-shift kit
Koni dampers
H&R springs
Racing Hart wheels: 8.5x18 in.
Toyo Proxes radials, f/r:
225/40ZR18, 235/40ZR-18
AA cross-drilled rotors