There's something compelling about this 560whp supercharged M3 with a 3.4 liter Bored motor.
Cover Story
The owner of this Imola red '02 M3 was previously a player in the import scene. In fact, he still owns a 350Z turbo. Yet 28 year-old Ronnie Cheung from Sunnyvale, CA inevitably saw the light and bought his first Euro. Except he was a little wiser than many who take their first tentative steps into Euros: He was smart enough to buy a project car that formerly belonged to Eurobahn Performance.
As you probably know, building a project car is a labor of love. You pour gallons of blood, sweat and tears into the car, as well as a ton of money; money you'll never see again when it comes time to sell. Few of us are prepared to pay for somebody else's modified car, not wishing to take a chance on buying a potential nightmare. Yet this attitude permeates down to our own projects when it comes time to sell.
Those who are brave enough to take a chance on a modified car are often rewarded with a load of mods for almost no money.
For example, at an early stage in this M3's life, it received an RMS supercharger. Over time, both the motor blew and the supercharger apparently failed, so Eurobahn sent it to Axiom Race Engineering.
We're told the Axiom crew addressed the blown motor with a set of CP pistons matched to Eagle rods, retaining the stock forged crank. With a damaged block, it made sense to bore the block slightly, allowing them to stretch the motor's capacity to 3.4 liters. They also machined the pistons to drop the compression to a boost-friendly 9.5:1.
Up top, the head was ported and polished. A set of Ferrara valves and springs were also fitted with a three-angle valve job.
The carbon fiber RMS intake remains, while the exhaust is Supersprint from the headers to race cats, X-pipe and the stainless steel muffler.
The next job for Axiom was to recreate the supercharger kit, which they did with a Vortech V2 blower. To feed the beast, the ignition timing was altered within the stock ECU, while a Split Second PSC1 works on the fuel supply. It's assisted by Split Second's AIC1 that controls the secondary bank of six RC440 injectors. These are mounted on a separate fuel rail under the painted aftercooler and squirt into the throttle bodies.
Previous engine damage meant motor was bored to 3.4 liters, head is ported and polished as well
The aftercooler itself is essentially a water-cooled plenum chamber, replacing the plastic factory plenum. As the supercharger pushes pressurized air into it, the air is chilled by water that's circulated through the cooler and back into its own radiator mounted behind the front spoiler. Such aftercoolers (or chargecoolers) are very effective, and not as prone to heat soak as conventional intercoolers.
Because the car spends its life in southern California, Axiom also decided to swap the stock radiator for a Fluidyne unit, and fit a separate oil cooler.
The transmission is BMW's paddle-shift SMG. While it remains stock, there's a lightened flywheel, six-puck clutch and a Quaife diff with lower 3.91:1 gearing for even better acceleration. "First gear is so short it barely reaches 25mph," Ronnie reported.
Top-mounted cast aftercooler replaces stock plastic plenum
The Vortech blower is currently producing 12psi boost pressure, allowing the motor to make a claimed 511whp at 7800rpm on 91 octane fuel. Running 100 octane its seen 560whp, which is almost double the output of a stock M3.
Apparently the car's very fast, but speed isn't everything to Ronnie. "What's nice about this car is you can drive it every day. It's happy in traffic, but if you want to go fast you just hit the gas and it goes crazy," he said.
"It's happy in traffic, but if you want to go fast you just hit the gas and it goes crazy."
"The ride is really comfortable; it has a plush interior and it's a nice car to drive. The only problem is the extra injectors. These run rich on cold-start, so it idles unevenly until the engine warms up," he continued.
With such a potent motor, Eurobahn took the precaution of fitting Brembo brakes all round, adding 14" rotors up front and 13.5" rear. Both are grabbed by four-piston GT calipers, as you'd expect.