Euro Tuner

It started out as a simple case of sibling rivalry. The owner of this M Roadster vowed to himself that he'd never see the taillights of his brother's Corvette, whether it was on the dragstrip, during one of their weekend games of tag in the mountains or even lining up for the drive-thru. More a case of the one-upmanship than jealousy, his obsession left to a bottle of nitrous being bolted down in the Roadster's tiny trunk and overindulgence led to a cracked piston.

The owner will confess that the Roadster often held its own even without the laughing gas, but he wanted to squash all doubts. So when Osh Minelian of Race Marque Systems dangled a supercharged carrot capable of 450 bhp in front of the power-starved owner, the car was quickly shipped off tot the RMS shop in Van Nuys, Calif. When asked about its absence, the owner told everyone that the car was at the dealers waiting on a new set of alloys.

The RMS crew started by pulling out the cracked piston and having the block shipped off and bored to accept supercharger-specific 87mm forged pistons. They then brought out their 95mm stroker crank and attached forged 4340 chromoly I-beam rods measuring 135mm. The new engine swelled from 3.2 to 3.4 liters while the compression dropped to 8.8:1 for supercharging purposes. RMS added a custom-ground cam (also supercharger-specific) into the ported and polished head, which utilizes larger intake and exhaust valves and titanium retainers. 

Sitting on top of the RMS Supercharged Supersport Cylinder Head is a '95 M3 intake manifold, which Osh believes flows better than the succeeding manifolds, and squirting the juice are 30-lb. Motorsport fuel injectors. And lastly, for better flow, they swapped the original mass air flow meter for a 70mm unit. The result is what they like to call the RMS 3.4 Supercharger Stroker Block, which, at 12 lb of boost at 6500 rpm, puts out a claimed 450 bhp. And that's on the conservative side, according to RMS.

A supercharged M3 motor from RMS may seem like old news. Euro Tuner’s sister publication, european car, has covered the process before. But that was what Osh now refers to as Stage I. To one-up himself, Osh's ever-tinkering mind devised an inter-cooler system that cools the air just before it enters the manifold instead cooling the air before it goes through the supercharger like most other systems. Called an "Aftercooler," it fits just aft of the supercharger and ahead of the throttle body. Inside the the tiny box is a solid-core radiator that's kept cool by an industrial-strength water pump. Another radiator sits just behind a fan which is activated whenever the supercharger spools. RMS claims an 85° to 100°F temperature drop compared to its conventional Stage I system, because the cooled air travels a shorter distance with fewer turns, resulting in a decrease in pressure drops (0.3 psi for the Aftercooler, compared to 3 to 4 psi on Stage I). RMS notes its Aftercooler bolts onto all the firm’s existing Stage I kits.

Once the engine is fired, the high-pitched whir of the superchargers bearings battles a Supersprint exhaust (Euro M Roadster spec) for your ears attention. As the revs build, the exhaust wins out by sounding like a kennel of rabid Rottweilers guarding its turf. Deep, throaty, raucous and raw, RMS modified it for even better flow.

Off the line and light on the throttle, the 3.4-liter six feels just like an unmodified Motorsport 3.2. Its tame and flexible until you step beyond the first quarter of pedal travel and get pressed into the back of the seat as you try to reach for another gear. Response is that quick. The sucking sound isn't Ross Perot behind the microphone, it's gobs of Aftercooled air being forced into the manifold and inhaled by the big valves.

A run through the first three gears is over before your body has time to pump out the adrenalin. Power delivery is brutal, causing the rear end to squat and the nose to get light. Fourth gear gives you a millisecond to breathe and watch the needle touch redline. Then it’s into fifth and hard on the throttle again as the short wheelbase tries to cope with the road’s many bumps and bruises. A few minor corrections of the wheel to keep it in line and a quick glance of the speedo reads 120. It’s sensory overload to the tenth degree. More car than there is road to run on. It makes the world seem smaller even withoutthe help of overpopulation, the Internet and satellite communications. Warp speed, shot out of a cannon, bat out of heIl...they’ve all been used to describe cars much slower than this.

We haven’t had a chance to speak with the driver since he drove out of the RMS shop back to his home 900 miles away, but it's safe to assume that the look of disbelief on his brother’s face is still frozen after the first blast of RMS’s Aftercooled M Roadster.