Ten years ago Jeff Gerner was heavily involved with the SCCA at the regional and national levels, racing front-wheel drive Civics and CRXs in autocross and road course events. It wasn't until he noticed how more much fun the Audi folks were having at these events that thoughts of an automotive affair crept in.
"Being German, I naturally started to gravitate toward the Audi crowd," Jeff told us. "They eventually told me how wimpy it was to run front-wheel drive, and that real men only drove all-wheel drive cars. So when I first experienced it, I was converted!"
That year Jeff bought a bone stock '94 Audi S4 quattro from the original owner. The first generation S4 was offered from 1991-94 and was a factory sleeper. With a five-cylinder, turbocharged 2.2 liter 20v engine produced 230hp at 0.8bar (11.6psi), coupled to an all-wheel drive system and five-speed manual transmission, the car was one of the quickest sedans of its time. The all-aluminum head, cast iron block and motorsport heritage meant there was potential for plenty of boost, which Jeff took advantage of.
Right away he performed heart surgery, yanking out the factory KKK K24 turbocharger and exhaust manifold. In their place, a ported and coated manifold with a turbo from the S4's European brother, the 315hp Audi RS2, were installed to the port-matched, polished and multi-angle cut cylinder head, which Jeff did himself. To further help flow, Jeff also ported the stock intake manifold, matching it to the head's intake ports.
The new turbo exhales through an 034 Motorsport downpipe and 3" mandrel-bent exhaust with a racing cat up front. The system is audibly tuned to a harmonious, deep rumble with an Ultra Flow stainless center resonator and an Aero Exhaust "turbine" muffler in the rear. Boost is controlled by ECU through the external factory wastegate, but with a stiff 1.9bar (27.6psi) spring fitted, the wastegate stays firmly closed during spool-up for maximum response. Henceforth, there is no low-boost setting.
The brains of the system is 034's software in the Bosch Motronic ECU. It reads through a Mass Air Flow sensor and controls ignition timing as well as the pulse width of the 42 lb/hr (440cc/min) injectors.
To transfer the anticipated torque to the wheels, Jeff fitted an 034 Motorsport clutch package, which features a heavy-duty Spec pressure plate and carbon-metallic disc grabbing an 11 lb aluminum flywheel.
 Big turbo is from European...  Big turbo is from European Audi RS2 |  |  Interior stock except for...  Interior stock except for boost gauge |
In order to see what the engine mods amounted to, Jeff drove to MKC Performance near Kansas City, KS. On its all-wheel drive Dynojet 424x dyno, the S4 performed a loaded fourth gear pull, the Auto Meter boost gauge registering 30psi before falling to 26psi after 5000rpm. As seen on the road, it indicated that the RS2 turbo was taxed out yet still recorded 330 all-wheel hp and 380 lb-ft - impressive for this daily driven 2.2 liter on pump fuel.
We're told it tends to surprise a lot of Detroit muscle on the streets of Kansas City. No doubt aided by the fact its 300awhp from 4200rpm through to redline is testimony to a quick spool-up, producing big block V8-like power in the midrange - something Jeff enjoys when powering out of turns at the track as well. The top end is also enough for Jeff to have exploited an indicated 167mph.
As a long-time member of the Kansas City quattro Club chapter, Jeff's been using the car for Audi Club driving events throughout the Midwest and Southern US. To reduce lap times, he installed H&R S6-Plus springs over Bilstein shocks with higher rate bushings throughout. Mechanical grip comes from Continental's Conti3 tires wrapped around 15.4 lb 17x8" Kosei wheels.