10-23-2009, 03:25 PM
Thought I would post this up here for interest sake as there is always a lot of talk and speculation when it comes to supercharing these cars, but not that many people have gone down the supercharging route and to my knowledge even fewer race cars.
I race a 968 powered 944 in the UAE. Last year it ran very well in the UAE Touring Car Series in Naturally Aspirated form. The engine was a stock junkyard purchase of unknown origin other than it tested up with good compression. Mods were minimal except for a custom race cam, Stahl headers and a free flow exhaust from Racers Edge, and tunedwith a Haltech Interceptor piggyback. It dynoed at about 210hp at the rear wheels, not a power monster but was quick and reliable.
This year I moved to the new UAE GT Series which is classed on power to weight. My GTB class has a minimum 3.9kg per horsepower limit meaning I can make 315hp at the wheels for my current weight with driver. I was looking for a power increase and considered turbocharging, but given the relatively modest power increase needed, my dislike for unresponsive throttles and the fact that I didn't want to do a whole engine change, the supercharger idea got my attention. After reading all the good and bad I bought the Speedforce Racing kit and installed it. Running the 4lb pulley it tuned to 281hp at the wheels, so I switched to the 7lb pulley then ran into belt slip issues which still aren't sorted. We have relocated the idler for more belt wrap and experimented with a couple of different belts, but the best boost I have seen is just over .4 bar. Dyno showed 294hp at the wheels. We ran the first race last weekend and the car went well. although I am probably 20hp down on where I want to be I was still quickest in class, so if I can find the missing boost all is looking good for the season. The race is 45 minutes with a 90 second mandatory pitstop whether or not you change driver. I don't. Heres a clip of the first few laps as I regain a few places lost from a crappy start
UAE GTC RND 1
I race a 968 powered 944 in the UAE. Last year it ran very well in the UAE Touring Car Series in Naturally Aspirated form. The engine was a stock junkyard purchase of unknown origin other than it tested up with good compression. Mods were minimal except for a custom race cam, Stahl headers and a free flow exhaust from Racers Edge, and tunedwith a Haltech Interceptor piggyback. It dynoed at about 210hp at the rear wheels, not a power monster but was quick and reliable.
This year I moved to the new UAE GT Series which is classed on power to weight. My GTB class has a minimum 3.9kg per horsepower limit meaning I can make 315hp at the wheels for my current weight with driver. I was looking for a power increase and considered turbocharging, but given the relatively modest power increase needed, my dislike for unresponsive throttles and the fact that I didn't want to do a whole engine change, the supercharger idea got my attention. After reading all the good and bad I bought the Speedforce Racing kit and installed it. Running the 4lb pulley it tuned to 281hp at the wheels, so I switched to the 7lb pulley then ran into belt slip issues which still aren't sorted. We have relocated the idler for more belt wrap and experimented with a couple of different belts, but the best boost I have seen is just over .4 bar. Dyno showed 294hp at the wheels. We ran the first race last weekend and the car went well. although I am probably 20hp down on where I want to be I was still quickest in class, so if I can find the missing boost all is looking good for the season. The race is 45 minutes with a 90 second mandatory pitstop whether or not you change driver. I don't. Heres a clip of the first few laps as I regain a few places lost from a crappy start
UAE GTC RND 1

