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
Welcome.
Nice post and thanx for the video.
The guys known for the 928 SC kits have recently done one for the 968. That discussion is now closed but can still be viewed on the site.
Very nice! This reminds me of another car -- which I believe is located in UK. If memory serves me correctly, the very first Speed Force Racing kit was installed by Ninemeister into a 968-motor in a 944 tub as well. They have some extensive experience in tuning that setup -- but their website seems to dead these days....
Great footage! Gotta love that power/acceleration...
Thanks guys.
For the curious, here are some more specs for this car.
Moton Clubsports all round
Torsion bar deleted, polybronze bushings. Currently running 900lb front/1100lb rear springs
Tarret adjustable bars
Racers Edge solid bushings throughout
Racers Edge front control arms
Racers Edge front hubs
Elephant Racing Bump Steer kit
Currently Enkei NT03+R 10inch rear/8.5 inch fronts running 260/640/18 and 235/640/18 Dunlop control slicks
Just fitting 968 fender extensions to run CCW 12 inch rear/11 inch fronts with 300/650/18s and 285/650/18s from next race
Stoptech ST-60 front brakes with 355mm rotors (adapted from an old 350Z kit I had lying around) Original M030 rear brakes
GT Racing fibreglassglass hood, front fenders and front bumper/splitter
Deutsch 9 side and rear lexan windows and fixed headlights
PWR integrated radiator/oil cooler
I built this car myself from a $5000 1991 944 S2 road car that had nice leather seats, a fancy sound system and a gps nav system. All that went in the garbage much to my wifes horror [img]style_emoticons/<#EMO_DIR#>/laugh.gif[/img]
Great driving - didn't see anybody passing you! GO GET 'EM - keep posting the vids. Looks like a fun track - short but some decent passing zones.
Cheers
cool vid & car! looks like you're going superb in braking. Pondering wheter to go with moton clubsports with mine aswell.. have to consider good combo for streetability + track.
Nice commitment on the brakes. You were really sticking it in there!
The engine sounds nice, I don't hear the supercharger at all.
bump steer kit? bump steer kit?
Flash, he listed having an Elephant Racing bump steer kit.
[img]style_emoticons/<#EMO_DIR#>/tongue.gif[/img]
yeah - i know - never heard of it, and i thought i had everything they made
i have seen it now - not sure that will work for me
It's just a glorified spacer to drop the tie rod. Convenient though, and I was able to dial out 99% of bump steer except at the extreme ends of the travel range.
<!--quoteo(post=82461:date=Oct 26 2009, 08:52 PM:name=Eric_K)-->QUOTE (Eric_K @ Oct 26 2009, 08:52 PM)
<{POST_SNAPBACK}><!--quotec-->Nice commitment on the brakes. You were really sticking it in there!
The engine sounds nice, I don't hear the supercharger at all.<!--QuoteEnd--><!--QuoteEEnd-->
That was one of the dissapointments. I was hoping it would whine like a banshee and scare the hell out of the opposition, but the procharger is far too civilised. [img]style_emoticons/<#EMO_DIR#>/rolleyes.gif[/img]
Can you give us a little more info about the engine?
Are you running intercooler at .7?
Stock compression?
What kind of head gasket?
What kind of engine temperatures are you seeing on the track? I have flown to Dubai a couple of times and if it doesn't run warm there it won't in Sweden, that's for sure!
How is the software altered through the Haltech piggyback as compared to stock? Why did you use a piggyback rather than go for a stand alone system?
Stock injectors?
Fuel pressure?
I'm going for a supercharger myself next winter and although I am contemplating the kit discussed in the closed thread here I'm still a long way from deciding what kit to use. The ability of retaining the AC is a nice feature with the above mentioned kit although I'd prefer a proper engine management, rather than simply upping the fuel pressure in relation to boost - seems a bit crude.
Thanks!
Magnus
<!--quoteo(post=82527:date=Oct 27 2009, 11:09 AM:name=firefish)-->QUOTE (firefish @ Oct 27 2009, 11:09 AM)
<{POST_SNAPBACK}><!--quotec-->Can you give us a little more info about the engine?
Are you running intercooler at .7?
<i>I am using a standard 944 Turbo intercooler</i>
Stock compression?
<i>Yes</i>
What kind of head gasket?
<i>Stock</i>
What kind of engine temperatures are you seeing on the track? I have flown to Dubai a couple of times and if it doesn't run warm there it won't in Sweden, that's for sure!
<i>I had high temp problems last season with the stock radiator, but I have just installed a big PWR radiator with built in oil cooler. Last weekend we had track temperatures of 45-50C. I haven't had a dedicated temperature gauge in the car since the supercharger install as I am converting to a Racelogic DASH-2 display, with half my old gauges out of the car, but on the factory gauge currently connected temps were rock solid just above the half way mark, which from memory is around 90C?</i>
How is the software altered through the Haltech piggyback as compared to stock? Why did you use a piggyback rather than go for a stand alone system?
<i>The Interceptor intercepts signals from the senders and modifies them by a percentage to pass on to the ECU. It tricks the ECU into using different values on the standard tables. I used it originally because the tuning of the naturally aspirated motor with limited mods didn't justify the cost of a stand-alone. It is easy to tune and so far has met my needs.</i>
Stock injectors?
<i>The SFR kit comes with 48lb injectors</i>
Fuel pressure?
<i>Can't remember the exact figure set on the rising rate regulator, but it was orignally set a bit higher than stock to keep the cams happy. No futher mods to fuel pressure since the supercharger install.</i>
I'm going for a supercharger myself next winter and although I am contemplating the kit discussed in the closed thread here I'm still a long way from deciding what kit to use. The ability of retaining the AC is a nice feature with the above mentioned kit although I'd prefer a proper engine management, rather than simply upping the fuel pressure in relation to boost - seems a bit crude.
<i>Can't comment on AC, wish I still had it as it gets extremely hot in the car here, but like most masochistic racers weight reduction was more important to me. My setup seems pretty civilised. Idles well, part to full throttle transition is good. A standalone would be nice for fine tuning and deleting the MAF, maybe later.</i>
Thanks!
Magnus<!--QuoteEnd--><!--QuoteEEnd-->
Thanks for the info!
What fuel are you using?
Is your kit made to use all 951 plumbing and hardware like the IC? What's the price of the kit? Is the kit made to use the Haltech unit (that you already had) or is it a only a partially complete kit that you need to "finish" in order to get going?
Ah, and of course, would you recommend this kit to others?
If you have pics of the engine bay it would be greatly appreciated.
Brgds,
Magnus
Magnus,
I suggest you read this thread which has more info and pics on the SFR kit by another user than I have time to post:
SFR thread
Check out the Speedforce Racing website also if you want more info on cost etc.
I use pump fuel, but we have very good quality pump fuel here 98RON.
I don't know anything about other kits. With the SFR kit you get the convenience of some decent brackets and pre-made plumbing, and the procharger seems like a good product. Intercooler and bigger injectors are included as is a preconfigured fuel computer that I don't know anything about because I didn't use it. Some improvemens would be a wiring harness extender so you don't have to cut and extend the MAF wiring yourself, pre-machined bolt clearance holes to allow relocation of the idler without machining and I personally think the clearance at the back of the supercharger is too tight making it hard to plumb the idle control valve if you still use it, and a challenge to get the thing bolted up without the snorkel intefering with the manifold, but it's all pretty good starting point.
It's expensive for what it is, but it suited my application perfectly. My car is a race car, so I am always re-engineering things anyway, on a road car you might find the cost a bit high and the compromises frustrating.
Great drive Steve! We ordered a compressor from speedforce as well. Next race is 3 January (hope it doesn't snow here in Holland...), do you think it will last for 4 hours? Still, we will try it out. We have a few 968 blocks lying around, so we take our chances. Very encouraging you are racing so well. We run a standard engine with probably less than 239 hp and the car (and I...) is screaming for so much more. 300 hp would be perfect.
Assuming the engines are ok to start with, I think that the longevity of this setup really comes down to careful tuning and heat management. Enough charge cooling, timing retard and fuel delivery to avoid detonation and limited boost. But, I'm not one to talk yet as the car has only run like this for a few hours of racing. [img]style_emoticons/<#EMO_DIR#>/tongue.gif[/img]
I think if I can get through a whole race season without problems it will be a good endorsement for the setup!
I have another race weekend starting tomorrow and assuming it doesn't blow up this round I will post some more results..
Looking forward to another in-car race video - season is over here in the North East part of the US.
I'm getting ready to take the car to RS Barn for some safety mods and maybe a few additional tweaks