Porsche 948

[Quarterflash]

Hello Everyone
Some of you will already be aware of my 948. There is a story behind it but for now here is a brief and some photos.
The car (an 89 250bhp turbo with M030) was bought with the intention of fitting the Chevrolet engine because, being a late model turbo it already had the right brakes and gearbox ratios to cope with 300 hp (224 kW) and 340 lb·ft (461 N·m) torque.
A conversion kit was imported from Renegade Hybrids in Las Vegas (http://www.renegadehybrids.com) and that was used as the basis for the conversion. The actual engine used is a 350 ci (5.7 litre) LT1 from a 1995 Corvette which has alloy heads and an iron block. Subsequent Corvette engines (LS series) are all alloy which has less effect on the weight distribution although the LT1 is OK. Fuel economy - don't ask.
The car is in shakedown at the moment (June 16) and there is work still to be done but for now at least I get to drive it.
Thanks to Pro-9 for all their hard work and to my understanding wife.
The wheels are Boxster fitted with Toyo Proxes T1 Sport.

 

[ralphmusic]

Nice looking car although not entirely sure about the air intake, but I guess that is a functional need.

Are the quoted 300 hp (224 kW) and 340 lb·ft (461 N·m) torque the new engine numbers?

Ralph

 

[Quarterflash]

Hi Ralph
Yes those are the new engine power figures. They are however theoretical as with any engine power figures quoted but I hope to get it tested on a rolling road soon.
Yes, I'm not sure about the bonnet extension either but for now that was the only way of getting it all to fit. The guys who do this conversion in the states manage to get it all in without bonnet mods. They may be lowering the cross member perhaps?
John

 

[944Turbo]

Glad you have it up and running, well done! Some do lower the cross member a little and I think I have also seen a different arrangement that puts the air filter where the Intercooler used to be, a straight run rather than the 90 - possibly it is flatter? That was probably an LS engine so maybe there are more options

 

[Quarterflash]

Thanks for your comments. I will investigate the cross member possibilities; I'm not sure about torque tube alignment etc. At the moment the engine is level both ways as checked with a spirit level. I have seen some who have the air intake coming straight out in a flatter configuration.
The common engine for this conversion was the lower powered Camaro engine with 2 bolt mains and around 280bhp.
Of course everyone is quite sensibly using LS series these days which I think is lower and definitely lighter with an alloy block.
Q

 

[944Turbo]

The 944 hybrid build manual mentions early short style motor mounts (energy suspension #3-1115G) for all applications (LT and LSx), however it then says lowering of the crossmember (and engine setback plates) are only needed for LS applications - they then show some drawings of custom engine mounts so the fore mentioned plates may refer to using those.
For street applications they recommend a max lowering of the crossmember of 0.5" 7-8mm for track the crossmember plates 6" x 1.5" but they also lower the control arms and antri-rollbar by the same amount 3.6" x 1.5" and 1.8" x 1.125"
there are some drawings if you want to go that route, let me know and I will email them to you.
Tony

 

[944Turbo]

just spotted in the 2009 revision the crossmember spacers are simple washers 1.5" dia 0.5in hole, 0.25" thick, 4 required plates for control arm and antiroll bar are same dimensions but also 0.25" thick.

Note has changed 0.5" for LSx 0.25" for LTx and SBC, but thicknesses may change for each conversion, Transaxle mount must be in satisfactory or new condition. Some cars may not need spacers at all with proper mounts, crossmember rib trimming and a satisfactory transaxle mount.

 

[944Turbo]

oh and a link to a video with it running would be nice

 

[carreraboy]

Hi Tony ... Wow a Cup car ... Did you see the reunion on Race Car Forum?


and yes video be good please ??

 

[944Turbo]

I dont have a cup, my sig is intended to just point out the 944 was the original
Midly confusing though as I do have a coupe and a cab

 

[carreraboy]

Any updates ....??

 

[Quarterflash]

Here is a link to a short video taken inside the car by a passenger. I ease off because we are already over the limit.
http://porschevy.co.uk/video/engine-sound-accelerating.mp4
Best heard through a good set of speakers with a sub woofer.

 

[944Turbo]

No sound on my laptop (it does that sometimes) will try at home later! How many miles have you done in it now?
Tony

(now heard it - very good!)