The ultimate rebuild

[nathan 1981 930 G50]

There was a chap in the UK that ran a supercharger on his stock car successfully with no problems. Of course you shouldn't run much boost pressure, maybe as little as .3bar even.

The other negative thing is more weight at the rear of the car

One of the things I like about my 3.2 compared to the 930 is the higher compression with its razor sharp throttle response. The 3.3 is dead, until the boost kicks in []

 

[alex.powell]

Yes i had written off superchargers because as you rightly noticed I have just bought new high compression mahles. I had a very good chat with one of the guys on club night who has a tpc supercharger kit on his 964. I did look at more angry cams when doing the rebuild, but wasn't sure if i would need to start messing about with piston to valve clearences aswell so stuck to stock. I guess the main driver for a supercharger was that i could simply bolt it on... I'm certainly in no rush with this - what is odd is why there is so much more on 964 superchargers and not 3.2,s...

Aswell as exhaust i went for custom wong chip and bought an LM1, which i cant wait to use...

I am however v interested in recommendations for air filter kits? and what was an ITB?

 

[alex.powell]

As you said the turbo suddenly wakes up, where as a supercharger from what i have read will deliver a much smoother surge much earlier... The worry is that if boost is turned down too much then it may cost more to run the supercharger than it gives me (kind of like cellery)...

 

[nathan 1981 930 G50]

Yes, but if the belt driven supercharger is geared correctly then it will be fine. You would need to talk to an expert about it.

Lower boost means less air is needed so it will be geared lower than if higher boost was needed. At high boost the compressor would need to move more air for the same RPM of the engine. The compressor would need to spin faster so it would need to be geared higher and therefore need more energy to drive it.

The disadvantage that I can see is the weight of the supercharger and all the parts needed which should affect the performance of the car (not top speed). The other worrying thing is that al this extra weight is at the wrong end of the car...

With a turbo you have to choose whether you want the high end or the low end compromised and I chose the latter. The other advantage of me going with a bigger turbo despite it being slower to spool up is less heat is produced for the same boost pressure.

Luckily I don't like celery anyway []

What rod bolts did you go with?

 

[Mike58]

A really nice supercharger was featured in the Bruce Anderson book from Supercharging of Knoxville ( USA)
It is based on the the whipple ( swedish I think ) design and in Bruces' words looks very Porsche. It kicked out 425 BHP so a very powerful upgrade.
I have a great design for an air intake from grill to filter if you choose a K&N type

Good luck

Mike

 

[alex.powell]

today didn't go quite as planned...

i turned the key for the first time. engine pressure was good. it didnt spray oil anywhere and it seemed to turn nicely.

when i connected the dme there was no change....poo....i think i am now in some sort of electrical hell....

no spark...no petrol on plug...

any one have any ideas?
would the ref sensors being too far from the wheel cause this?
cheers
Alex

 

[nathan 1981 930 G50]

The manual states how far they both are meant to be away from the teeth.

Are you sure you didn't muddle which one is which on the connections? Both plugs are the same, only the white one is different of the 3.

Did you plug the connector in that is between the shock mounts?

I wonder if your dme relay is ok?

 

[alex.powell]

cheers nathan- got it sorted today. i reset the speed sensor to .8mm away from the wheel and it fired up first time!! sounds and goes great...couple of leaky oil lines....but on the whole well chuffed...

 

[nathan 1981 930 G50]

Well done. It's satisfying when it all works out.

 

[alex.powell]

Quick update - Finally got my car back onto the rolling road. It has now jumped from 175 at the wheels to 200, really pleased with that. Not sure what the correct percentage is to get an engine value? or if it can be reliably done? or if i even should!!! I'll now pass on the co values to mr wong for the second stage, not that it will make much difference to the result, more that it was running a bit lean in places which i'm guessing he will iron out.....

cheers
Alex

 

[nathan 1981 930 G50]

15% seems to ring a bell. Might be 18% for 4WD.

 

[blease]

I've driven an RSR replica with a 3.2 engine fitted with vast PMO carbs. Made for a very nice, tractable and uncomplicated engine. Worth considering?

 

[polar964]

Just read your post for the first time Alex. Very interesting read and looking forward to seeing some pics once your epic project is complete.

 

[alex.powell]

I'm certain this car will never be complete!!! just fitted some renline monoballs this weekend just gone, was surprised at the difference. also stuck some wevo's on the rear engine mounts, also quite a surprise at the change in engine pitch and gear change. i'm just coming upto 5000 miles from my rebuild and thinking about service. next jobs are balls joints, turbo tie rods, front strut assembly and big brakes. I've also started to think about next engine which i'm hoping will be a 97 vram, although that probably is a long way down the road(the deal with the mrs is that i supply another child before i can have another engine!!!) i'm also trying to find a good n rated so2 replacement as i just cant seem to get any from anyone - as soon as I have those then i shall give the car a wash and get my brother round with his fancy camera....

cheers
Alex