John.

For those who were interested in the pictures of the twin turbo setup on my 81 S

<a href="http://boards.rennlist.com/upload/boostgauge1.jpg" target="_blank">http://boards.rennlist.com/upload/boostgauge1.jpg</a>

<a href="http://boards.rennlist.com/upload/psturbo.jpg" target="_blank">http://boards.rennlist.com/upload/psturbo.jpg</a>

<a href="http://boards.rennlist.com/upload/dsturbo.jpg" target="_blank">http://boards.rennlist.com/upload/dsturbo.jpg</a>

<a href="http://boards.rennlist.com/upload/topengine.jpg" target="_blank">http://boards.rennlist.com/upload/topengine.jpg</a>

<a href="http://boards.rennlist.com/upload/intercooler.jpg" target="_blank">http://boards.rennlist.com/upload/intercooler.jpg</a>

<a href="http://boards.rennlist.com/upload/microfueler.jpg" target="_blank">http://boards.rennlist.com/upload/microfueler.jpg</a>

<a href="http://boards.rennlist.com/upload/front.jpg" target="_blank">http://boards.rennlist.com/upload/front.jpg</a>

Chris Lockhart

Pretty wicked looking equipment there John. I'd hate to have to work on it though. Looks EXTREMELY cramped!!! Especially on the drivers side.

ViribusUnits

Wow, thats a tight instlation! I'm gald I don't have to work on it! Impressive bit of fabracation too, I might add.

I've got a question. From the picture on top of the engine, it looks as if your ducting the air from the pendelum, down to the turbo/after cooler and then back up to the penedlum. Why not just feed the turbo/aftercooler into the MAS? The biggest reason I ask is because the F.A.S.T kist seem to feed the supercharger/after cooler into the MAS. It would seem like an easyer fabraction job to me. I'm sure you have a reason, I just don't know it.

I'll tell you what though, my car need one. ;-)

Nice, yep, I deffently need that.

Mike B

Nice job John, very innovative...What is your impression on the upgrade?

<img src="graemlins/bigok.gif" border="0" alt="[thumbsup]" />

John.

Yes, it is very tight in there! Whoever worked for Callaway at the time did a very nice job with the pipework. All mandrel bent corners completely tig welded toghether. The exhaust work is really something else on the car. As for the air flow meter, well it has been moved down to the intercooler and is on the pressurized side of the system.

I have "custom" (i.e. cut in half) wrenches to get at the turbochargers. I have replace the PS, but never touched the DS turbo. It just takes time, patience and slinky fingers.

All in all it has proven pretty reliable, even after 20 years of being on the car. The car doesn't get driven all that much. If I ever blow the motor, I will probably go with a Euro motor, forged pistons, better rods and then run the boost up to about 14 psig. that should deliver well over 500 at the crank. It is nice to dream...

G Man

Very nice. It would sure be nice if someone were to offer a turbo setup in kit form for our 928's that a person could install themselves. I guess I'm just dreaming. Any way, I envy your setup. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

John.

A kit could be made, pretty easily. The manifolds on my car are nothing special and are bacically two large collector pipes with short stub pipes out the the engine. Whoever did the work was a very, very good welder.

If someone put their mind to it, it could be done. So, if I came up with a kit, how many people would by it and for how much?

Figure:

Turbos: $3000
Piping: $2000
Intercooler: $1000
Misc: $2000
Exhaust: $2000
Profits: $XXXX??

Sounds like about $10,000 or more in stuff....

Max

I say go with an aftermarket computer for the injection and timing, do away with the MAF or MAS, set it up as a blow through MPI (multi-port injection). This would make the set-up much easier and cleaner.

JM .02

John.

I have thought about removing the air flow meter and going to a mass air sensor or a MAP sensor then plugging back into the stock computer.

You are right, a stand alone has far more resolution than the stock system, since it was never really designed for positive manifold pressure.

I just finally got the car running really strong. As it turns out, I has about 20% too much fuel, because of the injectors Callaway had installed at the factory. I followed their lead on what they did on the newer Vettes, namely stock injectors.

It made a huge difference, opening up another 30 to 50 HP (my guess).

I would think a supercharger is the best way to go these days, just for cost alone. Doing a turbo conversion is very costly. I would like to see someone do a centrifugal blower system, that would be really trick.

PorKen

I've been looking at this programmable MAF converter, after I finish welding up my 3" Flowmaster exhaust system.

<a href="http://www.splitsec.com/products/psc1/PSC1009.htm" target="_blank">Link: Split Second MAF Conversion</a>