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Porsche 928 Turbo V8 Swap

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I don't think I've ever seen this done before, so here goes....




I work at an amazing engineering company with a bunch of car guys who are particularly found of Porsche. We have had three Porsche 928 cars and lots of engines. Recently I was given one from a 1982 928. Its an all aluminum 4.5l V8. The block is massively stout, and the thing is generally built quite well. They used another 928 block for their 1100hp project car...


The plan is to turbocharge it with a Turbonetics T04b. The transmission will be a little bit of a challenge. Porsche originally used a torque tube type setup. I'll be adapting a Z32 transmission with a custom bellhousing plate and modified flywheel. Custom rear sump oilpan, motor mounts, and other little pieces will be needed as well.


The first step was removing it from the donor car.


















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Glad to see the interest in it. I was a little bit skeptical at first about the idea, but now I've decided it can happen.


Frank, we work on it almost every weekend. Whether its pulling an engine, mocking up parts, or machining, you're welcome to join in anytime :wink:


Here are the existing exhaust manifolds. I plan on bringing them together in a Y pipe that will collect into the turbo flange.


I've started modeling the engine bay and block to get an idea of how much room I have to play with. The initial fit is good, although turbo placement is a little tricky.









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Do you know the weight on the Porsche engine? It's been a long time since I worked as a Porsche mechanic, but I seem to recall those suckers are HEAVY, despite the fact that they're aluminum. I'd also be a bit worried about the Z32 trans holding up. Given any thought to a T56?

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You're right, they are slightly heavy. The total weight is 550lbs. However almost 100lbs of that is belt driven pumps on the front end. I'm eliminating the AC compressor, air pump, and power steering pump. With other changes, I can get the weight to a reasonable level. The horsepower goal is 500 to the wheels, which is something the Z32 tranny should hold up to.

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I personally have seen the N/A z32 tranny hold up to 530bhp Im not ure if your using the tt trans or not but regardless they can take a beating.. as well if you are willing to spend the money the newer z32 jdm transmission i think around '99 have harded steel in them not the softer metal parts.. which in return obviously will last longer

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  • 2 weeks later...

I've started to model the problem of the transmission.


From left to right approximately.


Red is the engine block. Blue is the crankshaft. Yellow is the transmission adapter plate. Pink is the crank adapter plate. Green is the flywheel adapter plate. Beige is the flywheel. Orange is the clutch. Teal is the pressure plate. The grey shaft is the input shaft to the tranny.


Some of the pieces have been simplified for mockup's sake. I've been modeling for about 12 hours this weekend. Its nice to be working inside on the computer instead of out in the heat.


The reason I'm having to make this complicated adapter setup is because I'm wanting to use an existing 300zx flywheel/clutch with the porschecrankshaft, and obviously the two have quite different bolt patterns. If it becomes too much work, I may just cnc a custom billet flywheel.







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