78mm crank in S2 engine what’s new compression ratio

Talk and Tech about turbocharged 924/944/968 cars
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Yup, I have a running ‘87 951.


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People have skimmed the S2 pistons, and it can work that way. I know someone that used a standard 968 bottom end, and forged Porsche rods, and that worked too. You would be limiting the amount of boost you could run though.


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944m3 wrote: Thu Sep 14, 2023 5:42 am That’s what I’m working out in my head, what can I afford to do right. That being said, I do take inspiration from Peep and others I’ve read posts from. You can do a lot with just stock parts. Won’t win Le Mans but will work just fine for your grocery run and occasional track day.

At the end of the day, it’s just a hobby though, so I’m willing to make a mistake or two.

The other thought that has crossed my mind was selling the S2 engine and just going with a 944S 16v head that bolts on to a 2.5 block. (Yes I know I will still need custom intake and crossover). I can keep the internals I have now, just flycut the pistons for valve clearance, maybe upgrade rods with lighter Molnar rods.

If anyone has one laying around, let me know. I might be interested.
I'd be careful with the 2.5L 16V heads, the early ones had a casting fault and were prone to cracking from what I've read.


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