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[stevekat]

I got around to taking some photos of the pistons I've kept from my original 1981 931 many years ago. It originally melted down on the track and got the nickname 'Chernobyl.' It was due to a failed waste gate diaphragm, and I was unfamiliar enough with turbos to not have added a boost gauge.

One piston is the original factory piston, the other a TRW forged that was the first replacment that did not last long, before I went back to a factory set up - then adding what I think were GTR pistons that I had obtained from Holberts when they were shutting down race operations.

I am very pro spherical combustion areas after the TRW piston experience.


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"Never get out of the boat. Absolutely goddamn right. Unless you are goin' all the way."

Gone to new home: '81 924T, US version, CGT Intercooler, UTCIS-PT, Euro DITC, Greddy Trust MBC, Forged Fuchs Flat Dish 6's, Factory Recaro's.

[flosho]

I bet it really felt fast for a few seconds...
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[This Space For Rent]

[Dutch924-racer]

[RC]

Might be more to it than simply a concave piston Steve.

What was the CR in both cases?

Which cylinder (was worse)? #3 or 4 probably?

Would the top ring land height be similar between them both, before the melt down?

Looks like a much higher compression height on the OE piston, or just a deceptive image?

Tis much cheaper to learn from others mistakes. If it`s any consolation though you usually can get twice as much for forged pistons at the scrap metal yard than the cast ones that have integral steel reinforcing/ thermal straps.
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World`s quickest 924 2L slushbox

[morghen]

wow..that looks MUCH worse than the pistons from the 931 engine i just bought.
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