What's the diff. btw 951 pistons, and 944
07-05-2005, 08:25 PM
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What's the diff. btw 951 pistons, and 944
as a quick topic. What's the diff between the 2.5 turbo pistons and the 2.5 na pistons? strictly OE. TIA
07-05-2005, 09:06 PM
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Sorry for bein' a smartass. . . Couldn't resist.
N/A pistons are cast, except for '83's I believe which are forged. 951 pistons are forged.
N/A pistons have compression ratios ranging from 10.2:1 to 10.9:1 depending on spec/year. There might even be a couple others. 951 pistons are set up for 8.0:1 compression.
Oh yea, the 951 ones are more expensive. . .
N/A pistons are cast, except for '83's I believe which are forged. 951 pistons are forged.
N/A pistons have compression ratios ranging from 10.2:1 to 10.9:1 depending on spec/year. There might even be a couple others. 951 pistons are set up for 8.0:1 compression.
Oh yea, the 951 ones are more expensive. . .
07-05-2005, 09:25 PM
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The picture is not the best(not mine) but this is a 944S piston, the valve cutouts would be different for a regular 944. (do they have cutouts?)
This is a 944 turbo piston, which as you can see has a large depression, don't know if it's stock or not.
As for metallurgey, coatings, and other stuff, ask others.
This is a 944 turbo piston, which as you can see has a large depression, don't know if it's stock or not.
As for metallurgey, coatings, and other stuff, ask others.
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07-05-2005, 09:26 PM
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If you search the archives you will find good info, however I believe all 944 pistons are forged... the cast vs. forged argument comes in with the rods...
Above looks like a stock 951 piston to me ...
Above looks like a stock 951 piston to me ...
07-05-2005, 11:49 PM
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The NA pistons have 2 small valve reliefs cut into them, and have a round dish that covers about 1/3 - 1/2 of the piston crown area, that is also shallower than the dish on the turbo pistons. The 8V pistons were available in a 9.6:1CR and IIRC a 10.2:1, but it could have been 10.9:1. Then the 16V pistons were either 10.9:1 or 11.0:1 or something like that, not exactly sure on the compression ratio's.
Weight-wise, they're pretty similar to the turbo pistons, not much difference that I can tell (with one in each hand). If you're buying factory replacement pistons, the NA pistons are definately cheaper, as has already been mentioned.
What kind of details are you looking for?
ROW NA pistons have virtually no dish on them, with only the valve reliefs...
Weight-wise, they're pretty similar to the turbo pistons, not much difference that I can tell (with one in each hand). If you're buying factory replacement pistons, the NA pistons are definately cheaper, as has already been mentioned.
What kind of details are you looking for?
ROW NA pistons have virtually no dish on them, with only the valve reliefs...
07-06-2005, 12:52 AM
#14
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Originally Posted by Matt Sheppard
Ah, leave it to Michelle to display her 951 parts on a Gustav Stickley dresser(?). You gotta love that ceramic-coating on quarter-sawn oak!
BTW - It's a buffet. We have two of them (buffets, not Stickleys) so we use this one as a library table in the living room.
. all i know is that they are different compression