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Discussion Starter #1
Err dunno where to post this topic but i think i should start at turbo forum

As everyone know GTiR is 8.3.1 compression ratio
how to raise it up the compression to 11 or 12 ?
intend to run NA on the GTiR block
:)
 

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Coropate greed hater
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Shaving the head would also do raise the c/r.
 

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Discussion Starter #4
but what piston ?
i dont know how to calclulate it
even stock add 1.2mm metal gasket i no idea what is the new compression
 

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sleeper
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he's in malaysia, might be a pricey phone call :) I'm sure you can search for it somewhere.
 

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SE-R GREEK
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cmng said:
but what piston ?
i dont know how to calclulate it
even stock add 1.2mm metal gasket i no idea what is the new compression
300ZX normally aspirated.
You will need to trim a bit from the bottom of he piston skirt (like 1mm) but it will get you 11:1 compression.

If they arew available there post here for more info on what is needed.

Chris
 

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Discussion Starter #9
300zx NA piston
cut down 1 mm.

11.1 .
is that good compression for NA based GTiR block ?
 

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It will not be 11:1 in a GTIR. The GTIR has a different cylinder head CC, therefor it will be less than 11:1. I dont know what Z32's will make it. somewhere between 10.5 and 10.8:1 id guess.
 

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Witness The Power Of AWD!
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Remember that the GTi-R combustion chamber holds more volume than the other DE's, DET's. Because of this regular caluclations will be about 0.2 points off. For instance the 300zx pistons will only give a 10.8:1 CR (from my calculations)

With the 1.2mm head gasket your compression ratio should be 8.4:1 CR. If you get a Tomei 1mm head gasket and the 300zx pistons that should net you an 11.1:1 CR. You could always get some

Wiseco makes some 11:1 CR pistons for the DE. This would yeild a 10.9:1 CR in the GTi-R motor. With the Tomei 1mm head gasket you would get 11.2:1

Not worth it for that extra 0.1 points but the option is out there to use forged DE pistons, they will need to be machined to clear the oil squirters.
 
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