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hey guys. my names mark and i am from england. i drive a '98 civic coupe with the d16y7 engine.i have added a GReddy bolt on turbo kit with front mount intercooler and GReddy e-manage system, apart from that the engine is stock. I have got a d16y8 head to put onto the y7 block, would y8 low comp pistons be suitable to go into the y7 block or should i stick with ones intended for the y7? thanks, mark.
 

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The Y8 head is 2ccs smaller than the Y7. Compression height is also different, 1.181 for the Y7, and 1.154 for the Y8. A 9:1 piston for the Y7 has +2.2cc dome, while the 9:1 (same comp ratio) piston for the Y8 has a -11.9cc dish. Quite a difference. The greater dish on the Y8 piston, may reduce the CR too much when installed in the lower compression heigth of the Y7 block.

You need to spend some quality time with a CR Calculator, some piston and engine specs, and a few Red Bulls.

Let us know what you figure out!

Craig @ Tuner Toys

A quick test with the C-Speed CR Calulator yeilded CRs from 8.6 to 8.8, which is getting towards the low side.

You can check it out here - Comp Ratio Calc @ C-Speed
 
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