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I'm building a D15Z1 (Vtec-economy) for a commuter car, and want to bump up the compression a bit to get better gas mileage...I plan to shave the head to achieve this (cheaper method).

What's a safe compression ratio to aim for and still stay w/ 87 octane gas? (*as you raise the compression ratio, you have to start worrying about detonation)

*I've searched all around for answers...since this question is particular to this engine, I'm hoping someone here has done it before.

thanks!!!

 
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people who use these engine D15/16 pre 2001 have gone with 10.5-11:1 CR and still retained the use 87+ (pump gas)

 
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thanks for the info!