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911TT33 911TT33 is offline
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Join Date: Mar 2011
Posts: 471
When you tune for max power, 12.5 is typically the AFR to aim for I believe.

Bosch state that most spark ignition engines develop their maximum power at air/fuel ratios of 12.5:1 - 14:1, maximum fuel economy at 16.2:1 - 17.6:1, and good load transitions from about 11:1 - 12.5:1. However, in practical applications, engine air/fuel ratios at maximum power are often richer than the quoted 12.5:1, especially in forced induction engines where the excess fuel is used to cool combustion and so prevent detonation.

Given you are running a blower on a non decompressed motor, I'd stay between 11 - 12.5 AFR. you also have the advantage of twin plugs, which helps too

Please correct me if I'm wrong anyone

Edit: are you running an intercooler?! If not, I'd highly recommend it! If your motor is a 964, you have heaps of meat on the crown to machine down to a more boost friendly CR, and then you can run more boost

Last edited by 911TT33; 11-19-2011 at 07:09 PM..
Old 11-19-2011, 06:57 PM
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