Question about air/fuel

t-ray · 06-15-2009, 03:50 PM

First, in naturally aspirated form, the car runs too rich. There's a bit more power left on the table just by leaning the car out a bit. I've seen HR's run afr's in the 11's in the heat of the summer, bone stock. I know my wife's car does that(07 g35 with the hr). The factory ecu probably does that to manage heat - fuel cools the combustion chamber.

And because fuel keeps internal temps down, it can help prevent premature detonation. And that's the biggest fear when running forced induction - compressed air is much hotter than air at ambient pressure. If the combustion chamber becomes too hot, the air/fuel mixture in the chamber can combust prematurely - which can cause all kinds of nasty things.

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06-15-2009, 03:50 PM	#2 (permalink)
t-ray Base Member Join Date: Apr 2009 Location: bham al Posts: 91 Drives: 05 g sedan 6mt Rep Power: 17	First, in naturally aspirated form, the car runs too rich. There's a bit more power left on the table just by leaning the car out a bit. I've seen HR's run afr's in the 11's in the heat of the summer, bone stock. I know my wife's car does that(07 g35 with the hr). The factory ecu probably does that to manage heat - fuel cools the combustion chamber. And because fuel keeps internal temps down, it can help prevent premature detonation. And that's the biggest fear when running forced induction - compressed air is much hotter than air at ambient pressure. If the combustion chamber becomes too hot, the air/fuel mixture in the chamber can combust prematurely - which can cause all kinds of nasty things.