Originally Posted by
ccpl
:confused:
Fuel has nothing to do with keeping the turbo cool in any late model fuel injected car. Turbo's are cooled either via engine oil, or via coolant and engine oil combined (seperate lines of course). Fuel never even gets near the turbo of any "blow through" (turbo compresses air before the throttle body) turbo setup (which is pretty much 100% of cars these days)
The only turbo's that were ever inadvertently cooled by fuel would have been the old draw through (turbo compresses air after the throttle body) carby setups - even then, the majority of the cooling was still provided by oil/coolant.
What you may have been referring to is keeping the fuel mixture rich in the combustion chamber, as to decrease combustion chamber temperatures. Evo's/STi's tend to run very rich at top end on stock tunes to ensure that they dont lean out and melting things.