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I'm curious how much timing people are getting away with on pump gas, no methanol, and with little or no knock? I'm seeing folks running as much as 19psi on pump, and I know that would kill my motor.

I'm pushing 19 degrees of timing at 14psi on 93 octane. Any more boost or timing and knock becomes a problem.

I have a T71, Greddy 4-row, VW intake charge pipe, 4" TB, 264 cams, and a custom intake. Consequently, flow from the turbo through the head is very efficient. Is CFM more influential than boost pressure or timing when flowing a lot of air?

Can others please chime in with their numbers and setup?


Depends on CR, timing and AFR. Reduce the aforementioned and you can increase the boost but the responsiveness of the engine suffers. There is no definate black/white line.

The partial way round it would be to run high AFR and timing up until the turbo starts to spool and then drop them back.
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