tribaltib

As a rule of thump we should retard timing in boost on pump gas in a ratio of 1 degree per pound of boost.

So 10 psi boost would mean retard timing 10 degrees to be on the safe side far from detonation.

Of course all engines are different and and there are many variables.



But how much timing retard on higher octane fuels? Or E85 for that matter?



Is there some kind of calculator ?

SR Tech

Psi is irreverent without knowing turbo size, airflow is the denominator that will determine the timing needed to prevent detonation.



Any FI motor needs to run atleast 91, 93 or higher is preferred, Whats going to gain you the extra power you want under boost is advancing the timing while keeping it away from detonation. On pump gas 93 I was running about 14*-15* towards the top end, on E85 I'm at about 18* and could go more. I want to do a 110 race gas tune soon and see what I can get away with.



If you want to introduce meth into the CC with 93 pump gas you can achieve the timing numbers that you would with e85.



There is no real caculator, as you stated every motors different and every turbo flows differently. The only way to dial it in is to do some logs and adjust accordingly, keeping an eye on the knock sensor



More timing for an aggressive tune, less for conservative



Edit***Just realized that I'm talking about my stock turbo DI motor and referring to its stock timing.



The beta will be much different as the timing is already running advanced and will need to be pulled a bit to run boost safely.



Bottom line though for the most power, you want the timing advanced as far as the octane rating/CC temps will allow