Normal engine spark timing

[TheGrinch]

Can you not adjust the spark timing for normal driving, only WOT?

On a silverado, is says the 91 tune isn't available.

If I use the 93 tune, and run 89 octane gas, will the computer just adjust my timing when the knock sensors go off to where it should be for 89 (still better than stock 87?). If not, is there no way to adjust for optimum performance at 89 or 91 octane for normal driving (not WOT)? I may be a little confused on what adjusting WOT spark really adjusts. Thanks!

[mikel]

No, you need to run the 87 tune if you want to run cheap gas...

[06MonteSS]

correct... the timing adjustments in the unit are only for WOT... not part-throttle/normal driving...

the Diablo Tune for the trucks is made for 91/93 octane gas, and then you also have an 87 octane tune...

if you're only going to use 89 octane gas, then use the 87 octane tune... running the higher octane tune and having all kinds of KR to reduce the timing is definitely not the way to go haha...

or, pony up for better, higher octane gas and use the diablo tune for more performance than the 87 tune...

[TheGrinch]

Thanks. So 91 octane will work alright on the "93" octane tune? I like to shop at the places with real 100% gas, no eth, and I think 91 is as high as they have it there.

[06MonteSS]

yes, should be fine...

just do some WOT data logs and see if you get any knock retard with the 91 octane gas and the diablo tune.. if so, then you can pull out some timing/spark advance...

[TheGrinch]

Thank you!