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Aitch
12-29-2020, 03:40 AM
I have an ls1 with a small camshaft 215 223 duration 581 lift 112 lobe separation. Mafless otr and cat back exhaust.
Just wondering the maximum spark advance at wide open throttle and should it decrease in high rpm

2xls1
12-29-2020, 10:18 AM
A good starting point would be 20 degrees at 2000 rpm gradually ramping up to 28 degrees at 4800 rpm and beyond. That is assuming it is a real LS1 with stock heads on minimum 91 octane fuel. Monitor KR and adjust up or down from there. But 28 degrees seems to be about all an LS1 needs. Even if you can run 29 or 30 degrees without knock they usually don't make any more power beyond 28 degrees. I've always seen them make more power with more timing and richer air fuel than less timing and leaner air fuel.

Aitch
12-29-2020, 10:19 PM
Thanks for the information, it seems to be a sensitive topic when it comes to spark advance, there's not too much information out there on maximum spark advance.
I forgot to mention I only run 98 octane fuel, not sure if that changes anything.

In-Tech
12-29-2020, 10:29 PM
Ignition advance is mainly contributed to combustion chamber. I will agree with 2xls1 that the majority of LS type engines only like a max of ~28 degrees regardless of octane. Combustion pressures may require less due to intake temp, superchargers and turbo changes a lot of this. Superchargers have the ability to "super cool" during overlap and turbo does not.