knock at WOT with 9.9A/F

[SIXBANGR]

24.5 lbs of boost, 5000 rpm, A/F way rich at 9.9,timing at 20. Have a FAST so can change everything. Razors alky. Knock could be at shift point? But why so rich?

 

[Bens87tr]

I've heard knock can be a result of being too rich as well. Try lowering the boost a tad and see where that gets you. Then creep your way up. Not to speak for Razor, but I'm sure he'd recommend pulling out a little fuel and toss in more alky. There's lots you can do with that fast system that us poor saps can't.

 

[Razor]

Ben is rite on. Any knock seen can be cured by adding alky volume into the motor. This means pulling additional fueling out of the VE table. And logging the runs you'll see exactly where RPM wise in what gear the knock is happening.

If the car is at 9.9:1 then it obviously need a bunch of fuel pulled out.

Datalog a run, when you play it back... as the dot goes into the spaghetti bowl look at the numbers there, the ones surrounding, and drop them till the AFR gets into the 11's.

A good safe AFR target is 11:0-11:3.

On my FAST I have my correction limits to -3 negative and 25 positive. Once you pull enough fuel that its starting to make positive corrections to your target AFR, at that point bump the numbers to minimize the correction.

My 126 run was on target 11:3, 25 PSI, 21 degree's timing.. My 123 run was at 10:8 cuase the boost started dropping off. Just keep experimenting to what your car likes best. I've still got to try going 12:0.. just have to keep playing with the tune.

Hope the above info helps.