F
Fred 86 GN
Guest
My GN is running well, but it keeps getting some knock retard and a knock count at WOT. It never goes above 3 degrees of KR, and most of the time is less than 2 degrees. I would like to tune for zero knock.
Here is an example of when the knock retard occurs:
boost pressure = 17psi
4000rpm
820mv from oxygen sensor
27ms of injector pulsewidth
LV8 = 255
MAF = 225
fuel pressure static with vacuum removed = 42psi
running a mix of octane in the tank -- 10gal 93 and 5gal 110
chip base timing at WOT = 23.6 degrees
The KR is not occurring at a shift. It really does not seem to be triggered by anything shown on DirectScan. The DirectScan A/F ratio is less than 10:1 when the knock retard occurs.
Engine has a RJC power plate installed, 009 injectors, TE-44, CASV4, 3-angle valve job and relief above the valves in the stock heads. The power plate has reduced the KR some. :smile:
I don't think the engine can use 90-95% of the fuel capacity of the 009 injectors at 17psi. That would be over 450hp, and based on a 107-109mph trap speed I believe the engine is more like around 380hp in the present tune.
So if it is rich, can that cause KR?
Thanks,
Here is an example of when the knock retard occurs:
boost pressure = 17psi
4000rpm
820mv from oxygen sensor
27ms of injector pulsewidth
LV8 = 255
MAF = 225
fuel pressure static with vacuum removed = 42psi
running a mix of octane in the tank -- 10gal 93 and 5gal 110
chip base timing at WOT = 23.6 degrees
The KR is not occurring at a shift. It really does not seem to be triggered by anything shown on DirectScan. The DirectScan A/F ratio is less than 10:1 when the knock retard occurs.
Engine has a RJC power plate installed, 009 injectors, TE-44, CASV4, 3-angle valve job and relief above the valves in the stock heads. The power plate has reduced the KR some. :smile:
I don't think the engine can use 90-95% of the fuel capacity of the 009 injectors at 17psi. That would be over 450hp, and based on a 107-109mph trap speed I believe the engine is more like around 380hp in the present tune.
So if it is rich, can that cause KR?
Thanks,