ive been street tuning my turbo'd ls1 trans am with HP Tuners for about 6 months now upping the boost and playing with timing and havenít had any knock issues running 15 psi from a 67/66 t4 precision turbo on 93 octane.
last week i went with my buddy to get his Honda dyno tuned it is running a built gsr block and head with a gt35r tubro from reading about similar builds online we were expecting to see 550 or so to the wheels on 93 octane pump gas
after a few pulls the tuner came and said itís done we look at the numbers and were disappointed with 415 hp to the wheels.
i began to pick his brain asking why he stopped there and what the limitation was. (Iím no tuning expert by any means but Iíve done a bit of research as well as looked at similar builds and seen what they made on pump gas)
he said the limiting factor was 93 octane injectors were only running at 52% duty cycle (id1000's) and the turbo only running at 16 psi.
he wouldnít really explain it any further he seemed to be secretive about his whole tuning process
my question is what makes 93 octane the limiting factor at that point i know octane numbers represent the resistance to detonation.
but canít you just run a much richer mixture to keep detonation from occurring?
for instance if you experience knock at 12.5:1 in a certain cell wouldnít running richer say 11.8:1 in the same cell under the same conditions reduce or eliminate the knock? sure its not near as efficient but should still make more power allowing the tune to be pushed further on the same fuel?
i know pulling timing is another option but i'm more curious as to why a richer mixture wouldnt fix the problem instead
any info would be greatly appreciated as im still trying to learn as much about tuning as possible.