knock?

how many knock is safe for engine?usually you use race gas to have less knock ,so i am trying to get most hp out of dr 650s with pump gas.

Well the ECU starts pulling timing at 7 counts, I believe. Ideally you want 0 counts of knock. The fewer the better, but you definantly don't want more than 7 or you'll start to lose power. If you can't nail your tune down to 0, I'd seriously aim to stay 3 or lower.

I know I've said this before, but I REALLY mean it. If you are going with a turbo upgrade, especially a larger td04 or td05 turbo, you really should read as much as you can. There is SOOO much great info on 3si on tuning. You are going to have to be dealing with injector sizing, timing control, fuel pressure, etc...tossing in race gas doesn't equal a good tune, and it's worthless without one.