What do you guys typically see causing knock in the 4K rpm range. I had 20 counts of knock, and my tuner was having a hard time tuning the car. I have HKS intake, helix downpipe, test pipe, apex noir exhaust, helix 272 cams, injen intercooler piping, walbro fuel pump, and pte injectors.

The car also has 90k on it.

I made sure all my clamps were on good, and that the downpipe wasn't hitting anything. So give me some guesses.

 

91 octane cali bas is a bish - you need to have good tuning approach to tackle it 0- try a gallon or two of race gas in the tank and see if that corrects the problem

 

we were basically narrowing it down to a tank of bad gas, but didn't have conclusive results because we spent all day fiddling with the car trying to make power, and gave up because we had been at it for almost 6-7 hours. I was just wondering what other things I should look for, because I only made 253hp and 241lbs of torque on his mustang dyno. (Still have sock 03 turbo)

I want to go back all prepped and ready to go.

 

Try 76 brand 91 oct the next time you go in.