How much knock does everyone get on their power FC knock reading? Just today, I drove my car and took it full throttle in 4th gear up to about 7000rpm's and the thing read my knock to be 147!!! This has never ever happened to me before, as i always drive my car hard and the most it's ever seen before was only mid 70's at most. Can anyone help explain this? no changes were made to the car and my intake temperatures where only 28 degrees at the time. 147 just seems dangerously high...

 

mine does the same thing. i hit 164 the first day and it has gone down steadily and slowly the past few days. there is no dsound of detonation that i can hear. i am around 65-75 now. let me know if yours goes down.

 

The sensor is a microphone. It does go bad. It also picks up gear changes. It is true that everyone's sensor can read differently and the changes in behavior is what is getting your attention. Keep the boost in check, get some good gas, watch and datalogit (if you have one). A little application of the scientific method helps.

 

Some cars like mine have very noisy drivetrains. Either the trans or diff have too much play in the gears. This has been verified on my car using the datalogit. Noise below 20 while doing a run of 12 or 14psi boost. But letting off the fuel on the top end or shifting to a higher gear causes readings (especially in cold weather) to sometimes go above 100. An is erratic at that.

 

could also be seal chattering, seen it before...also how much oil inj. do you have/ might not be enough... or it could be as simple as some bad gas ...

 

so what's a safe level of knock? I used to see high 70 max...now i'm starting to hit over 100 on a daily basis when i rev the car hard

 

It's relative. If you run 10's normally, and we're talking about a knock number somewhere other than at peak torque, you my have a problem. You need to know where your peak torque is, a general idea what your car is tuned for in AFR, air density or at least temperature, and boost being applied along with INJ duty cycle.

So, you're at 100knock, 10C IAT , 8000RPM, 14PSI, running 12 AFR and 90% INJ Duty, that is still related to what you run at 7000rpm, 4000rpm. Graphing it helps to see irregular transitions. Here is what I consider normal for me:

 

When you see a spike to 100 then down to say 20 then right back up to 100, yhou might have a problem!

 

I have never seen consistent knock above 30, it has usually been occasional spikes from spoolup to just past peak torque. I have assumed this means I had a ping or two, never thought about seal chatter or some other cause. I don't get too carried away with ignition retard unless there is a consistent knock in an area of the map after multiple data logs. Usually don't consider adding fuel since tuning with wideband to a conservative AFR.

Getting more comfortable running with the occasional peak knock value in the 20/30's, guess I'm a bit more conservative than some others on this forum and happen to have a quiet motor/drivetrain. Never get high knock while shifting, always under throttle.

 

thanks guys...