What knock means?
 

Im trying to learn how to read the knock numbers on my apexi commander but what do these numbers mean? I know knock is premature combustion but when my commander is saying 30 knock what does that mean?

It is nothing more than a noise indicator which can be knock or car noise.
If you knock values for low or no boost are high, then it is noise. Check suspension, engine compartment, and exhaust for loose, rubbing, etc. noisy parts.

Knock will normally be higher when first getting on boost do to drivetrain slack being tightened up. First couple of runs are normally noisier due to loose carbon fluff burning off and parts heating up. It is best to do some partial runs to heat up the turbo/s and exhaust and burn off the carbon fluff. Then do full tuning runs.

Oh okay so why do people say dont let your knock go over 60?

Cause under high boost and seeing knock over 50 or 60 and you're motor will be breaking soon

So that number just means how much noise is under your hood? I dont get it. How does that determine if your motors gonna blow?

It tells you mostly how much your engine is knocking inside, which is bad, so the higher the number the worse it is. Best think to do is do some datalogging to see when you get the knock and how much. For example I might see knock in the teens just revving the engine which is not true knock inside the engine, then I'll get some in the 20s or 30s before I hit full boost, same thing. But once you're full throttle full boost you want to see knock very low with some occasional little knock spikes is ok but I get worried if I get any more than 40. With lots of water injection the knock is very low at 1 a lot of the time.

Do some more research about the subject.

Read the notes on page 13 & 37

http://www.banzai-racing.com/store_i...werFC_FD3S.pdf