I recently installed a Cobb Acessport with the stage 2 map. Other mods are in my signature.

With the AP I can monitor engine knock sum, timing, etc. But, what numbers should I be looking for with knock sum and timing? I want to make sure I'm running good, but I have heard different range of numbers. And what would happen if the knock sum is greater than the normal values?

Also, if someone could give me a better definition of knock and timing I would appreciate it. I'm somewhat new to tuning.

Thanks in advance!!

 

Knock is detonation, Timing is when energy is sent to the spark aka ignition. Detonation is premature ignition or ignition from source other than the plug.

This is how I understand it. I am no engineer. It is worth a wiki.

 

For Evo 8s <= 3 counts of knock is ok, ideally you want as much timing as possible without knock, but that's theory. In practice, with your logs, determine where the knock is happenening (what rpm range and timing and AFR values etc) and either decrease timing, encrease fuel mix (lower AFR) or both.

Knock can be attributed to many factors (ones listed above) and grade of fuel ... you can try keeping your current timing and AFR values and run higher octane fuel to reduce knock.

 

ok thanks. I was told <=3 but also heard 7-8 is ok. I have hit up to 10 sometimes, but i will have to take notice of where those spikes occur.

 

3 is normal anything over three with WOT is not good....

 

More than 3 on the knock counter is a no no as far as timing you need a dyno to properly adjust just because you have no knock when advancing doesnt mean it is making more power -you could be just creating more heat and stress with no gains

hope this helps

 

Good point.. Hmmm..

 

3 counts of knock is equal to one real knock because the EVO knock sensor is so sensitive.

 

So how many knocks is needed for the ecu to trigger a knock retard? they go by number of knocks or the intensity of the engine noise detected?

 

I have read by an old Evom Member who left the EVO scene a while back, that the Cobb AP can read up to 5 knock sum and it seems to be OK. I also have read others saying even up to 6/7 is OK therefore what evolvd276 said could be true; that our knock sensor is extremely sensitive. I have seen up to 3 and 4 knocks through my AP.

 

3 is the max you want