​How can I see how much Knock Retard I have? 

  • Datalog, Datalog, Datalog and Review it on your PC-------use these PIDS

The Trinity, Predator or scanguage will display KR as you drive, but it's not a very accurate way to tune. You will get a MUCH better view of the Knock profile from looking at the log file by exporting it and viewing it in the DS Dataviewer. 

I was viewing Knock on my Trinity and it looked like it extended from 3k-5k. But after I looked at it in the Dataviewer I could see that I had ONE initial spike at 4300 and the PCM was just slowly tapering it off to 0. The ONLY reason that  Knock Spike occurred was because the Boost briefly shot over the stock MAP limit

I would have pulled too much timing(i added 2 degrees from 4k-5k) if I had just looked at the display. Here's what I mean:

Ok, I have Knock what do I do about it? 

First off, for the Diablo tunes: <1.5 degrees of KR, every once in a while is perfectly acceptable. 

  • NOTE: For a 100% STOCK tune 2-3 degrees is ok. The difference is that Diablo tunes use less sensitive knock settings.

If, for the majority of the time, Kr is less than that, I would not remove any timing. So if you're not getting ANY LT knock and your ST knock is less than 2.0 you should NOT remove any timing. 

If the A/F is ABOVE 12.0(stock turbo) in the same RPM range that is experiencing knock, Lower the A/F BELOW 12.0 and retest.

If you still choose to remove timing use these guidelines:

  • If you're getting 4 KR but Only from 4k-5k don't go overboard and remove timing from 1k-6k.You should remove 1 degree from 3k-4K and 1 degree from 4K-5K.
    • 90% of the time that will reduce KR to under 2.0 for the majority of pulls. If ST KR is still above 2.0 pull 1 more degree from 4k-5k; do not pull any from 3k-4k and retest.
  • Rule of thumb is to keep the amount of timing you pull to 1/2 the amount of KR.

Rarely should you ever have to pull timing 1:1 with KR. If your getting 6degrees of ST KR, the 3 degrees of timing is the most you should need to pull. BUT always start with 1 degree first and work up to it the max.


You may see that around 5k-5400rpm, dodges will show some knock. This isn't uncommon and often just from the harmonics of the engine. This might be due to the Bosch Knock Sensor (they're tuned to Chrysler's specs.)

What is ST and LT Knock? 
Both KNK LT RETARD(Long term Knock retard) and KNK ST RETARD(Short Term Knock retard) show the amount of timing pulled because of Knock in degrees(you can see the units are "deg"=degrees.) ST Knock is the real time instantaneous knock. If your timing was supposed to be 25 but you have 4 ST knock, your timing will display as 21. 

  • If you're are getting ST knock constantly and a particular RPM/MAP the PCM will start to pull LT knock to try to keep ST at 0.
  • So using the same example: if your timing was supposed to be 25 but you have 4 ST knock AND 4 LT knock your final timing will only be 17(25-4-4=17)
Injectors & Tuning Work

more torque than you'll ever need. 

knock tuning