Diablosport Forums

I have a 2006 SRT8 with Zoomers, and K&N drop in with a 180 t-stat, otherwise it's stock.. I am running the 9r12 crom with the 91 OCT Tune and did a data log for the first time today. I am getting 2.5 to 5.5 ST Knock under heavy load for 1-2 seconds but little to no LT Knock, I sometimes see 1 to 2.5 LT but it's rare and very quick. My question is should I be concerned with the ST Knock and have it looked at by a cmr tuner or is it something I can tweak? The car runs great and feels strong, I just don't want to hurt the internals of my engine. This ST knock comes on at about 2200 rpm and peaks at around 4-4500 and drops after that. Any advise.. I heard the LT is the worse and can cause damage, But can the ST cause damage also?

You heard right. LT knock is worse. You can add some fuel in the rpm range where your getting the ST knock and maybe bring it down some. All the Hemi engines have some ST knock. I would start with adding 5% and go up from there. Remember that when your adding fuel go to the left of center to add and to the right to take away. This may help answer some of your questions too. http://www.case-enterprises.com/xeryder ... edator.htm

It's the gas, buy better gas. Any LT knock is bad, eliminate it or your car's performance will suffer. The computer is pulling timing all of the time if you have LT knock.

From what I understand you never want to add fuel to try to null out knock...Pulling timing (Retarding) is what needs to be done to eliminate ST KNK. When I added fuel to cover up knock when I was just starting out using the DSP, i went from 2 counts of knock to 6 counts by adding 5 fuel. pulling timing is what made it go away.

adding fuel should help, if it doesn't, it is not fuel related, but its a good place to start. reducing timing will reduce performance more than adding fuel will

And if adding fuel makes it worse, your gas is bad. Try something else.

Heres a noob question, AFR and Timing go hand and hand right? Ive read that 12.5 AFR is the where you want to be with in Hemi's, but when you adjust the AFR then logg and get some ST Knock, do you pull timing to eliminate the knock? Considering you want to keep the 12.5 AFR.


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2005 300C
K&N Typhoon CAI
Catch Can
93 Oct Perfomance Tune

1SYCRYD,

oil in the intake manifold can cause knock. could need to install a catch can, and clean the intake.

flo90 wrote:Heres a noob question, AFR and Timing go hand and hand right? Ive read that 12.5 AFR is the where you want to be with in Hemi's, but when you adjust the AFR then logg and get some ST Knock, do you pull timing to eliminate the knock? Considering you want to keep the 12.5 AFR.


_________________
2005 300C
K&N Typhoon CAI
Catch Can
93 Oct Perfomance Tune

yes, if WOT a/f is where you want it, pull timing to get rid of knock.

there are many different opinions on best WOT a/f for Hemi's.

I've heard 12.0 up to 12.6, even as high as 12.8

usually try to set WOT a/f for 12.3:1 in my tunes.