u7135 2007 stock jeep srt8 getting knock on 93 tune. FIXED

2001z06 · Post by **2001z06** » Mon Sep 14, 2009 11:18 am

u7135 2007 stock jeep srt8 getting knock on 93 tune.

read alot of post regarding the srt8 getting knock even with a 91 tune, my question is why did the Diablo put such an agressive tune in?

I could not tell I had knock till I logged the run.

Post by **mikel** » Mon Sep 14, 2009 11:19 am

There really is nothing aggressive about our canned Jeep tunes, just ask any of the hardcore GCSRT8 guys....

2001z06 · Post by **2001z06** » Mon Sep 14, 2009 11:23 am

thanks for the reply,

based on your experience, how much timing should I pull to start with?

Post by **mikel** » Mon Sep 14, 2009 11:49 am

I would start by adding a bit of fuel....

09SuperBee · Post by **09SuperBee** » Tue Sep 15, 2009 1:55 am

Run a log, and add some fuel in the range it's needed, that's what we all have had to do. But it gets rid of the knock! Add a little, and run a log, add a little, and run another log, until you get rid of that knock completely. Once you get rid of that knock you will notice it runs better too.

2001z06 · Post by **2001z06** » Tue Sep 15, 2009 11:08 am

09SuperBee wrote:Run a log, and add some fuel in the range it's needed, that's what we all have had to do. But it gets rid of the knock! Add a little, and run a log, add a little, and run another log, until you get rid of that knock completely. Once you get rid of that knock you will notice it runs better too.

question:

I ran the 91 tune and got st knock of max 2 at 5000 rpm, when I ran the 93 tune I got st knock max 5 at 5000rpm.

which tune would you keep and modify? My thoughts are that the 91 tune should be easier to correct with a bit of fuel.

Cruisin1966 · Post by **Cruisin1966** » Tue Sep 15, 2009 11:47 am

Both can be corrected with adding fuel (or at worst, maybe removing a degree of timing). The question is, are you always able to find good 93 (or better) octane gas? The 93 tunes have more aggressive timing and really require good fuel.

How did each of the tunes feel to you? If either "felt" better then go with that one. Maybe posting up your logs might help us to make a suggestion.

2001z06 · Post by **2001z06** » Wed Sep 16, 2009 1:20 pm

Cruisin1966 wrote:Both can be corrected with adding fuel (or at worst, maybe removing a degree of timing). The question is, are you always able to find good 93 (or better) octane gas? The 93 tunes have more aggressive timing and really require good fuel.

How did each of the tunes feel to you? If either "felt" better then go with that one. Maybe posting up your logs might help us to make a suggestion.

I will post up a log shortly, quick run down on a 91tune.

added 1.5% fuel 4-4.8k
added 1.00% fuel 5-6k

st term knock down to 1 @ 4500rpm
st term knock down to .5 @ 5000rpm

heading in the right direction

rfoker · Post by **rfoker** » Wed Sep 16, 2009 4:29 pm

Got to make sure your not running 10% ethanol gas. if so, I would drop back to the 91oct tune and pour in 93octane gas. If you have ethanol this is what i do to my 5.7L Ram and it runs like a top. You'll certainly have more power in 91tune than you would with a KR'ing 93tune.

just my thoughts...

2001z06 · Post by **2001z06** » Wed Sep 16, 2009 4:41 pm

rfoker wrote:Got to make sure your not running 10% ethanol gas. if so, I would drop back to the 91oct tune and pour in 93octane gas. If you have ethanol this is what i do to my 5.7L Ram and it runs like a top. You'll certainly have more power in 91tune than you would with a KR'ing 93tune.

just my thoughts...

yep...in my head it made sense to drop down to a 91 tune and control the kock and it seems like its going to take just an increase of 2% of fuel to take care of that issue.

Post by **mikel** » Wed Sep 16, 2009 4:48 pm

rfoker wrote:Got to make sure your not running 10% ethanol gas. if so, I would drop back to the 91oct tune and pour in 93octane gas. If you have ethanol this is what i do to my 5.7L Ram and it runs like a top. You'll certainly have more power in 91tune than you would with a KR'ing 93tune.

just my thoughts...

FWIW, we are stuck with E10 here too...all of these tunes were developed on 93 octane E10...so I dont know that its fair to blame the fuel. It has more to do with chryslers overly sensitive knock sensors.

rfoker · Post by **rfoker** » Wed Sep 16, 2009 4:54 pm

^^^^ That's actually really good 2 know Mike. Another thing is that i thought Ethanol sours gas quicker??? Maybe i am incorrect but that's what I had assumed.

Regardless, I'll always run a 91tune with 93poured down it's throat...lol I didn't notice anything going from 91-93 and i get 2mpg better on the highway with the 91 tune vs 93tune.

DGatzby1 · Post by **DGatzby1** » Wed Sep 16, 2009 9:07 pm

rfoker wrote:^^^^ That's actually really good 2 know Mike. Another thing is that i thought Ethanol sours gas quicker???

A problem can occur if you leave ethanol around for a while. That is why you should never use it in small engines (lawn mowers). The alcohol evaporates quickly and water (moisture) will combine with the fuel in storage. As quick as we burn it in our cars, it should not be a problem. If you guys get enough ethanol (alcohol) in that fuel it will raise the octane! Imagine that?

2001z06 · Post by **2001z06** » Thu Sep 17, 2009 1:13 pm

thanks for all you help.

solution:

stock 2007 jeep srt8 fuel 93 octane

changed to a 91 tune

added 2% fuel at 4k range
added 1.5% fuel at 5k range

st knock zero!!!!

Post by **mikel** » Thu Sep 17, 2009 1:44 pm

good deal.

u7135 2007 stock jeep srt8 getting knock on 93 tune. FIXED

u7135 2007 stock jeep srt8 getting knock on 93 tune. FIXED

RE: u7135 2007 stock jeep srt8 getting knock on 93 tune.