[Jverado]

So I've got a stock engine except for a ported throttle body and I'm getting about 3 degrees of knock retard on premium. Any ideas? Is This normal? Thanks

[laynlo15]

Sounds like you need some custom tuning. Ported TB shouldn't cause that, is yours an SS, Zl1?

[95 imp]

Originally Posted by Jverado

So I've got a stock engine except for a ported throttle body and I'm getting about 3 degrees of knock retard on premium. Any ideas? Is This normal? Thanks

You need higher octane fuel. Do you have 92 at the pump there?

[TJay74]

Originally Posted by Jverado

So I've got a stock engine except for a ported throttle body and I'm getting about 3 degrees of knock retard on premium. Any ideas? Is This normal? Thanks

What octane fuel are you running?

If you are running 91, yes it will be normal. Even if you are on 93, it could be very possible depending on how hot it was outside and what the intake air temps were going into the motor.

At the least, run at least 93 if you are going to track the car. If you have E85 you can add 3 gallons to a full tank of 91 or 93 and it will give you a nice octane boost and help with detonation.

[Jverado]

It's a SS. The best I can get here is 92 octane and the iat at launch was about 130 or so. It calmed down a bit and was pulling timing less often, bit still a degree or 2 especially around 5200-5400.

[95 imp]

You can try the E. I don't know how much you'll pull the octane up. It would be cheaper.

If you go to Home Depot or a paint store and get 1 gal of Xylene and throw it in the tank to every 9 gal of 92

You should be @ 94.5 octane. 2 gal will take you to 96.5. Doubt you'd need 2 gal though for 2-3*. If it clears it up with one, back it down until you get the knock again and you'll know exactly how much you need (1/2 gal, 3 qt).

I don't know which would net you more hp. I'm guessing option B. You lose a little cooling effect but gain btu content. Try both ways and see what it does to your top end #'s.

[6spdhyperblue]

You need like 60* iats to see if you have excessive kr on a stock tune.

[Jverado]

The da at the end of the night was around 1300. And my mph hovered right around 112. they have one night for test and tune open in October and hopefully that one won't get rained out. Is the xylene different than octane booster?

[6spdhyperblue]

How much timing is it running? 21*?

[TJay74]

How do you know timing was being pulled, what are you using to data log?

If the Intake Air Temps were around the 110°-130° range that may have been timing pulled from the IAT table. It starts pulling timing at 85° of intake air temp.

[95 imp]

Originally Posted by Jverado

Is the xylene different than octane booster?

It's one of the components they use to make gasoline. Used as a straight up fuel, it is 117 octane. They probably do use it in octane booster as well, but the small quantity in the bottle doesn't raise the octane high enough to do any good.

[Jverado]

I'm using HP tuners and logging runs. I do believe it was 21 or 22 *. I'm still getting used to it all and that was only my second night at the track.

[6spdhyperblue]

I think you’re good. Stock tune is Aggressive and designed to have kr

All in is 24* in cool weather and 93 octane.so 22 in the heat is fine

[TJay74]

Originally Posted by Jverado

I'm using HP tuners and logging runs. I do believe it was 21 or 22 *. I'm still getting used to it all and that was only my second night at the track.

There are about 5-6 timing channels you need to log in order to see what is pulling the timing.

final advance
PE advance
IAT advance
coolant advance
knock retard
torque management advance

Log those and then try it again, that will tell ya what is really pulling the timing.