Detonation and SCT Tune???

[instangator]

I bought an SCT custom chip from JMS Chip that is set up to work with the mods listed in my sig. They bumped the timing 2 degrees and leaned out the A/F 3% and WOT. After I installed it I noticed some detonation in 3rd and 4th gear under hard accelerating. After filling up with fresh 93 octane and Octane booster, I ran the car again. This time the detonation was worse(80 degree weather) so I removed the chip and the detonation was gone. I called JMS and they told me that the tune may have been a little aggressive and to send it back for them to pull a 1.5 degrees of timing. With the chip removed, I filled up with 87 octane and the detonation is back but not nearly as bad. So, does this mean my car is running lean because of my mods, and since the chip leaned it out even more the detonation was worse? I am wondering because if they just pull timing but leave the car lean I don't think the detonation will go away. Thanks for any advice.

 

[LizardKing 2002]

I have to ask...

My car has virtrually all the same mods as yours. Except for the 75 T/B & plenum.

What do you run? Or hope to run? And what do you think you have for WHP.

 

[twogts4us]

Sounds like 90% of your detonation was caused by the tune of the SCT Chip. Hopefully, when they dial it back it will cease. My wife and run 91 octane or better, preferrably 93 octane, and neither of us has any detonation problem. I have the Superchip SCT as well on my 02, but yet to be dyno-tuned with the newer parts - MAF, TB, plenum. But no detonation before or after I installed these mods.

 

[instangator]

I haven't run it yet, but I am hoping for 13.0-13.2 on drag radials. As for WHP I would say 260+ but that may be a little optimistic.

I am sure that the detonation was caused by the SCT chip, but I am wondering why it is still detonating without the chip.