spark knock~detonation? is killing me.

[BDASPNY]

ok i'm not a mechanic so i'm clueless about somethings. i got the car tuned and it was doing it bad. he tuned it well its that it does it on the 87 oct tune it still does it. usually only when its in over drive and the ac is on. i have a built aod, so if i choose drive its no as bad but in over drive. even when i use 93 it does it. so can someone explain to me why, how or whatever. what can i do to resolve this issue???? i know the ethanol is part of it cuz that crap has ruined the gas. please help!!!!!!!!!!!!!!:cussing::help::nonono1::ponder:

[crumbie]

tuned as in someone dyno tuned it with a burned chip or something? or tuned by just turning the distributor and setting timing? either way, I think I'd go back to my "tuner" and tell him he sucks. LOL

[BDASPNY]

yeah i had it dynotuned w/ a fresh chip and all. i had spoke with him breifly he said to pull back the timing 2 degrees and try it. so thats the plan today. i was wondering if the compression is too high to run 87? i'm not sure the exact ratio. i have the mods in my sig. a dss 331 rotating assy with afr 185 heads. is there anything i could try?

[Stable]

It hard to tell, but I would back it down like he says...it could be on the edge of timing with the AIT (air temp)...
or if you feel up to it, make your own octane boost...
http://www.team.net/sol/tech/octane_b.html

[BDASPNY]

It hard to tell, but I would back it down like he says...it could be on the edge of timing with the AIT (air temp)...
or if you feel up to it, make your own octane boost...
http://www.team.net/sol/tech/octane_b.html

that was some interesting reading. something to think about.

[Badass1993]

With that kinda engine combo....you all but need to run 93 octane.......To run 87,you are gonna have to back off the timing some....I'd start with base timing 10 degrees,and wouldn't be surprised if it will take coming down to 8 degrees to make it run on 87 octane.

[Notch93]

With that kinda engine combo....you all but need to run 93 octane.......To run 87,you are gonna have to back off the timing some....I'd start with base timing 10 degrees,and wouldn't be surprised if it will take coming down to 8 degrees to make it run on 87 octane.

I agree with Chuck.:yes1:

[nastynotchback1]

I would think he tuned it with a base timing of 10.there is no way i would run less than 93 in a h/c/i motor and you have a 331 so i would for sure only run 93.

I WOULD THINK YOU WOULD BE SOMEWHERE AROUND 10.5-1 BUT WITH OUT YOUR CHAMBER CC'S AND WHAT PISTONS YOU HAVE I CAN'T TELL YOU THE COMP.

[BDASPNY]

With that kinda engine combo....you all but need to run 93 octane.......To run 87,you are gonna have to back off the timing some....I'd start with base timing 10 degrees,and wouldn't be surprised if it will take coming down to 8 degrees to make it run on 87 octane.


yeah i figured this was goifn to eb the case, but fgured could not hurt to try if it would run on 87. its my only car so i was just hoping mayne it could use it. so i'm stuck w/ 93 or better. i beleive it is set at 10 now gonna check tonight and try 8 see if it helps.