Why am I getting detonation?? HELP!
03-17-2006, 12:50 AM
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Why am I getting detonation?? HELP! Ok guys, help me figure this one out..
I'm tuning a car for a friend..
01 Vette M6
395 stroker
LSX 90 mm intake, TPIS 90 mm TB
240/244ish duration cam
SVO 30 lb injectors (set at 58 psi via the "spreadsheet")
etc..
I've gotten the VE corrected and i'm dialing in the MAF (both using % error with a WB)..
The timing was set at 24 degrees and the AFR at WOT was at 12.5 (the actual was between 12.5 and 13.0 since I haven't finished the MAF calc, but its getting very close)
Here is the thing, with the old tune (it was tuned before) it was seeing 30 degrees of timing and AFR in the low to mid 12's.. but the tune was jacked up and the fueling was all wrong (VE, MAF, IFR..etc)
BUT.. there wasn't any auditible detonation and the owner said it never detonated.. so i'm wondering.. could the right tune reveal the fact that the car needs a little more than pump gas (91 octane out here)? BTW, I believe the compression is right at 11.5 to 1.
I turned it down more to 20 degrees WOT and 12.2 AFR and drove it alittle and didn't hear anything but got KR, but I didn't push it much. Whats the deal?
PS, one more thing.. what timing tables can ADD spark?? (it wasn't smoothing, I know that one for sure) I was commanding 24 and seeing 27, then KR would kick in and/or I would hear a little ping and immediately let out, then I command 20 and would see around 20 but with between 2-6 degrees of knock, so obviously it wasn't commanding 20. It did this with the previous tune as well.
The only thing I can think of right now is to add some good gas (100 octane or so) but I was wondering if there is anything i'm missing!
I have all the logs and files for anyone that would like to take a look..just post an email addy.. I have EFIlive flashscan.
Any help would be great, this thing has my nerves shot!
Chris
I'm tuning a car for a friend..
01 Vette M6
395 stroker
LSX 90 mm intake, TPIS 90 mm TB
240/244ish duration cam
SVO 30 lb injectors (set at 58 psi via the "spreadsheet")
etc..
I've gotten the VE corrected and i'm dialing in the MAF (both using % error with a WB)..
The timing was set at 24 degrees and the AFR at WOT was at 12.5 (the actual was between 12.5 and 13.0 since I haven't finished the MAF calc, but its getting very close)
Here is the thing, with the old tune (it was tuned before) it was seeing 30 degrees of timing and AFR in the low to mid 12's.. but the tune was jacked up and the fueling was all wrong (VE, MAF, IFR..etc)
BUT.. there wasn't any auditible detonation and the owner said it never detonated.. so i'm wondering.. could the right tune reveal the fact that the car needs a little more than pump gas (91 octane out here)? BTW, I believe the compression is right at 11.5 to 1.
I turned it down more to 20 degrees WOT and 12.2 AFR and drove it alittle and didn't hear anything but got KR, but I didn't push it much. Whats the deal?
PS, one more thing.. what timing tables can ADD spark?? (it wasn't smoothing, I know that one for sure) I was commanding 24 and seeing 27, then KR would kick in and/or I would hear a little ping and immediately let out, then I command 20 and would see around 20 but with between 2-6 degrees of knock, so obviously it wasn't commanding 20. It did this with the previous tune as well.
The only thing I can think of right now is to add some good gas (100 octane or so) but I was wondering if there is anything i'm missing!
I have all the logs and files for anyone that would like to take a look..just post an email addy.. I have EFIlive flashscan.
Any help would be great, this thing has my nerves shot!
Chris
