I,m hearing audible knock when i last ran @track & this was with 94 octane fuel.My lt1 scanmaster shows timing as high as 45.I have the MSD opti and need to reduce timing.How much timing do you guys remove&how is it done?Btw the best mph that day was 99.1 where last yr.the best was 102.95&never under 101 so that knock really sucks.

 

I just put in a new fuel filter and NGK Iridium spark plugs(one range colder)and tested my 94 on buddies TAZZO(similiar to Gtech)and got 102.5 trap speed but the audible knock was still there even with colder plugs thus confirming too much timing!

 

How much knock retard are you seeing on the ScanMaster? The factory tuning can pull up to 15-degrees of timing in response to the signal from the knock sensor. If you can hear knock, either the knock sensor circuit has been desensitized, the PCM has had the retard tuned out, or you have a major problem that requires more than 15-degrees of retard. You have the ScanMaster - why not use it to watch the knock retard? Its the default screen.

45-degrees of advance is stock timing, but only under low load (cruise) conditions. Not likely you would see that much advance at WOT unless someone went nuts with the tune.

 

The knock sensor was disabled by MADZ28 last yr.&the kr. always shows 0.I also need to raise my idle speed from 550/575 rpm to around 750/775 rpm(due to u.d &stall convertor).Does reducing total timing affect curb idle?How does a person raise curb idle;the startup,etc. is fine.

 

I was seeing 44 degrees of timing @65mph and 41 degrees @50 both under cruise cond.