2003-04 Mach 1 Registry Owners Club - View Single Post - Thread for those of us who tune our own cars

Mach828 · 03-12-2015, 03:38 PM

How much spark can I get away with without detonating on 91?

Bumped her up to 19 at 3k, 18 at 4k, 17 at 5k, then 16 at 6k+. It was not happy and had some detonation just before 4k. Whoops. Also had my base fuel table set to taper from lamba to about .78. So I'm thinking combined with 18-19 degrees of timing with a 12.2 air fuel and 3-4lbs of boost, it was not happy. Is my timing too aggressive for 91, or should I just change the base fuel table transition?

Can timing affect your AFR? Advancing timing just means you are commanded spark earlier, right? Where is the piston at during ignition at 0 degrees vs. 20 degrees advanced?

Do I need to change anything in the tune because I have 96 cobra intake cams with the extra 20* of duration?

03-12-2015, 03:38 PM	#134
Mach828 Dark Knight Join Date: Nov 2009 Location: Albuquerque, NM Posts: 5,759	Re: Thread for those of us who tune our own cars How much spark can I get away with without detonating on 91? Bumped her up to 19 at 3k, 18 at 4k, 17 at 5k, then 16 at 6k+. It was not happy and had some detonation just before 4k. Whoops. Also had my base fuel table set to taper from lamba to about .78. So I'm thinking combined with 18-19 degrees of timing with a 12.2 air fuel and 3-4lbs of boost, it was not happy. Is my timing too aggressive for 91, or should I just change the base fuel table transition? Can timing affect your AFR? Advancing timing just means you are commanded spark earlier, right? Where is the piston at during ignition at 0 degrees vs. 20 degrees advanced? Do I need to change anything in the tune because I have 96 cobra intake cams with the extra 20* of duration? __________________ Vortech V2 S-trim, E85, A2A Treadstone, Comp cams, built engine, full exhaust, built rear, built 4r70, more mods. Tuned by me with SCT Advantage