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Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Madbomber88, May 20, 2005.
How much advance are you guys running with stock 91 K5s?
I run both of my TBI motors on 0' as they're supposed to be as the ECM takes care of what is needed. As far as I know you shouldn't set it advanced from that. Maybe someone who has/does will chip in and correct me?
If I've got my GM EFI timing strategy understood, you can advance the base timing, BUT that affects the entire curve. If you advance it 2*, when the ECM commands say 34*, you are adding 2* the ECM doesn't "see".
It won't hurt you down low probably, but up high, you may start running into knock retard, actually losing performance, and you may never know it.
Best way to do it is like you do with mechanical, experiment until you find what the engine likes best. With an ECM, that means chip burning.
I run mine 4* advance, set with the bypass disconected on the stock chip. But I also have an adjustable FPR and map sensor and use a scanner to make sure everything is set right so there is no pinging. Cant run gas less then 87 octaine either. Running more advance will help a lot in performance but you need a scanner so you know what is going on. And an adjustable FPR to richen up the fuel/air mixture so you dont get detonation.
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