does the prom's initial timing get added to the initial base timing?

if I set my base timing at 8 and the chip is burned to have 10 at start up does that give me 18 degrees advance at engine start?


thx

jeff

 

no, they should be set the same. it's just a reference for the ECM, as in let's it know what the timing is supposed to be set to.
In your example you'd be 2 degrees retarded across the whole curve because the ECM thinks the base timing is at 10* when mechnically it's @ 8*

 

what if my base timing is set to 14? Is this bad?

thx

jeff

 

if your prom is still set to to stock, then you have 6*( if the stock is 8* ) across the whole curve. People do this a lot, but it's not really the right way to go about it. It might not want that at some RPMs. Best way is to start tuning the curve with making a custom prom.