i have a L31 vortec 350 with a 91 tune i am wondering if my timing is a lil low ? on a wot run i get a max 26*of timing. Does that sound about right ? for some reason i remember useing 30-32*in some old SBC with a mechanical advance comming in full timing at 3,400rpm ? Thanks

 

Depending on what its in, the gears and the torque converter installed you could get into the low to mid 30s at WOT. Vortec iron heads can handle a lot of spark advance without detonating, a lot compared to say swirl port TBI heads that is. If you are just looking for a generic tune and be done I would say 30 would be more than safe and 32 if not 34 would be fine on 91 octane. I'm running my 95 as high as 36 on 87 with a 180 thermostat and it has vortec heads on it. Also the amount of cam overlap has an effect on how much advance you can run. Keep in mind there comes a point where more timing won't make you more power. Basically the combustion event starts too soon and ends up trying to push the piston down as its still coming up on the compression stroke.

 

ok so my 26*is a safe conservitive number for 91 fuel . i was planing to add a wet 50-75 shot and i was conserned with my timming being its got a generic 91 tune from black bear . i have a mild stall and my water temp runs a solid 166* and gets to 175* on a hot day . its a stock cam so there is probley not much overlap . do you think i will be good with 26* on a 75hp shot. using 91 fuel and my low water temp ? thanks

 

Going to be honest and say I don't know a thing about nitrous and its effects on engine timing.

 

i know you should retard timming 2 degrees for every 50hp . but i am not really sure what the L31 came with on its stock tune ? but my 26* seems very conservitive tune

 

On a tune what is the PE table ?

 

PE Table is for power enrichment (for going WOT). Basically its the table that gets adjusted to give you as examples, 12.5 NA or 11.5 FI.

 

Thanks