What would you guys recommend for MAX timing in the main spark table for a 10 - 10.5 : 1 vortec headed TPI 350?

Just curious.

Right now I'm running 38* total. I've been told that's a couple degrees too high.

 

It's not too high IF there is no detonation. BUT you'll need to make timed runs to find the best total,while checking for detonation. I would start with 32* and time a 1/4mi run. Then go to 34*,36*,38*, taking notes of your mph and et for each degree setting(make sure to come off the line exaxtly same each time). Use the degree that nets the best et.I might reduce or increase timing in the upper rpms, if the engine likes it. Let me know what kind of timing you end up with.

You can see in the log data that I just make it flatline from 3X00rpms and up.

 

How did you get the Air fuel ratio to show, do you have a DIY-Wide-band setup?

 

ignore that....it's just the calculated a/f ratio. I use a wideband o2. That version of datamaster is a beta(listed on thier site). I think trax said you can hook up the w/b to that beta version but i don't know how......

 

Sounds like you may have missed the tune.

If you run too rich, then you need too much timing. If your just racing then you can sort of use extra fuel to up the CR, but it's hard on things.

Might try taking some timing out, and then try leaning down a LITTLE bit at a time.

You have to accurately use a stop watch at this level to make sure you don't miss, best performance. The buttometer can be fooled.

 

The WB has nothing to do with the scanning software that you use. The only 'hook up' is hooking the WB Vout to the correct pin on the ECM and running the hacked binary that pushes the REAL AFR to the AFR placeholder in the ALDL stream.

Tim

 

thanks

 

Mike

Use the total timing spec given by GM for all their Vortec crate engines as a starting point, its the same for all of them?

38* is way to high to start at, why are you just picking random numbers anyway?