Max vac advance

[demonram]

What should the max advance be with vacuum . I've got 10 initial, about 38 mechanical, upwards of 50 with vac hooked up. Getting detonation on full throttle. This was before trans situation. Thanks in advance Howard

 

[Hemi Rebel]

You have 38 including the initial, or 48? Vacuum advance isn't a factor at wide open throttle.

 

[rumblefish360]

As per the MP book, IIRC, a max of 52*'s with he vacuum advanced hooked up.
Try and limit that. Is your vacuum advance canister adjustable?
Performance wise, run as much initial as you can and limit mechanical to 36*'s (again, IIRC) and then total to 52*'s.

However, all this is also octane dependent as well.

 

[Cranky]

Timing is usually dependent on the combination of the engine. Low compression engines with high performance cams can and usually do require more timing to make them run good but engines with little or no quench can sometimes have ping problems. Higher compression with tight quench usually require less timing (total) because they are much more efficient in the burn.

 

[demonram]

I'm at 10.5 comp.. This just kind of started. I'm running 93 octane. The vacuum advance is adjustable, it's a Mopar performance. The cam is a 484 lift hydraulic. How much and which way do you turn the adjustment screw? I also have aluminum heads. Thanks!

 

[Meep-Meep]

Pinging can also be one or several cylinders leaning out. lots of factors contribute to pinging.