Atomic EFI from MSD

[xgecko]

That, my friend, is a very interesting question indeed...

I should be running somewhere around 34 to 36 degrees of total timing somewhere around 2,500 or so. Lynn at Mondello's seems to think I should have it all in by 2,200 but I am somewhat skeptical at the moment but cannot really confirm or deny that as...



Try as I might I cannot get more than about 28 or so degrees of advance without significant detonation at WOT. I have looked for causes and for the most part cannot find anything other than perhaps the compression ratio is actually much higher than we calculated based on piston dish, combustion chamber and so on. I should be down around 9.7 or so which should not be subject to detonation.

The only other thing that might have a chance at explaining my predicament is if I made a mistake in the initial timing yet this seems unlikely as I have had this problem since the beginning with this motor - even with different pistons and cam as well as timing controlled by the EFI or not. I plan on running a few more diagnostics but am likely to end up adding Water/Methanol injection to eliminate the problem. I do not see this as having anything to do with the EFI as the same issues were present when I had a carb on the engine.

[Mikel]

All centrifugal timing in by 2200 seems a bit early. 160PSI cranking compression does not seem excessive.
Have you checked that the timing mark in your balancer is accurate? Outer rings in balancers are known to shift.

You may want to try posting at ROP. Hopefully someone can shed some light. Good luck.

That, my friend, is a very interesting question indeed...

I should be running somewhere around 34 to 36 degrees of total timing somewhere around 2,500 or so. Lynn at Mondello's seems to think I should have it all in by 2,200 but I am somewhat skeptical at the moment but cannot really confirm or deny that as...



Try as I might I cannot get more than about 28 or so degrees of advance without significant detonation at WOT. I have looked for causes and for the most part cannot find anything other than perhaps the compression ratio is actually much higher than we calculated based on piston dish, combustion chamber and so on. I should be down around 9.7 or so which should not be subject to detonation.

The only other thing that might have a chance at explaining my predicament is if I made a mistake in the initial timing yet this seems unlikely as I have had this problem since the beginning with this motor - even with different pistons and cam as well as timing controlled by the EFI or not. I plan on running a few more diagnostics but am likely to end up adding Water/Methanol injection to eliminate the problem. I do not see this as having anything to do with the EFI as the same issues were present when I had a carb on the engine.

[xgecko]

I agree that all advance in by 2,200 seems rather quick but that is indeed what Lynn told me. I am not saying it is correct, just that he seems to think the engines want it this way. I have no way to test this at the present time as I have the bigger issue of extreme sensitivity to detonation at the present time.

My balancer is a brand new Performance Products unit, and the issues were present in an entirely different build as well that had the original balancer on it. I am quite confident these are correct.

Thanks for the suggestions. I have investigated every potential cause except for one new one I was informed about by the MSD Engineer I have been corresponding with. I need to double check that I am not getting any oil in the intake from the PCV valve. I doubt I am but it is possible so I will be checking that later today.

Aside from that potential cause everything points to a bit too high a CR for the gas I can buy. This strongly indicates that Methanol/Water Injection is my best bet - it will allow me to run much more advance without fear of detonation.