Mechanical Advance question?

[JayRolla]

My brother just got tuned awhile back and it seems the tuner at the shop added timing like an idiot. He hits about 28* by redline at 17psi. We pulled the CAS back and it hits about 24* at 19psi with no knock. My question what is the highest timing you want to hit and what damage does this high timing cause?

 

[GVR4592]

Maximum timing should be, the minimum best timing needed to make the maximum torque at a given RPM. You need a load holding dyno to determine this. Too much timing will cause detonation, which can destroy pretty much all of your engine internals, but it usually starts with pistons and piston rings, or the headgasket.

 

[sbiggi]

How do you know its hitting 28 degrees? A logger?
What was it tuned with?

The logger is only accurate if the base timing is at 5 degrees, so if it is advanced/retarded with the cam sensor it has no idea that has been done and will not account for it.

So if its reporting 28 then thats what it thinks is happening regardless of what the real timing is.

 

[JayRolla]

Well we think its at around 7* base. The logger has a choice where you can switch it to 7*base timing and should account for the difference right?

 

[pneumo]

You 'think' it's at 7 degrees base? The only way to know for sure is to grab a timing light and check it. The logger will not show you what your base timing is.

 

[JayRolla]

Ok im sorry I know its at 7* because I put it there.