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I always wanted to see how a mechanical advance distributor's Timing Curve looked in 3-D
The way the EFI ones are presented.
So here you go. 12* initial. 36* max. 12* vac can.
I could not get Excel to do this in a surface map.
But it should give you the idea.
All slopes are linear vs the EFI map.
The big difference in a mechanical advance map, is there are only two slopes, and they are both linear.
All you can change is there beginning and ending point, and their degree* values.
ie: 12* at 800rpm, 36* @ 3200rpm.
0* @ 6" vac, 12* @ 12" vac
Last edited by leigh1322; Jun 10, 2024 at 12:49 PM.
Leigh, this if for you:
Here is a 3D graph of a typical EFI setup that mimics a standard timing for a Gen 1 SBC.
I've smoothed the table to stay away from sharp transitions.
The second timing 3D curve is on my application (although not current). Notice I pull timing when under boost, and I flattened the area that I typically idle in. Pulling some timing under boost is self explanatory, but flattening the idle area ensures a more stable idle timing regardless of fluctuations in engine manifold pressure.
