Any opinions about this spark table for my EFI system?
351C, 4V heads (unknown type of chamber), Torker manifold modified for port injection, 3/4 race cam, GTS headers and mufflers.
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A few notes in timing. First, you can do with EFI much more than you can do with a regular ignition.
Tip timing will depend on your engine and fuel. 36 deg is fine if all is right. It is probably maximum for power and often at 6000 and above, you can actually take off a couple of degrees and make more power.
I suggest about 10 to 15 degrees to start the engine depending on compression and then about the same at all vacuum ranges at idle speed. This can stabilize idle. IF your cam is too big, you can actually add some vacuum at idle to stabilize idle.
Mechanical timing increasing with rpm should build from idle to max at 2500 to 3000.
You need to add some vacuum timing. Increase vacuum from 10 to 15 degrees as vacuum increases. Start at about 80 kpa and increase to full advance at the vacuum the engine will have at 2000 rpm. Keep the same timing value from there to total vacuum. You can back off on vacuum advance above 4000 rpm and at idle. Why use vacuum advance - - It increased fuel econemy.
One thing to avoid are rapid changes in timing. If you jump 10 degrees in a single step, you can cause some nasty stability problems.
Tip timing will depend on your engine and fuel. 36 deg is fine if all is right. It is probably maximum for power and often at 6000 and above, you can actually take off a couple of degrees and make more power.
I suggest about 10 to 15 degrees to start the engine depending on compression and then about the same at all vacuum ranges at idle speed. This can stabilize idle. IF your cam is too big, you can actually add some vacuum at idle to stabilize idle.
Mechanical timing increasing with rpm should build from idle to max at 2500 to 3000.
You need to add some vacuum timing. Increase vacuum from 10 to 15 degrees as vacuum increases. Start at about 80 kpa and increase to full advance at the vacuum the engine will have at 2000 rpm. Keep the same timing value from there to total vacuum. You can back off on vacuum advance above 4000 rpm and at idle. Why use vacuum advance - - It increased fuel econemy.
One thing to avoid are rapid changes in timing. If you jump 10 degrees in a single step, you can cause some nasty stability problems.
Let me take some time tomorrow, and i will try and make a table and post it. It would be easier than working back and forth.
