Quick question if you guys have time.

My dist. is set at 6* BTDC for base timing. My chip also has the initial timing field set to 6*.

Here is the question. Does this field alter any other timing fields? For simplicity lets say my Timing vs. RPM vs. LV8 field was set for 36* at an RPM of 4800 and an LV8 of 192. Does the computer advance 36* for a total of 42* or does it only advance 30* knowing that it has 6* in the distributor already?

Thanks!

 

It is the last, the timing at the crank ends up being 36°.

The ECM subtracts out the initial timing knowing that the distributor position (base setting) will add it back in.

RBob.

 

Great! Thanks for the quick answer.

 

I know this is an old post as I have done a search, but does this apply to 6e?? I just unplugged the ecm timing from the firewall and had 20degs. of timing. Plugged it back in and was 36degs. at idle.In the timing charts at idle at low lv8(sp?) I have 16 in there presumably they are being added together for total timing...???

 

Wow, your engine starts with 20 degrees of base timing? I feel bad for your starter .
If your main "warm" SA table has 16 in the idle area and your "Spark reference angle - Base timine" (from TunerPro's $6e.xdf) is 20 in the chip then yes, 36 is what the engine is going to see give or take the other compensation tables like choke/temp/idle correction.
Can I ask why you're running 20 degrees of base timing? I've never found the need to set it above 10. The good thing about running more base and less computer advance is that you get more spark energy. Smaller gap to jump in the dizzy . Maybe I'll go and try this. I know you can retard the timing... starting a new thread.

 

Actually, the tip of the rotor sweeps past each post for a large enough crank angle as to not need to jump a "gap" per se. Sure there's normal clearance gap, but no leading or trailing gap as long as 0-45 degrees of crank timing are used. It might have to jump a gap if the base timing is less than 0, but it would be a small small gap.

I think this was discussed over a year ago, if you'd like to look it up again. I think I had posted in it saying what I saw inside a 4-cylinder distributor.

 

Hmm, so how long is the "sweep" during normal HEI? In degrees? At higher RPM vs lower say 6000 vs 600.

 

It's degrees, so RPM won't matter. I don't recall off hand, and have no time or way to check personally. I'm late for breakfast, and we're driving to the border of Russia today, to do some super cold calibration/testing, woohoo. Hope they have warm hotels!

 

With inductive ignition at lower RPMs the spark is longer which would increase the sweep angle? yes/no

 

If I am reading this correctly I have less in the chip.Would decrease(at the dizzy) but car seems to stumble off idle. I could decrease initial and increase tables. Using tunercat's 6e df.

 

If your engine starts without fuss and doesn't seem to have any issues then I see no reason to change anything. Don't do it because it's "normal" do it as a test to see if there are any differences, good or bad.

 

sounds like a test I need to do....curious....