How advanced do you run your L05 base timing?

[Yeti_Owner]

I've heard different opinions on this one. Some run it at 0 degrees, some 2, some 6. Besides an anecdotal "butt dyno" impressions, are any of ya'll that run the timing advanced seeing any mileage improvements?

 

[Yeti_Owner]

Anybody? L05=350TBI, if that helps?

 

[1993-Sierra-Z71]

id run a max of 5 degrees advanced.

 

[Yeti_Owner]

id run a max of 5 degrees advanced.

Does it actually do anything though, for MPG real world? I've been doing a search on the 'net, and it's so all over the map that it's sickening.

 

[Yeti_Owner]

Hmm.

As I understand the theory behind the ESC on this truck, it "loops" like the o2/mixture, in that it has a base timing map, but continuously tries to advance the timing right up till it knocks, then it retards it a bit, then advances, etc (as the fuel sides runs back and forth over stoich in a continous rich/lean swing).

Is that correct?

If so, is there any point at all at monkeying around with the base timing, given that all you are doing is changing the timing at startup/cold conditions?

 

[Yeti_Owner]

Actually, there is another issue, I think may come into question - INJECTOR timing.

If you adjust the base timing, won't it also adjust when the injector's pulse? If so, wouldn't advancing the timing actually cause issues with the pulse coming too soon on the injectors? I'm sure it's a very small effect, as these systems aren't exactly precise to intake valve's opening, they basically spam fuel down onto the intake and hope enough gets sucked in when the motor needs it, but still... you'd think there would be some measurable difference.


Am I getting too technical for the forum? lol

 

[1997chevydriver]

If so, is there any point at all at monkeying around with the base timing, given that all you are doing is changing the timing at startup/cold conditions?

You are shifting the whole timing map when you do that do it will affect it all the time.


Sent from somewhere in MN

 

[Yeti_Owner]

You are shifting the whole timing map when you do that do it will affect it all the time.


Sent from somewhere in MN

Well, sort of, I guess. But the distributor/knock sensor work in a closed loop, right? So you advance the curve a little, it detects knocks, and just neutralizes the additional base advance. As far as I understand it, the electronic ignition, in closed loop, advances the timing up to knock, backs it off, then back up to knock, etc in a constant cycle anyways. With the base timing, aren't you only really changing what it does outside of closed loop (IE something wrong with the automated system or during startup), unless you *REALLY* go outside of the computer's trim limits (IE advance it so far the ECM can't retard it enough to put it where it should be)?

Am I off base with my understanding? Any really hard-core techs here with some engineering knowledge of the system?