Spark advance theory.

[turbovanman²]

This was kinda hit on in 1Badvan's G-head cal thread but should we treat the vacuum and maybe partial boost the same as an n/a engine, so lots of advance all in by say 2500, like a V8 or ?

I know, every engine is different but it would be nice to see what some of you guys are running, mostly interested in the 16 valve stuff.

[turbovanman²]

OK, why does the auto cal have a kinda down then up "multiplier on map advance" whereas the MP cal is a flat line? Most of the other spark tables are close. Is it due to the auto loading up the engine differently?

[ShelGame]

OK, why does the auto cal have a kinda down then up "multiplier on map advance" whereas the MP cal is a flat line? Most of the other spark tables are close. Is it due to the auto loading up the engine differently?

Most of the 2.5 cals (except for the MP and HT cals) have some shape to the multiplier table. All of the 2.2's have it set to 1.

This table really just takes out more timing in boost with RPM. In vac, or in boost, the multiplier is positive, so if the advance from MAP is negative (usually, only in boost), then the multiplier is applied to the MAP advance value. So, if the MAP advance table shows -6deg, and the multiplier at that particular RPM is 1.5, then the actual MAP advance (at that RPM) would be -9deg. It's kind of a crutch to get a 3D table shape from a bunch of 2D tables...

[turbovanman²]

Thanks.

So what if I ran the 2.2 setup? I know about knock, just wondering if its easier to tune that way than the 2.5 way?

[ShelGame]

Thanks.

So what if I ran the 2.2 setup? I know about knock, just wondering if its easier to tune that way than the 2.5 way?

What 2.2 setup?

[turbovanman²]

What 2.2 setup?

MP 2.2 cal.

[ShelGame]

MP 2.2 cal.

Why would that be easier?

[turbovanman²]

Why would that be easier?

It seems that it uses the spark curves you see and doesn't use other methods to set spark timing, ie that graph I mentioned but I could be over thinking, lol.

[ShelGame]

It seems that it uses the spark curves you see and doesn't use other methods to set spark timing, ie that graph I mentioned but I could be over thinking, lol.

You can just set the multiplier table to 1...

[turbovanman²]

I'll try that, thanks.

[turbovanman²]

Ok, so just to be 100% clear, those numbers in the chart are the actual numbers at the given rpm and vacuum or boost, so I changed that MOMA table and the numbers when lower, and it seems easier to get the numbers I want in the right area.

Thanks for the help.

[R/Tony]

And do you have like an advance table to share?... Im actually looking for how much timing will be acepted by the 2.5T

[turbovanman²]

Bump anyone?

And do you have like an advance table to share?... Im actually looking for how much timing will be acepted by the 2.5T

I can post mine but it won't work for you as I have 16 valve. I can snap shot the MP cal if you want?

[1BADVAN]

wowzer mentioned something about the new MPTune version to be able to type in a value into the chart. Maybe check that out

[turbovanman²]

Bump!!

[1BADVAN]

wowzer mentioned something about the new MPTune version to be able to type in a value into the chart. Maybe check that out

Edit, I read that slower this time, and it was just saying that it will actively update as you change the 2D tables, not the other way around. It will be cool if Rob could port the 3d tables to the SMEC someday.

[turbovanman²]

I don't think those tables are real, had to add a ton of timing today at the track, if I really had that much, it would be a diesel.

[ShelGame]

I don't think those tables are real, had to add a ton of timing today at the track, if I really had that much, it would be a diesel.

The tables are real. Are you sure you're saving your work correctly? I think you had this problem before where it didn't save your changes...

[turbovanman²]

The tables are real. Are you sure you're saving your work correctly? I think you had this problem before where it didn't save your changes...

I know Wowser had it changed so all you had to do was compile but I've been saving, then compile just to be sure and yes, the changes work, I dropped over a second with fuel and spark changes, was pig rich then not enough timing.