How do you calculate total timing?

[turbovanman²]

What tables do you add up to get the total timing at any given point in the cal.

Maybe sticky this too?

TIA.

[roachjuice]

Just guess it. Works for me.

[1BADVAN]

You take
'AdvanceFromRPM2' +(MAPTiming x MAPMultplier)

And the 'MAPtiming' can be substituted for WOTMAP, HOTMAP, or Cold map.

But the 'MAPmultiplier' only comes into the equation when the raw 'MAPtiming' number is a negative number.

This is who i love the addition of the calculated tables in MPTune

[1BADVAN]

Wowzer and Shelgame explain it in the MPTune thread about post 677

[turbovanman²]

Just guess it. Works for me.

And that's why you have cracked pistons,

You take
'AdvanceFromRPM2' +(MAPTiming x MAPMultplier)

And the 'MAPtiming' can be substituted for WOTMAP, HOTMAP, or Cold map.

But the 'MAPmultiplier' only comes into the equation when the raw 'MAPtiming' number is a negative number.

This is who i love the addition of the calculated tables in MPTune

Thanks. Need to find those tables, still learning all the features in MPTune.

Wowzer and Shelgame explain it in the MPTune thread about post 677

I'll link it but just looking at it.

http://www.turbo-mopar.com/forums/sh...l=1#post862311

[1BADVAN]

Thanks. Need to find those tables, still learning all the features in MPTune.

here is where i find it. The Graph is cool but the Spreadsheet is the useful part

[turbovanman²]

here is where i find it. The Graph is cool but the Spreadsheet is the useful part

Snap, that is damn cool, thanks.

[turbovanman²]

That chart is f*cking awesome, and DAMN, I have way too much advance going on, lol, no wonder she rattles.

[Dez]

So just to fully understand the calculation. Does this mean that the initial/distributor timing of 12* does not have to be added to the calculation? Also, is the initial timing ever added to any of the calculations in the cal?

[turbovanman²]

So just to fully understand the calculation. Does this mean that the initial/distributor timing of 12* does not have to be added to the calculation? Also, is the initial timing ever added to any of the calculations in the cal?

I always forget this but the 12 deg is simply the correct spot for everything to be synced up, so IIRC, 12 is really 0 deg's. I am sure Shelgame can correct if I am wrong.

[Reaper1]

From everything I've read over the years the distributor timing of 12* is simply where the computer knows to start calculating from. It really has nothing to do with actual ignition timing of the engine, though it can move the entire scale around simply because the "0" point for the computer is no longer where it is supposed to be.

[Dez]

Understood. So basically for stock calibrations I see that the total timing at WOT is 20* from 14psi and up...would this be correct?

Simply trying to figure this out so I won't break anything, haha.

Edit. That was a 3bar, +40 cal. My bad.

[ShelGame]

I always forget this but the 12 deg is simply the correct spot for everything to be synced up, so IIRC, 12 is really 0 deg's. I am sure Shelgame can correct if I am wrong.

12* is simply where the computer sets the ignition timing for the purpose of syncing the distributor to the crankshaft. They chose 12* because the engine doesn't idle so well at 0*. Once you plug the coolant temp sensor back in, the timing is calculated normally and is always referenced to 0*.

So, if you offset the sync position 2* (at 10* instead of 12*), the computer will have no way of knowing that. And, in that case, you will need to subtract 2* from all of the calculated timing to know your actual advance. But, if you're making your own cals, there's never a reason to subtract 2* mechanically. You can just take 2* out of the Advance from RPM table instead and achieve the same result - without getting lost in the mechanical offset.

[Dez]

Great explanation! Now I understood. Thanks guys!