megasquirt + ign timing and how much we should be running ? ?

[Sundance 6g72]

okay so as some of you know, i felt a power increase when running timing of like 40-45* at around 5500rpms. Today, i swear i felt a power increase after i brought the timing back down across the board.

At drag week, ed and i increased his timing a whole bunch and thought we made an improvement but when he hit the dyno after drag week he found a power increase after knocking the timing back down.. as to how much, im not sure.

this is my current table. ignore anything over 100kpa and under 70kpa..

best picture i could get as of now



this is really fricken hard to perfect without a dyno so i figured id try and get the factory ign numbers for WOT and then add 2* (just like we normally did with the dizzy) Shel game told me he could find the numbers but wont get back to me.. not sure whats going on but whatever.

so what all do you guys think we should be running with slightly modded 3.0s? im talking ported stock intake, 3inch exhaust, stock headers, 52mm TB. nothing fancy like custom twin intakes, headers, port work bla bla bla.

i think i remember reading that stock max timing was 38* but im unsure. any input would be nice!

[Sundance 6g72]

im glad everyone is interested in this

[Force Fed Mopar]

I don't think Rob has got very far w/ the 3.0 code yet, so he probably hasn't found the numbers yet. I would check the 3Si forums, the base model Stealths had the same engine.

[shadow88]

Between 2pm and 5 pm, many of us are at work. I am interested to see where you end up with this. I would suspect around 34-38 to be about where detonation sets in. What is your knock detection method?

[Force Fed Mopar]

I know that Slant 6's typically like 54-55 total at cruise. My 2.2 runs 33-35 I think.

[Sundance 6g72]

my knock detection is when the car starts to miss when driving

i never thought about checking 3si... they would be the ones to ask and they have knock sensors i think. Only guy around these parts would be brent (i think) with a knock sensor

i have found that an afr of 15.5ish and 40* is not good when cruising but 37 seems to work well from 14.7-16.5 afr when cruising.

im not really interested in cruising timing because to me it seems like the more you run when cruising, the better the gas mpg.. and if the car cruises fine and happy at such high timing paired with a lean mixture.. then why change it.

WOT is what i want to know because i dont want to be at a max of 43* if my car runs faster at 38* total.

and shelgame seemed to hint that he could find them if i told him what year i wanted.. not sure what hes doing about that. Ill check on 3si and see what they think.

[Ondonti]

He previously found 26 degrees of electronic timing advance. With 12 degrees base that is 38 degrees total. 2 valve head, this is not crazy.
Running more then what we have already found (advancing 2-3 degrees, so 40-41 degrees) is questionable.

I will say that what I have learned from huge power turbo guys (like the ones on 3si, mostly info from Ray Pampena), the less backpressure you have in your exhaust before the turbo, the less timing you run. The best turbo setups require the least timing if you are looking for power.

Ed's motor is no longer a bolton so his old dyno bolton tests may be worthless to compare against his new ones.
Bolton's car I would go for the standard practice advance. The advance at peak torque would probably be less but that is something you can't just guess at.
The post about OEM timing was on this board but I don't remember where or care to look for it. Probably in a megasquirt OR thread about custom cals.

[Sundance 6g72]

ill look for that thread if i get time

so less timing at peak torque? i guess the timing wouldnt be as dramatic from 2000rpms to 4200rpms and then it should ramp up a bit do to toque loss?



i wish i had time + a dyno and a big cam because that ^ is embarrassing

[Ondonti]

Peak torque = highest cylinder pressure, and most likely to detonate. The higher your rpms get, the less time there is for detonation to occur. Cylinder pressure drops off after peak torque so everything gets safer.
I read the thread back then and that was the exact timing info that Nathan Wilbur used in his original cal, but I don't know if he had any base timing. The information also might be in his personal thread since he was down on power with megasquirt just like Ed.

[Sundance 6g72]

well im searching around on some mitsu forums and i found this

Nope.... the increase of 1.1 CR yields only 5HP:

Bowling & Grippo CR/HP Calculator

The main difference is in the camshaft grind.... plus it's also likely that ignition timing is a little closer to the curve for best power. I don't think I'd run 87 octane in a 10:1 engine, but all engines react differently.

Here's the FSM that covers the 6G72 SOHC 12v and DOHC 24v variants in the Diamante and Montero, including the differences in the SOHC FWD and RWD engines. Note the difference in valve timing between the SOHC FWD and SOHC RWD cams:

6G72

Frank

http://www.4x4wire.com/forums/showfl...fpart=all&vc=1

its the third post. RWD cam different than fwd cam?

[Force Fed Mopar]

Yes they are different.

[Ondonti]

That truck cam will have even less top end.

[nmw2006]

Here is the info i got from Shelgame a long time ago. You will just have to put this info into your timing table.

I got the stock timing numbers from Rob Lloyd So here we go....

From the '89 V6, the advance from MAP @ WOT looks like it goes from 15deg @ -9.5psi to 0 deg @ -3.0psi.

The advance from RPM has these points:
1) 1500 rpm x 10.0 deg
2) 2000 rpm x 14.5 deg
3) 2800 rpm x 17.5 deg
4) 4000 rpm x 18.0 deg
5) 4800 rpm x 26.0 deg

Now I just have to convert this info over to my tables and I should have a much better running car...once I get my WBO2 back from being worked on.

[Sundance 6g72]

and we add base timing to those numbers though. so +12 right?

1500rpm 22
2000rpm 26.5
2800rpm 29.5
4000rpm 30
4800rpm 38

so for those who advanced their timing to 15* base they would add 3 to those numbers.. and sense thats proven horsepower that would make it

1500rpm 25
2000rpm 29.5
2800rpm 32.5
4000rpm 33
4800rpm 41

problem is, does it really sit at 41 all the way to 6200rpm? If timing is ramped up after the preak toque, which judging by the timing numbers right there ^, we would ramp it up after 4000rpms (my peak is at 4200 then it goes down)

so 5600rpms = 49* timing?
6400rpms = 56* ?

or should i not be adding 1* for every 100rpms.. that seems like to much but going from 4000rpm to 4800 (tq going down) the timing is ramped alot BUT does it keep that trend or just hang out in the 41 area until redline. i need a dyno

does the distributor have a limit on how much or how little advance you run?

---------- Post added at 10:07 AM ---------- Previous post was at 10:01 AM ----------

this is what i changed my table too

[Force Fed Mopar]

If it works the same as the 4-cyl computers, then no, you do not add the base timing to it. When you set the timing, all you are doing is syncing the dizzy to the computer. Basically when you unplug the coolant sensor, at idle the computer will fire at the base timing setting set in the rpm advance table (in this case looks like 10*), and you move the dizzy to match the firing time w/ the mark on the trans. This way the distributor is synced up w/ the computer and is for sure firing at the point that the computer thinks it is. The computer does all timing advance, including the initial timing.

Simply put, advancing the dizzy 2 degrees will advance the entire timing curve 2 degrees, but the computer will not know it.

Of course that is just how the factory computers work. Not sure if that carries over to Megasquirt or not.

[shadow88]

It's my understanding that the numbers you enter into the timing table on megasquirt is the actual number.

Yes, sundance6g72, you do need a dyno and knock detection.

[Sundance 6g72]

with megasquirt, you synch the timing to the dizzy. basically in MS you set it to a fixed 10* and then get out the timing light and turn the dizzy (or trigger angle setting in MS) until the timing light reads 10* and MS reads 10*

then any value you put into the MS ign table is exact. BUT its been my understanding that the stock timing is whatever value the computer puts out, plus 12 (or whatever you have it at)

so if the stock pcm calls for 10*, i would add 12 to that and get an exact number of 22.

10* at 1500rpms just seems way to low.

---------- Post added at 11:12 AM ---------- Previous post was at 11:08 AM ----------

if someone with a 1996 and up could get an obdII scanner in their car we would be in business. stealth guys have been no help

[Force Fed Mopar]

No, the stock computer works just like you describe the MS. You do not add initial timing to it. I didn't say it would 10* at 1500 normally, I said when you are setting the timing it will fire at 10* and you sync the dizzy to it. In normal running and driving, it is more. Your total timing is rpm advance + map advance.

So, at idle you would have 10* rpm + 15* map, which = 25* total. Or say if you matted it at 2800, you would have 17.5* rpm + 0* map= 17.5* total at 2800 at WOT. (going from the numbers from Shelgame).

[Sundance 6g72]

i guess im not understanding the whole map advance thing.. i guess i skipped over that

From the '89 V6, the advance from MAP @ WOT looks like it goes from 15deg @ -9.5psi to 0 deg @ -3.0psi.

?? hmmm

[Sundance 6g72]

ive never dealt with custom cals so i dont know how stockers work.. i just plug in values in the MS ign table and hope for the best