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View Full Version : megasquirt + ign timing and how much we should be running ? ?



Sundance 6g72
11-03-2011, 01:49 PM
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

http://a7.sphotos.ak.fbcdn.net/hphotos-ak-ash4/392731_10150440680238899_534573898_10147445_103236 6536_n.jpg

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
11-03-2011, 04:54 PM
im glad everyone is interested in this

Force Fed Mopar
11-03-2011, 07:51 PM
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
11-03-2011, 08:04 PM
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
11-03-2011, 08:35 PM
I know that Slant 6's typically like 54-55 total at cruise. My 2.2 runs 33-35 I think.

Sundance 6g72
11-04-2011, 12:49 AM
my knock detection is when the car starts to miss when driving :confused:

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
11-04-2011, 03:49 AM
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
11-04-2011, 08:54 AM
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?

http://a7.sphotos.ak.fbcdn.net/hphotos-ak-snc6/253791_10150260606898899_534573898_8688963_8217905 _n.jpg

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

Ondonti
11-05-2011, 05:18 AM
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
11-05-2011, 11:19 AM
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 (http://www.bgsoflex.com/cgi-bin/crchange?hp=143&oldcr=8.9&newcr=10.0)

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 (http://asog.net/images/pdfs/6g72.pdf)

Frank

http://www.4x4wire.com/forums/showflat.php?Cat=0&Number=1026387&page=0&fpart=all&vc=1

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

Force Fed Mopar
11-05-2011, 12:12 PM
Yes they are different.

Ondonti
11-06-2011, 05:07 AM
That truck cam will have even less top end.

nmw2006
11-06-2011, 10:47 AM
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
11-06-2011, 11:07 AM
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

http://a7.sphotos.ak.fbcdn.net/hphotos-ak-ash4/317717_10150444262098899_534573898_10168735_305163 108_n.jpg

Force Fed Mopar
11-06-2011, 11:52 AM
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
11-06-2011, 12:00 PM
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
11-06-2011, 12:12 PM
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
11-06-2011, 12:26 PM
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
11-06-2011, 12:40 PM
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
11-06-2011, 12:51 PM
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 :D

Force Fed Mopar
11-06-2011, 12:53 PM
The psi is -psi, meaning it's vacuum. -9.5psi is like 20inHg, -3.0psi is about 6inHg. The more vacuum you have, the more timing you need.

Although, those are WOT settings. The map advance from part throttle is likely to be a bit higher. So, the timing at idle would actually probably be like 26-28 total maybe? I don't think Rob has got that far in the V6 code yet, but if he had the wot tables, he may have the part-throttle too.

Sundance 6g72
11-06-2011, 01:02 PM
well my current idle and cruise timing numbers are close to the edge. i can run 37* at like 16.1afr and be fine (in the current weather.. i think intake air temp above 80f causes the need to richen up to 15.3afr) but anything more than 37* causes the car to "miss" when cruising.

right now i just want to make sure i have the stock timing numbers plus 2-3* (proven hp) so i know im not lacking anything. without a dyno its hard to go off on my own and see if 45* at 5500rpms is actually an improvement. i sweat the car pulled harder in 4th all the way to redline with the timing up at 45* but ed found that when he brought his timing down he made more power on the dyno. then again his car has much more done than most of us so he will have different timing numbers. He actually gos above atmospheric pressure sometimes when WOT.


oo and just realized you have a conquest.. balllin!

Force Fed Mopar
11-06-2011, 04:57 PM
Hehe, it'd be even more ballin' if it ran properly :D Needs a fuel pump.

Ondonti
11-06-2011, 11:50 PM
base timing is base timing. Its something that the ecu is not accounting for. Newer mitsu 12 valves don't have adjustable base timing so that is a mod some people do. Same for the DOHC boys. They try to add the early DOHC CAS system because it allows some fooling with timing.

Electronic advance is electronic advance. Anything created by electronic means. Base timing is offsetting the distributor. Your total timing is all factors combined. Base timing would happen even if your ecu provided no advance.

Sundance 6g72
11-07-2011, 12:03 AM
okay sooo the question is, do i take the numbers posted earlier and ad 12 (or whatever the dizzy is set to?) in order to find the real ign timing number? It made sense when i added 12 to all the numbers because i got a final timing advance of 38 degrees (assuming 12* base timing)

---------- Post added at 11:03 PM ---------- Previous post was at 11:00 PM ----------

i had the intercooler on the car because i wanted too (no turbo) and after actually looking at my datalogs.. it was bogging me down after 4000rpms (you could feel it too)

once i removed it, the car bacame violent per say.. with the timing set like this too.. all the way to 6800rpms.

http://a7.sphotos.ak.fbcdn.net/hphotos-ak-ash4/317717_10150444262098899_534573898_10168735_305163 108_n.jpg

power is still off after 4200rpms or so due to stock cams, no getting around that. but now it feels right.

im thinking about calling a place in my town (super close to me ! ! ) called "All speed customs" you can google "all speed customs Muskegon Mi" and check it out. they have a dyno i could use. i need to find a price per pull or for an hour. i dont want to spend to much time in there while NA.. finding the best timing at 100kpa wont do me any good later on but maybe i can help someone else out?

Ondonti
11-07-2011, 03:59 PM
But, you guys are using different methods to get your distributor "just right."

I don't know how much offset your distributor has to get that particular value you guys are looking for. I just stick with OEM base timing and everything seems to work fine and I know what my total timing is.

Can't you stick a timing light on there and figure it out? Or do you already know what the distributor is set too? Don't add 12 degrees to the table. You have that offset crank setting that allows you to take care of things and I thought you already did it.
I am talking about how to add up OEM timing, and that just happens to be how I have mine set up. You have yours different. I like mine the way it is, its not hard to remember that I have to add my base timing to know my total timing. I might change that in the future but its not a problem. Actually knowing your total timing is not exactly helpful once you run well. At that point you are already close so you don't have to guess and type in numbers. You are adding and subtracting. Knowing the total number is only helpful when sharing your info.

I think you are adding timing too aggressively with rpms. I understand the idea of adding timing as torque starts to plummet at 4500 but you are getting pretty aggressive for probably no gain. If it feels good, then go for it though. N/A ain't gonna get too hurt. Its when you add a little boost.

Sundance 6g72
11-07-2011, 04:50 PM
i was under the impression that whatever showed up on my laptop was the actual timing that i was running.

what i did was set the megasquirt to a fixed timing of 10*

then i get out the timing light and check the crank.. lets say it reads 12*. i then adjust the trigger angle ofset until the light reads 10*

i was told that after doing this, i would have the exact numbers showing up on the laptop. no need to add or subtract anything

the current timing feels good. i want to get on the local dyno and do a pull or two to see whats going on.

ShelGame
11-07-2011, 05:01 PM
The stock V6 timing is setup a little different from the turbo stuff. But here's the basics:

Cold advance (for when the coolant temp is below ~65F):

CLDMAP + GOVNER

35176 + 35177

Warm P/T Advance (when temp is above ~65F):

HOTMAP + RPMAdj + GOVNER

35179 + 35178 + 35177

For WOT, the MAP portion is gone (I assume because being NA, MAP is essentially 0):

WOTrpm + GOVNER

35180 + 35177

Similar to the turbo cals, the max timing is also SPKLMT:

35181



It's kind of an odd timing arrangement, but it is what it is. This is for the SMEC V6. I think the SBEC and SBECII are very different due to the 3D tables.

Sundance 6g72
11-07-2011, 05:09 PM
timing should be close to the same though regardless of ecu.. at least i would think.

am i dumb or do those pictures not tell me any numbers?

thanks though, i appreciate it.

Force Fed Mopar
11-07-2011, 07:50 PM
They don't tell you any numbers, you would have to open that cal in Dcal and look at it yourself to see all the numbers. He was just showing what the factory slopes looked like and what tables are used to calculate it.

Also, the base timing you see with the light is not added to the timing in the factory computers. It is simply a sync point.

Not sure if any of that helps you w/ the MS, but from the sound of what you describe MS is the same, you just get the dizzy synced to the engine and then the computer does the rest.

Ondonti
07-07-2013, 06:06 AM
The stock V6 timing is setup a little different from the turbo stuff. But here's the basics:

Cold advance (for when the coolant temp is below ~65F):

CLDMAP + GOVNER

35176 + 35177

Warm P/T Advance (when temp is above ~65F):

HOTMAP + RPMAdj + GOVNER

35179 + 35178 + 35177

For WOT, the MAP portion is gone (I assume because being NA, MAP is essentially 0):

WOTrpm + GOVNER

35180 + 35177

Similar to the turbo cals, the max timing is also SPKLMT:

35181



It's kind of an odd timing arrangement, but it is what it is. This is for the SMEC V6. I think the SBEC and SBECII are very different due to the 3D tables.

I am a bit confused as to how these two posts of yours worth together...
Your post on TD seems pretty simple and the # tables make the pictures useful. The post here, I don't understand. Specifically Advance from Warm WOT.
http://www.turbododge.com/forums/f11/f69/395514-stock-spark-manifold-absolute-pressure-sensor.html#post2467126

I made a pretty extensive spreadsheet using the info you posted on TD that changes WOT numbers into the lower load numbers based on the WOT/map chart as well as frame by frame plotting my own video datalogging of my DRBII plugged into my 1994 a670 Spirit.
The numbers I have datalogged for 1994 are pretty similar to the 1989 numbers you posted on TD except the "pre dip" has less of a timing peak and the timing comes up much sooner after the dip.

I only have old 3.0 bin files for use in Dcal that I downloaded off one of your sites. They don't have all that goodness you posted.