Would someone please explain "timing" and "knocks" within Dodge ECU to me?

[tryingbe]

What is an acceptable knock voltage at rpm and/or boost range?

How is the total timing calculated? Base timing + AdvancefromRPM + AdvancefromMap?

It's pretty hard to tune when I have no idea how timing is calculated and what is a safe range.

Thanks.

[cordes]

There is a table which has a knock threshold set based on knock voltage. It's a very good place to start. You could also log the knock voltage that your motor puts out with no load on it, add 10% and adjust the table accordingly.

I don't have it on this computer, but I hope that someone can attach the total timing spreadsheet for you. It's quite helpful in understanding how everything comes together.

In all reality you just need to adjust the part and full throttle timing tables.

[Aries_Turbo]

http://www.squirrelpf.com/bucar/ecu%...5L%202-bar.xls

here is the one that i made years ago. i updated it with the values in the latest turbonator lm 2.5L mtx cal. (swirl head)

the timing values are determined by the AdvanceFromMapWarmFull, AdvanceFromMapWarmPart (depending on throttle position) added to the AdvanceFromRpm table values and added to the distributor advance value.

the other modifiers in the cal change the value as well but after the above tables determine the timing value.

knock retard.



depending on what RPM you are at this table determines how much knock voltage the knock sensor can produce before the computer deems it as knock. there are other tables that determine how much timing is pulled and how fast and how fast it is added back.

brian

[Force Fed Mopar]

Just to make it clear to people, the initial timing is NOT added into the total timing equation. Basically when you pull the coolant sensor plug and set the "timing" to 12 degrees, you are actually just syncing the hep and distributor cap to the computer.

[zin]

Just to make it clear to people, the initial timing is NOT added into the total timing equation. Basically when you pull the coolant sensor plug and set the "timing" to 12 degrees, you are actually just syncing the hep and distributor cap to the computer.

So I am clear on this.... The timing shown in the cal, and on a Scan Tool, will be the total timing. This number assumes the base timing of 12* (or whatever is called for on the emissions label) is there. So the number shown in a cal is not necessarily the number used in a calculation, correct?

I may be over-explaining, so I hope I'm not too confusing in my question.

Mike

[Force Fed Mopar]

The timing shown on a scan tool is total timing, yes. If you change the initial timing to 14*, you would have to add 2 degrees to that number because the computer has no way of telling that you added that 2* in. See what I mean?

[ShelGame]

So I am clear on this.... The timing shown in the cal, and on a Scan Tool, will be the total timing. This number assumes the base timing of 12* (or whatever is called for on the emissions label) is there. So the number shown in a cal is not necessarily the number used in a calculation, correct?

I may be over-explaining, so I hope I'm not too confusing in my question.

Mike

The 12* is just the fixed timing used to set the sync between the distributor and the crank. The reason they chose 12* is simply because an engine generally will not run @ 0* advance. The 12* is not a 'base' timing at all. It's simply a reference point. It never gets 'added' to anything. All the timing figures in the cal are relative to TDC (0*).

If the sync is in fact wrong (ie, you set the sync at 14* instead of 12*), then the actual timing will be off by the same amount. But, the ECU will not know about that difference and will not be able to report it to a scan tool.

[roachjuice]

ok i dont really get how to use the table.

[turbovanman²]

Great thread.

[roachjuice]

you know if i pull too much timing it gets a little blow out. if i dont take enough out then it knocks. i think im just gonna go back to the gary donovan way. just flood it with fuel. everytime i think i have this ---- figured out something else pops up.

[turbovanman²]

How do you get blowout if you take out timing? What tables are you adjusting?

[roachjuice]

Advancefullthrottle. I'm gonna try two things. Teflon tape it. And if that's not gonna work lower the timing some more. I figured -1 deg per psi of boost. Its at -22.31 right now at 20 psi of boost. Like honestly. HOW MUCH IS TOO MUCH!?!? No one has chimed in any of my threads and said "well my timing table for advancefullthrottle is here at this boost level with a 2.5. Try that." I know everyones car is different. If I pay someone for a tune I really don't think that will solve the problem. Because they aren't here with the car running in and out the house buring chips. My afr is flat and perfect! 11.1 and gets a bit rich above 4800. Like 10.6 at worst.

[Force Fed Mopar]

The problem is most people w/ a big turbo 2.5 are running g-heads, which are totally different timing wise. I get the same thing as you when I pull too much timing, feels like the spark blows out. It isn't really, but it feels like it.

I think the question that needs to be asked, is does the 2.5 require more or less timing than a 2.2?

[ShelGame]

I think the question that needs to be asked, is does the 2.5 require more or less timing than a 2.2?

Less timing for sure.

[Aries_Turbo]

10.6 afr doesnt help with high boost misfires either.

yeah you are better off tuning it yourself than getting a wild guess custom cal.

2.5 requires less timing than a 2.2L. the map timing tables look like they have a little more than a 2.2L but the govner rpm table has significantly less.

Brian

[roachjuice]

This is good info.

[Aries_Turbo]

by the way, there is a mistake on the 2.5L mtx turbonator lm cal on the AdvanceFromRPM2 table. its the same as the 2.2L table. compare it to the ATX 2.5L LM cal and add points and match that table. the atx table is the correct 2.5L one.

ill let rob know.

Brian

[roachjuice]

now thats good to know. geez i find ---- out all the time lol

[Aries_Turbo]

yeah i just found that out now.

Brian

[ShelGame]

It was fixed on V13.

Of course, no one but me seems to like MP Tune 2. So, I guess that's why everyone is using old stuff...