Torque limiting?

[Rich Z]

From what I can see, there is an EFILive limit on this value of 640 ft. lbs.

What happens if your car exceeds that limit?

Surely there are a number of cars using EFILive that easily surpass that power.

[gpr]

I have also wondered that. I know for a fact there are a lot of cars with more torque than that. My thoughts were most with that much torque would be force induction and using a COS so there is not torque limiting in those os?

[Rich Z]

I've got a COS in my tune, and I don't see anything in there that would negate the torque control. Heck, for that matter, I don't think it's all that tough these days to get a NA engine over 640 ft.lbs at the crank.

Speaking of which, could lowering the torque limit WAY DOWN be a quick and dirty way of creating a "valet mode" tune? I've got a tiger shark front bumper fascia I'm going to need to be painted and installed, and I certainly don't want to leave my car somewhere and have some yahoo take it out for a joy ride after hours and wrap it around a tree.

[hog]

This LPE product keeps an overtorque from being transmitted to the BCM in the TBSS's. So this must be an issue on that platform.
http://www.lingenfelter.com/mm5/merchant.mvc?Screen=PROD&Store_Code=LPE&Product_Code=L460021105&Category_Code=C163

Isnt a valet mode included in 1 of the COS's?

I wonder how close the calculated torque is to actual crankshaft torque?

peace
Hog

[ScarabEpic22]

This LPE product keeps an overtorque from being transmitted to the BCM in the TBSS's. So this must be an issue on that platform.
http://www.lingenfelter.com/mm5/merchant.mvc?Screen=PROD&Store_Code=LPE&Product_Code=L460021105&Category_Code=C163

Isnt a valet mode included in 1 of the COS's?

I wonder how close the calculated torque is to actual crankshaft torque?

peace
Hog

That was an issue back in 06/07, not an issue today. EFILive has the necessary Torque tables so you can raise the TQ limits and not get REP mode. I believe this module was developed to keep StabiliTrak from freaking out with the added TQ, but again the tables exist in the calibration now so I dont think you need this anymore.

Calculated TQ vs crankshaft TQ is an extremely good point, for the Gen III PCMs Im not sure you can do much regarding it (matching it up). Then Gen IV (E40 excluded) with the TQ Model means you can adjust the TQ output to match what you have from a dyno. It makes a HUGE difference in the way the ECM delivers power and the TCM shifts. There's a PID you can log that tells you what the ECM thinks the TQ output is, if you're on dyno you can adjust the TQ Model until it matches the dyno output.

[Rich Z]

Well, okey dokey... Since I DO have a Gen III PCM, is this or is this not an issue I need to be concerned about? I was getting close to 640 ft.lbs at the crank with my stock LS6 and the twin turbos having only 6.5 lb springs in the waste gates. Now with the 427 and 10 lb springs, well............... I didn't see any place to adjust the cap on the torque value.

[Rich Z]

That was an issue back in 06/07, not an issue today. EFILive has the necessary Torque tables so you can raise the TQ limits and not get REP mode. I believe this module was developed to keep StabiliTrak from freaking out with the added TQ, but again the tables exist in the calibration now so I dont think you need this anymore.


OK, darn if I can find the torque tables you speak of to change that upper limit. Can you throw a table number at me to help out?

I found B4360 which shows a max limit of 1280 ft.lbs for A/C torque loss correction. And of course there are B1901, B6611 and B6614 which show the MAX Allowed engine torque. Then there are tables B6615 thru B6620 showing various max torque values with an upper limit of 41943039 (!).

Sorry if I am missing something here...

[ScarabEpic22]

Rich, the module hog posted was for a TBSS aka E40/E67 so the tables wont match up with your LS1B PCM anyway.

Are you having an issue with the PCM pulling timing, fuel, something else at 640lbs?

[Rich Z]

Rich, the module hog posted was for a TBSS aka E40/E67 so the tables wont match up with your LS1B PCM anyway.

Are you having an issue with the PCM pulling timing, fuel, something else at 640lbs?

Well, no, as I have yet to even got WOT with the car. I'm spending much of my time just looking through the tables to get familiar with what I have to work with, and this LIMIT caught my eye.

So I figured this would be the place to ask about it where the developers hang out. Rather than wait to run into a problem, I want to know what WILL happen when my engine produces torque over that limit. Sure don't want to get a REP when I'm up near the top of my torque curve.

Surely I can't be the first person to ask this question? I tried doing a search on "torque limit", but that wasn't very productive. So is this REALLY a limit or what? If it is a REAL limit, then surely there must be a workaround. Otherwise a lot of guys producing decent power are going to get a severe disappointment when they hit that limit.

[joecar]

It seems to me that setting the LS1 max torque to 640 ftlm tells the PCM that there is no limit... I've seen various tunes easily making 700+ ftlb.

[Rich Z]

It seems to me that setting the LS1 max torque to 640 ftlm tells the PCM that there is no limit... I've seen various tunes easily making 700+ ftlb.

Yeah, I know. If it actually were a limit, I would think people would be screaming about this. But anyone know for sure about how this works?

Sure would have been a dirty trick if GM put in that limit into the PCMs, now wouldn't it?

[ScarabEpic22]

It seems to me that setting the LS1 max torque to 640 ftlm tells the PCM that there is no limit... I've seen various tunes easily making 700+ ftlb.

This is what I've seen as well, but I havent done many LS1 PCMs. I know guys making well over that, both at the wheels and flywheel with no issues.

But, Rich it's a great question. If you dont ask, it might bite you later on!

[GMPX]

Rich, I think it's just a mathematical limit (I haven't actually checked), so even if the engine is actually making more torque than that it'll still think 640ft-lb is where it's at.