: Torque Management



CaddyGeek
11-05-05, 02:31 AM
I didn't search for the answer, but can someone (or several members) explain what torque management is? I've read that the CTS-V and the C6 Z06 both suffer from this and yet I can't understand how this comes into play with a stick shift and a 4,000 rpm clutch drop or on a dyno graph in 4th or 5th gear...

Also, how does torque management save / preserve the drive train when the engine RPM is high enough to make peak power numbers?

Joey'sVee
11-05-05, 02:58 AM
I didn't search for the answer, but can someone (or several members) explain what torque management is? I've read that the CTS-V and the C6 Z06 both suffer from this and yet I can't understand how this comes into play with a stick shift and a 4,000 rpm clutch drop or on a dyno graph in 4th or 5th gear...

Also, how does torque management save / preserve the drive train when the engine RPM is high enough to make peak power numbers?

Good question...I wonder the same thing!!!

ewill3rd
11-05-05, 08:32 AM
As far as I know, torque management is just a function of the traction control system (TCS).
If the rear wheels start to break traction, the EBCM (Brake control module) sends a signal to the PCM to tell it to reduce engine torque output in order to regain traction. When the PCM sees this signal it reduces torque by retarding ignition timing, and turning off selected fuel injectors.
If it still can't regain traction it will begin applying the brakes.
There is typically a two wire setup going between each module. One wire tells the PCM what the "requested torque" is and the other coming back from the PCM tells the EBCM what the "delivered torque" is.
Looking at the schematics I see that the CTS-V is set up in exactly this fashion.

Hope that answers your question.

obzidian
11-05-05, 01:37 PM
ewill3rd hit it on the nail. T. M. is used to reduce the engine output for a predetermined amount of time until the issue, it being traction, miss-fire, or on an auto, in-between shifts. It hurts the performance because the engine is being told to produce less torque to induce less wheel spin or most likely, it was introduced to eliminate the amount of strain the driveline will recieve at any or specific situations like "zero to sixty in under 5 sec shananagans!!!"

Though the motor is capable of generating 400hp/395tq., it will fall under that in order to save itself, well in a way since it was programed for this.


The amount of TM can be viewed and disabled with a tuning software of your choice. But it should be done with care and knowledge of the available parameters for if done aimlessly, you'll end-up with a limping engine and it wont be covered under warranty!!! There are a few programs ls1edit, hptuners (i own this one for my Z28 with a 408 stroker), efilive, and a few others.

04CTSVFLA
11-05-05, 03:14 PM
when you turn t/c off and turn into comp mode, is TM inactive?

ewill3rd
11-05-05, 03:17 PM
When Traction is turned off the torque management feature should be disabled. It's just a software function of the traction control system.

CaddyGeek
11-07-05, 08:31 PM
ewill,

Thanks for the reply. Sounds ok to me...

I bumped this to get a few more people to chime in because I recall TM being a question asked by one of the tuners (stealth?)... as in do you want to disable TM? If TM not an issue with TC turned all the way off, then it doesn't completely make sense why you would want to disable it. Must be murder on the brake pad life in the rain / wet weather with the TC left on because the computer can't retard the engine timing.

Am I off base guys?

Luna.
11-07-05, 08:51 PM
When Traction is turned off the torque management feature
should be disabled.

I've heard this rumor--can anyone confirm?

V Amazed
11-07-05, 09:40 PM
from prior experience with different cars, i call BS on this one.

Ben

ewill3rd
11-07-05, 09:44 PM
First here is a quote from description and operation out of the service manual.


When drive wheel slip is noted while the brake is not applied, the EBCM will enter traction control mode.

First, the EBCM requests the ECM to reduce the amount of torque to the drive wheels via the requested torque signal circuit. The ECM reduces torque to the drive wheels by retarding spark timing and turning off fuel injectors. The ECM reports the amount torque delivered to the drive wheels via the delivered torque signal circuit.

If the engine torque reduction does not eliminate drive wheel slip, the EBCM will actively apply the drive wheel brakes. During traction control braking, hydraulic pressure in each drive wheel circuit is controlled to prevent the drive wheels from slipping. The master cylinder isolation valve closes in order to isolate the master cylinder from the rest of the hydraulic system. The prime valve then opens in order to allow the pump to accumulate brake fluid in order to build hydraulic pressure for braking. The drive wheel inlet and outlet solenoid valves then open and close in order to perform the following functions:

Pressure hold
Pressure increase
Pressure decrease

ewill3rd
11-07-05, 09:49 PM
I am trying to think of the best place to look for a difinitive answer on the torque management thing.

I know automatic transmissions use TM to control shift points also, but on a stick it shouldn't matter.

Blacksport350
11-08-05, 03:14 PM
I am trying to think of the best place to look for a difinitive answer on the torque management thing.
I know automatic transmissions use TM to control shift points also, but on a stick it shouldn't matter.

I'm surprised StealthV hasn't chimed in as he knows the answer! :D

globed70
11-08-05, 04:24 PM
I've asked this question more than a few times, and heard plausible stories, but NO FACTS. The tuners I have asked have talked about reducing it for good effect, but still NO FACTS.

alcast082
11-08-05, 07:26 PM
With tc off Torque management is still on!!!!!!!!!
:banghead:
It makes a big difference when the tuner disables or lessens torque management:D

CaddyGeek
11-09-05, 01:32 AM
bump

V Amazed
11-09-05, 02:58 AM
With tc off Torque management is still on!!!!!!!!!
:banghead:
It makes a big difference when the tuner disables or lessens torque management:D

Bingo.

Ben

lawfive
11-09-05, 03:45 PM
Rick's on a business trip; you may not hear from him until November 21.

timmayz
11-09-05, 08:33 PM
Supposedly my 03 Silverado with 5.3 has Torque management as well, but ain't got no T/C. I think it is just the computer limiting torque at certain times (aka choking back the motor when you want it most...). Another ECM tuner who sells his stuff on www.gm-trucks.com (http://www.gm-trucks.com) turns off TM for LS powered trucks along with other adjustments of course...

StealthV
11-09-05, 11:11 PM
Sorry for the delay; the wireless interent here at the hotel has been extremely flakey all week.

Without having the tuning software handy, the best I can remember is the V is torque limited to something like 340 ft-lbs of calculated engine output. This value can be raised independent of the traction control system.

For Silverados (or any other Gen III V8 with a slushbox), removing TM really wakes up the vehicle; my Silverado SS is slightly more violent than stock. :lildevil:

After this week's trip in the States is over, I'm off to Italy for a week. Wonder what rental car I'll get from Europcar? At least I did reserve one with a stick but will probably be some anemic POS. God bless America and push-rod V8s. :)

rbrown81
08-17-06, 01:23 AM
Without having the tuning software handy, the best I can remember is the V is torque limited to something like 340 ft-lbs of calculated engine output. This value can be raised independent of the traction control system.

For Silverados (or any other Gen III V8 with a slushbox), removing TM really wakes up the vehicle; my Silverado SS is slightly more violent than stock. :lildevil:


Sorry to revive an old thread, but I need to ask a couple of questions.

1. How easy is it to edit the specfied torque using a programmer? Can you use a programmer such as the predator or ls1edit to change the torque figure?

2. Can the differential in the 2004 CTS-V handle 395 ft-lbs of torque?

Thanks!

atdeneve
08-17-06, 06:16 AM
Wow, that is absolutely nutballs! What the hell is that?! I want all 395 ft-lbs of my engine's torque, not no wussified 340 max. What kind of horseshit is that?

That makes no sense at all to me. The engine produces 395 ft-lbs of torque, but the computer dumbs it down to 340? Absolute stink balls. I need a tune. Gez-Lu-Ez.

rbrown81
08-17-06, 10:24 AM
Wow, that is absolutely nutballs! What the hell is that?! I want all 395 ft-lbs of my engine's torque, not no wussified 340 max. What kind of horseshit is that?

That makes no sense at all to me. The engine produces 395 ft-lbs of torque, but the computer dumbs it down to 340? Absolute stink balls. I need a tune. Gez-Lu-Ez.

Lol

Couldnt have said it better myself.

hurley64
08-17-06, 10:52 AM
HHMMM...I might have to call BS on that one....I just had my V dynoed recently and made 323 TQ. That 340 number was pulled out of someones' ASS.

I will caveat with this, vehicle speed is taken into consideration by the on board ecm, there is some built-in tq management in the lower gears, i dont know if this is completely removable. I know that my tuner was able to bump my stock TQ up to 342.

Hope this helps...

John

HushH
08-17-06, 11:34 AM
HHMMM...I might have to call BS on that one....I just had my V dynoed recently and made 323 TQ. That 340 number was pulled out of someones' ASS.

I will caveat with this, vehicle speed is taken into consideration by the on board ecm, there is some built-in tq management in the lower gears, i dont know if this is completely removable. I know that my tuner was able to bump my stock TQ up to 342.

Hope this helps...

John

I think the discrepancy may be in RW vs. crank numbers.

rbrown81
08-20-06, 06:11 PM
I want me torque to be 395 at the crank, whatever that translates into at the wheels.

The Tony Show
08-20-06, 08:06 PM
The answer is pretty simple. The above dyno number doesn't really tell the story, since it's just a peak number. Torque management doesn't affect the peak, it affects how rapidly torque is applied.

Systems such as Traction Control and Stability Control are reactive- When sensors feed information to the car that are interpreted as loss of traction or stability, the car responds with the appropriate action (reduction of throttle and torque, followed by braking at one or more wheel).

Torque Management is a preventive, or proactive measure that limits the amount of torque that can be suddenly applied in situations such as shifting. Even though you floor the throttle after shifting from 1-2, you don't get the full dose of torque immediately. Instead, it gradually ramps it up to avoid exploding driveline parts and sudden loss of traction.

Disabling it will allow for better 0-60 times and quicker throttle response, but without responsible driving could lead to even quicker destruction of differentials and half-shafts.

austin
08-21-06, 01:53 AM
Isn't this a feature in tuning software used just for the automatic transmission vehichles?

ewill3rd
08-21-06, 06:49 AM
Torque management is controlled by the EBCM and the PCM.
It's part of the traction system. It's not designed to limit the output of the powertrain, it's designed to keep you from killing yourself.

The auto/manual trans is an interesting question, however I am sure that, even though computer up or down shifting is not an option on a manual, the system still works with engine management and ABS to help control the power applied to the wheels under certain conditions.
From what I have been taught, this feature only works to help maintain traction, and possibly works with stabilitrak to maintain vehicle control and prevent understeer and oversteer.

The Tony Show
08-21-06, 12:42 PM
Torque Management and Traction control are two different animals enitrely. While they both reduce torque by adjusting timing and throttle position, one works before a slip and the other works after.

Mazda runs a similar system on their RX-8. When datalogging and working on a tune for that car, we found that the computer wasn't giving throttle in the same manner we asked it for during shifts. Even with full "to the floor" throttle after a shift, it was gradually feeding throttle up to 100%. If you spun the tires, then the TC would kick on and reduce it even more.

austin
08-21-06, 02:14 PM
>I want all 395 ft-lbs of my engine's torque, not no wussified 340 max. What kind of horseshit is that?

Me too... I realy wish they would use net hp instead of providing gross in there specifications. I was so charged up when i got mt "V"... "400 hp 395 fptq". I was shocked when i saw cts-v dyno figures from other members postings. It seems like in the old days they were more accurate, as most cars were considered "under-rated"... A problem i wish the "V" had!!

wildwhl
08-21-06, 10:02 PM
Somebody like StealthV can spell this out much more clearly than I, so I shouldn't even try.

Basically, think of it this way. TM isn't reducing torque unless another control module is requesting it (at least this is how I see it). TM and TC aren't bad things - just ask urby :burn:

You're getting all of the power from the LS6 if all systemsd are "go". I seriously doubt that TM is affecting dyno #'s on the V the way they do on the RX8. The various systems in the RX8 make it nearly impossible to get an accurate dyno without disassemblying and disabling half of them.

Of course, there's also abuse management :stirpot:

WW

The Tony Show
08-22-06, 09:42 AM
You're right about dynoing an RX-8- unless you disconnect the wheel speed sensors it goes crazy, but that isn't what I was talking about. Driving on the road, if you floor it after a shift the throttle position did a "40%-60%-80%-100%" in the span of a second or two. It was pre-emptively trying to keep the rear wheels from spinning on a shift.

My point is that TM is working under certain conditions even if a slip isn't detected. If TM was tied into the TC, why would Stealth offer to disable it? If that were the case, you could just thumb the TC button on the wheel.

wildwhl
08-22-06, 09:05 PM
Tony Orlando and :yawn:

Sorry - couldn't resist :D

You win...

WW

Team ZR-1
08-23-06, 11:18 PM
I have been custom tuning GM cars/trucks for over 10 years and most do not understand what TM is verus what TC is.

With electronics the power and drivetrains have much more can be controlled or regulated.
Easy way is to control fuel flow ( injector ON time ) throttle angle ( controlled by TAC module) of drive by wire, torque converter and timing.

TM is not just for safety features but also to protect the drivetrain for warranty reasons

The engine can put out more torque then the specs of the trannie or rearend was designed for.

TM is not limiting the maximum torque allowed but a sudden spike of torque that would stress the drivetrain or cause car to loss traction or wheelhop

TM works on any trannie type, for Mx6 types upshifts are monitored.
For auto types it also looks for abuse and can also unlock the torque convertor and limit injector flow.

It is unwise to turn TM off during a ECM tune for that renders safety features and I have seen many Corvettes then get loose and crash.

Proper tuning of the TM tables in the PCM will allow better performance but still maintain safety functions.

The ECM can be smarter then us for realtime data and instead of costing time of wheel spin is it reduces timing to reduce performance and better traction, limit wheelhop and lessen engine from sudden cylinder pressure and cause knock

Well tuned TM via tuning will allow car to perform much better over all engine loads where turning TM off could cost performance overall plus long term stress on drivetrain to reduce it's live and cause loss of parts like halfshafts or bent shifting forks.

Newer trannies like the A6 used on C6 Corvettes and it gets worse since it has it's own internal controller and can relearn how someone drives the car and adapts more then older A4s do.

JR

ewill3rd
08-24-06, 09:15 AM
You know I become more curious all the time.
I hear people talk so matter of factly about these things but I am just wondering what all this is based on.

Where do you gather information like this on Torque management systems?
I have never seen any documentation to state that GM uses TM to reduce power output to protect components....?

Maybe I am thinking of something that is different but the EBCM and PCM have circuitry running between them in the form of a "torque requested" and "torque delivered" circuit respectively. These circuits are used to control wheel slip in either acceleration or deceleration and for stability control by VSES.
Everything else is simply managed by the PCM to control emissions and engine output based on inputs and the algorithms in the PCM.
In the few thousand hours of GM training that I have gone through no one has ever told me that we use TM to "prevent damage" to parts.

If you could point me in the direction of your information source I would appreciate it. I don't like being in the dark.

Thanks for any info you can pass my way.

2004ctsv
08-24-06, 09:37 AM
In the few thousand hours of GM training that I have gone through no one has ever told me that we use TM to "prevent damage" to parts.

I don't know if it's true or not, but what's the problem with "preventing damage to parts"? I think it's pretty good. And we can block a lot of it out anyhow with the button on the steering wheel.

ewill3rd
08-24-06, 10:39 AM
I think it would be a great idea, I just don't think they do it that way.

Not trying to argue, I just want to be sure I understand if someone asks me what it's for. I thought I knew but I keep hearing more and more.
Just wanted to base what I know on facts. No offense intended.

I do see where they use it on many transmissions to protect the clutches (automatics) during shifting, specifically the Allison 5 and 6 speed autos.