Torque management question
09-17-2014, 08:26 PM
#1
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Torque management question
Is there a ecm torque management AND a tcm torque management (on the automatic).
Is it OK to reduce or remove the TQM on the tcm? I was told not to because the gears will walk on each other during shifts. True?
Is it OK to reduce or remove the TQM on the tcm? I was told not to because the gears will walk on each other during shifts. True?
09-18-2014, 09:08 AM
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be very careful what you do when it comes to altering the torque tables in the E92.
09-20-2014, 06:13 PM
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it's predicted based on stock configuration and factory measurements.
when you modify the airflow capabilities, now you must also modify the values that tell the engine what power it is making (as well as all the normal tuning items)......it's a work in progress for every tuner out there, the known items are altered but there may be more in there that the code crackers haven't found yet.
for example, idle and cold start on a lot of cammed cars is not even close to as good as with the Ls motors and computers. issues with the throttle closing at wide open throttle and other new opportunities have presented themselves to the tuning community, some solved, some not (yet).
when you modify the airflow capabilities, now you must also modify the values that tell the engine what power it is making (as well as all the normal tuning items)......it's a work in progress for every tuner out there, the known items are altered but there may be more in there that the code crackers haven't found yet.
for example, idle and cold start on a lot of cammed cars is not even close to as good as with the Ls motors and computers. issues with the throttle closing at wide open throttle and other new opportunities have presented themselves to the tuning community, some solved, some not (yet).
09-20-2014, 07:31 PM
#5
Safety Car
Well, I suppose this is the way to go to save weight. Aircraft design has faced this dilemma for ages. Jeremy Clarkson said that the F12 had too much power. It has a very heavy DCT which apparently can do the job but poor traction is more effective in limiting torque but that can kill you.
How do you measure torque other than on a dyno? From there you calculate HP. The only way I can think of is to place a sensor on either end of the drive shaft and measure the twist like they do on ship's drive shafts. It is always wise to design a weak link in any system. A clutch slip is the cheapest way or a torque converter. Tire technology has upped the necessity for torque limitation elsewhere.
Nissan and Porsche limit loads by transferring torque to other clutch systems electronically together with engine management. Cars are going the way of aircraft in this regard and Corvette is no different. Class 8 trucks can design for it without weight considerations. F458s replace their clutches every 2500 miles.
The output shaft on the gearbox could be another place to measure torque the same way as you would do it on the drive shaft but it gets very expensive like it is on aircraft.
You could measure crankshaft acceleration and throttle position and gear selection and determine torque but it doesn't cover all contingencies and is not accurate.
IEM (International Electronic Machines) makes torque measuring systems in aircraft engines and helicopter shafts. Helicopters and turbo prop aircraft have had torque limiting mechanisms since the 70s which are easily over ridden by pilot error.
There is an increasing need for an accuracy of less than 2% methods for measuring the torque in aircraft and with ever increasing torque in modern vehicles with low mass drive trains. Can production cars be far behind? F1 is already there at aircraft standards.
Current methods are expensive and suffer from a number of other flaws including complicated manufacturing/installation issues and limited accuracy of 5% or more.
IEM Corp's sensor instrumentation technology for transportation applications has developed a non-contacting torque sensor for helicopter tail rotor drive systems which could be applied to Vette drive shafts cheaply. IEM's encoder technology achieve accuracies of 1% and less.
The system is able to log data for analysis or use in fatigue models, for tracking transient loads and adaptable to various shaft locations. This means you can replace parts on your Vette before they fail.
Without this technology, cars can become quite dangerous. F12s and Veyrons are cases in point. Very few people could drive early Vipers.
Watch for communist legislator intervention soon.
How do you measure torque other than on a dyno? From there you calculate HP. The only way I can think of is to place a sensor on either end of the drive shaft and measure the twist like they do on ship's drive shafts. It is always wise to design a weak link in any system. A clutch slip is the cheapest way or a torque converter. Tire technology has upped the necessity for torque limitation elsewhere.
Nissan and Porsche limit loads by transferring torque to other clutch systems electronically together with engine management. Cars are going the way of aircraft in this regard and Corvette is no different. Class 8 trucks can design for it without weight considerations. F458s replace their clutches every 2500 miles.
The output shaft on the gearbox could be another place to measure torque the same way as you would do it on the drive shaft but it gets very expensive like it is on aircraft.
You could measure crankshaft acceleration and throttle position and gear selection and determine torque but it doesn't cover all contingencies and is not accurate.
IEM (International Electronic Machines) makes torque measuring systems in aircraft engines and helicopter shafts. Helicopters and turbo prop aircraft have had torque limiting mechanisms since the 70s which are easily over ridden by pilot error.
There is an increasing need for an accuracy of less than 2% methods for measuring the torque in aircraft and with ever increasing torque in modern vehicles with low mass drive trains. Can production cars be far behind? F1 is already there at aircraft standards.
Current methods are expensive and suffer from a number of other flaws including complicated manufacturing/installation issues and limited accuracy of 5% or more.
IEM Corp's sensor instrumentation technology for transportation applications has developed a non-contacting torque sensor for helicopter tail rotor drive systems which could be applied to Vette drive shafts cheaply. IEM's encoder technology achieve accuracies of 1% and less.
The system is able to log data for analysis or use in fatigue models, for tracking transient loads and adaptable to various shaft locations. This means you can replace parts on your Vette before they fail.
Without this technology, cars can become quite dangerous. F12s and Veyrons are cases in point. Very few people could drive early Vipers.
Watch for communist legislator intervention soon.
Last edited by Shaka; 09-20-2014 at 07:49 PM.
10-03-2015, 03:39 AM
#6
Old thread but im curious...Seems like torque managment is whats hurting these cars,Are tunes nowdays eliminating Tq Mang r reducing it ?? Also i read that the cars throttle body doesn't openn 100% till 3600 rpm??
10-03-2015, 07:59 AM
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torque management has been reducing performance for 15 years or more. the only difference is now the ECM is torque based rather than airflow based so how one handles the torque model is different.
you still have to do all the normal tuning stuff, just that now you can't "eliminate" the torque model, you have to shape it. so far, we can manipulate the shape with a hammer, hopefully as the "decoding companies" reveal more information and the people who use the software understand the complex relationships between the tables in the programs, we will put away the torque model hammer and get out the scalpel.
It's true, you don't get full throttle until higher up in the RPMs, but I think this is one of the big reasons the car is so easy to launch for so many people for good 60 ft times. You don't have to know how to drive! ;-) besides, after the initial launch, you are never below that RPM level again....
you still have to do all the normal tuning stuff, just that now you can't "eliminate" the torque model, you have to shape it. so far, we can manipulate the shape with a hammer, hopefully as the "decoding companies" reveal more information and the people who use the software understand the complex relationships between the tables in the programs, we will put away the torque model hammer and get out the scalpel.
It's true, you don't get full throttle until higher up in the RPMs, but I think this is one of the big reasons the car is so easy to launch for so many people for good 60 ft times. You don't have to know how to drive! ;-) besides, after the initial launch, you are never below that RPM level again....
10-03-2015, 10:51 AM
#8
Yeah but maybe good 60ft times for people who mess around on street tires,but its not so good for a drag racer with a sticky tire on back...we need the car to be free and let the sticky tires do their job.. so higg do u think eventually someone will firgure it out,or is it that the tuning software that out isnt able to mess with everything??
10-03-2015, 12:13 PM
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Yeah but maybe good 60ft times for people who mess around on street tires,but its not so good for a drag racer with a sticky tire on back...we need the car to be free and let the sticky tires do their job.. so higg do u think eventually someone will firgure it out,or is it that the tuning software that out isnt able to mess with everything??
we are learning every day how to shape the torque model and more is being decoded as well.
most of it is decoded and available and we know what to do with it. 90% was available in 2013! opening up the power and throttle, etc is easily done with a tune today.
don't get me wrong, if you are staying naturally aspirated, there are no limitations with a tune. in fact, even making 1000 rwhp with a blower is done at will, so it is arguably no longer an issue.....do we have everything we need to make it perfect? i don't think so. does it work ok? yes, for sure.....again, that is for blown big power stuff....under 700 rwhp or so is no problem.
10-09-2015, 12:51 AM
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St. Jude Donor '13-'14-'15
The TQ management system on the E92 ECM is far different than ever before--Depending on whose software you use HP or EFILIVE the TQ management systems are described completely different
On an E38 ECM (C6) with EFILIVE TQ control was accomplished by a simple yes or no option
Those options were for:
Axle protection
T/C TQ reduction
Wheel hop
Clunk reduction
Throttle tip in
TCS max TQ (controlled by actual TQ numbers)
On the C7 E92 there is nothing like this
TQ management is now called "TQ Response" and TQ TCS control
In TQ control you can change the TQ limits with the TC button ON
In TQ Response you can "ask" for a certain amount of TQ and the ECM will try to get it up to the max amount it can by adjusting spark timing and fuel all on it's own
Even if you only have commanded like 20* of timing in your tune say at 3000 RPM's IF you asked the ECM to try and make more HP and TQ at that level it may add a lot of timing--all the way up to 30*----
The TQ management during shifts now is achieved by momentarily shutting off the fuel during shifts on an auto trans---hence the sputter at WOT shifts---Never before used---These tables are all in the engine file and not the TCM file--- and seem to over-ride any engine tuning during shifting ---other than "minimal final timing" which above 3600 RPM's there is no need to alter as that's where the sputter shift begins--Below 3600 Yes you can increase min final timing as it has little affect on below 3600 shifting--but can increase your car's response at lower RPM's
There are also a few new tables in the ECM that control TQ all the time---The greatest one being that No matter if you floor the throttle--The blade will never go to WOT until you hit apprx 3600 RPM's----That sucks !! However it is tunable to allow WOT off idle
EFILIVE is constantly adding new tables to the E92 ECM--and fine tuning is now become more aggressive and easy to figure out----
On an E38 ECM (C6) with EFILIVE TQ control was accomplished by a simple yes or no option
Those options were for:
Axle protection
T/C TQ reduction
Wheel hop
Clunk reduction
Throttle tip in
TCS max TQ (controlled by actual TQ numbers)
On the C7 E92 there is nothing like this
TQ management is now called "TQ Response" and TQ TCS control
In TQ control you can change the TQ limits with the TC button ON
In TQ Response you can "ask" for a certain amount of TQ and the ECM will try to get it up to the max amount it can by adjusting spark timing and fuel all on it's own
Even if you only have commanded like 20* of timing in your tune say at 3000 RPM's IF you asked the ECM to try and make more HP and TQ at that level it may add a lot of timing--all the way up to 30*----
The TQ management during shifts now is achieved by momentarily shutting off the fuel during shifts on an auto trans---hence the sputter at WOT shifts---Never before used---These tables are all in the engine file and not the TCM file--- and seem to over-ride any engine tuning during shifting ---other than "minimal final timing" which above 3600 RPM's there is no need to alter as that's where the sputter shift begins--Below 3600 Yes you can increase min final timing as it has little affect on below 3600 shifting--but can increase your car's response at lower RPM's
There are also a few new tables in the ECM that control TQ all the time---The greatest one being that No matter if you floor the throttle--The blade will never go to WOT until you hit apprx 3600 RPM's----That sucks !! However it is tunable to allow WOT off idle
EFILIVE is constantly adding new tables to the E92 ECM--and fine tuning is now become more aggressive and easy to figure out----
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10-09-2015, 05:43 PM
#11
The TQ management system on the E92 ECM is far different than ever before--Depending on whose software you use HP or EFILIVE the TQ management systems are described completely different
On an E38 ECM (C6) with EFILIVE TQ control was accomplished by a simple yes or no option
Those options were for:
Axle protection
T/C TQ reduction
Wheel hop
Clunk reduction
Throttle tip in
TCS max TQ (controlled by actual TQ numbers)
On the C7 E92 there is nothing like this
TQ management is now called "TQ Response" and TQ TCS control
In TQ control you can change the TQ limits with the TC button ON
In TQ Response you can "ask" for a certain amount of TQ and the ECM will try to get it up to the max amount it can by adjusting spark timing and fuel all on it's own
Even if you only have commanded like 20* of timing in your tune say at 3000 RPM's IF you asked the ECM to try and make more HP and TQ at that level it may add a lot of timing--all the way up to 30*----
The TQ management during shifts now is achieved by momentarily shutting off the fuel during shifts on an auto trans---hence the sputter at WOT shifts---Never before used---These tables are all in the engine file and not the TCM file--- and seem to over-ride any engine tuning during shifting ---other than "minimal final timing" which above 3600 RPM's there is no need to alter as that's where the sputter shift begins--Below 3600 Yes you can increase min final timing as it has little affect on below 3600 shifting--but can increase your car's response at lower RPM's
There are also a few new tables in the ECM that control TQ all the time---The greatest one being that No matter if you floor the throttle--The blade will never go to WOT until you hit apprx 3600 RPM's----That sucks !! However it is tunable to allow WOT off idle
EFILIVE is constantly adding new tables to the E92 ECM--and fine tuning is now become more aggressive and easy to figure out----
On an E38 ECM (C6) with EFILIVE TQ control was accomplished by a simple yes or no option
Those options were for:
Axle protection
T/C TQ reduction
Wheel hop
Clunk reduction
Throttle tip in
TCS max TQ (controlled by actual TQ numbers)
On the C7 E92 there is nothing like this
TQ management is now called "TQ Response" and TQ TCS control
In TQ control you can change the TQ limits with the TC button ON
In TQ Response you can "ask" for a certain amount of TQ and the ECM will try to get it up to the max amount it can by adjusting spark timing and fuel all on it's own
Even if you only have commanded like 20* of timing in your tune say at 3000 RPM's IF you asked the ECM to try and make more HP and TQ at that level it may add a lot of timing--all the way up to 30*----
The TQ management during shifts now is achieved by momentarily shutting off the fuel during shifts on an auto trans---hence the sputter at WOT shifts---Never before used---These tables are all in the engine file and not the TCM file--- and seem to over-ride any engine tuning during shifting ---other than "minimal final timing" which above 3600 RPM's there is no need to alter as that's where the sputter shift begins--Below 3600 Yes you can increase min final timing as it has little affect on below 3600 shifting--but can increase your car's response at lower RPM's
There are also a few new tables in the ECM that control TQ all the time---The greatest one being that No matter if you floor the throttle--The blade will never go to WOT until you hit apprx 3600 RPM's----That sucks !! However it is tunable to allow WOT off idle
EFILIVE is constantly adding new tables to the E92 ECM--and fine tuning is now become more aggressive and easy to figure out----
10-09-2015, 06:29 PM
#12
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10-09-2015, 06:50 PM
#13
10-09-2015, 07:40 PM
#14
Drifting
How does one launch my mostly stock Z51 A8 with Mag Ride at the Strip. I tried everything last Fri. nite. (made 15+ runs - temp was 60 deg). Had only 3 runs where 60's were in the 1.9's. Best runs were after a heavy burnout and then turning on the T/C and making my passes in Touring. They were only running 1/8 mi and my best was a 7.95 @ 93.4 mph. My G8 on DR's gets 1.7's and runs in the low 12's consistently, so this was like a completely new experience for me. I had 60's as high 2.3 when I couldn't get any traction using the launch control feature. Felt and looked like my first time ever!~
Definitely need DR's.
Definitely need DR's.
10-12-2015, 03:05 AM
#15
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St. Jude Donor '13-'14-'15
It is a double edged sword-----IF you turn the TC OFF and have your ECM tuned to hit WOT off idle---these cars have so much TQ and HP that all you will do is spin the tires uncontrollably------
With the TC on whether or not you have the t-body tuned to hit WOT off idle the TC system will override it and you will still get 2.0 or more 60' times
From my own experience---The best route is to have it tuned to hit WOT off idle and run it with the TC OFF however this will take many runs to get the perfect balance of spinning and bogging off the line----Of course with drag radials or sticky tires that learning curve shortens-------With stock tires and a tune to allow WOT off idle you will have to balance feathering the throttle off the line just enough to allow a little tire spin then hit it WOT just right---and you should eventually be able to learn and hit consistent sub 1.80 60' times as well as sub 12 second runs---
Plain fact with the TC on you will never get better than a 2.00 60' time and more like a 2.2 tuned or not
With the TC on whether or not you have the t-body tuned to hit WOT off idle the TC system will override it and you will still get 2.0 or more 60' times
From my own experience---The best route is to have it tuned to hit WOT off idle and run it with the TC OFF however this will take many runs to get the perfect balance of spinning and bogging off the line----Of course with drag radials or sticky tires that learning curve shortens-------With stock tires and a tune to allow WOT off idle you will have to balance feathering the throttle off the line just enough to allow a little tire spin then hit it WOT just right---and you should eventually be able to learn and hit consistent sub 1.80 60' times as well as sub 12 second runs---
Plain fact with the TC on you will never get better than a 2.00 60' time and more like a 2.2 tuned or not