Would the Corvette Be Better With Torque Vectoring?
10-13-2015, 01:50 PM
#1
CorvetteForum Editor
Thread Starter
Would the Corvette Be Better With Torque Vectoring?
Perhaps Chevy might want to consider swapping the Corvette’s current eLSD system for a torque vectoring system.
Read the rest on the Corvette Forum homepage. >>
10-13-2015, 02:01 PM
#2
This article has nothing to do with the corvette at all. All it says is that hey look at this other car, that didn't start with the E-LSD, our do-dad made it better.
Then it goes on to say, why not use this in the corvette. The article assumes that this would be better than the E-LSD. Even when no such comparison has been done.
Then it goes on to say, why not use this in the corvette. The article assumes that this would be better than the E-LSD. Even when no such comparison has been done.
10-13-2015, 02:17 PM
#3
Le Mans Master
Nuclearranger is correct, though it would be at least "interesting" to compare the E-LSD to the TV system. Not sure that can be done without meeting significant engineering challenges just to set up the comparo.
The article may have stated elsewhere, though not in the part we saw, that TV adds $1800 to the price of the Lexus. The lap time was reduced by 4/10 of a second, which is a 1.2% improvement at the track, virtually zero in street driving. I really don't see many (any?) Lexus buyers shelling out the extra dough for TV if they know the marginal improvement they will be buying. Even less will buy it if they realize such improvement will only be realized when on the very edge of extreme handling challenges.
The article may have stated elsewhere, though not in the part we saw, that TV adds $1800 to the price of the Lexus. The lap time was reduced by 4/10 of a second, which is a 1.2% improvement at the track, virtually zero in street driving. I really don't see many (any?) Lexus buyers shelling out the extra dough for TV if they know the marginal improvement they will be buying. Even less will buy it if they realize such improvement will only be realized when on the very edge of extreme handling challenges.
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Nuclearranger (10-13-2015)
10-13-2015, 04:34 PM
#4
The new Z is already faster around the track.. Lets not waste valuable R&D money of the vette program for a diff that shaves .000x off the lap times... Thats a bit of tech geek mentality(no offense). I think the money would be better spent on cooling and adding a bit more power...No one wants to blow their engine, have reduced power or lose to a helltrash.
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Nuclearranger (10-13-2015)
10-14-2015, 08:20 AM
#6
Race Director
I'll wait for the Flux Capacitor.
10-14-2015, 09:35 AM
#7
Guys, torque vectoring is simply a different name for exactly what the eLSD does. Or better yet, explain to me what "torque vectoring" does that the eLSD doesn't do.
Limited Slip Differential
The track-oriented Z51 Performance Package features an intelligent electronic limited-slip differential (eLSD). The module attempts to make the most of the torque split between the rear wheels.
The setup features a hydraulically-actuated clutch that can infinitely vary clutch engagement and respond from open to full engagement in tenths of a second. The eLSD utilizes a unique algorithm to shift torque based on factors such as vehicle speed, steering input, and throttle position — all to improve steering feel, handling balance, and traction.
“The electronic limited-slip differential transforms the Stingray by optimizing handling for the driving situation,” said Mike Bailey, vehicle systems engineer, chassis. “By continuously modulating the torque split between the rear wheels, the eLSD can improve traction accelerating out of corner, improve stability on the highway and enhance steering turn-in and responsiveness.”
Far from being an isolated feature, the eLSD is fully integrated with the Stingray’s StabiliTrak and Performance Traction Management systems. Calibrations vary among three modes, based on the Drive Mode Selector setting:
Mode 1: the default setting for normal driving that emphasizes vehicle stability
Mode 2: engaged when electronic stability control is turned off in the Sport or Track Driver Modes. This calibration enables more nimble turn-in and traction while accelerating out of a corner
Mode 3: automatically selected when Performance Traction Management is engaged. This calibration has the same function as Mode 2, but is fine-tuned to work with Performance Traction Management.
The track-oriented Z51 Performance Package features an intelligent electronic limited-slip differential (eLSD). The module attempts to make the most of the torque split between the rear wheels.
The setup features a hydraulically-actuated clutch that can infinitely vary clutch engagement and respond from open to full engagement in tenths of a second. The eLSD utilizes a unique algorithm to shift torque based on factors such as vehicle speed, steering input, and throttle position — all to improve steering feel, handling balance, and traction.
“The electronic limited-slip differential transforms the Stingray by optimizing handling for the driving situation,” said Mike Bailey, vehicle systems engineer, chassis. “By continuously modulating the torque split between the rear wheels, the eLSD can improve traction accelerating out of corner, improve stability on the highway and enhance steering turn-in and responsiveness.”
Far from being an isolated feature, the eLSD is fully integrated with the Stingray’s StabiliTrak and Performance Traction Management systems. Calibrations vary among three modes, based on the Drive Mode Selector setting:
Mode 1: the default setting for normal driving that emphasizes vehicle stability
Mode 2: engaged when electronic stability control is turned off in the Sport or Track Driver Modes. This calibration enables more nimble turn-in and traction while accelerating out of a corner
Mode 3: automatically selected when Performance Traction Management is engaged. This calibration has the same function as Mode 2, but is fine-tuned to work with Performance Traction Management.
Last edited by mjw930; 10-14-2015 at 09:44 AM.
10-14-2015, 10:33 AM
#8
Race Director
This article has nothing to do with the corvette at all. All it says is that hey look at this other car, that didn't start with the E-LSD, our do-dad made it better.
Then it goes on to say, why not use this in the corvette. The article assumes that this would be better than the E-LSD. Even when no such comparison has been done.
Then it goes on to say, why not use this in the corvette. The article assumes that this would be better than the E-LSD. Even when no such comparison has been done.
10-14-2015, 11:24 AM
#9
E-Ray, 3LZ, ZER, LIFT
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https://www.corvetteforum.com/forums...rack-mode.html As he said, he was willing to discuss what they do, despite the fact that it gives info to the competition! I am surprised at all the info he provides in his answers! Don't see any other Chief Engineers providing this info detail!
Looks like this would be a step backward, unless you would want to put it on a C6 or earlier Vette. IMO, no way you'd integrate the computer, sensor driven eLSD in an old Vette.
Last edited by JerryU; 10-14-2015 at 11:28 AM.
10-15-2015, 12:51 PM
#10
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Hmm, just read the Car & Driver article, doesn't say that much about how it works and the GM patented eLED appears to me to be much more sophisticated and it's integrated with all the other electronic stability control features. Look at Tadge's answer to a question about variations in controls with various Mode settings:
https://www.corvetteforum.com/forums...rack-mode.html As he said, he was willing to discuss what they do, despite the fact that it gives info to the competition! I am surprised at all the info he provides in his answers! Don't see any other Chief Engineers providing this info detail!
Looks like this would be a step backward, unless you would want to put it on a C6 or earlier Vette. IMO, no way you'd integrate the computer, sensor driven eLSD in an old Vette.
https://www.corvetteforum.com/forums...rack-mode.html As he said, he was willing to discuss what they do, despite the fact that it gives info to the competition! I am surprised at all the info he provides in his answers! Don't see any other Chief Engineers providing this info detail!
Looks like this would be a step backward, unless you would want to put it on a C6 or earlier Vette. IMO, no way you'd integrate the computer, sensor driven eLSD in an old Vette.
eLSD out of C7.
10-15-2015, 01:00 PM
#11
Pro
I'm certainly no technical expert but when I read the article it certainly seemed to me like what they call "torque vectoring" is actually doing the same thing as the Z51 E-LSD.
Still, the article was a reasonable approach to doing a with Vs without test. You couldn't really compare one Corvette with and one without E-LSD because the "with" car would have to be a Z51 while the "without" car would be a base model. The fact that there are other differences between a Z51 and base model would make it hard or impossible to tell if the handling improvements were from the E-LSD, other upgrades, or (most likely) a combination of all those things.
Last edited by ratman6161; 10-15-2015 at 01:10 PM.
10-15-2015, 01:01 PM
#12
Racer
I was here wondering "doesn't anyone realize the c7 already does this..." Glad I'm not the only one 
It's like that post full of people that don't understand the F12 came before the C7 not the other way around and they don't want to hear the the F12 came first lol oh you uneducated people.
It's like that post full of people that don't understand the F12 came before the C7 not the other way around and they don't want to hear the the F12 came first lol oh you uneducated people.
10-15-2015, 04:34 PM
#13
E-Ray, 3LZ, ZER, LIFT
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eLSD (electronic Limited Slip Differential) comes only with the Z51. I am still amazed at the $2800 I paid for that option in 2013! The eLSD alone could be worth the price. The eLSD, dry sump, larger wheels/tires, larger brake rotors, added rear sway bar, manual trans cooler and rear spoiler all came for that price!
10-15-2015, 05:06 PM
#14
Ummm eLSD is NOT the same as torque vectoring.
eLSD is simply varying the amount of lock/slip between the two driven wheels.
Torque vectoring can overdrive one of the driven wheels to help rotate the car or underdrive for stability.
eLSD is simply varying the amount of lock/slip between the two driven wheels.
Torque vectoring can overdrive one of the driven wheels to help rotate the car or underdrive for stability.
10-15-2015, 05:16 PM
#15
Torque vectoring can overdrive the outside wheel coming out of a turn to help it rotate or underdrive the inside wheel when entering a turn for stability. eLSD cannot.
10-15-2015, 07:39 PM
#16
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That is what eLSD does with muti-plate clutches on each wheel. They don't use electric motors to actuate, they use high pressure oil and fast acting valves similar to an automatic trans. Sounds like both could accomplish the same- more torque to one wheel and less to the other.
Last edited by JerryU; 10-15-2015 at 07:56 PM.
10-15-2015, 08:45 PM
#17
Drifting
Well, the TV discussed in the article sounds very much like the 'throttle steer' or 'torque steer' that was discussed and demonstrated during track laps at Spring Mountain in the C7. That was a kinda of an 'ah-ha' moment for me.
10-16-2015, 06:58 AM
#18
This is what Lexus explains how its torque-vectoring differential works in the RC F. "It differs from a standard differential is that, where as a basic mechanical diff spins the outer wheel faster than the inner wheel (it has longer to travel), the TVD in the RC F employs electronic motors and actuators that apply pressure to multi-plate clutches that can control the distribution of torque."
That is what eLSD does with muti-plate clutches on each wheel. They don't use electric motors to actuate, they use high pressure oil and fast acting valves similar to an automatic trans. Sounds like both could accomplish the same- more torque to one wheel and less to the other.
That is what eLSD does with muti-plate clutches on each wheel. They don't use electric motors to actuate, they use high pressure oil and fast acting valves similar to an automatic trans. Sounds like both could accomplish the same- more torque to one wheel and less to the other.
http://www.roadandtrack.com/car-cult...rentials-work/
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JerryU (10-16-2015)
10-16-2015, 08:14 AM
#19
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Again, eLSD and Torque Vectoring Differentials are not the same... I'll let Road and Track explain why...
http://www.roadandtrack.com/car-cult...rentials-work/
http://www.roadandtrack.com/car-cult...rentials-work/
•What It Does
•Using additional geartrains to overdrive the half-shafts, torque-vectoring differentials fine-tune the torque delivered to each drive wheel. This produces a yaw moment that can slow or quicken the car's rotation in a corner. Still confused? Read the damn story. That link was an article in Car and Driver that defined it better but no pics:
"Proper go-fast torque vectoring requires at least one overdrive gear in the differential (though often there are two) capable of spinning the wheels faster than if they were driven through a conventional diff." It continues,
"When the computers decide to divvy up the torque, clutch packs connect the overdrive gears to the differential output, varying the clamping force to adjust thrust between the left and right wheels. Because the clutches don’t fully engage, the outside wheel doesn’t actually spin faster. Instead, the partially meshed overdrive gears provide a push, like paddling harder—not faster—on one side of a canoe."
A pic in one of the other articles I found that did not have a good explanation does show a partial view of what looks like planetary gears that properly arranged could speed up that half shaft. Be interesting to see some pics with a good explanation.
Thanks for the reference. "Gear Heads Like To Know!"
Last edited by JerryU; 10-16-2015 at 08:20 AM.
10-16-2015, 09:24 AM
#20
Funny that R&T Article didn't really define the difference! However the author knew he couldn't (probably in the space allotted) so he ended the paragraph with (see Bold Print!):
•What It Does
•Using additional geartrains to overdrive the half-shafts, torque-vectoring differentials fine-tune the torque delivered to each drive wheel. This produces a yaw moment that can slow or quicken the car's rotation in a corner. Still confused? Read the damn story. That link was an article in Car and Driver that defined it better but no pics:
"Proper go-fast torque vectoring requires at least one overdrive gear in the differential (though often there are two) capable of spinning the wheels faster than if they were driven through a conventional diff." It continues,
"When the computers decide to divvy up the torque, clutch packs connect the overdrive gears to the differential output, varying the clamping force to adjust thrust between the left and right wheels. Because the clutches don’t fully engage, the outside wheel doesn’t actually spin faster. Instead, the partially meshed overdrive gears provide a push, like paddling harder—not faster—on one side of a canoe."
A pic in one of the other articles I found that did not have a good explanation does show a partial view of what looks like planetary gears that properly arranged could speed up that half shaft. Be interesting to see some pics with a good explanation.
Thanks for the reference. "Gear Heads Like To Know!"
•What It Does
•Using additional geartrains to overdrive the half-shafts, torque-vectoring differentials fine-tune the torque delivered to each drive wheel. This produces a yaw moment that can slow or quicken the car's rotation in a corner. Still confused? Read the damn story. That link was an article in Car and Driver that defined it better but no pics:
"Proper go-fast torque vectoring requires at least one overdrive gear in the differential (though often there are two) capable of spinning the wheels faster than if they were driven through a conventional diff." It continues,
"When the computers decide to divvy up the torque, clutch packs connect the overdrive gears to the differential output, varying the clamping force to adjust thrust between the left and right wheels. Because the clutches don’t fully engage, the outside wheel doesn’t actually spin faster. Instead, the partially meshed overdrive gears provide a push, like paddling harder—not faster—on one side of a canoe."
A pic in one of the other articles I found that did not have a good explanation does show a partial view of what looks like planetary gears that properly arranged could speed up that half shaft. Be interesting to see some pics with a good explanation.
Thanks for the reference. "Gear Heads Like To Know!"
As far as the original topic is concerned, I recall reading an article about this when the C7 was first introduced and I think Tadge said they considered using a TVD because they saw value in its performance but it did not offset added weight, complexity and cost over the eLSD they decided on.
