No lift shift feature with M7?
10-30-2018, 07:52 PM
#1
No lift shift feature with M7?
What settings are needed to enable the no lift shift feature (or is it always enabled)? What I've read about it, the no lift shift is supposed to hold the rpms at what they are at the start of a shift sequence, despite the throttle position. If the throttle has to be floored, then you'd need traction control and/or launch control enabled to stop tire spin in 1st gear. There's also the issue of someone (or at least me) being willing to hold the throttle floored on a 1st to 2nd gear shift, after reading about some incidents with tire spin on the 1st to 2nd gear shift getting the Z06 a bit sideways (I think there is a youtube video of this with a red Z06 failing to demo launch control.).
10-30-2018, 08:09 PM
#2
Drifting
No lift shift doesn't have anything to do with holding a throttle at any specific position. You literally floor the car and hold the accelerator down to the floor when making a FAST up shift. All this does it keep the boost built so it doesn't have to rebuild it after every shift. What you are referring to with the throttle being held at a certain position sounds like launch control.
Last edited by HorsePowerObsessed; 10-30-2018 at 08:10 PM.
10-31-2018, 10:13 PM
#3
Racer
Requires some practice and overcoming what your brain tells you not to do .. make sure the nannies are on otherwise bye bye car.. Once you get it right its awesome..
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LagunaSecaZ06 (11-02-2018)
10-31-2018, 11:12 PM
#4
Le Mans Master
What settings are needed to enable the no lift shift feature (or is it always enabled)? What I've read about it, the no lift shift is supposed to hold the rpms at what they are at the start of a shift sequence, despite the throttle position. If the throttle has to be floored, then you'd need traction control and/or launch control enabled to stop tire spin in 1st gear. There's also the issue of someone (or at least me) being willing to hold the throttle floored on a 1st to 2nd gear shift, after reading about some incidents with tire spin on the 1st to 2nd gear shift getting the Z06 a bit sideways (I think there is a youtube video of this with a red Z06 failing to demo launch control.).
If doing this this I would make sure you have stabilitrac on otherwise these cars get whiggy with the e-diff. There are a few here that have crashed doing the 1-2 or 2-3 shift and blame it on the computer fart malfunction or mechanical malfunction in the e-diff even with stability track on.
Ymmv- experimenting and don’t be surprised if you get bit square in the ***.
launch control is a ridiculous useless feature. Tadge introduced this feature in the c6 line up around 2010 as a me too feature keeping up with the Jones and their Nissan GT-R. The only difference is when you used launch control in the gtr it voided your warranty as it was tracked in the ecm. In the corvette it didn’t void the warranty. Launch control is choppy , hard on the drive train and is probably slower then gently rolling off the clutch at 1200 rpm and gradually going to the floor with the throttle. Never tried launch control in my c7z. Tried it in s base c7 I test drove. It didn’t work very well in an m7. Launch control in the a8 is a different story. It works well there
Here is a launch control a8 and m7 Demo
here is an m7 fail with launch control
Last edited by Mr. Gizmo; 10-31-2018 at 11:36 PM.
11-01-2018, 01:57 PM
#5
Team Owner
No lift shift feature is great for drag racing once you get used to it. Works like a charm and as designed, kind of like the old speed shift but better.
11-01-2018, 02:53 PM
#6
Tadge answered:
No Lift Shift (NLS) works in all driver modes and with rev match on or off. In other words, all the time. Many manufacturers seek to reduce the stress in their drivelines by sensing the conditions for a power shift and close the throttle regardless of what the driver is doing with the throttle pedal. The problem with closing the throttle is that when the next gear is selected and the clutch is re-engaged, the intake manifold has very low pressure. The throttle then has to re-open to fill it and feed the cylinders. Although this all happens very quickly, there is a delay for the engine to back up to full torque (and these effects are magnified in charged engines where intake manifold pressures are higher). Although I can't share the calibration details, the NLS algorithm looks for the conditions where the driver is requesting maximum performance and, within certain bounds, keeps the throttle fully open during the shift to keep the manifold pressure relatively high. In this way the engine is ready to provide full torque upon completion of the shift. The performance difference is easily measured in our straight line acceleration testing. And of course the Corvette is designed for and fully validated for this usage.
https://www.corvetteforum.com/forums...hift-work.html
No Lift Shift (NLS) works in all driver modes and with rev match on or off. In other words, all the time. Many manufacturers seek to reduce the stress in their drivelines by sensing the conditions for a power shift and close the throttle regardless of what the driver is doing with the throttle pedal. The problem with closing the throttle is that when the next gear is selected and the clutch is re-engaged, the intake manifold has very low pressure. The throttle then has to re-open to fill it and feed the cylinders. Although this all happens very quickly, there is a delay for the engine to back up to full torque (and these effects are magnified in charged engines where intake manifold pressures are higher). Although I can't share the calibration details, the NLS algorithm looks for the conditions where the driver is requesting maximum performance and, within certain bounds, keeps the throttle fully open during the shift to keep the manifold pressure relatively high. In this way the engine is ready to provide full torque upon completion of the shift. The performance difference is easily measured in our straight line acceleration testing. And of course the Corvette is designed for and fully validated for this usage.
https://www.corvetteforum.com/forums...hift-work.html
11-01-2018, 05:18 PM
#7
Racer
Tadge answered:
And of course the Corvette is designed for and fully validated for this usage.
https://www.corvetteforum.com/forums...hift-work.html
And of course the Corvette is designed for and fully validated for this usage.
https://www.corvetteforum.com/forums...hift-work.html
Last edited by MacRoadie; 11-01-2018 at 05:36 PM.
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LagunaSecaZ06 (11-02-2018)
11-01-2018, 05:34 PM
#9
Still seems risky. If not in launch control, then based on my experiments (on a private road) in order to get to full throttle in 1st gear, the tires will spin for about 1/4 second or so before TC stops them from spinning. What I'm then wondering is then on a no lift shift from 1st to 2nd, if the tires spin again, then does the TC have to go through another 1/4 second or so of tire spin before it stops them. This could be an issue. At this point I don't plan on testing no lift shift.
11-01-2018, 05:37 PM
#10
Racer
Unfortunately, "But Tadge said on CorvetteForums" doesn't often fly with the GM warranty crew...
There has to be at least a hundred posts spread across every forum where guys printed out the MRC update info FROM TADGE AND JIM MERO, took it with them into a dealership, and were accused of making it up, or told it wasn't an actual GM document (even those guys who DID print out the actual document)
There has to be at least a hundred posts spread across every forum where guys printed out the MRC update info FROM TADGE AND JIM MERO, took it with them into a dealership, and were accused of making it up, or told it wasn't an actual GM document (even those guys who DID print out the actual document)
Last edited by MacRoadie; 11-01-2018 at 06:44 PM.
11-01-2018, 06:11 PM
#11
no specific settings per say. Just floor it stab the clutch with your left foot while shifting car the same time holding your right foot on the gas all the way to the floor and don’t let up. I have not tried it. But it’s probably best to do the no lift shift at 5400 to 6000 rpm. While the lt4 redlines At 6400 or 6500 rpm. These cars peter out at anything much above 5500 rpm. If you stay in it until the redline you’ll hit the rev limiter and you’ll be losing ground.
If doing this this I would make sure you have stabilitrac on otherwise these cars get whiggy with the e-diff. There are a few here that have crashed doing the 1-2 or 2-3 shift and blame it on the computer fart malfunction or mechanical malfunction in the e-diff even with stability track on.
Ymmv- experimenting and don’t be surprised if you get bit square in the ***.
launch control is a ridiculous useless feature. Tadge introduced this feature in the c6 line up around 2010 as a me too feature keeping up with the Jones and their Nissan GT-R. The only difference is when you used launch control in the gtr it voided your warranty as it was tracked in the ecm. In the corvette it didn’t void the warranty. Launch control is choppy , hard on the drive train and is probably slower then gently rolling off the clutch at 1200 rpm and gradually going to the floor with the throttle. Never tried launch control in my c7z. Tried it in s base c7 I test drove. It didn’t work very well in an m7. Launch control in the a8 is a different story.
They do not "peter out" until beyond that rpm.
https://www.enginelabs.com/engine-te...e-power-curve/
Last edited by dar02081961; 11-01-2018 at 06:12 PM.
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dvilin (12-13-2018)
12-13-2018, 02:37 PM
#12
Melting Slicks
Max power in the LT4 is at 6400 rpm.
They do not "peter out" until beyond that rpm.
https://www.enginelabs.com/engine-te...e-power-curve/
They do not "peter out" until beyond that rpm.
https://www.enginelabs.com/engine-te...e-power-curve/
12-13-2018, 03:46 PM
#13
Still seems risky. If not in launch control, then based on my experiments (on a private road) in order to get to full throttle in 1st gear, the tires will spin for about 1/4 second or so before TC stops them from spinning. What I'm then wondering is then on a no lift shift from 1st to 2nd, if the tires spin again, then does the TC have to go through another 1/4 second or so of tire spin before it stops them. This could be an issue. At this point I don't plan on testing no lift shift.
Last edited by Cercone; 12-13-2018 at 03:46 PM.
12-16-2018, 03:38 AM
#14
I would say that's about right.
Keep in mind there is little difference in time to execute a NLS and a quick lift shift.
So any gains in a NLS will come from additional power put to the ground directly after the shift when the manifold would normally need to re-pressurize and build boost. With a NLS the manifold stays pressurized and retains boost between shifts because the throttle isnt lifted. Normally when the throttle is lifted any boost in the manifold is relieved. This is true during a normal shift as well. Looking at some data logs it looks like it takes between 250-400 milliseconds for boost to be recovered during a shift.
Assuming you have the traction on an M7 in the 1/4th mile with NLS you could get up to 500-800 milliseconds more time at full throttle transmitting power to the ground. I don't know what that translates to in reduction of ET in the 1/4 mile, but I would say 1 tenth of a second possibly 2 is a fair assumption.
But like others have said the problem becomes traction especially on the street when its cool out or the tires are cold.
Keep in mind there is little difference in time to execute a NLS and a quick lift shift.
So any gains in a NLS will come from additional power put to the ground directly after the shift when the manifold would normally need to re-pressurize and build boost. With a NLS the manifold stays pressurized and retains boost between shifts because the throttle isnt lifted. Normally when the throttle is lifted any boost in the manifold is relieved. This is true during a normal shift as well. Looking at some data logs it looks like it takes between 250-400 milliseconds for boost to be recovered during a shift.
Assuming you have the traction on an M7 in the 1/4th mile with NLS you could get up to 500-800 milliseconds more time at full throttle transmitting power to the ground. I don't know what that translates to in reduction of ET in the 1/4 mile, but I would say 1 tenth of a second possibly 2 is a fair assumption.
But like others have said the problem becomes traction especially on the street when its cool out or the tires are cold.
05-20-2019, 06:56 PM
#16
Safety Car
NLS is a very valuable feature for road course work. I love it and it improves lap times. Below is a short 1:30 video of a single lap at Hallett demonstrating NLS. I only shift twice per lap at Hallett so you only see it twice, once at the 0:30 second mark and the other at around the 1:13 mark. You might notice a slight bobble on my part at the 1:13 shift as I missed the 3rd gear gate at bit which cost me somewhere about 0.05 - 0.10 seconds.
You can also see how well the PTM feature works once you override your brain's attempt at self preservation. The brain doesn't like going to the floor with the accelerator at the apex of a corner. Takes a certain amount of trust but boy does it work well!!! Notice throttle position exiting most corners, if I'm going 100% throttle at the apex of corners then PTM is metering out the power and helping with lap times.
You can also see how well the PTM feature works once you override your brain's attempt at self preservation. The brain doesn't like going to the floor with the accelerator at the apex of a corner. Takes a certain amount of trust but boy does it work well!!! Notice throttle position exiting most corners, if I'm going 100% throttle at the apex of corners then PTM is metering out the power and helping with lap times.
Last edited by rikhek; 05-21-2019 at 11:18 AM.
05-20-2019, 10:02 PM
#17
Mr. Gizmo....you stated in your post #4, above...
"Launch control is a ridiculous useless feature. Tadge introduced this feature in the c6 line up around 2010 as a me too feature keeping up with the Jones and their Nissan GT-R. The only difference is when you used launch control in the gtr it voided your warranty as it was tracked in the ecm. In the corvette it didn’t void the warranty. Launch control is choppy , hard on the drive train and is probably slower then gently rolling off the clutch at 1200 rpm and gradually going to the floor with the throttle. Never tried launch control in my c7z. Tried it in s base c7 I test drove. It didn’t work very well in an m7. Launch control in the a8 is a different story. "
Just to set the record straight and I can not speak for early year GT-R's, Nissan would not have installed the Launch Control feature in their GT-R if they were going to nix the warranty should the owner used it. I owned a 2013 GT-R, bought it new in 2013 and it did have Launch Control and the Owner's Manual explained in detail how to use it. There was a warning that you shouldn't use it I believe more than 3 consecutive times without a cool down or risk potentially causing a failure, which could deny warranty. The GT-R launch in that production year was 0-60 mph in 2.7 seconds....you didn't have to do anything special, just set it up, put the car in Drive, and hold on, then pull the trigger. Front wheel drive and that twin clutch transmission were outrageous.
"Launch control is a ridiculous useless feature. Tadge introduced this feature in the c6 line up around 2010 as a me too feature keeping up with the Jones and their Nissan GT-R. The only difference is when you used launch control in the gtr it voided your warranty as it was tracked in the ecm. In the corvette it didn’t void the warranty. Launch control is choppy , hard on the drive train and is probably slower then gently rolling off the clutch at 1200 rpm and gradually going to the floor with the throttle. Never tried launch control in my c7z. Tried it in s base c7 I test drove. It didn’t work very well in an m7. Launch control in the a8 is a different story. "
Just to set the record straight and I can not speak for early year GT-R's, Nissan would not have installed the Launch Control feature in their GT-R if they were going to nix the warranty should the owner used it. I owned a 2013 GT-R, bought it new in 2013 and it did have Launch Control and the Owner's Manual explained in detail how to use it. There was a warning that you shouldn't use it I believe more than 3 consecutive times without a cool down or risk potentially causing a failure, which could deny warranty. The GT-R launch in that production year was 0-60 mph in 2.7 seconds....you didn't have to do anything special, just set it up, put the car in Drive, and hold on, then pull the trigger. Front wheel drive and that twin clutch transmission were outrageous.
Last edited by tzoid9; 05-20-2019 at 10:03 PM.
05-28-2019, 05:20 PM
#18
Melting Slicks
NLS is a very valuable feature for road course work. I love it and it improves lap times. Below is a short 1:30 video of a single lap at Hallett demonstrating NLS. I only shift twice per lap at Hallett so you only see it twice, once at the 0:30 second mark and the other at around the 1:13 mark. You might notice a slight bobble on my part at the 1:13 shift as I missed the 3rd gear gate at bit which cost me somewhere about 0.05 - 0.10 seconds.
You can also see how well the PTM feature works once you override your brain's attempt at self preservation. The brain doesn't like going to the floor with the accelerator at the apex of a corner. Takes a certain amount of trust but boy does it work well!!! Notice throttle position exiting most corners, if I'm going 100% throttle at the apex of corners then PTM is metering out the power and helping with lap times.
https://www.youtube.com/watch?v=WeAHCHHo7Zc
You can also see how well the PTM feature works once you override your brain's attempt at self preservation. The brain doesn't like going to the floor with the accelerator at the apex of a corner. Takes a certain amount of trust but boy does it work well!!! Notice throttle position exiting most corners, if I'm going 100% throttle at the apex of corners then PTM is metering out the power and helping with lap times.
https://www.youtube.com/watch?v=WeAHCHHo7Zc
05-31-2019, 05:39 PM
#19
Burning Brakes
I'm a newb to the Z06 and still learning my car so don't plan to personally use NLS until post-break-in and likely would only try it on the 2-3 shift first to try and take some of the traction issues out of it as much as possible the first time. On my gen6 2SS we also had NLS and it was awesome, used it all the time. My SS would lay a very short scratch on the 1-2 using NLS so I can see how traction would be an issue on the 1-2 in the Z06 with 200 more ponies and a ton less weight. You also have to initiate the NLS from 1-2 a little sooner than you would think because the revs are climbing so fast. You will likely hit the limiter if you don't initiate it at 5500-6000 RPM. NLS on the 2-3 or 3-4 is much easier. Besides traction issues I think the biggest risk is missing a gear in the wrong direction trying to shift super-fast and having an over-rev situation. If you go from 3 to 2 by accident trying to NLS instead of hitting 4 the rev limiter won't help you. The only other risk I see is bouncing off the rev-limiter repeatedly if you don't do it right but I wouldn't think that would be a huge issue unless you make a habit of it.