[ANSWERED] How Does No-Lift-Shift Work - CorvetteForum - Chevrolet Corvette Forum Discussion

Go Back  CorvetteForum - Chevrolet Corvette Forum Discussion > Ask Tadge > Ask Tadge
Reload this Page >

[ANSWERED] How Does No-Lift-Shift Work

Notices
Ask Tadge Post your questions here for Corvette's Chief Engineer Tadge Juechter and then discuss the questions and his answers.

[ANSWERED] How Does No-Lift-Shift Work

Old 10-02-2015, 04:24 PM
  #1  
jvp
Tech Contributor
Support Corvetteforum!
Thread Starter
 
jvp's Avatar
 
Member Since: Mar 1999
Location: Oak Hill VA
Posts: 8,594
Thanked 1,509 Times in 417 Posts
"Ask Tadge" Facilitator
Default [ANSWERED] How Does No-Lift-Shift Work

Original question is here.

BJ67 asked:
Exactly how does NLS work and exactly what mode do you have to be in? and what other settings are required. Also does rev match have to be on or off or does the system work the same regardless of rev match. Non z51 base car. I know how to power shift but the technical details are important.


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.
jvp is online now  
The Following 2 Users Say Thank You to jvp For This Useful Post:
JerriVette (09-15-2018), Z51VetteFan (10-10-2018)
Old 10-03-2015, 01:09 PM
  #2  
BJ67
CF Senior Member
 
Member Since: Nov 2012
Location: SUFFIELD CONNECTICUT
Posts: 1,697
Thanked 151 Times in 124 Posts
Default

Thank you Tadge, Although the calibration details would have been extremely interesting.
BJ67 is offline  
Old 10-04-2015, 05:37 AM
  #3  
Jolt
Junior Member
 
Member Since: Oct 2015
Location: Oregon
Posts: 19
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Which Model/Year corvettes does this work on?
Jolt is offline  
Old 10-04-2015, 11:00 AM
  #4  
BJ67
CF Senior Member
 
Member Since: Nov 2012
Location: SUFFIELD CONNECTICUT
Posts: 1,697
Thanked 151 Times in 124 Posts
Default

All C7's and later C6 cars
BJ67 is offline  
Old 10-04-2015, 11:45 AM
  #5  
jvp
Tech Contributor
Support Corvetteforum!
Thread Starter
 
jvp's Avatar
 
Member Since: Mar 1999
Location: Oak Hill VA
Posts: 8,594
Thanked 1,509 Times in 417 Posts
"Ask Tadge" Facilitator
Default

Originally Posted by BJ67 View Post
All C7's and later C6 cars
I'm pretty sure the answer Tadge gave was in reference to the C7s. The system in the C6s was a little different in that it only worked with launch control. In other words: only from a dead stop. The C7's version is on all the time.
jvp is online now  
Old 10-04-2015, 12:05 PM
  #6  
BJ67
CF Senior Member
 
Member Since: Nov 2012
Location: SUFFIELD CONNECTICUT
Posts: 1,697
Thanked 151 Times in 124 Posts
Default

launch control has nothing to do with NLS on the C7. I also believe launch control does not have to used or activated for NLS on the Camaro, Cadillac or the later C6 cars.
BJ67 is offline  
Old 10-04-2015, 12:07 PM
  #7  
jvp
Tech Contributor
Support Corvetteforum!
Thread Starter
 
jvp's Avatar
 
Member Since: Mar 1999
Location: Oak Hill VA
Posts: 8,594
Thanked 1,509 Times in 417 Posts
"Ask Tadge" Facilitator
Default

Originally Posted by BJ67 View Post
I also believe launch control does not have to used or activated for NLS on the Camaro, Cadillac or the later C6 cars.
The NLS system in the later C6 cars is different than what's in the Caddies and Camaro. It requires you to use launch control, and is not on otherwise. I can assure of that fact.
jvp is online now  
Old 10-04-2015, 03:29 PM
  #8  
Streetk14
CF Senior Member
 
Streetk14's Avatar
 
Member Since: Mar 2007
Location: Santa Barbara CA
Posts: 2,392
Thanks: 0
Thanked 21 Times in 21 Posts
Default

Originally Posted by jvp View Post
The NLS system in the later C6 cars is different than what's in the Caddies and Camaro. It requires you to use launch control, and is not on otherwise. I can assure of that fact.
Interesting.... I didn't know the C6 had NLS at all. So I'd assume that my '13 GS has it. If my car were stock, I'd love to go out and grab some logs to see how it works. I'd be a little worried to try it with my methanol injection, though.

Do you have any idea what GM uses to control RPM during a NLS? If it's keeping the throttle wide open, then it has to be either spark or fuel. Since stock cars use fuel-cut as the default for the rev limiter, that would be my guess. More info would be cool, though.
Streetk14 is offline  
Old 10-04-2015, 06:13 PM
  #9  
ElCid79
CF Senior Member
 
ElCid79's Avatar
 
Member Since: Aug 2002
Location: Zion NC
Posts: 1,447
Thanked 186 Times in 101 Posts
Default

So basically any driving mode. Just leave the gas fully depressed, and clutch. Shift. Drop clutch. Leave gas fully depressed the whole time?
ElCid79 is offline  
Old 10-06-2015, 09:31 PM
  #10  
BJ67
CF Senior Member
 
Member Since: Nov 2012
Location: SUFFIELD CONNECTICUT
Posts: 1,697
Thanked 151 Times in 124 Posts
Default

when you initiate a no lift shift , foot on the floor and keep it there, do your shift as close to 6500 as you can with out hitting the rev limiter first. If for instance you initiated your 1-2 shift at 6400 rpm, the NLS feature keeps the rpm at 6400 during that split second foot to the floor blip the clutch and shift all at the same time technique. The feature holds the rpm you initiate the shift for a very short time. If you are slow doing the power shift or screw up, the system just lets the engine hit the rev limiter which is 6600 rpm if you are slow to lift of the throttle.
BJ67 is offline  
Old 10-06-2015, 09:38 PM
  #11  
BJ67
CF Senior Member
 
Member Since: Nov 2012
Location: SUFFIELD CONNECTICUT
Posts: 1,697
Thanked 151 Times in 124 Posts
Default

Originally Posted by ElCid79 View Post
So basically any driving mode. Just leave the gas fully depressed, and clutch. Shift. Drop clutch. Leave gas fully depressed the whole time?
Yes, gas pedal right on the floor, slight pressure on the shifter, blip clutch and shift at the same exact time at your desired rpm. Hard part is to train yourself not to lift.The other hard part is shifting quick enough or early enough to not hit the rev limiter (fuel shut off)
BJ67 is offline  
Old 10-07-2015, 03:15 PM
  #12  
SBC_and_a_stick
CF Senior Member
 
SBC_and_a_stick's Avatar
 
Member Since: Nov 2012
Location: North California
Posts: 4,611
Thanked 465 Times in 271 Posts
Default

I thought about NLS when doing the Mojave Magnum 1.5 mile run. I couldn't fight my instinct to let of the gas. Decades of driving manual says it's all wrong!

Great question and great response.

Thank you Tadge!
SBC_and_a_stick is offline  
Old 10-07-2015, 05:12 PM
  #13  
ElCid79
CF Senior Member
 
ElCid79's Avatar
 
Member Since: Aug 2002
Location: Zion NC
Posts: 1,447
Thanked 186 Times in 101 Posts
Default

I tried this and hit the rev limiter. Guess I wasn't fast enough.... Will try again.
ElCid79 is offline  
Old 10-07-2015, 05:53 PM
  #14  
Huntsman2007
CF Member
 
Member Since: Aug 2014
Posts: 97
Thanks: 0
Thanked 2 Times in 2 Posts
Default

Question, can NLS be tuned into the earlier cars? I would love to have this on my 08.
Huntsman2007 is offline  
Old 10-07-2015, 09:06 PM
  #15  
rcooper
CF Senior Member
 
rcooper's Avatar
 
Member Since: Oct 2012
Location: Austin Texas
Posts: 4,436
Thanked 481 Times in 366 Posts
St. Jude Donor '15
Default

When I do the NLS I start the action at 5800 rpms, peak hp. also gives a bit of room for a screw up...haven't had that problem yet but you never know.
Mt '09 was not fun to do the NLS in as it dogged going into the next gear, was better dong speed shifts.
rcooper is offline  
Old 10-07-2015, 09:20 PM
  #16  
BJ67
CF Senior Member
 
Member Since: Nov 2012
Location: SUFFIELD CONNECTICUT
Posts: 1,697
Thanked 151 Times in 124 Posts
Default

Originally Posted by ElCid79 View Post
I tried this and hit the rev limiter. Guess I wasn't fast enough.... Will try again.
Initiate the power shift at 6200, you shouldn't hit the rev limiter. The No lift shift starts to work when you move the shift lever. If you push the clutch in before you pull or push the shift lever it will go right to redline and hit the rev limiter.
BJ67 is offline  
Old 10-07-2015, 09:28 PM
  #17  
BJ67
CF Senior Member
 
Member Since: Nov 2012
Location: SUFFIELD CONNECTICUT
Posts: 1,697
Thanked 151 Times in 124 Posts
Default

Originally Posted by rcooper View Post
When I do the NLS I start the action at 5800 rpms, peak hp. also gives a bit of room for a screw up...haven't had that problem yet but you never know.
Mt '09 was not fun to do the NLS in as it dogged going into the next gear, was better dong speed shifts.
You are leaving some power on the table if you actually shift all three shifts at say 6000. I am thinking the engine rpm increases 200 rpm for the delay it takes from reading the tach and initiating the shift. So making shifts at 6000 rather than closer to 6500, you could be a tenth or 2 off in a 1/4 mile timed track and your trap speed will be a little slower.
BJ67 is offline  
Old 10-07-2015, 09:34 PM
  #18  
BJ67
CF Senior Member
 
Member Since: Nov 2012
Location: SUFFIELD CONNECTICUT
Posts: 1,697
Thanked 151 Times in 124 Posts
Default

Originally Posted by Huntsman2007 View Post
Question, can NLS be tuned into the earlier cars? I would love to have this on my 08.
In 2009, the ctsv and the zr1 vette had NLS, the Camaro zl1 had it in 2010. From what I understand, it was developed for the charged cars so the charge boost doesn't drop when you shift.
Do not know if it existed in 08, and not sure what year the naturally aspirated vettes got it.
BJ67 is offline  
Old 10-08-2015, 10:09 AM
  #19  
xlr8nflorida
CF Senior Member
 
xlr8nflorida's Avatar
 
Member Since: May 2002
Posts: 10,293
Thanks: 0
Thanked 4 Times in 3 Posts
Default

This kills the life of the clutch no?
xlr8nflorida is offline  
Old 10-08-2015, 10:58 AM
  #20  
BJ67
CF Senior Member
 
Member Since: Nov 2012
Location: SUFFIELD CONNECTICUT
Posts: 1,697
Thanked 151 Times in 124 Posts
Default

Originally Posted by xlr8nflorida View Post
This kills the life of the clutch no?
No worse than a speed shift. Actually the less you slip a clutch, the less wear you have.
BJ67 is offline  

Thread Tools
Search this Thread
Quick Reply: [ANSWERED] How Does No-Lift-Shift Work


Sponsored Ads
Vendor Directory

Contact Us About Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2018 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.