No Lift Shift vs Traditional Shifting

[2NASSTY]

My dealer is friendly but at the end the day they can do but only so much on warranty claims. It was an opportunity to either replace what was broke or go big. Both on me. We went big. BTR stage 3 cam, ported, milled factory LSA heads with upgraded springs, retainers, hardware. Car turned into a beast and went 10's @ 129 mph

Never NLS again. Which is why I posted in this thread. When you mod this blower motor don't rely on the rev limiter or springs to stop the top end from spinning on a missed shift.

[STUNNAH]

Check...

[AJensen383]

Originally Posted by crazydave

Ahh, you raised the limiter quite a bit. My tuner knew that the stock springs couldn't keep up with an increased limiter and kept it stock.

x2...6700 is quite a bit of RPM for stock springs and OEM lifters

[KaBoom1701]

I've done it twice stock and never after I started adding power mods.....

[Olddudesrule]

Originally Posted by 2NASSTY

My dealer is friendly but at the end the day they can do but only so much on warranty claims. It was an opportunity to either replace what was broke or go big. Both on me. We went big. BTR stage 3 cam, ported, milled factory LSA heads with upgraded springs, retainers, hardware. Car turned into a beast and went 10's @ 129 mph

Never NLS again. Which is why I posted in this thread. When you mod this blower motor don't rely on the rev limiter or springs to stop the top end from spinning on a missed shift.

There you have it, straight from the horses mouth........can debate stock springs and and extra 200 RPM on top, but you can't debate the experience...

[2NASSTY]

Originally Posted by AJensen383

x2...6700 is quite a bit of RPM for stock springs and OEM lifters

Agreed, but it's all a matter of perspective. The CTS-V in the sig never had the valve covers off and ran the same tune for 30,000 miles on factory springs with a upper & lower pulley. Same rev limiter setting. No issues what so ever. Common practice in the CTSV community. Those Guys have 3 more years of data and tuning on this platform and are absolutely flying.

The only difference is this car is a Manual and I missed a shift while NLS. Live and learn. Just sharing my experience so fellow ZL1 racers with a Manual doesn't have to make the same mistake.

[AJensen383]

Originally Posted by 2NASSTY

Agreed, but it's all a matter of perspective. The CTS-V in the sig never had the valve covers off and ran the same tune for 30,000 miles on factory springs with a upper & lower pulley. Same rev limiter setting. No issues what so ever. Common practice in the CTSV community. Those Guys have 3 more years of data and tuning on this platform and are absolutely flying.

The only difference is this car is a Manual and I missed a shift while NLS. Live and learn. Just sharing my experience so fellow ZL1 racers with a Manual doesn't have to make the same mistake.

Interesting... what do you shift the CTSV at??

Just from my experience with Hyd roller lifters in BBC and SBC , they need a really good Morel lifter to rev good to 7000+.. not so much the spring being the problem, but the lifter itself...

Love your ZL1 BTW!

[2NASSTY]

Thanks for compliment on the ZL1. Looks like you picked one of the best colors.

The CTSV was shifting through the auto at 6500 rpm with the rev limiter set at 6700. Same as the ZL1 when they both had similar bolt-on mods (pulley, tune, injectors, 160 stat). The General set the factory rev limiter in the LSA at 6200 for a reason. The blower is connected to the crank via a pulley and is spinning at a lot higher rpm than the motor. The more pulley the higher rpm the blower spins. The LSA will make more power up to 6500 rpm bone stock.

The missed shift in a positive displaced blower in a Manual car is the point here The valve train is still moving after the rev limiter is hit. That's what caused the valves to float when the NLS shift was missed at 6500 rpm. The blower pulley does not stop on a dime when the rev limiter is hit. Stronger valve springs would have helped here.

You Cant miss a shift in an Auto however. And there is no NLS feature in an Auto. Live and learn I guess.

BTW, I'm Now shifting at 7100 rpm with the upgraded valve train. No missed shifts with the MGW shifter and no more NLS for me. Hope this helps

[d454brisson]

i don't get the tie in between the rotors and valve float. Saying interference motor is appropriate. Not sure on the positive displacement comment.

The rev limiter cuts spark but missing the shift keeps the valve train and crank speed increasing, thus the stock springs not closing the valves before the the pistons hit them.

I don't see where the blower type has anything to do with this. the motor stayed in time via the chain and the rotors are completely divorced of the issue, would have happened with a centrifugal also.

If on nitrous or turbo what ever caused the rpm to go above what the speed in which the valves could close would cause contact and bend pushrods valves and make piston contact.

Not going to test on my car but i wonder if NLS chops at a specific programmed rpm or the rpm the clutch in engaged in. FOr example if you plant the gas and then shift at 4k does bounce no higher then 4k because you engaged the clutch and started a shift or does it hit another preset rpm level. I don't have a lot of faith in GM working that angle and there is nothing notable via google on the parameters of gm's mls. On the Ford launch control you could set specified rom and nls boxes has user settings.

[crazydave]

Originally Posted by d454brisson

Not going to test on my car but i wonder if NLS chops at a specific programmed rpm or the rpm the clutch in engaged in. FOr example if you plant the gas and then shift at 4k does bounce no higher then 4k because you engaged the clutch and started a shift or does it hit another preset rpm level. I don't have a lot of faith in GM working that angle and there is nothing notable via google on the parameters of gm's mls. On the Ford launch control you could set specified rom and nls boxes has user settings.

All it does is keep it slightly off the rev limiter. It does not care what RPM you shift at, its going to go up to 6200. I forget what it is, but you only have a specific time to complete the shift. Zoom into the tach on the video and you can see it working. This was 3 WOT, No-lift shifts.



Been to the track almost every week with the car sine Sep 2012 and missed a few shits along the way, both stock and with various modifications (stock rev limiter and valve train) and I have not have any problems. 2NASTY's issue was valve float due to high RPM on the stock springs. The NLS didn't directly cause his failure, it just contributed to it since when he used it over-rev'd the stock valve train during the missed shift. On the stock limiter, you are fine to use the system, and the only downsides in my mind are increased clutch wear and the danger of breaking traction at high speed. (Also I am not a tuner, so I am not sure what else effects the NLS when you increase the rev limiter)

[DrkPhx]

GM did a good job on the NLS feature, but it doesn't prevent a mechanical over rev or missed shift. If you do a search here you will find a lot of info on it. It's built into the ECM and if executed correctly it maintain full boost, spark and fuel through the shift. You have to shift very fast right before the redline (otherwise the rpm will flare up) and the rpm will just drop like an auto. Also, you can raise it by adjusting it in the ECM calibration. I have countless data logs and a few videos to confirm it.

For the record, I would never shift the stock cam and valvetrain above the factory 6200 rev limiter. The intake valves are simply too heavy and the stock springs don't have enough pressure to control them.

[2NASSTY]

Well I'm glad we glad we got that out of the way lol. Thanks for the back-up Guys (crazydave, DrxPhx).

Lessoned learned. Don't mess with your rev limiter on stock valve train in a 6M and NLS. Unless you want to GoFaster and risk breaking shit.

On a serious note, the only reason I replied to this thread is so someone does not have to experience what I did while NLS.

[ZEV1L ONE]

Originally Posted by 2NASSTY

Well I'm glad we glad we got that out of the way lol. Thanks for the back-up Guys (crazydave, DrxPhx).

Lessoned learned. Don't mess with your rev limiter on stock valve train in a 6M and NLS. Unless you want to GoFaster and risk breaking shit.

On a serious note, the only reason I replied to this thread is so someone does not have to experience what I did while NLS.

I appreciate you sharing the lesson learned! Might have to pull back on the no lift shifting once I start to modify the power. I'm sure a clutch/trans is not cheap in these things, but I still have my warranty, so I guess that's the best I can ask for right now.

The only upside is that I'm in Denver, CO, and actual wheel HP here is closer to 400, so driveline wear will be even further reduced up here with less actual HP.

[2NASSTY]

You're welcome! Enjoy your Ride and NLS that thing at the track. I actually miss that feature. Tried it my 1st time at the track bone stock and lightly modded 1 week before I missed a shift.

https://m.youtube.com/watch?v=e0vOJmDoLAU

https://m.youtube.com/watch?v=QhrxjeQ7uS8

The other thing I noticed was how tight the shifter gates felt during NLS lightly modded vs bone stock. I believe my trap speeds would be 2-3 mph faster running bottom 10's on a 1.6 sixty if I had the balls to NLS now.

I don't. LOL