speedy41

I have been trying NLS for a while now, but it can't be working. I know that it would typically be used only for shifts near redline but I have tried at lower rpm just to see if it's working. My understanding is that it is supposed to hold refs so that they do not climb rapidly while shifting. When I do it, the revs still climb like you would expect without NLS, which can't be good for the drivetrain.

I am expecting to hear a temporary throttle cutoff until the shift is completed.

I have tried searching but I can't find anything definitive. Any help would be greatly appreciated.

jabeasley1

I use NLS every time I am on the dragstrip. It took me a couple of times fighting the urge to keep it at wide open throttle and go against 30 years of driving habits. I think the solution to your problem is stated in your question. You say you have tried at lower rpms. I do not have my owners manual in front of me but RPM'S are irrelevant to the shift. Yes, NLS holds your rpms from revving up but it's all in the Throttle. I think the owners manual states you have to have at least 70% throttle in order for it to engage. I am sure someone will chime in and give you the exact numbers as this forum is very helpful. I am just working off of memory right this sec. Hope this helps.

speedy41

Right now I am keeping the throttle to the floor and shifting gears using the clutch as fast as I can. No matter what rpm I am at, revs skyrocket like you would expect them to if NLS didn't exist. I thought it was supposed to keep the revs from spiking like that.

jabeasley1

If that is the case, I am stumped as well. Especially at WOT, there should be no issues. Maybe someone else can chime in.

Warp Factor

Just speculating (I have an A8):
Maybe it only works at higher rpms? Shouldn't be any harm in trying this. If it doesn't restrain the rpms like you expect, the engine will just hit the limiter, and there's no harm in that.

6Speeder

I was under the impression that NLS only keeps the engine from over-reving. It allows the engine to hold at redline (not on the rev-limiter) by cutting some power while shifting. This would explain the revs climbing if you use NLS while at lower rpm.

speedy41

That could be the case. When I do it at high rpm near redline it could be working (but sometimes not sure if it's just hitting the limiter or if it's NLS).

I guess that's the next question. How can I find out if it only holds revs below redline, or at a lower rpm as per the scenario if the shift is executed before redline.

Thank you for your help.

phantasms

I frustratingly have had the same experience. I have done it once near deadline. However after Higgs posted the parameters of it I tried at lower RPMs several times and it never worked. Throttle was 100% and I was definately speed shifting. No luck. There's more to the story than what HP tuners shows. Maybe there is a minimum rpm. If there is id love to know what it is.

Thanks!

Best,
Gene

JMB

Use a scanner like HPTuners and record your run....you'll be able to look at the data and see exactly what the RPMs are doing.

Poor-sha

I think it would be great to tee this up as an ask tadge question. I use nls in the track but have had quirky issues that make me wonder if its working correctly. A detailed answer on all the parameters required and expected behavior from the engineering team would be awesome.

Ltrain925

Try shifting 6k or above, iv noticed if I shift anything lower Iv found some instneces where it wasn't working. However you really have to bang the gear, going even remotely slow NLS won't work, or it works but it's milliseconds it works then will disengage.

you should be shifitng it so fast with NLS that even if you didn't have NLS on this car a blip in the throttle is all you would hear/fee, and not the Rpms skyrocketing. It took me a few times to get the 3-4 NLS down and if I went the slightest bit slow it wouldn't work, and I'd bang the limiter.

phantasms

How I shift every time I go down the strip my friend!

Glenn Kline

Today I tried it going from 4th to 5th. I was at about 2300 RPM at maybe 15% throttle when I shifted and as soon as I clutched it the RPMs jumped to over 3k and my wife said what the heck was that? It definitely does not work under normal street driving coditions.

When on a track for HPDE if I'm pushing hard, an upshift only takes a fifth of a second so I'm not sure there would be any noticeable difference for me if NLS worked as by the time I complete the shift, the RPMs never drop below the match in the next gear anyways. Of course there could be a drop in boost, but at my level, I doubt I would notice.

Higgs Boson

only works over 75% throttle and over 31 MPH

discussed many times on corvette forum

spearfish25

On the CTS-V the NLS parameters were 100% throttle and within 500rpm of redline. I've tried on both the CTS-V and the Z06 and neither felt very good. Even being at or near redline it seemed like the engine and SC would suddenly scream and the shift was abrupt. I felt like I was doing harm rather than good.

I'm all for the Ask Tadge idea. Also wish GM made a video that really demonstrates the gauges, foot work and gear shift all together. I recall a video of Mero going down a straight saying 'here's a NLS from 4-5...' and it seemed like nothing unusual or unpleasant as I've experienced.

HEX122

Please see here (found thanks to the forum's Related Topics view at the bottom ).

spearfish25

Nice find. It doesn't really discuss the mechanics of how to execute it properly though.

HNK

Higgs, i might be wrong but I thought I saw where it can be changed in the tune.

Higgs Boson

yes under Cutoff/DFCO tab

davepl

Maybe they're being held at or near redline whereas you're expecting them to be held where they were when you initiated the shift. And you very well may need to be within some fraction of redline when you start, though that's not in the manual.

The goal of NLS is to not overrev the motor, I presume, not to hold the shift RPM, so maybe it's just incorrect expectation?