Turbo Lag mostly as... Transmission Lag!

[jmccorm]

You floor it. Nothing happens for what feels like an eternity. Perhaps it's just a second? Your engine isn't responding and you're needing to pour on the gas to avoid an accident. NOW! Why does this happen? It's really uneasy to floor the gas pedal and feel nothing happening.

Looking back, I think in those situations I might be going 40-43MPH and the transmission is in 7th gear. For city driving. When I floor it, it tries to downshift somewhere around 3rd or 4th gear. It takes FOREVER trying to accomplish that. Is there any kind of adjustment available to keep the gearing closer to where it can deliver power upon command? A city or sport mode? I'm looking for instant response from the engine when I need it.

Anything that'll fix that, or am I the problem?

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[rickinAZ]

A throttle enhancer like Pedal Monster or Pedal Commander would likely help.

https://www.jlwranglerforums.com/forum/threads/throttle-enhancers.64534/

 

[JL MADDOG]

7th gear in full auto at that speed means a very low RPM and not much torque. An increase in throttle response or keeping the engine at a higher RPM is the solution.

A Pedal Commander will definitely make a difference. This will improve throttle response. I am not sure if it really does anything else as far as transmission gear kickdown.

Driving around town with your transmission in manual mode will also work. You just have to keep shifting as speeds increase and decrease to keep the engine at a higher RPM needed for the response you are looking for. When around town I drive mine in manual mode all the time and try to keep the vehicle around 2500 RPM.

YMMV

 

[jmccorm]

I went for a drive to get more info. The delay between floor the pedal and actually accelerating are MORE than a second! That's DANGEROUS.

Steps to reproduce (2021 JLUR 2.0L Turbo No eTorque Automatic):
1. Go 41MPH on flat terrain (cruise control if needed) until it puts you into 7th gear.
2. Very quickly FLOOR the accelerator (like it's an emergency).
3. Wait. No acceleration, no sound, no nothing. Wait. Wait.
4. The vehicle completes the shift into 3rd gear and you start to accelerate over a full second after you needed it.

I wouldn't complain, but two or three times now when I floored it and needed power, it wasn't there. And those were in times which I was avoiding a potentially dangerous situation in traffic. IMHO, stomping the pedal and having a surprise delay > 1 second is unpredictable and dangerous.

 

[GATORB8]

I went for a drive to get more info. The delay between floor the pedal and actually accelerating are MORE than a second! That's DANGEROUS.

Steps to reproduce (2021 JLUR 2.0L Turbo No eTorque Automatic):
1. Go 41MPH on flat terrain (cruise control if needed) until it puts you into 7th gear.
2. Very quickly FLOOR the accelerator (like it's an emergency).
3. Wait. No acceleration, no sound, no nothing. Wait. Wait.
4. The vehicle completes the shift into 3rd gear and you start to accelerate over a full second after you needed it.

I wouldn't complain, but two or three times now when I floored it and needed power, it wasn't there. And those were in times which I was avoiding a potentially dangerous situation in traffic. IMHO, stomping the pedal and having a surprise delay > 1 second is unpredictable and dangerous.

What if you don't actually floor it, and use more like 75% throttle. There may be a kick down programmed into the computer at 100% throttle.

And what the heck's with the drivers in Tulsa that you need to do this all the time?

 

[jmccorm]

What if you don't actually floor it, and use more like 75% throttle. There may be a kick down programmed into the computer at 100% throttle.

I'll give that a shot later and report back. Not a bad idea to try.

And what the heck's with the drivers in Tulsa that you need to do this all the time?

You know... "road stuff". HAHAHA.

Hey, I'd say it's been a just a few memorable situations so far. But what made them memorable was the surprise of flooring it and nothing happening. When you start to get that panic feeling is when it finally accelerates (and nothing to tell you why this happened when it works fine any other time).

It sounds trivial, but for me, this is a safety issue. I'd feel much safer if I wasn't city driving in such a high gear. I also wonder what makes the shift down from 7th to 3rd so slow, you know?

 

[grimmjeeper]

Turbo lag is a real thing. They've gotten better at reducing it but you can't totally eliminate lag because physics.

 

[GATORB8]

It sounds trivial, but for me, this is a safety issue. I'd feel much safer if I wasn't city driving in such a high gear. I also wonder what makes the shift down from 7th to 3rd so slow, you know?

Could be related to durability in the transmission/drivetrain. I also don't pretend to understand enough about how Auto transmissions work and what's required to down shift four gears immediately in todays crazy 9+ speed transmissions, but I would assume it may be more complicated than moving a lever like a manual.

 

[word302]

Sounds like turbo lag.

 

[jmccorm]

A throttle enhancer like Pedal Monster or Pedal Commander would likely help.

A Pedal Commander will definitely make a difference. This will improve throttle response. I am not sure if it really does anything else as far as transmission gear kickdown.

Turbo lag is a real thing.

Sounds like turbo lag.

Unless I'm overlooking something obvious, a third party pedal mod won't help, and it's not turbo lag. The vehicle is literally coasting for over a second when you floor it under the above conditions. If you've got a similar vehicle, try it!

Based on what I'm hearing, I'll see if I can't get it added to an existing dealer appointment to have them take a look at it. Maybe they've got an update especially for people who come to them about this issue. I'm just glad I figured out how to faithfully reproduce this intermittent gas pedal issue!

 

[grimmjeeper]

Unless I'm overlooking something obvious, a third party pedal mod won't help, and it's not turbo lag. The vehicle is literally coasting for over a second when you floor it under the above conditions. If you've got a similar vehicle, try it!

Based on what I'm hearing, I'll see if I can't get it added to an existing dealer appointment to have them take a look at it. Maybe they've got an update especially for people who come to them about this issue. I'm just glad I figured out how to faithfully reproduce this intermittent gas pedal issue!

I have a Banks Pedal Monster and Derringer tuner on my turbo diesel Wrangler. If I'm stopped, it still takes a full second or longer for the turbo to spool up and get me going. When it does, it really kicks in. A lot more than stock now, but it still takes time.

You can't get around physics. Turbos take time to spool up no matter what you do.

 

[jmccorm]

You can't get around physics. Turbos take time to spool up no matter what you do.

Understood about the turbo spooling up. I'm probably not communicating my side well enough. Let me give it another shot:

Before I was able to nail down the issue, I thought it might have been turbo lag or slow response from the throttle controller. And it was intermittent, too. Just happened some of the time. I sought to figure out exactly what was happening, and you may disagree on that account, but what I am able to do is to reliably trigger the problem on command (which will make actual diagnosis easier).

So here's what I'm seeing now that I can study it:

Using the conditions (given above) to recreate the issue, it isn't just that there's sluggish acceleration like the turbo is minimally spooled. There's no acceleration at all for over a second! You're flooring it. The vehicle becomes inert. Yes, in the wrong situation, this is scary!

This is my explanation for what I'm seeing:

Effectively, the vehicle still says it is in 7th, but it is in a neutral gear (clutch enabled, engine disconnected from the wheels) until that shift from 7th into 3rd completes. As it turns out, that's what appears to be taking over a second to finish. No idea what makes that take so long to shift. Once completed, the vehicle suddenly comes back to life and launches forward as originally commanded.

Mind you, I'm not saying the Wrangler is horrible or anything like that. It just happens to be an occasional safety problem that I was motivated enough to reproduce. And now that I can, I'd like to see if it could be fixed or improved upon. I'm crossing my fingers that they already have an update for people who come in with this issue!

 

[Jeepeto]

Talk to a tuner. You’ll need more than a pedal commander I would think. The way I understand it, they just remap the requested throttle. (I.e. you ask for 20% and it gives you 50%, this makes it feel faster even though your just driving it harder) A tune will be able to remap the motor as well as transmission shift points. You should be able to enable something like a “sport” tune that holds gears longer, responds to throttle quicker, and if you want to make more boost or stay in boost more often they should be able to do that as well.

i understand you’re having transmission issues for the most part, but, while you’re in there… might as well make it fun to drive

 

[jmccorm]

Talk to a tuner. i understand you’re having transmission issues for the most part, but, while you’re in there… might as well make it fun to drive

If I don't get any traction with the dealer or with Jeep corporate, I think I'm going to take your advice. But I really hope it doesn't come to that extreme to avoid a safety issue.

 

[Retrograde]

You floor it. Nothing happens for what feels like an eternity.

That's throttle lag. It's a thing. And I feel your pain.... Kids who came up driving EFI vehicles just accept it because it's something that's always been. But for those of us who grew up on Holley four-barrels, modern EFI is excruciating. Seems everything today is slower than death compared to that pump shot and the instant snapping open of the throttle blades.

Pedal Commander helps, or so I've been told. Personally, I've "programmed" the lag into my driving style; I'll drop the boot a second or so before I actually need the power. It's the same lag every time, so I've been able to get quite precise with it.

And more broadly speaking, being able to anticipate when to apply the power (or brakes) like that is just an invaluable skill to have, period. You'll be a much smoother & faster driver if you learn to anticipate what happens in front of you, instead of just reacting to the stupid in front of you after it occurs.

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