Hmm 0-60 worlds away from jeeps claimed 4 flat for the XR

[Azreed2000]

What do you mean flogging it as much. It doesn't have any modes so it's simply traction off and smash throttle. That's all we did lol

Did you use the launch control feature... Where you hold on the brakes while depressing the gas pedal about 1/3 to 1/2 way down. The engine will change pitch to let you know it's ready, then you let off the brake and fully depress the gas.

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[Rosco P]

I floor the gas and hold the brake. Chirps all the tires. No LC program on earth requires you to press the accelerator 1/3 or any other fraction of the way down.

 

[thegame81]

I floor the gas and hold the brake. Chirps all the tires. No LC program on earth requires you to press the accelerator 1/3 or any other fraction of the way down.

Literally everyone that has done it and knows how to do it say that's exactly what you do.

 

[Rosco P]

Literally everyone that has done it and knows how to do it say that's exactly what you do.

Ok

I’ve done it. I do it as I described. Works perfectly

 

[thegame81]

Ok

I’ve done it. I do it as I described. Works perfectly

Didn't mean it in a rude way. I haven't done it yet. I just meant everyone that I've read their posts says do not floor it because it will walk through the brakes.

I wanna try it soon. Here's what I've heard.

Be in off road plus

Press the brake firmly

Off road page had to show 0 % pitch or it will not engage.

Press gas 1/4 to 1/2 pressure

Wait a second or so. Listen for a distinctive change in exhaust note

Get off brake and floor it.

Right or not I have no idea but that seems to be what I've seen over and over. Thanks for the reply

 

[SLORubi]

Ok

I’ve done it. I do it as I described. Works perfectly

If your chirping the tires, I’d say that’s just a bit to much throttle for perfect. Splitting hairs for sure, but if we are talking fractions of seconds, you want to be at max power to the road, just on that edge of chirping.

 

[Bzinsky]

If your chirping the tires, I’d say that’s just a bit to much throttle for perfect. Splitting hairs for sure, but if we are talking fractions of seconds, you want to be at max power to the road, just on that edge of chirping.

Right before the launch, the engine is spinning and the transmission is not. So when you finally launch the transmission rapidly speeds up and the engine rapidly slows down until they match their speeds, this transfer of inertia creates a temporary surge of torque. Same thing happens with a very fast shift.

chirping tires is fine

i guess from a physics point of view any loss of traction is lost energy, but from a real world point of view it just means your getting it done.

 

[Deleted member 59498]

So Jeep didn't actually say 4.0?

 

[thegame81]

So quick update. I tried it today but it didn't work.

Pressed brake firmly.

Started giving it gas. It immediately reacted to the gas. It held in place but it wanted to go. I noticed no change at all in exhaust or engine note so I don't think it was ready to launch.

One thing to mention though on the off road page it did show 0 pitch but there was 1 degree of roll showing.

Guessing if there is any pitch or roll it will not engage?

 

[Bzinsky]

So quick update. I tried it today but it didn't work.

Pressed brake firmly.

Started giving it gas. It immediately reacted to the gas. It held in place but it wanted to go. I noticed no change at all in exhaust or engine note so I don't think it was ready to launch.

One thing to mention though on the off road page it did show 0 pitch but there was 1 degree of roll showing.

Guessing if there is any pitch or roll it will not engage?

One guy said mash the brake then the gas all the way.

The typical way to launch an auto is brake and throttle at the same time until you reach the stall speed of the torque converter, usually around 2k rpms on a stock vehicle. It sounds like you’re doing this, but jeep has some sort of built in mode beyond that you just mash the brake then throttle.

I might suggest being less gentle with it. You’re not going to break anything. Just don’t hold it for more than a few seconds. The trans fluid is absorbing the energy of the motor during this time and it heats up pretty quickly. It’s not that sensitive but don’t want hold it for like 5 seconds multiple times while stationary.

Also during this process, it is just the two sides of the torque converter spinning different speeds and the fluid flow between them that is creating the resistance. Kinda like if a jet ski had two impellers in series and only one is spinning. I know it feels a lot like burning the clutch or some sort of friction material on a manual trans, but it’s not. It really does zero harm at all unless you overheat the trans fluid.

You might already know all this, but just incase.

 

[thegame81]

One guy said mash the brake then the gas all the way.

The typical way to launch an auto is brake and throttle at the same time until you reach the stall speed of the torque converter, usually around 2k rpms on a stock vehicle. It sounds like you’re doing this, but jeep has some sort of built in mode beyond that you just mash the brake then throttle.

I might suggest being less gentle with it. You’re not going to break anything. Just don’t hold it for more than a few seconds. The trans fluid is absorbing the energy of the motor during this time and it heats up pretty quickly. It’s not that sensitive but don’t want hold it for like 5 seconds multiple times while stationary.

Also during this process, it is just the two sides of the torque converter spinning different speeds and the fluid flow between them that is creating the resistance. Kinda like if a jet ski had two impellers in series and only one is spinning. I know it feels a lot like burning the clutch or some sort of friction material on a manual trans, but it’s not. It really does zero harm at all unless you overheat the trans fluid.

You might already know all this, but just incase.

So you're saying Brake hard - punch the gas - wait for the exhaust note sound to change and good to go? ill give that a try as well lol it's so weird that this is so mysterious and even my friend who's a big car guy and sells these had no idea it has launch control. I do wish they at the very least had some sort of visual tell on the display saying its enabled. I mean if they say it's the same system from the gc track hawk then why not also have the button and screen saying enabled. Seems so weird lol

 

[Bzinsky]

So you're saying Brake hard - punch the gas - wait for the exhaust note sound to change and good to go?

I have no clue as I’ve never tried or read the official procedure, that is what a guy on the previous page said to do and that is what I would try if I was a 392 owner. (I am a jealous 4xe owner) It does make sense though and I would assume you would know if it works within 1 second.

If that is how you launch it, that is actually way better than some official launch control procedure. It means you can do it at a stop light on a moments notice, which is the biggest problem with most modern launch controls.

 

[thegame81]

I have no clue as I’ve never tried or read the official procedure, that is what a guy on the previous page said to do and that is what I would try if I was a 392 owner. (I am a jealous 4xe owner) It does make sense though and I would assume you would know if it works within 1 second.

If that is how you launch it, that is actually way better than some official launch control procedure. It means you can do it at a stop light on a moments notice.

Jealous why> Have you seen gas prices lol 4XE is a badass Jeep as well. Yea I'll have to just play around with it more when I have some downtime.

 

[Bzinsky]

Jealous why> Have you seen gas prices lol 4XE is a badass Jeep as well. Yea I'll have to just play around with it more when I have some downtime.

Lol I’m not seriously jealous, but I know I would have a lot more fun in the 392. I’m mostly here because we have a lot of the same drivetrain and the 392 section is more performance oriented. Topics are more my flavor.

 

[Bzinsky]

The 392's full-time four-wheel-drive system doesn't offer a two-wheel-drive mode, and that's probably for the best since this rig can do four-wheel-drive burnouts if the pavement's even slightly damp. For launches that feel like they might involve a wheelstand, apply left-foot braking to cue up Torque Reserve, which is basically launch control for dummies. Similar to the Gladiator Mojave, the 392's Off-Road Plus driving mode lets you lock the rear differential at high speeds, leading us to wonder what Jeep thinks people are going to try to do with this thing. Maybe the better question is: What won't they try to do?

excerpt from the car and driver article. They for sure locked the rear diff to achieve that time. Man I love car and driver 0-60’s, they do not screw around trying to get the fastest possible time.

Anybody know if the rear diff will unlock at speed? Wondering if you could lock the rear diff at a stop light, launch it, then unlock rear diff and switch to 4auto mid acceleration. I switch from 4auto to 2wd after the 1-2shift in my pickup, but it was just a knob that is turned. Obviously would be somehwat challenging while going balls to the wall in the 392.

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