Brake Torque Launch

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Any current owners do a launch yet? How did it perform? What are the steps you have to do to make it happen? I've looked at some you tube videos with one saying you don't use the brake, but a paddle shifter. Confusing. Anyone that can properly explain? Thanks
 
I asked a similar question on a different forum. No response. I don't think people know about it but according to a car and driver write up it is activated with a left foot brake and throttle applied. I don't have mine yet or I would try it and let you know,
 
I asked a similar question on a different forum. No response. I don't think people know about it but according to a car and driver write up it is activated with a left foot brake and throttle applied. I don't have mine yet or I would try it and let you know,
Yeah I downloaded the performance guide and it explains how it works but doesn't tell you how to do it. I looked on you tube and found vids mostly other models, but one vid the guy was explaining and said it's controlled with the paddle shifter. I'm not sure how that would work. But yeah, if no one responds, I guess I'll figure it out after I pick mine up and break it in.
 
I had no idea it had a launch control.

In other cars you simply apply the brake with the left foot and fully depress the accelerator with the right foot (this activates the mechanism) and then release the brake. In a porsche panamera turbo it's about as close to aircraft carrier launch as we can get. That car has all wheel drive as well so the tires are totally hooked up.

I have about 2500 miles on the 392 now, so I will have to give it try and report back.
 
I had no idea it had a launch control.

In other cars you simply apply the brake with the left foot and fully depress the accelerator with the right foot (this activates the mechanism) and then release the brake. In a porsche panamera turbo it's about as close to aircraft carrier launch as we can get. That car has all wheel drive as well so the tires are totally hooked up.

I have about 2500 miles on the 392 now, so I will have to give it try and report back.
Yeah, go to jeep.com and go to owners, then go to manuals and download the performance guide for the 392. It explains the automatic torque reserve for launching. Just doesn't say how to do it. I'm curious what rpm do you build it up to and if the guy on you tube is correct when saying hold the shift paddle instead of the brake.
 
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I haven't taken delivery yet so I don't know if Jeep is providing full printed manuals. My 18 Sahara didn't come with a full manual, just partial, with a note letting owners know a full manual is online for download. Anyway, if it doesn't come with a printed guide, this is what it looks like.
 

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Okay so I got my 392 and 1k miles on it. It is activated with brake and throttle together not using the paddle. It takes a second for the tone to change on the exhaust then your set. It launches hard and works great.
 
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Okay so I got my 392 and 1k miles on it. It is activated with brake and throttle together not using the paddle. It tales a second for the tone to change on the exhaust then your set. It launches hard and works great.
Sounds like added fun factor. I'll definitely be giving it a go once I hit the recommended break in mileage. Thanks for coming back to fill us in. Yeah I thought the YouTube video guy probably had no idea what he was saying. It didn't make sense to hold shift paddles and accelerator for a launch.
So there is a distinct change in exhaust sound huh? Feels harder than just stomping on the pedal?
 
Sounds like added fun factor. I'll definitely be giving it a go once I hit the recommended break in mileage. Thanks for coming back to fill us in. Yeah I thought the YouTube video guy probably had no idea what he was saying. It didn't make sense to hold shift paddles and accelerator for a launch.
So there is a distinct change in exhaust sound huh? Feels harder than just stomping on the pedal?
Yes definitely a sound change in the exhaust it is noticeable. It launches hard, harder than just throttle alone. The driveline is loaded up at that point so it makes sense it would.

Before I got it broke in I tried it without launching to see how it activated. Just apply brake and some throttle wait a second or two and you will hear the change in the exhaust. It will try and push through the brakes if you give it to much throttle, it does not take a lot of throttle to activate it. After that its ready, I bet 90 percent of people that will own these will not be aware it does that.
 
Yes definitely a sound change in the exhaust it is noticeable. It launches hard, harder than just throttle alone. The driveline is loaded up at that point so it makes sense it would.

Before I got it broke in I tried it without launching to see how it activated. Just apply brake and some throttle wait a second or two and you will hear the change in the exhaust. It will try and push through the brakes if you give it to much throttle, it does not take a lot of throttle to activate it. After that its ready, I bet 90 percent of people that will own these will not be aware it does that.
Awesome to know!!! Once I get off work I'm gonna try it!!!!

It's interesting that the sound change is noticeable and that 'sound change' is your que that you've built up your torque reserve. I imagine that's because the timing retards and the fuel flow stops to some of the cylinders... so I'm assuming because of that alone the engine/exhaust just sounds different.?. Or perhaps there's something else that comes into play to alter the sound to que the driver, Hey - Let's Do This!!!
 
I finally reached my recommended break in mileage yesterday and yep, went to a straight section of quiet highway and did it 3 times. First time was fun, the second time I guess I hit it just right because it turned my stomach upside down, or some would call it butterflies, but I usually feel that feeling when I'm on a roller coaster. So with that feeling on second round, of course I had to do it a third. Yep it's really cool getting that sound and feeling knowing it's ready to launch. Yep, another reason I really like this thing.
 
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I use this often, to do it right you sometimes need to not go full WOT right out of the gate and be more progressive over the first 30 feet, or you may notice it just spins the tires and upshifts early.

What I did notice is this ZF trans seems to have another shift program for the torque reserve launches. If you've done a few of these you may know what I'm talking about. In some ZF trans they call this program QuickShift 3 (common in BMW) and it shifts much quicker and keeps full torque through the shift. - But This shift program doesn't always happen it seems, so there must be some mystery logic behind it. - Similar to what @Hydro Blue 392 said, it's a noticeable difference when the torque reserve launch and this shift program are in unison.
 
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These are 2 quotes I found doing a quick google search looking at torque reserve, shifting and the 392.
Other writings seem to indicate that maybe shifts may be quicker and harder and that engine power is not reduced as much (if at all) during the shift. Hopefully it is true balls to the wall, but I'm gonna have to get out there and do more research.


Torque Reserve is a type of launch control for on-pavement antics allowing the Rubicon 392 to eagerly grip solid-pavement, accessible during a brake torque launch. AMax shifting makes the most of engine torque and cog swaps, the same found on the Hellcat-powered Grand Cherokee Trackhawk.

The Wrangler Rubicon 392’s powertrain calibration includes Torque Reserve and AMax shifting, accessible when doing a brake torque launch, that delivers maximum acceleration for solid-pavement launches. Torque Reserve, an engine strategy used by drag racers, manages fuel flow to the cylinders and controls spark advance or retard to balance engine rpm and torque to maximize power delivery and launch performance. AMax shifting, a performance-enhancing strategy used on the Jeep Grand Cherokee Trackhawk, maximizes forward torque by coordinating shift time and engine torque management.
 

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