Too much power?!?

I appreciate the honest review dude. All the power in the world is useless if you can’t control it with precision. I am an instructor pilot and am constantly telling my guys “it’s all about energy management” you can stand it on the tail at takeoff but it’s a different animal at 51,000 ft. I’m sure the 392 has it’s own nuances that I will need to learn but it’s nice to know the pitfalls where I might get myself into trouble, so thanks for the report.
I wonder if there is a difference between the 392XR and the regular 392 in the road manners department. I am sure there are some gyroscopic forces at work due to the tire size, and torque on tap.
Mine is the XR. I think you will quickly figure it out. When I first got mine (especially during break in), I thought it was overpowered and that I might not be able to put all the power to use at full throttle. This is because, part throttle performance on this beast is amazing. With just moderate throttle inputs, it accelerates very quickly. The engine has a broad shouldered torque curve that almost made it feel like there was unlimited power under your right foot.

After I got past 500 miles and did some full throttle pulls, I realized that it is manageable. The first few launches felt squirrelly, but that is because things are dramatic in this vehicle. Unlike the mercedes s65 which launches flat (thanks to hydraulically controlled suspension, the 392's front end raises quite a bit during launch, but after you do this a few times, you realize that things are under control. The 4wd system works well. The rear tires do spin under full throttle launches but only for a split second before the transfer case sends power to front. All of this happens very quickly and you are off like a rocket.

Straight line road manners are great (for a jeep). Had a little steering play that I had to tweak out, but mine drives fine at 90mph straight line (not that I cruise at ninety, but if you stay on the gas, it comes quickly). Ride is very smooth. Soaks up bumps in road nicely. Have not noticed any bump steer. Way less noise in every department than JK (except engine). Even in loud mode, noise is mild while cruising. Give it gas and it sounds like the exhaust is inside the vehicle (in a good way) :). Quiet mode, engine is too quiet IMO.

This is not a canyon carver. Not a ridiculous amount of body roll when turning, but I don't drive like I'm on a slalom course. I've seen jeeps spin out when owners used too much throttle in curves in the rain and I am very cautious when it is wet. I believe the 392 is essentially rear wheel drive until the rear wheels slip and then power is diverted to front wheels via clutch packs, but the clutches in transfer case could be partially engaged all the time (I don't know). I think much throttle application in curves when it is wet is dangerous. Straight line acceleration when it is wet is surprisingly good. I used to turn traction control off on my JK and spin the tires through intersections when it was wet (to entertain the kids; cough, cough). I goosed the 392 in a wet intersection (not full throttle, but maybe 1/2 or 2/3) and it just took off, no wheelspin, no drama. I think that standing on it when its wet would create some drama......

When it is dry, gentle curves are pleasurable. Moderate to heavy part throttle acceleration in gentle curves is very gratifying. Not gonna stand on it in hairpin curves, but freeway entrance ramps can be wicked fun. It is cool to come up to speed on the ramp and overtake all those cars that were zipping by. I was pulling out onto a 4 lane highway that had a curved entrance with a very short merge lane. There were cars coming so I had to stop but was able to get almost parallel to the road I was merging onto. I stomped it as the transfer truck was going by and was absolutely shocked how close behind the truck I was when I got up to 60 mph. This thing gets up to road speed in a very short distance.

Passing people that are going 45 mph on a 55 mph is just a hoot. I know they have got to be like WTH or WTF. It will pass people at lower speeds in a very short distance. Stomp it at 45 and the front end comes up and the engine sounds awesome. Easy to get up to 80 mph while passing. An exciting experience for the jeep driver and hopefully a bit unsettling for the slow poke (they should drive faster anyway). At least go the speed limit.....

Most of all, the 392 is fun to drive. It feels ridiculous. It sounds ridiculous. It is ridiculous. Yes, I hit the offroad + button and pop the exhaust in the school line while dropping the kids off and rolling down main street. Yes, I launch harder than I need to at red lights. Yes, I leave it in loud mode during the day in town. Yes, I grin like a 12 year old boy just thinking about it. My 14y daughter loves it. She will not let you run it in quiet mode if she is in the car.

I actually think the 392 is a wise purchase. Most of the people that get it are going to have a little bit of hooligan in them (I hope) and they are going go around grinning while driving this thing. You will be darn near an apex predator in stoplight wars. The middle school kids will look at you while you're letting the exhaust pop while decelerating in the school line (either thinking you're cool or a jackass). Entertainment for all concerned anyway. Life is too short to not have fun. 392's will likely retain high resale value. The poor fuel economy and expensive oil changes are a small price to pay.

Having said all this, I'm not forcing 2wd and doing line lock burnouts on main street or in the school line. I'm not piss revving the engine to get attention, but unless you drive like a grandma and keep it in quiet mode, you cannot hide this thing. That huge engine has got a huge personality. It makes all kind of cool sounds and does all kinds of cool stuff in different modes. Tell me you don't grin at the full throttle shifts in offroad + or manual....

I know this doesn't answer your question, but I enjoyed typing it :). You are going to love it..
 
Mine is the XR. I think you will quickly figure it out. When I first got mine (especially during break in), I thought it was overpowered and that I might not be able to put all the power to use at full throttle. This is because, part throttle performance on this beast is amazing. With just moderate throttle inputs, it accelerates very quickly. The engine has a broad shouldered torque curve that almost made it feel like there was unlimited power under your right foot.

After I got past 500 miles and did some full throttle pulls, I realized that it is manageable. The first few launches felt squirrelly, but that is because things are dramatic in this vehicle. Unlike the mercedes s65 which launches flat (thanks to hydraulically controlled suspension, the 392's front end raises quite a bit during launch, but after you do this a few times, you realize that things are under control. The 4wd system works well. The rear tires do spin under full throttle launches but only for a split second before the transfer case sends power to front. All of this happens very quickly and you are off like a rocket.

Straight line road manners are great (for a jeep). Had a little steering play that I had to tweak out, but mine drives fine at 90mph straight line (not that I cruise at ninety, but if you stay on the gas, it comes quickly). Ride is very smooth. Soaks up bumps in road nicely. Have not noticed any bump steer. Way less noise in every department than JK (except engine). Even in loud mode, noise is mild while cruising. Give it gas and it sounds like the exhaust is inside the vehicle (in a good way) :). Quiet mode, engine is too quiet IMO.

This is not a canyon carver. Not a ridiculous amount of body roll when turning, but I don't drive like I'm on a slalom course. I've seen jeeps spin out when owners used too much throttle in curves in the rain and I am very cautious when it is wet. I believe the 392 is essentially rear wheel drive until the rear wheels slip and then power is diverted to front wheels via clutch packs, but the clutches in transfer case could be partially engaged all the time (I don't know). I think much throttle application in curves when it is wet is dangerous. Straight line acceleration when it is wet is surprisingly good. I used to turn traction control off on my JK and spin the tires through intersections when it was wet (to entertain the kids; cough, cough). I goosed the 392 in a wet intersection (not full throttle, but maybe 1/2 or 2/3) and it just took off, no wheelspin, no drama. I think that standing on it when its wet would create some drama......

When it is dry, gentle curves are pleasurable. Moderate to heavy part throttle acceleration in gentle curves is very gratifying. Not gonna stand on it in hairpin curves, but freeway entrance ramps can be wicked fun. It is cool to come up to speed on the ramp and overtake all those cars that were zipping by. I was pulling out onto a 4 lane highway that had a curved entrance with a very short merge lane. There were cars coming so I had to stop but was able to get almost parallel to the road I was merging onto. I stomped it as the transfer truck was going by and was absolutely shocked how close behind the truck I was when I got up to 60 mph. This thing gets up to road speed in a very short distance.

Passing people that are going 45 mph on a 55 mph is just a hoot. I know they have got to be like WTH or WTF. It will pass people at lower speeds in a very short distance. Stomp it at 45 and the front end comes up and the engine sounds awesome. Easy to get up to 80 mph while passing. An exciting experience for the jeep driver and hopefully a bit unsettling for the slow poke (they should drive faster anyway). At least go the speed limit.....

Most of all, the 392 is fun to drive. It feels ridiculous. It sounds ridiculous. It is ridiculous. Yes, I hit the offroad + button and pop the exhaust in the school line while dropping the kids off and rolling down main street. Yes, I launch harder than I need to at red lights. Yes, I leave it in loud mode during the day in town. Yes, I grin like a 12 year old boy just thinking about it. My 14y daughter loves it. She will not let you run it in quiet mode if she is in the car.

I actually think the 392 is a wise purchase. Most of the people that get it are going to have a little bit of hooligan in them (I hope) and they are going go around grinning while driving this thing. You will be darn near an apex predator in stoplight wars. The middle school kids will look at you while you're letting the exhaust pop while decelerating in the school line (either thinking you're cool or a jackass). Entertainment for all concerned anyway. Life is too short to not have fun. 392's will likely retain high resale value. The poor fuel economy and expensive oil changes are a small price to pay.

Having said all this, I'm not forcing 2wd and doing line lock burnouts on main street or in the school line. I'm not piss revving the engine to get attention, but unless you drive like a grandma and keep it in quiet mode, you cannot hide this thing. That huge engine has got a huge personality. It makes all kind of cool sounds and does all kinds of cool stuff in different modes. Tell me you don't grin at the full throttle shifts in offroad + or manual....

I know this doesn't answer your question, but I enjoyed typing it :). You are going to love it..
Hardhat, you described perfectly what I was hoping for when I ordered his beast……..most all cars with power nowadays are so electronically controlled and suspension tuned that the driver is isolated and you miss the real feel of a true American “sports car”. Sure it is awesome fun to slalom a perfectly tuned sports car through windy roads but it just doesn’t give you hat gut adrenaline feeling and rush of a beast that has to be handled properly to be tamed…….part of why motorcycles are so fun…….anyway, after your description I am chomping at he bit to get my hands on mine….hopefully real soon! Basically we are getting a hooligan, old school 5 seat convertible sports car that happens to go off-road 😎😎. Nothing else like it to be had in today’s world!!
 
I’ve had my 392XR for two weeks now and I love it. That being said I feel like the motor is somewhat wasted in a Wrangler. The handling is definitely better than the previous JK, but I feel like it should be more dialed in for what’s under the hood. I’ve also noticed the front end jerks a bit to the right when you open it up on the highway…kinda scary. I was thinking maybe stiffer springs and different shocks would help? I plan to add the Fox steering stabilizer - I know it won’t do much but it’ll tighten that steering up a bit. Thoughts?

A lot of torque for a somewhat soft suspension. Theres also quite a bit of rubber between a 35" tire and a 17" wheel... so the slightest bit of difference in tire pressure will make a make larger difference.
 
Reading some of the commentary regarding performance, suspension, etc. my curiosity is, what’s your intended purpose of the vehicle?
Considering this design is strictly utilitarian, many do not expect cornering, high speed turns, high speed stability, etc. which is why it’s governed at either 100 or 110(XR). Also, too stiff of a suspension won’t permit axle articulation. The cargo capacity is around 900#, as a result.
I had a Jeep GC SRT, and even that, with a suspension designed for cornering, was still an absolute pig in the turns.
Jeep built the JL with a 392 for that specific crowd who wanted a V8, and they’ve been waiting 40 years.
Power, suspension, vehicle platform, are all relative to intended use, and more on the responsibility of the driver to manage it.
With my JK, I had a 3.5” lift and wouldn’t let people without experience, drive it. Reason being, high center of gravity, and, with that much change in geometry, it handles very differently than an IFS/IRS or IFS/Solid rear set up. With excessive suspension travel, you can’t hold the steering wheel firmly as you roll down the highway at 70-80mph. Otherwise, they’re “wandering”. Many people don’t understand these intricacies of a solid axle vehicle and what specifically happens when that axle travels vertically while connected to a fixed length, linear track bar set up.
The horsepower? The enthusiasts love. My goal is to eventually add an S/C. Why? Because I can. 😎
 
Last edited:
I’ve had my 392XR for two weeks now and I love it. That being said I feel like the motor is somewhat wasted in a Wrangler. The handling is definitely better than the previous JK, but I feel like it should be more dialed in for what’s under the hood. I’ve also noticed the front end jerks a bit to the right when you open it up on the highway…kinda scary. I was thinking maybe stiffer springs and different shocks would help? I plan to add the Fox steering stabilizer - I know it won’t do much but it’ll tighten that steering up a bit. Thoughts?
If I was going to replace the steering stabilizer I would try the Roadmaster Exact-Center
 
Mine is the XR. I think you will quickly figure it out. When I first got mine (especially during break in), I thought it was overpowered and that I might not be able to put all the power to use at full throttle. This is because, part throttle performance on this beast is amazing. With just moderate throttle inputs, it accelerates very quickly. The engine has a broad shouldered torque curve that almost made it feel like there was unlimited power under your right foot.

After I got past 500 miles and did some full throttle pulls, I realized that it is manageable. The first few launches felt squirrelly, but that is because things are dramatic in this vehicle. Unlike the mercedes s65 which launches flat (thanks to hydraulically controlled suspension, the 392's front end raises quite a bit during launch, but after you do this a few times, you realize that things are under control. The 4wd system works well. The rear tires do spin under full throttle launches but only for a split second before the transfer case sends power to front. All of this happens very quickly and you are off like a rocket.

Straight line road manners are great (for a jeep). Had a little steering play that I had to tweak out, but mine drives fine at 90mph straight line (not that I cruise at ninety, but if you stay on the gas, it comes quickly). Ride is very smooth. Soaks up bumps in road nicely. Have not noticed any bump steer. Way less noise in every department than JK (except engine). Even in loud mode, noise is mild while cruising. Give it gas and it sounds like the exhaust is inside the vehicle (in a good way) :). Quiet mode, engine is too quiet IMO.

This is not a canyon carver. Not a ridiculous amount of body roll when turning, but I don't drive like I'm on a slalom course. I've seen jeeps spin out when owners used too much throttle in curves in the rain and I am very cautious when it is wet. I believe the 392 is essentially rear wheel drive until the rear wheels slip and then power is diverted to front wheels via clutch packs, but the clutches in transfer case could be partially engaged all the time (I don't know). I think much throttle application in curves when it is wet is dangerous. Straight line acceleration when it is wet is surprisingly good. I used to turn traction control off on my JK and spin the tires through intersections when it was wet (to entertain the kids; cough, cough). I goosed the 392 in a wet intersection (not full throttle, but maybe 1/2 or 2/3) and it just took off, no wheelspin, no drama. I think that standing on it when its wet would create some drama......

When it is dry, gentle curves are pleasurable. Moderate to heavy part throttle acceleration in gentle curves is very gratifying. Not gonna stand on it in hairpin curves, but freeway entrance ramps can be wicked fun. It is cool to come up to speed on the ramp and overtake all those cars that were zipping by. I was pulling out onto a 4 lane highway that had a curved entrance with a very short merge lane. There were cars coming so I had to stop but was able to get almost parallel to the road I was merging onto. I stomped it as the transfer truck was going by and was absolutely shocked how close behind the truck I was when I got up to 60 mph. This thing gets up to road speed in a very short distance.

Passing people that are going 45 mph on a 55 mph is just a hoot. I know they have got to be like WTH or WTF. It will pass people at lower speeds in a very short distance. Stomp it at 45 and the front end comes up and the engine sounds awesome. Easy to get up to 80 mph while passing. An exciting experience for the jeep driver and hopefully a bit unsettling for the slow poke (they should drive faster anyway). At least go the speed limit.....

Most of all, the 392 is fun to drive. It feels ridiculous. It sounds ridiculous. It is ridiculous. Yes, I hit the offroad + button and pop the exhaust in the school line while dropping the kids off and rolling down main street. Yes, I launch harder than I need to at red lights. Yes, I leave it in loud mode during the day in town. Yes, I grin like a 12 year old boy just thinking about it. My 14y daughter loves it. She will not let you run it in quiet mode if she is in the car.

I actually think the 392 is a wise purchase. Most of the people that get it are going to have a little bit of hooligan in them (I hope) and they are going go around grinning while driving this thing. You will be darn near an apex predator in stoplight wars. The middle school kids will look at you while you're letting the exhaust pop while decelerating in the school line (either thinking you're cool or a jackass). Entertainment for all concerned anyway. Life is too short to not have fun. 392's will likely retain high resale value. The poor fuel economy and expensive oil changes are a small price to pay.

Having said all this, I'm not forcing 2wd and doing line lock burnouts on main street or in the school line. I'm not piss revving the engine to get attention, but unless you drive like a grandma and keep it in quiet mode, you cannot hide this thing. That huge engine has got a huge personality. It makes all kind of cool sounds and does all kinds of cool stuff in different modes. Tell me you don't grin at the full throttle shifts in offroad + or manual....

I know this doesn't answer your question, but I enjoyed typing it :). You are going to love it..
So well put!

The 392 is fun like a wooden rollercoaster is fun. Loud, just enough squirrelly, and fast!
 
its the drivetrain pulling, torque steer

when I force2wd it goes away
 
Reading some of the commentary regarding performance, suspension, etc. my curiosity is, what’s your intended purpose of the vehicle?
Considering this design is strictly utilitarian, many do not expect cornering, high speed turns, high speed stability, etc. which is why it’s governed at either 100 or 110(XR). Also, too stiff of a suspension won’t permit axle articulation. The cargo capacity is around 900#, as a result.
I had a Jeep GC SRT, and even that, with a suspension designed for cornering, was still an absolute pig in the turns.
Jeep built the JL with a 392 for that specific crowd who wanted a V8, and they’ve been waiting 40 years.
Power, suspension, vehicle platform, are all relative to intended use, and more on the responsibility of the driver to manage it.
With my JK, I had a 3.5” lift and wouldn’t let people without experience, drive it. Reason being, high center of gravity, and, with that much change in geometry, it handles very differently than an IFS/IRS or IFS/Solid rear set up. With excessive suspension travel, you can’t hold the steering wheel firmly as you roll down the highway at 70-80mph. Otherwise, they’re “wandering”. Many people don’t understand these intricacies of a solid axle vehicle and what specifically happens when that axle travels vertically while connected to a fixed length, linear track bar set up.
The horsepower? The enthusiasts love. My goal is to eventually add an S/C. Why? Because I can. 😎
I talked to livernois and they said you would have to ditch the hydroguide. I would like to see a low profile SC that used the stock airbox. Even a roots running a 5psi (maybe avoid new pistons) would be enough. Even a modest 25% increase in power (which 5 psi should provide) would put you close to 600hp..... pulleys and pistons could put you into hellcat territory.
Having said that, I'm loving it like it is right now. I've had aftermarket superchargers in the past and unless the tune is spot on, there are driveability issues that negate some of the fun....Right now the thing drives great.
 
I talked to livernois and they said you would have to ditch the hydroguide. I would like to see a low profile SC that used the stock airbox. Even a roots running a 5psi (maybe avoid new pistons) would be enough. Even a modest 25% increase in power (which 5 psi should provide) would put you close to 600hp..... pulleys and pistons could put you into hellcat territory.
Having said that, I'm loving it like it is right now. I've had aftermarket superchargers in the past and unless the tune is spot on, there are driveability issues that negate some of the fun....Right now the thing drives great.
Last I read, the pistons in this motor is the same as the Trackhawk. MOPAR is known for doing that. It’s also lean manufacturing.
 
So does that mean this engine has boost capable pistons? I read that the 6.4 in the dodges had pistons that did not like boost
 
Reading all this make me wonder if mine has something wrong with it. At no point do I think it is ridiculous. To pass a slow moving vehicle I can put the pedal all the way down. And then let up and i never think it is too much. I live at 8000 feet and not many of the road are flat. But not many are dry right now either. It is a Jeep and doing a 12k foot pass with a lot of turns on snow pack roads it handles fine, it is now fun to get groceries over rabbit ears pass. I had to flog my JKUR, which was never fun. I guess it is what you get used to, but I see a lot other vehicles that you all own I thought were sporty? My truck has 900ft/lbs of torque and is rear wheel drive, so the Jeep is pretty tame I think…
 
That 900 foot pound truck is probably turbo charged and that’s better at altitude than the naturally aspirated Jeep. Eight and 12,000 feet altitude decrease the power output of naturally aspirated engine significantly and that’s probably why it feels tame compared to your truck. Just a thought
 
Last edited:
That 900 foot pound truck is probably turbo charged and that’s better at altitude than the naturally aspirated Jeep. Eight and 12,000 feet altitude decrease the power output of naturally aspirated engine significantly and that’s probably why it feels time compared to your truck. Just a thought
Yup, turbocharged.
 
I’ve had my 392XR for two weeks now and I love it. That being said I feel like the motor is somewhat wasted in a Wrangler. The handling is definitely better than the previous JK, but I feel like it should be more dialed in for what’s under the hood. I’ve also noticed the front end jerks a bit to the right when you open it up on the highway…kinda scary. I was thinking maybe stiffer springs and different shocks would help? I plan to add the Fox steering stabilizer - I know it won’t do much but it’ll tighten that steering up a bit. Thoughts?
I have over 8K miles on mine and have not experienced any problem with the steering pulling under acceleration. Accleration while cornering can be quite exciting sometimes especially with a Pedal Commander set too much toward the performance side.
 
Last I read, the pistons in this motor is the same as the Trackhawk. MOPAR is known for doing that. It’s also lean manufacturing.
Where did you get this information? When I look online, it looks like our 6.4 has CR of 10.9 and trackwawk has CR 9.5. I saw one place where it said 392 was 10.25, but either way would indicate different pistons, assuming same cc in combustion chamber on the head side...... Also the top ring seems to be concern with boost, both the gap and how close ring is to top of piston. I would love to believe that our engines have more boost friendly pistons than run of the mill 6.4 hemis....so any information you have would be appreciated.

I'm still happy with stock performance, but being a gear head, always interested in exploring options :)
 
This is best I have found

57B3D16F-6898-4735-915F-07A29EB8A0D3.webp
 
Where did you get this information? When I look online, it looks like our 6.4 has CR of 10.9 and trackwawk has CR 9.5. I saw one place where it said 392 was 10.25, but either way would indicate different pistons, assuming same cc in combustion chamber on the head side...... Also the top ring seems to be concern with boost, both the gap and how close ring is to top of piston. I would love to believe that our engines have more boost friendly pistons than run of the mill 6.4 hemis....so any information you have would be appreciated.

I'm still happy with stock performance, but being a gear head, always interested in exploring options :)
So no boost…. hypereutectic pistons.
 
So no boost…. hypereutectic pistons.
Easy
Piston swap
Bolting on an S/C will benefit with injectors, fuel pump, port/polish the heads, etc.
Swapping pistons is the easy part.
 
Easy
Piston swap
Bolting on an S/C will benefit with injectors, fuel pump, port/polish the heads, etc.
Swapping pistons is the easy part.
Agreed. It just raises the install difficulty by a lot. Easy to drop on sc and injectors vs. Pulling engine to do pistons and rods. No longer a weekend job in the garage.
 

Create an account or login to comment

Join now to leave a comment enjoy browsing the site ad-free!

Create account

Create an account on our community. It's easy!

Log in

Already have an account? Log in here.

Back
Top