Powerwagon 6.4 vs rubicon 392

[Stuffpower]

From my understanding these are both the same engines but have different power ratings. Why is this?

 

[392DevilDog]

They are not the same engine. The 392 in the Rubicon is the SRT motor. The 392 in the HD is a BGE and is made for towing.

They were completely different til 2018 then they got a bit more similar.

The HD is made for running at peak output constantly.

The SRT 392 is made for peak output a few moments at a time.

Best way I can describe it.

No real need to get any more technical than that they are 2 totally different applications of an engine with similar displacement.

 

[Fatbob Frank]

Yep...
My Bro in law bought a 6.4L scat pack Challenger and was amazed at how much more power he has than my Power Wagon.
Then he talked about the awesome burnouts, 0-60 time and 1/4 mile times (which are impressive)
I nodded and told him "now do all that towing a 9,000 lb. camper."
He got the reason for the different engines real quick...
Frankly I'm at a loss as to why they stuffed a Challenger 392 in the Rubicon and didn't go with the truck version which would still be impressive in a Jeep.

 

[crash68]

Frankly I'm at a loss as to why they stuffed a Challenger 392 in the Rubicon and didn't go with the truck version which would still be impressive in a Jeep.

Most likely packaging size and there is no need for a Wrangler to be able to pull a heavy trailer like a HD truck does. Cooling is factor also, the EcoDiesel they put in the Wrangler is derated for cooling reasons.

 

[Fatbob Frank]

True, plus FCA is constantly stuffing big HP #s into platforms to boost sales.
(I'm talking to you Trackhawk!)
The higher HP of the 392 looks great on paper but the platform isn't going to need the pulling ability of the truck motor...

 

[Stuffpower]

I was just hoping it was a simple tune to jump the hp up to 470. The power wagon is amazing but I wouldn’t be shy about adding simple hp

 

[392DevilDog]

I was just hoping it was a simple tune to jump the hp up to 470. The power wagon is amazing but I wouldn’t be shy about adding simple hp

It is not a simple tune.

The 392 in the chassis cabs are even lower on Horsepower because the redline is lowered. For longevity and constant power output.

 

[392DevilDog]

I was just hoping it was a simple tune to jump the hp up to 470. The power wagon is amazing but I wouldn’t be shy about adding simple hp

I am hoping the Powerwagon gets the 6.2l supercharged.

Thought the tremor was gonna make it up its game...but so far it hasnt really raised the bar.

For awhile a Rebel Subbrand was rumored...where the off road trucks and future street trucks were gonna live.

But so far it has been just a bunch of smoke and mirrors form ford about competing with the TRX

 

[62Blazer]

They are the "same" engine if you say they are both 6.4L Hemi based applications. Also there is not a huge power difference between the engines as you are only talking 60 HP, which some minor mechanical changes could accomplish easily. The biggest difference in performance comes from the weight difference. You are talking about a 7,000 lb. Power Wagon versus a 5,000 lb. Rubicon....and the weight difference is more than just adding 2,000 lb. in the back of the Rubicon. Rolling resistance is much higher in the PW because of the larger components....harder to turn the heavier axles, etc... This is really true for the comment about the Hellcat having a lot more power....it's 2,500 lb. lighter and MUCH less rolling resistance.

 

[LeesEvoX]

They are the "same" engine if you say they are both 6.4L Hemi based applications. Also there is not a huge power difference between the engines as you are only talking 60 HP, which some minor mechanical changes could accomplish easily. The biggest difference in performance comes from the weight difference. You are talking about a 7,000 lb. Power Wagon versus a 5,000 lb. Rubicon....and the weight difference is more than just adding 2,000 lb. in the back of the Rubicon. Rolling resistance is much higher in the PW because of the larger components....harder to turn the heavier axles, etc... This is really true for the comment about the Hellcat having a lot more power....it's 2,500 lb. lighter and MUCH less rolling resistance.

The power an engine makes has nothing to do with how much the vehicle weighs, or how much rolling resistance the vehicle has.

All of the manufacturers base their HP ratings at the crank.

And just FYI. 60hp IS a pretty big difference in power. depending on the engine of course. my old street car was at about 450WHP on pump gas (93). i wanted to bump up to E85 for some more power gains. right off the bat got another 20WHP out of it. However, i maxxed out my fuel pump.. so i had to replace with a bigger one.. After that, picked up a bit more HP.. but the duty cycle on the injectors was through the roof! so, bought larger injectors. after all that. i made a total of 50 extra WHEEL hp. this is also ringing the engine out to a 8500RPM rev limiter to squeeze as much as i could out of it.

Which also included cams, valvetrain, head work.

 

[62Blazer]

The power an engine makes has nothing to do with how much the vehicle weighs, or how much rolling resistance the vehicle has.

All of the manufacturers base their HP ratings at the crank.

And just FYI. 60hp IS a pretty big difference in power. depending on the engine of course. my old street car was at about 450WHP on pump gas (93). i wanted to bump up to E85 for some more power gains. right off the bat got another 20WHP out of it. However, i maxxed out my fuel pump.. so i had to replace with a bigger one.. After that, picked up a bit more HP.. but the duty cycle on the injectors was through the roof! so, bought larger injectors. after all that. i made a total of 50 extra WHEEL hp. this is also ringing the engine out to a 8500RPM rev limiter to squeeze as much as i could out of it.

Which also included cams, valvetrain, head work.

Never made any comment that the horsepower at the crankshaft of an engine somehow "changes" with the weight of the vehicle, but rather specifically stated the "performance" of the vehicle changes based on weight and rolling resistance. If you put two vehicles with the same engine but otherwise drastically different (i.e. Power Wagon versus a Challenger or Charger car) on a wheel dyno they will have a difference in rear wheel power based on driveline loss....big difference between something like a Power Wagon going through a transfer case, heavier driveshafts, larger rear axle, bigger tires, etc..... versus a car. In that case the total weight isn't a big deal but rather the rolling resistance.
Now in the real world the total weight comes into play in addition to the rolling resistance. Again, put the exact same engine in a 7,000 lb. PW and a 4,500 lb. Charger. If both engines put out identical power numbers at the crank the Charger will "feel" like it has much power and be way faster in a drag race (and get way better MPG). That is also why my 185 HP 4 cylinder car has a faster 0-60 mph time than my 410 HP PW.

 

[LeesEvoX]

Never made any comment that the horsepower at the crankshaft of an engine somehow "changes" with the weight of the vehicle, but rather specifically stated the "performance" of the vehicle changes based on weight and rolling resistance. If you put two vehicles with the same engine but otherwise drastically different (i.e. Power Wagon versus a Challenger or Charger car) on a wheel dyno they will have a difference in rear wheel power based on driveline loss....big difference between something like a Power Wagon going through a transfer case, heavier driveshafts, larger rear axle, bigger tires, etc..... versus a car. In that case the total weight isn't a big deal but rather the rolling resistance.
Now in the real world the total weight comes into play in addition to the rolling resistance. Again, put the exact same engine in a 7,000 lb. PW and a 4,500 lb. Charger. If both engines put out identical power numbers at the crank the Charger will "feel" like it has much power and be way faster in a drag race (and get way better MPG). That is also why my 185 HP 4 cylinder car has a faster 0-60 mph time than my 410 HP PW.

Ahh ok. just wasnt entirely sure with your first comment because everything else was pretty obvious.

Carry on!

 

[retired]

GEN III HEMI® Engine Quick Reference Guide Part IV

MORE CUBES AND MORE POWER: 2011 – 2021 6.4L/392 HEMI® V8 ENGINE So far in this series, we have covered the beginning of the great HEMI® engin...

www.dodgegarage.com

as you can see there is a fair amount of difference between what is in the HD truck and the jeep. face it our 6.4L are in need of an upgrade power wise....

 

[62Blazer]

GEN III HEMI® Engine Quick Reference Guide Part IV

MORE CUBES AND MORE POWER: 2011 – 2021 6.4L/392 HEMI® V8 ENGINE So far in this series, we have covered the beginning of the great HEMI® engin...

www.dodgegarage.com

as you can see there is a fair amount of difference between what is in the HD truck and the jeep. face it our 6.4L are in need of an upgrade power wise....

More power is never a bad thing. Maybe I'm just getting old but always chuckle a little when I see people say the 410 HP Hemi needs more power. I remember in '88 when Chevy introduced fuel injection on the 350s that bumped power up to 200 HP (about a 25% increase from previous) and people were raving about it....even remember truck magazines having a cover shot of the new trucks doing a burn out. That was the standard in power when I was growing up. Then in the early 2000s I bought a Dodge 1500 with the Magnum 5.9L that had 245 HP and thought it felt strong. A few years later I got a Chevy 2500HD with the 6.0L gas at 300 HP and thought it was fast!

 

[retired]

More power is never a bad thing. Maybe I'm just getting old but always chuckle a little when I see people say the 410 HP Hemi needs more power. I remember in '88 when Chevy introduced fuel injection on the 350s that bumped power up to 200 HP (about a 25% increase from previous) and people were raving about it....even remember truck magazines having a cover shot of the new trucks doing a burn out. That was the standard in power when I was growing up. Then in the early 2000s I bought a Dodge 1500 with the Magnum 5.9L that had 245 HP and thought it felt strong. A few years later I got a Chevy 2500HD with the 6.0L gas at 300 HP and thought it was fast!

I started driving in the early 70's and I too remember how gutless my 460's and 454's were. I remember when a a 305 made 165 hp and that felt fast

 

[Grand Mesa]

I started driving in the early 70's and I too remember how gutless my 460's and 454's were. I remember when a a 305 made 165 hp and that felt fast

The 1975 base 350 V8 engine Corvette was also rated at 165 hp.

 

[Fatbob Frank]

I have no problem with my PWs power either.
Seems plenty capable to me.
But then, I remember when my 1990 5.9L (EFI) Ramcharger seemed powerful and my wife's V6 pentastar has that beat all to heck on HP and Torque...

 

[SeppW]

Vastly different engines.

 

[ramffml]

I have no problem with my PWs power either.
Seems plenty capable to me.
But then, I remember when my 1990 5.9L (EFI) Ramcharger seemed powerful and my wife's V6 pentastar has that beat all to heck on HP and Torque...

I bet it doesn't. OK, peak HP and torque numbers, yes, but those old v8's had gobs of power low down. That pentastar is a great motor all things considered, but you need to wind it up to make any power. Used to own one in my Jeep GC with the 5 speed mercedes transmission and a 3.12(?) (3.08??) rear end. Completely Gutless. I didn't feel the power begin to come on until about 2700 RPMs.

My hemi lives between 1000 and 2000 when it's just me in the empty truck. Can go months before it goes over 2000 and that's freeway driving as well.

 

[Fatbob Frank]

LOL...
I must have a lead foot cause my PW is breaking 3500 all the time! (and sounds badass doing it)
At 60mph the 8speed is running about 1,700rpms or so but that's the only time it's ever under 2K unless I'm in traffic...