If Wrangler and Gladiator are the same from the cab forward ......?

[Gvsukids]

Trusting AI, it's a quadratic relationship; faster you go, the penalty increases, but slightly. A smaller engine will work harder (actual output vs. total output) at higher speeds to overcome the aero penalty. The 3.6L "makes" 285hp, and mild Gladiator builds such as mine seem to use every bit of it at speed.

First - Coefficient of Drag (Cd) change

At 30mph, a change in Cd of .04 would be equivalent to adding 150# to the vehicle, but at 65mph it would be 800#. At 80mph it'd be almost 1750#. And this is all things equal, only the coefficient of drag changing from .32 to .36 for an average vehicle.

Gladiator vs. Ram
If the Ram 1500 Cd=.36, the estimates of the JT fall around .52-.58, depending upon the accoutrements we add. If I'm directing AI correctly (75% confidence I am), the jump between a Cd=.36 and Cd=.58 adds a lot more resistance.

Adding in the JT's frontal area (approx 3.4m^2) and going from Cd=3.6 to Cd=.58, the graph looks the same, but the values are *just* a little different. I know it's 2 variables changing, but if we're comparing a 1500 to a JT, might as well.

So, roughly speaking and if I'm doing this right (letting AI do the maths I can't, I'll end up pulling a Michael Bolton), compared to a Ram 1500, the JT would have approx. 10,000# worth of weight to equal the aero penalty at 80mph; only ~7000# at 65mph. It would feel like you're towing a heavy-ass trailer or have your emotional baggage in the bed.

Air Resistance
Overall, the actual force from air resistance (sea level average assumptions) at 80mph is ~340#. Dropping just the Cd to .36 drops air resistance to ~211#. The frontal areas are similar between the JT and Ram 1500 (~3.4m^2 to ~3.44m^2), but the Cd really shines for the Ram here.

The JT is pushing an extra 130# at 80mph, or an extra 70# at 60mph than the 1500.

Worst Current Aero Vehicles in the USA
The 5-6 worst aero vehicles (based on Cd) in the USA are:
JT & JL (pretty similar, but the JT bed adds about .02-.03 'worseness')
M-B G-Wagen (.54; AMG is .56-.57)
Ford Bronco (estimated, no published #s)
Land Rover Defender (estimated at .38-.42)
Toyota Land Cruiser (estimated at .34-.36)

Even M-B's AMG V8TT has a lackluster 14-16mpg estimate. It only puts out 577hp/627tq, so no one here would be interested in something like that, right? Regardless of the $200k price tag.

Just for Funsies
And because I was curious, and have no idea if it's correct, with the published 0-60 times and 1/4 mile times, I ran some numbers for my JT. It takes an additional ~250hp (at the crank) to move a modded JT (lift & tires) from 60-80mph in under 8 seconds. The JT is using roughly 40hp to maintain speed at 60mph, so those calculations don't seem out of line with the 3.6L hp rating compared to real-world experience. Getting up to 80mph is not very effortless (compared to our older BMW w/ 325hp), usually dropping to 5th/6th gear and a good amount of dino juice application. The numbers would indicate I'm using 90%+ capacity of the powertrain at higher speeds with my setup. Again... if this guy - who hated maths in school but tries to find solutions using maths and logic all the frickin' time - is mostly on the right track with estimates and loose assumptions.

So that's why I'm losing drag races to a Ram.

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[Zachanadandy]

Trusting AI, it's a quadratic relationship; faster you go, the penalty increases, but slightly. A smaller engine will work harder (actual output vs. total output) at higher speeds to overcome the aero penalty. The 3.6L "makes" 285hp, and mild Gladiator builds such as mine seem to use every bit of it at speed.

First - Coefficient of Drag (Cd) change

At 30mph, a change in Cd of .04 would be equivalent to adding 150# to the vehicle, but at 65mph it would be 800#. At 80mph it'd be almost 1750#. And this is all things equal, only the coefficient of drag changing from .32 to .36 for an average vehicle.

Gladiator vs. Ram
If the Ram 1500 Cd=.36, the estimates of the JT fall around .52-.58, depending upon the accoutrements we add. If I'm directing AI correctly (75% confidence I am), the jump between a Cd=.36 and Cd=.58 adds a lot more resistance.

Adding in the JT's frontal area (approx 3.4m^2) and going from Cd=3.6 to Cd=.58, the graph looks the same, but the values are *just* a little different. I know it's 2 variables changing, but if we're comparing a 1500 to a JT, might as well.

So, roughly speaking and if I'm doing this right (letting AI do the maths I can't, I'll end up pulling a Michael Bolton), compared to a Ram 1500, the JT would have approx. 10,000# worth of weight to equal the aero penalty at 80mph; only ~7000# at 65mph. It would feel like you're towing a heavy-ass trailer or have your emotional baggage in the bed.

Air Resistance
Overall, the actual force from air resistance (sea level average assumptions) at 80mph is ~340#. Dropping just the Cd to .36 drops air resistance to ~211#. The frontal areas are similar between the JT and Ram 1500 (~3.4m^2 to ~3.44m^2), but the Cd really shines for the Ram here.

The JT is pushing an extra 130# at 80mph, or an extra 70# at 60mph than the 1500.

Worst Current Aero Vehicles in the USA
The 5-6 worst aero vehicles (based on Cd) in the USA are:
JT & JL (pretty similar, but the JT bed adds about .02-.03 'worseness')
M-B G-Wagen (.54; AMG is .56-.57)
Ford Bronco (estimated, no published #s)
Land Rover Defender (estimated at .38-.42)
Toyota Land Cruiser (estimated at .34-.36)

Even M-B's AMG V8TT has a lackluster 14-16mpg estimate. It only puts out 577hp/627tq, so no one here would be interested in something like that, right? Regardless of the $200k price tag.

Just for Funsies
And because I was curious, and have no idea if it's correct, with the published 0-60 times and 1/4 mile times, I ran some numbers for my JT. It takes an additional ~250hp (at the crank) to move a modded JT (lift & tires) from 60-80mph in under 8 seconds. The JT is using roughly 40hp to maintain speed at 60mph, so those calculations don't seem out of line with the 3.6L hp rating compared to real-world experience. Getting up to 80mph is not very effortless (compared to our older BMW w/ 325hp), usually dropping to 5th/6th gear and a good amount of dino juice application. The numbers would indicate I'm using 90%+ capacity of the powertrain at higher speeds with my setup. Again... if this guy - who hated maths in school but tries to find solutions using maths and logic all the frickin' time - is mostly on the right track with estimates and loose assumptions.

The 3.6L only makes 285hp at 6k+ rpm. If you're using it all you'd be in ~4th gear on the freeway (not sure your exact build but that's what it would take for me to see 6k at freeway speed). It doesn't break 250hp at the crank until 5600. I think that's why you'd see better fuel economy from the v8 on the freeway. It doesn't have to spin half that number of rpms to do the same work.

 

[Blade1668]

I've not poured though all of this thread... I definitely would have jumped on a Hemi, straight out of the gate. But definitely not with the ridiculous upsell price for V-8. A base model truck with a N.A. V-8 or even a N.A. I-6 of reasonable C.I. displacement I'm all in on. I'm not wanting a race truck or to do burnouts. But a simple KISS vehicle that can pull a trailer or haul $#%# when I want to.

Actually, he says w/ 5.13 gears on their trip to FL they got the same fuel mileage as the 3.6L and after they changed to 4.56s they improved "2 to 3mpg". In the comments of that video, he says he gets 14mpg (not towing).

I'm not surprised, my 05 Wrangler Unlimited gets about the same mileage towing as my JT and my XJ actually got better MPG's after I re-geared to 4:56 and towed better. (In the past) I actually averaged 20 mpgs towing with it from Savanna GA to Bloomington IL. and back. It was definitely not cutting the wind as good as a JT, with somewhere around 8 in lift, heavy MT tires on steel rims, heavy gauge steel bumpers with roof rack and tire hanging on rear.

 

[MPMB]

The 3.6L only makes 285hp at 6k+ rpm. If you're using it all you'd be in ~4th gear on the freeway (not sure your exact build but that's what it would take for me to see 6k at freeway speed). It doesn't break 250hp at the crank until 5600. I think that's why you'd see better fuel economy from the v8 on the freeway. It doesn't have to spin half that number of rpms to do the same work.

I'm referring to acceleration, not cruising. So I do see high RPMs when rapidly moving from 60mph to 80mph, or any speed zone changes that are plentiful in the West (and annoying AF). I don't look down and see what gear I'm in, so yeah, I may be anywhere between 3rd and 7th at anytime. 8th is reserved for level w/ a tailwind and maybe a downhill run.

Cruising at 80mph only requires a fraction of the HP, about 85hp, but in my case, probably closer to 100hp (calculations done w/ sea level & optimum numbers yet I live at 5000').

 

[Wheelin98TJ]

Trusting AI, it's a quadratic relationship; faster you go, the penalty increases, but slightly. A smaller engine will work harder (actual output vs. total output) at higher speeds to overcome the aero penalty. The 3.6L "makes" 285hp, and mild Gladiator builds such as mine seem to use every bit of it at speed.

First - Coefficient of Drag (Cd) change

At 30mph, a change in Cd of .04 would be equivalent to adding 150# to the vehicle, but at 65mph it would be 800#. At 80mph it'd be almost 1750#. And this is all things equal, only the coefficient of drag changing from .32 to .36 for an average vehicle.

Gladiator vs. Ram
If the Ram 1500 Cd=.36, the estimates of the JT fall around .52-.58, depending upon the accoutrements we add. If I'm directing AI correctly (75% confidence I am), the jump between a Cd=.36 and Cd=.58 adds a lot more resistance.

Adding in the JT's frontal area (approx 3.4m^2) and going from Cd=3.6 to Cd=.58, the graph looks the same, but the values are *just* a little different. I know it's 2 variables changing, but if we're comparing a 1500 to a JT, might as well.

So, roughly speaking and if I'm doing this right (letting AI do the maths I can't, I'll end up pulling a Michael Bolton), compared to a Ram 1500, the JT would have approx. 10,000# worth of weight to equal the aero penalty at 80mph; only ~7000# at 65mph. It would feel like you're towing a heavy-ass trailer or have your emotional baggage in the bed.

Air Resistance
Overall, the actual force from air resistance (sea level average assumptions) at 80mph is ~340#. Dropping just the Cd to .36 drops air resistance to ~211#. The frontal areas are similar between the JT and Ram 1500 (~3.4m^2 to ~3.44m^2), but the Cd really shines for the Ram here.

The JT is pushing an extra 130# at 80mph, or an extra 70# at 60mph than the 1500.

Worst Current Aero Vehicles in the USA
The 5-6 worst aero vehicles (based on Cd) in the USA are:
JT & JL (pretty similar, but the JT bed adds about .02-.03 'worseness')
M-B G-Wagen (.54; AMG is .56-.57)
Ford Bronco (estimated, no published #s)
Land Rover Defender (estimated at .38-.42)
Toyota Land Cruiser (estimated at .34-.36)

Even M-B's AMG V8TT has a lackluster 14-16mpg estimate. It only puts out 577hp/627tq, so no one here would be interested in something like that, right? Regardless of the $200k price tag.

Just for Funsies
And because I was curious, and have no idea if it's correct, with the published 0-60 times and 1/4 mile times, I ran some numbers for my JT. It takes an additional ~250hp (at the crank) to move a modded JT (lift & tires) from 60-80mph in under 8 seconds. The JT is using roughly 40hp to maintain speed at 60mph, so those calculations don't seem out of line with the 3.6L hp rating compared to real-world experience. Getting up to 80mph is not very effortless (compared to our older BMW w/ 325hp), usually dropping to 5th/6th gear and a good amount of dino juice application. The numbers would indicate I'm using 90%+ capacity of the powertrain at higher speeds with my setup. Again... if this guy - who hated maths in school but tries to find solutions using maths and logic all the frickin' time - is mostly on the right track with estimates and loose assumptions.

I appreciate the work you put into this.

I was most curious about how the 5.7 and 3.6 MPG compares in varying platforms. And if for some reason, one or the other struggles more to get good MPG when you put it in something like a Gladiator.

I said the 3.6 and 5.7 Ram get similar MPG implying a Gladiator could do the same. I don’t think it’s that wild of an assumption, but someone else said “can’t compare”.

 

[MPMB]

I appreciate the work you put into this.

I was most curious about how the 5.7 and 3.6 MPG compares in varying platforms. And if for some reason, one or the other struggles more to get good MPG when you put it in something like a Gladiator.

I said the 3.6 and 5.7 Ram get similar MPG implying a Gladiator could do the same. I don’t think it’s that wild of an assumption, but someone else said “can’t compare”.

Thanks.

In my research I discovered that the 5.7l is the same basic config in every consumer platform. You can find some examples of the same engine but in different vehicles with different tunes. I would have thought Stellantis would have that.

I, too, thought the 5.7l would end up with slightly better mpg since it wouldn't have to "work" as hard. It might for those with big lifts & tires, or big towers. Dunno.

 

[Zachanadandy]

Thanks.

In my research I discovered that the 5.7l is the same basic config in every consumer platform. You can find some examples of the same engine but in different vehicles with different tunes. I would have thought Stellantis would have that.

I, too, thought the 5.7l would end up with slightly better mpg since it wouldn't have to "work" as hard. It might for those with big lifts & tires, or big towers. Dunno.

I think around town it's probably pretty similar as neither are working that hard, the shift points are similar so they'll run through the gears the sane getting up to speed, and the v8 burns more at idle. The massive difference in drag makes me still believe that the 5.7L would get better fuel economy on roadtrips at speed because of how hard the 3.6L has to work to maintain 70+. Being able to maintain higher gears in head winds and up hills and accelerating thus keeping the average rpms much lower has got to save fuel.

 

[ChrisNLA]

Kinda comparing assholes to elbows, but this reminds me of the numbers we see comparing my Jeep to my buddies 2019 GMC Denali 2500HD (6.6 Duramax)

My truck tends to hang overall around 17.5-18.5 MPG. I do a lot of backroads, and when I'm on the interstate its typically 70MPH or less.

His truck stock tended around 23-24MPG. With the delete, it's hanging out around 26-28, and we'll see nearly 30 at 65 on the interstate.

It get's the same damn fuel mileage pulling a loaded car trailer as I get empty.

So, being a diesel those tend better than gas motors in general, but all that's to say - more power / less struggle / better MPG...generally speaking...

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