2014 Jeep Wrangler (20 mpg hwy) vs 2015 Ram 1500 (25 mpg) differences?
 

http://ecomodder.com/forum/attachmen...1&d=1414507027

I have a coworker who bought a Jeep Wrangler last year with the 3.6L Pentastar engine and 5 speed automatic. He has seen the commercials for the 2015 Ram 1500 with the 3.6L Pentastar, and saw the 25 mpg highway EPA rating versus his Wrangler's 20 mpg highway rating.

He was wondering why his Jeep is rated so much lower than the Ram is. I am sorely lacking in Chrysler knowledge. Do you guys have any insight into why there is such a large difference in the mileage? The Jeep is 4wd and the Ram is only 2wd with those ratings, but it doesn't seem like that should account for a 5 mpg difference.

final rear ratio...... come on, that was easy!

1. ram was specifically designed to get better mileage than all trucks
2. check weight of both
3. ram has 8 speed tranny
4. I believe the ram actually lowers at speed
5. tire size (back to final ratio)

5 spd vs 8 spd
4.10's standard vs 3.23's standard
Both have basically the same size tire (255-75 vs 265-70, oth 17's, both just shy of 32" tall)


But the biggest reason?
Huge concentration on aero on the Ram, claimed cd as low as 0.36.
The JK? cd of 0.495 and 0.50 are what I'm finding online.


My 01 Wrangler was even worse. 0.58 cd, and a 3 speed auto. At absolute best I could eek 17 mpg from it. Typically it was a 14-15 mpg ride. With trailer in tow I managed a lot of sub-10 mpg tanks. A friend with a Dodge diesel took my trailer to a race in Utah once with me, managed nearly 19 mpg, with way more power too. Made me sad for myself.

EDIT: HA! You beat me to it by 1 minute, adam728!

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That RAM has (had?) best in class drag: (cD = 0.363) -- from http://ecomodder.com/forum/showthrea...ion-24177.html

The Dodge may have more frontal area, but I'm certain the Jeep's drag coefficient is significantly higher.

The 2-door Jeep of that body style is 0.55. The 4-door JK is 0.495 -- from http://www.jk-forum.com/forums/jk-ta...-105364/page4/

So, aero strikes again. There's that plus all the other things.

I am seeing 4,277 pounds for the Jeep and 5,441 for the Dodge--the truck is 27% heavier!

Compare a 4 door Jeep and 2wd, reg cab Ram.

Go to a 4 door 4wd Ram and you can get up over 5700 lbs.

It took me a while just to get that number, I found the Jeep weight right away, although it specified each axle individually, I had not seen that. I am not trying to find the four-door, so I will go off of your numbers. 5,701 pounds is 33.3% heavier and 5,749 lbs is 34.4% heavier.

You can find the the curb weight on Ram's web site. I can post some links tomorrow, using my wife's iPad right niw

Either way, the Dodge is much heavier, but gets significantly better fuel economy.

You fail, Jeep.

The Dodge doesn't have twin live axles with a heavy-duty transfer case and lockers.

Those things add up to horrendous fuel economy, whatever the weight of the car.

It just goes to show that weight doesn't much affect fuel economy.

Surprisingly, the EPA rates the truck at 1 MPG better than Jeep in city driving. Aero and weight can't explain the advantage the truck has, so I'm guessing it's the transmission.

CRR is a big factor on the city cycle and light truck tyres can be considered LRR's compared to any of the off road-ish treads.

Here's a good link.
http://www.rambodybuilder.com/2014/d...ammlup1500.pdf
On the low end you have a 2wd, regular cab, short bed Tradesman at 4,512 lbs.
On the high end you have a crew cab 4x4 with the diesel at 6,147 lbs.

On Ram's site they list the lightest as a 2wd, regular cab, short bed Sport, 4,525 lbs.

According to Jeep's webpage a 4 door Rubicon is 4,340 lbs.

That high-end 6,147-pound diesel is rated 19/27.

Its the 8 speed. A Jeep grand Cherokee which gets the 8 speed beats the Ram in fuel economy comparing 4x4 to 4x4.

It shows that how you use the power is what has the most effect. Taller gearing helps a lot, and in the EPA test where driving style is consistent, cramming more gears into the slushbox will get you more efficient operation.

I made a mistake. His Jeep is a 6 speed manual, not 5 speed auto. They are rated the same though.

Here is the comparison I came up with off of fueleconomy.gov. Looks like the 4wd to 2wd makes up a 2 mpg highway difference.

Sadly, the Grand Cherokee doesn't come with a manual, so I couldn't compare it real accurately.

http://ecomodder.com/forum/attachmen...1&d=1414783693

As a 1995 Wrangler owner I will attest that this is a perfect platform to show that aerodynamics is the greatest factor in gas mileage. I average 22 mpg either suburbs or highway. Pulled the cage off the roof and went from 16 mpg to 20 mpg. Smaller thinner tires no significant change. Synthetic oil, free flow cat back, new plugs and KN air filter, no significant change. Tire pressure at 40 lbs over 36 adds 1-2 mpgs. Tail wind on the highway and I can hit 24 mpg. Some day I will add belly pans or air dam.