2017 Jeep Wrangler JL
 

Hey all,

I work for a Jeep aftermarket parts company. As you can see from my sig, my current Jeep has a huge motor. Efficiency is not in my Jeep's vocabulary when it comes to fuel. With that said, my short term goal (within the next 2 years) is to sell my Jeep and both my Trans Ams. I plan to use the profits from them as a down payment on a 2017 Jeep Wrangler JL diesel (Rumor that I believe is true).

According to this site: Next-Gen Jeep Wrangler To Have Diesel, 8-Speed Auto Combo - The Truth About Cars, among countless others, the Wrangler will have a diesel and 8 speed auto trans. I'd 100% FIRMLY rather have a manual trans, but if the only diesel is automatic, I'll have to settle for such.

I've never had an auto with diesel, and never had an 8 speed auto. I'm hoping it produces good fuel efficiency. One of the drawbacks right now of my current Jeep is the lack of being able to take long trips (I'm talking from PA to TN or Colorado or Utah and more). 11 MPG would kill the trip. I'm hoping for 30+ highway (35-40 highway would be even better!) out of this new Wrangler, but only time will tell.

Anyone here have a Grand Cherokee diesel, or a 2007-2015 Wrangler JK diesel in Europe or elsewhere? If so, what are you seeing for FE?

Thanks,

Fuel economy will probably be better than your gas Jeep, but given how the current 2.8 does, I doubt it'll be very economical.

Most of the economy issues with the Jeep are down to the heavy dual live axles and the poor aerodynamics.

I once ran a 2.8 CRD Wrangler for a week. Got much worse economy than the bigger, longer and heavier Colorado 2.8 (exactly the same VM Motori diesel) that I loaned a few months prior. (I don't live in the US... our Colorado is different).

I suppose the 8-speed will help city economy somewhat. Won't hold my breath for big numbers on the highway.

Do you recall approximately what the numbers were? Were both 4wd? Manual trannies?

Both Auto. Both 4WD (switchable). I believe the Colorado could do 7-8 km/l in traffic (our traffic is that bad), where the Wrangler did 5-ish. Highway was about 14-16 versus 10-12. I could be wrong, though...

Hmmm... seems like my Colorado review was in print. I do have a review of the Trailblazer (Colorado seven seater... not US bound) and the Wrangler up on our site:
Review: Jeep Wrangler Rubicon Unlimited | TopGear.com.ph
Review: Chevrolet Trailblazer 2.8L 4x4 LTZ | TopGear.com.ph

Yeah... 5-6 km/l (11-14 mpg) in traffic. Better than big V6s, but a far cry from less hardcore 4x4 diesel pick-ups and SUVs with the same weight and power.

Those drivetrain components weigh a ton. Let off the gas and you can feel those big tires and heavy differentials sapping away whatever momentum you've built up. There's also a lot of slush in the current automatic... probably using a high stall speed for better off-road ability.

If I recall, 0-60 mph times are quite a bit slower, as well... maybe 1-2 seconds with the exact same 200 hp engine.

I think the multi-speed auto will make a decent difference in economy, but again, I don't expect miracles.

I wouldn't hold my breath for that, but I have seen some quoted that the next-generation Wrangler would feature IFS for the first time. Anyway, depending on the gear spread of that 8-speed transmission, I wouldn't doubt it to come with a lighter single-speed transfer case (or a center differential instead).

I could see mid to high 20's. Remember, its still will have heavy driveline components (please do not go IFS Jeep...please) and the aerodynamics of a house. No matter the axle configuration, it is going to need a lot of ground clearance, chunky tires, and abrupt departure angles to be usable off road. They are moving in the right direction, but I don't see an automatic, off road capable vehicle breaking 30mpg on the highway any time soon.

My friend has a brand new Wrangler automatic, and I've driven it. I really don't think the engine is the problem, it's the aerodynamics. The gearbox keeps the revs close to 1000rpm until top gear, but the engine is working pretty hard keeping that thing going down the road. The second you let off the gas at even 35mph it feels like there's a massive parachute slowing it down, even compared to other tall SUVs and crossovers. I have never seen a car that does that before.

The new Grand Cherokee might do a bit better because they've made the body less boxy.

The Grand Cherokee has independent suspension at all corners. It's also more aerodynamic, with a lower ride height.

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The Wrangler will be difficult to transition to IRS or even IFS. Part of the appeal is it's one of the few cars with twin live axles left on the civilian market. The others we have here are the Defender and the Jimny (not available in the US). All three are still sold with twin live axles because these are more rugged, and can withstand more abuse off-road.

It may be possible to forego that need, while cleaning up underbody aero with portal axles... but say sayonara to any semblance of fuel economy when you go down that route. :D

An independent suspension can be as off-road capable as a solid axle, and usually also provides an overall better ground clearance due to the less-protruding differential casing. Anyway, the easiest excuse for going from solid axles to a fully-independent suspension would be a mine-protected vehicle, not a redneck-oriented mud digger.

Just an fyi, those 8 speed transmissions only use 6 or 7 gears of you stay under 65mph. The 8th gear is for 80mph interstate driving.