What the local Jeep dealer told me about diesels JKs

[ActionCamper]

Just got the new ActionCamper base vehicle, a 2012 Rubicon Unlimited Diesel Automatic which has in stock configuration 200 HP @ 3.600 RPM and 460 Nm @ 1.500 RPM. After we did the OCT tuning ( they work directly for Chrysler so this doesn't interfere with the warranty ) it has 226 HP @ 3.600 RPM and 510 Nm @ 1.500 RPM.

 

[JDaPP]

I would like to meet the Rubicon owner who is getting in the 20's for mpgs with a 2012. I have one and the best I have seen is 18.

 

[BradJ]

I've had an '06 KJ CRD for 50k+ miles now. Stock it got low to maybe mid 20's mpg. Lifted with 31's it's right at 20 mpg in combined driving, a little better highway only.
My '12 JKU Rubicon with a manual has gotten 18-19 mpg in combined driving in about 6k miles. I've maybe touched 20 mpg in limited highway only.
The real difference I've experienced between the two motors is when pulling a trailer. I have an off road popup that is tall and wide and weighs in at close to 3000# loaded. Both motors pull it fine on level ground, however the CRD is stronger in the hills and still manages at least 16-17 mpg.
On a recent 1600+ mile trip out to Big Bend in West Texas the pentastar started to struggle in the hills towing the trailer. I ended up averaging a disappointing 13+ mpg overall.
The pentastar may be an improvement over the 3.8 but a diesel would be perfect.

 

[upcruiser]

I would like to meet the Rubicon owner who is getting in the 20's for mpgs with a 2012. I have one and the best I have seen is 18.

My buddy Doug who drove down to Expo from Montana. He got 18 towing an enclosed motorcycle trailer behind his 2012 JKU Rubicon with an AEV 3.5" lift and 35's with stock gearing. He told me he was seeing 21 highway driving at a relaxed pace. I would assume his rig stick would have been better.

 

[Septu]

My buddy Doug who drove down to Expo from Montana. He got 18 towing an enclosed motorcycle trailer behind his 2012 JKU Rubicon with an AEV 3.5" lift and 35's with stock gearing. He told me he was seeing 21 highway driving at a relaxed pace. I would assume his rig stick would have been better.

Would have depended on the gearing. Personally I think the stock Rubi setup with 32s and 4.10s is geared to low for optimal highway mileage. At 60m/100kph my RPMs are 2400/2500. I'm completely stock, and the best I've seen on the highway was 19.5 according to my dummy gauge. And I had been trying to get the best mileage possible (didn't push the speed up the numerous hills, etc). Unfortunately I took the panels off for the last 160km and the wind killed my mileage. Ended up with 18.1 (hand calculated). It was also windy as ****. I think I might be able to hit 20, but I don't see how I'd do better than 21.

 

[K2ZJ]

The June Car and Driver has a list of vehicles base and with a diesel added. It gives price and mpg comparisons, interesting on some cars how much difference there is. Audi A3 goes from 24 to 34 mpgs. You can get a Benz CHEAPER with a diesel!

 

[dugedug]

My buddy Doug who drove down to Expo from Montana. He got 18 towing an enclosed motorcycle trailer behind his 2012 JKU Rubicon with an AEV 3.5" lift and 35's with stock gearing. He told me he was seeing 21 highway driving at a relaxed pace. I would assume his rig stick would have been better.

Vegas to Flagstaff, 15.05mpg; Flagstaff to Vegas, 14.89mpg all at the speed limit. Gears are 3.73s and stock tires, ony mods are a Gobi rack and a XHD front bumper/winch but I only got marginally better when I was bone stock. Maybe your friend was going downhill both ways?

 

[upcruiser]

Vegas to Flagstaff, 15.05mpg; Flagstaff to Vegas, 14.89mpg all at the speed limit. Gears are 3.73s and stock tires, ony mods are a Gobi rack and a XHD front bumper/winch but I only got marginally better when I was bone stock. Maybe your friend was going downhill both ways?

Haha, maybe! Not going to lie, I was having some major jealousy over his mileage. This makes me feel better. ;-)

 

[-XJ-]

There won't be any chance of a JK(U) with a diesel stock till they redo the wrangler again somewhere between 2014-2016

 

[Dan Grec]

There won't be any chance of a JK(U) with a diesel stock till they redo the wrangler again somewhere between 2014-2016

What makes you so certain?
The 2012 Wrangler changes mean the engine bay is perfect for 4-cylinder engines and V6's.
The Wrangler now shares the same trans as the GC, which is getting a diesel for 2013 in the US.

-Dan

 

[TxJprs]

I agree with XJ, the Wrangler is due for a refresh in the next few years and that would make sense to me to be the time to introduce a new engine option. But you know, I'd love to see what Jeeps research has shown concerning this. I mean sure there are a ton of us out here who would jump on a good diesal option, but we still represent the minority of Jeep owners. It's sad, but mall crawler Wrangler owner is what continues to keep Jeep so strong. Do those Jeepers want a Diesal? Hmmmm.

And, I call BS on the JKUR owner saying he's getting over 20MPG. I have a 2012 JKUR, Manual, 4.10's, on stock tires and the I'm yet to break 18. And do I try too.

 

[haven]

I continue to believe that if and when the Wrangler gets a diesel engine, it won't be the 3.0L V6 heading for the Grand Cherokee. The Grand with V8 weighs about 1000 lb more than the Wrangler Rubicon. I expect the diesel will be some variation on the Fiat 4 cylinder MultiJet diesel, and will have around 2.2L displacement.

 

[ActionCamper]

I continue to believe that if and when the Wrangler gets a diesel engine, it won't be the 3.0L V6 heading for the Grand Cherokee. The Grand with V8 weighs about 1000 lb more than the Wrangler Rubicon. I expect the diesel will be some variation on the Fiat 4 cylinder MultiJet diesel, and will have around 2.2L displacement.

Why would Jeep use the Fiat engine when the 2.8L VM engine was sold 4 years with 177 HP and now since 2012 is sold with 200 HP?

 

[SSF556]

People lie about their fuel mileage...it makes them feel better and it justifies their decision to put 35" tires on a highway vehicle.

 

[Dan Grec]

I continue to believe that if and when the Wrangler gets a diesel engine, it won't be the 3.0L V6 heading for the Grand Cherokee. The Grand with V8 weighs about 1000 lb more than the Wrangler Rubicon. I expect the diesel will be some variation on the Fiat 4 cylinder MultiJet diesel, and will have around 2.2L displacement.

Interesting. Remember, the Wrangler has the aerodynamics of a brick, and that is much more important than overall weight when talking about how much energy you need to move the thing at speed.
The main reason I'd like them to use the 3.0 is that it's already passed EPA testing, etc. in the US, so it would essentially be "free" for them to drop it in the Wrangler. If they run with something else (the 2.2 you propose) that will be a huge cost barrier because it's not certified.

In any case, if they ever do offer a diesel Wrangler from the factory, my guess is they would really push the excellent mileage aspect of it, hoping the mall crawlers will go for it based on that. In that case, they'll use whatever engine offers the best mileage.

Just my thoughts.

-Dan