Finally...

The Jeep Breaks 30 MPG!

Posted June 28 2011 12:53 PM by Mike McGlothlin
Filed under: What's New, Diesel Suvs

Over the weekend I managed to obtain exactly 30 mpg with the Jeep Liberty CRD—and then squeezed even more out of it on the drive home...

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Thanks to Green Diesel Engineering's Eco tune (and a lightweight right foot), the mighty CRD took me to the Thunder In Muncie event in eastern Indiana on Saturday (which I'll talk about tomorrow) and then inched its way back home. Here's the first fill up's info:

Speed: 65 mph (cruise control, no A/C)

Route: I-72/I-74 east, I-465 north, I-69 north

Trip: 421.8 miles

Gallons: 14.08

MPG: 30 mpg (29.96)

After refilling at the above station (which was located along I-74 west in Indy), I headed due west at 65 mph, then dropped to 64 mph, followed by 63 mph. 195.5 miles later, and promptly after getting off the highway, I filled up again for a 100% highway number. Here it is:

Speed: 63-65 mph (cruise control, no A/C)

Route: I-74/I-72 west

Trip: 195.5 miles

Gallons: 5.724

MPG: 34.15 mpg

Did I have to drive like a grandpa to do it? Yes. Was it hard to drive 65 (or slower) hour after hour? Yes. Would I do it again? Maybe. If I do, I'll drive like a great grandpa, and go 55-60. The Jeep seemed to really sip fuel at 65 (where the tach rests at 1,900 rpm). I've always found that my vehicles get the best mileage when engine speed is kept at its peak torque rpm. For the Jeep, that's 1,800 rpm, so that's on the to-do list.

It's not a lot of fun getting passed by semis and Cadillac DeVille's, so I don't know how soon I'll be attempting the 55 or 60 mph run.

I also have some "normal" Interstate cruising numbers. Here they are:

Speed: 70-72 mph (cruise control, no A/C)

Route: I-72/I-74 east

Trip: 375.6 miles

Gallons: 13.203

MPG: 28.45 mpg

Reader Comments:

1. Your a better man than I Mike. I just did 900 miles over the last few days and I couldnt stand to do less than 80mph.

65mph or less takes some patience for sure (a virtue I lack), but nice MPG figures man!!

I have been wanting a smaller diesel vehicle lately. A car or SUV, something for errands and around town stuff. Parking long pick-ups can be a pain in town with a bunch of bone heads who cant stay in their spot with their Smart car..

Bigger tires will lower your cruising RPM, but they also add rotating mass (weight).

I am wondering how your Jeep CRD will react with a little bigger tire and therefore a little lower cruising RPM. I think it would be interesting to see if the lower RPM with a tad more weight increases fuel mileage or if the added weight lowers fuel mileage even at a lower RPM. Or if its a wash.

It would be fun to find out, plus who doesnt like bigger tires :) .

Smoken_Gun - Posted June 28 2011 01:44 PM

2. MAN! you guys drive fast! I like never drive faster then 65 mph sometimes 70, (and no I dont get passed by semis that much Lol)

444getsitdone - Posted June 28 2011 05:08 PM

3. Never thought of bigger tires...Might have to give it some thought when the time comes for new tires.

I'll be honest. I never go 80 mph in anything, unless it's at the end of a wide-open throttle run or something. In the truck, the needle never goes higher than 70, and in the Jeep I usually keep it at 72 or under.

Plus I live in Illinois. You'll get pulled over for 70 in a 65 all day long here.

Mike McGlothlin - Posted June 28 2011 06:09 PM

4. 80mph is were you end your fun Mike!?!? WHAT! Haha. You need to hang around Sands more.

I almost always go 10-15mph over the speed limit. I know my area well and know where to slow down (cop hiding spots) and where I can blast around.

Cops around here dont care much about someone going 5-10ishmph over. Ive never gotten a speeding ticket.

Smoken_Gun - Posted June 28 2011 07:36 PM

5. Here is a link to a nice RPM calculator: http://www.ringpinion.com/Calc_RPM.aspx

Enter R&P ratio, tire height, speed (mph), and trans ratio and it will spit out your RPM.

Smoken_Gun - Posted June 28 2011 07:39 PM

6. I drive about like Mike does....I just run it up to about 90 really quick a bunch of times, mostly to impress myself lol. I got lots of ideas for you now that you're the fuel economy guy Mike ;) Grille block, aero hubcaps, 80psi in the tires, 55mph, electric fans (do you have those stock?) I think you can hit 40mpg at 55mph ;)

Then you can get a bunch of emails calling you a sissy cause you like fuel economy ;)

Jason Sands - Posted June 29 2011 10:21 AM

7. Check out this site for ideas...these guys don't mess around!

www.ecomodder.com

Jason Sands - Posted June 29 2011 10:27 AM

8. I am formulating my scathing email about how your a total puss for saving money Mike as we speak!!

..kidding, haha.

Jason, did you really get a bunch emails from readers that didnt like your fuel hoarding ways?? I wouldnt doubt it.

Its an interesting dichotomy that you focus on going as fast as possible in the 1/4 mile as well as getting great fuel economy on the street.

Guess what you save on the street goes into parts for the track :).

Smoken_Gun - Posted June 29 2011 10:46 AM

9. I'll take my 34 mpg number for now. Maybe next May I'll drive to Diesel Power Challenge (or should I say "creep" to Diesel Power Challenge?).

55 mph for 900 miles...then 55 mph for 900 miles home...

Mike McGlothlin - Posted June 29 2011 12:04 PM

10. Hope you have a passenger for that one!! The drive back from Vegas at 55mph in my dually was the most boring drive ever.

Jason Sands - Posted June 29 2011 01:20 PM

11. I have a crd, and on good weathered days I get 34 mpg staying just under 75, I try run about 72 tops, but that's kindda hard. These jeeps just run so smooth you forget to watch your speed, and end up doing about 85

Kane765 - Posted June 29 2011 05:10 PM

12. Kane,

That's good to know. I was told that my CRD was, for some reason, achieving less than the typical fleet average in stock form (a measly 22 mpg). While I was impressed with my 34.1 mpg figure, it wouldn't surprise me if other CRD owners see 36, 37, maybe more on the highway.

Thanks for chiming in.

Mike McGlothlin - Posted June 29 2011 06:43 PM

13. Maybe you should convert to manual steering and put some sloppy tie rods in? That way it'll feel like your driving really fast even at 55 mph plus save on the pump drag.

I'm jealous of that Liberty especially on this 4th of July! Part of Diesel Power's message is giving power back to the people by increasing efficiency.

Liberty = Liberty

jason.thompson - Posted June 30 2011 10:14 AM

14. Ha ha. Very fitting for our nation's birthday.

And let us not forget who named the Jeep's series of stories ("Life, Liberty, and the Pursuit of Compact Diesel Power")— the great Jason Thompson himself

Mike McGlothlin - Posted June 30 2011 01:02 PM

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