mpg not so good with Jeep Grand Cherokee

[phln]

You need to remember what the gas engine is doing while towing. The engine is changing from power to torque. It is getting into the torque band and for a naturally aspirated hemi engine that is around 3200rpm. They don't produce torque like a diesel does (at about 900rpm on the torque band). Using tow/haul mode will keep the engine running at top end of torque and which could be around 4800rpm. It will take a lower gear to get the engine into the torque. This is just how the engines work under natural aspiration.

You need to remember to service your transmission a heck of a lot more when towing with a gas engine. Your transmission fluid is being worked hard.

Just to twist your mind a bit. The 6.4L gas Hemi in the 2500 will get worse fuel economy than the 5.7L in the 1500 when mated to the 8 speed transmission and pulling the same equal weight. Doesn't that blow your mind? It's all in engine and transmission programming. Don't forget. Tow haul mode puts your engine into higher RPM for a purpose. It saves your transmission from shift searching under load.

[mnoland30]

I have a 2.8 diesel in my 2005 Jeep Liberty. It gets about 25 on the highway, and about 20 towing my boat. I use my big boy diesel 6.0 Superduty to haul my 4500 lb. Roo. My truck gets 10 to 11 towing up here in the mountains.

[rat4spd]

Originally Posted by phln

You need to remember what the gas engine is doing while towing. The engine is changing from power to torque. It is getting into the torque band and for a naturally aspirated hemi engine that is around 3200rpm. They don't produce torque like a diesel does (at about 900rpm on the torque band). Using tow/haul mode will keep the engine running at top end of torque and which could be around 4800rpm. It will take a lower gear to get the engine into the torque. This is just how the engines work under natural aspiration.

You need to remember to service your transmission a heck of a lot more when towing with a gas engine. Your transmission fluid is being worked hard.

Just to twist your mind a bit. The 6.4L gas Hemi in the 2500 will get worse fuel economy than the 5.7L in the 1500 when mated to the 8 speed transmission and pulling the same equal weight. Doesn't that blow your mind? It's all in engine and transmission programming. Don't forget. Tow haul mode puts your engine into higher RPM for a purpose. It saves your transmission from shift searching under load.

I have the 5.7 in my 2500. With a little heavier trailer and a 6700# truck I got about 13 MPG. It has to be the transmission programming in that 8 speed. It should happily pull that around 2600 rpm-ish.

[Steelframer]

I had a Jeep Commander limited 5.7l Hemi with all the bells and whistles.....loved that vehicle, great for around town and on the back roads, with that said, I absolutely hated the gas mileage for highway 15mpg and especially towing our 274 DBH, 8mpg at 55 mph. Had to stop every two hours to fill up. Wasn't practical to keep it so I had to let it go. My DW said to get a newer vehicle that will suit our 'now and future' needs so I picked up a 2011 ram Laramie Longhorn 6.7 DRW for a song with only 20,000 miles on it. What an amazing difference in towing and fuel mileage. I'm getting almost three times the mileage and I can barely tell it's behind me. Now this big of a vehicle might not be practical for most people, but I personally could not go back to a gasser now that I have pulled with the diesel. JMOpinion not trying to start a fight here.


TT-2015 Cherokee 274dbh TV-2011 Ram 3500 Longhorn Limited

[The_Rhino]

New Engine vs. Old:

At 96K miles Ram replaced my 5.7 Hemi under their 100K mile powertrain warranty... The old engine got 17 mpg commuting / 8.5 mpg towing hand-calculating mpg... The new engine got 14 commuting / 7 towing for first 10K miles. Now with 35K miles, the new engine gets 16-17 commuting / 8 towing & is still improving...

Gas w/lower MPG vs. Pricier Diesel w/higher MPG:

In 2013 I only paid $14,000 for a 2 year-old rust-free 2011 Ram 2500 CC w/5.7 Hemi & balance of Ram's 100K Powertrain Warranty (which came in handy when a rod dropped & engine blew!) At the time 2 year-old diesels were fetching $40K+... I pay about $2,400 / year for gas whereas a diesel with better MPG would cost $1,700 or $700 less/year... My $14K truck is paid-off whereas friends who bought $45K+ Jeeps/diesel trucks are still making $700/mo. payments...

The lowly 5.7 Hemi has plenty of torque at rpm so I have no trouble towing our 8,000 lb. TT (15,000 GCVW) throughout the Smoky Mts. The biggest downside to only getting 8 mpg is having to stop for fuel every 220 miles vs. 300+... However, we have 3 kids & a dog, so we kinda have to stop every 3-4 hours anyway...

Jeeps as TVs vs. Jeeps as Toads:

Like noted everywhere on the 'net, Jeeps' shorter wheelbases & cushy suspensions are not the best for towing... but I'd LOVE to tow a Jeep BEHIND a MH for some great back/off road adventures at destinations. However if I work'd extra 'nough to afford 'em I wouldn't have 'nough time-off to enjoy 'em!

[X96mnn]

Originally Posted by cdog7201

xk96 My liberty is a 2012 I think there were some changes from the 2008 and the 2012. some time I will only get 10mpg if the wind is around 20 mph. but I will average about 12 now I pull in the tow mode most of the time and that stops the tranny from shifting all the time .I conserve gas all of the time I take my foot off of the gas when I can I start costing a long way from a stop light or stop sign and never make Jack rabbit starts. I have learned you can conserve gas and I still get there within a few minutes of all the ones passing me in a hurry to go no where fast. The best I ever got not towing is 20 mpg , I have also learned that all gas is not the same some has more water content in it then others therefore less mpg. I only saw 20mpg one time I filled up yesterday no towing involved and I got 18.8mpg driving around town and country combined. I figure a loss of 10% in mpg is normal while towing.

My driving habits do not match yours at all although they should! I am sure some improvements between the 08 and 12 may factor in as well! I traded it for the 2011 Ram I described above. Jeep was fun though, owned a compass and a liberty.

[closecreek]

I have a 2009 Grand Cherokee and usually average around 12mpg when towing my 4500lb Minnie Lite which I find quite acceptable. The GC has the 5.7 Hemi with 6 speed automatic and variable valve displacement. I do try to drive with a "light" foot but on flat interstate roads will average around 65-70mph