Diesel vs gas......................

This is from "Ram Hemi owners - What octane do you use?"

GOrsted wrote:

Dougie123 wrote:
Since we are on the subject, what kind of mpg do you all average while towing?

I'm hitting 10mpg towing my #6500 HTT.

OhhWell wrote:
87 around town, 89 or higher mix when towing. Alot of the time there is quite a bit of 87 in the tank so I will top off with 93 before leaving on a trip.

I would love to see if someone has done the hand calculations to find if there is a noticeable increase in MPG by running 89 octane.

For the person asking about MPG, I get about 7.5 to 9 depending on wind etc with the camper in my Sig. I did have one miracle trip coming back from coco beach with what must have been a tail wind the whole way where I just broke 10 mpg.

With my previous '93 Sunline low slung 6,000GVWR trailer I used to break 10 every now and then but that thing sat so low it was about even with my truck topper.

I know I have the largest truck equiped with a Hemi but I would be very suspect of anyone that claims consistant towing MPG in the double digits with a full size TT.

I average 8.5 MPG towing our 30' fifth wheel.

The 5.7L Hemi in my Power Wagon recommends 89 octane for normal driving and premium (high-octane) while towing:

"When pulling a heavy load or driving a fully loaded vehicle when the humidity is low or the temperature is high, use a premium (high-octane) unleaded fuel to help prevent spark knock."

Living in AZ, I tow in low humidity AND high temperatures. When I first purchased my Power Wagon I followed this and used 91 octane while towing until someone on another forum said it was not necessary and I was wasting money, so I tried towing with mid-grade 89. Well, the difference was quite noticeable. I had always been able to tow our fifth wheel on 260 on the grade to the top of the Mogollon Rim in 2nd gear. With mid-grade I was down into 1st gear with about a mile to go to reach the top. Back to premium for towing and the next trip (and subsequent ones) I was once again able to keep it in 2nd gear and maintain a higher speed to the top. This last spring the temperatures were a little cooler and with the price of fuel I again tried mid-grade and again I was down into 1st gear with about a mile to go to reach the top.

I didn't notice much difference in MPG, but there was a definite improvement in performance. I will be towing with premium fuel from now on.

Wow! Now I know why I changed from a gasser to Diesel!

Premium fuel to tow and only getting 7.5 to 9 mpg. I can't make a statement on the grade on 260 never been there, but 1st and second gear??

My Cummins is a daily driver 12 mpg towing (12K 5er), 14 city, and 20 mpg @ 65 on the open road.