Went on vacation back in july towing my 33ft 5th wheel camper and with the setup I have (see below) I managed to pull that big camper to Gatlinburg Tennessee and back right at 18 mpg. This is done in "tow" with the EFI live also in "tow" and the trans locked to 5 gears only. Now last week we went to Mackinaw city Michigan and the truck still got just over 18 mpg's going up but coming back it fell off to 12.1!! WTH where did the mileage go? Truck runs great and no lights or codes. Took 1 1/2 tanks of fuel up and 3 1/2 tanks to get back. Could a stiff head wind kill it by that much with that camper??
18 towing, I could see the possibility on a 5% down grade with a 70 mph tailwind.:rofl
Even 12 towing a 33' 5th wheel is stretching it a little, maybe with a decent tailwind.
I've never had anywhere close to 18 empty over the past 9 years I've owned my truck.
Towing my 32' 5th wheel toybox @ 13,500 lb 9-10 tops. With no tailwind.
My previous truck was a 2001 identical truck but with a 8.1 gas engine with the Allison trans and it got 13 mpg towing the same camper. With my EFI live set on econ I can pull 21-23 mpg out of it just casual driving. Other than the mods listed the truck is bone stock, not lifted or crazy oversize tires and my max tow speed is 60. I have done mileage both ways, with the truck computer and numbers on paper and they are both close. That Michigan trip worked out like this... 426 miles 24.3 gallons up and coming back was getting 288 miles and 23.8 gallons, stop and go makes it worse and speeds faster than 65 the mileage really falls off.
I would be trying to figure out how you managed to get 18 mpg towing a 5th wheel so you can sell the formula and get rich. Even with my "small" 5th wheel, I never got more than about 13.2 calculated.....
This tread has the wrong title, it should be titled who can come up with the biggest BULL CHIT mileage claims.
So far 5th hauler is leading the pac.:rofl
Honestly, I've had a lot of Duramax's and typically 17mpg is good fuel mileage. I had some runs between AZ and TX where I got exceptional mileage, I think my best was 23 or 26 maybe (5+ years ago, bad memory), but I'll tell you it was a 1 off. Not sure if the pump wasn't calibrated in my favor or what.
I'd love to tell you there is a way to do it, but 12 towing a heavy load seems normal to me.
Diesel truck mileage expectations across all manufactures:
Empty - 15 to 21.
Any load - sub 15.
Moderate load - 10 to 13.
HEAVY load - 8 to 12.
High profile fifth wheels are in the HEAVY bracket. You guys making ridiculous claims aren't going to reinvent the wheel here.
This is nuts on. I pull a trailer several times a year that is in the 12-14k range my mileage is right at 11-12mpg on the highway. Lighter loads (4k boat and the like) I'm right around 14-15.
12 towing is possible on flat ground, but try towing heavy up to Flagstaff, Forest Lakes, places where there's 7% + grades going from 1100' to 7000', then see what kinda mileage you'all get.
I'll ave around 10 mpg round trip up to 7000' back down to 1100', 145-160 miles one way.
Me, mines very lucky to get 10 towing flat 13,500lbs from Phx to Wickenburg at 50-60 mph.
Solo city/little highway 13-13.5 lots of stop and go traffic, street lights every .5-1 miles, I have to get on the freeway once in a while just to get this mileage.
Driving solo on long trips, I really don't do in my Dmax.
I fill up till I see fuel in the filler neck. So my claim is not bs. The tune used to get fuel economy is 380 horsepower at the rear wheels via Danville performance
You hadn't even posted before I said the fact BS, I'm sure on flat ground with a good tail wind driving solo, tires aired up to the max, anything is possible.
But a 8.1 gasser getting 13, pulling the same trailer that the Dmax is getting 18.
I've owned 2 8.1, I know many fellars with 8.1 in our off road group.
Maybe 7-9 with the gasser, maybe, again on flat ground with a real good tail wind, and a Dmax getting 18 pulling the same trailer. I'm sorry but
Yes, I am being a bit of a prick. I dont like poor information to be thrown out.
These forums are full of cheer leaders that praise products to justify buying them. Guys buy this crap and load for positives even when there aren't any. If people want to be uninformed and spend their cash foolishly, oh well.
I just wanted to make it clear that I've noticed you're one to bash people's MPG claims (some are full of shit, but I've seen a few who arent). I will agree to disagree, mostly because I know for a fact 20+mpg is possible, and not a fairly tale like you seem to portray it to be.
At the risk of being bashed here I recently got back from a labor day trip with my camper and kept track of the mileage on paper not the dic on the dash. The trip down about 300 miles south on I75 the truck managed to pull 13.81 mpg's with a slight head wind most of the way. Coming back north it was a little better, ran at night (cooler) and wind behind me managed to get 15.24. This is figured with the tank full till foam in the neck and I don't drive like a fool with that camper behind me. Currently I suspect there is an issue with my truck because I have another thread going and some of you think I'm loosing boost pressure. I didn't think this topic would cause any fights.......sorry!
No need to apologize for others getting upset off of your thread. I think it is tough to believe your excellent towing gas mileage but you might be the one in bunch that had the perfect setup or something like that. I would be excited to get 13.81 towing with my 5th wheel, and praising the wind gods for 15.24. All that being said, you may want to do some serious work (total weight, driving conditions, speeds driven, tune used, etc) with Ryan's Diesel to replicate the tunes and your setup for others to gain from your good findings. Best of luck
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