Tow Mileage Stinks. Suggetstions?

[CYauch]

Ok, this weekend if the first time i've towed anything with real weight for a long distance. Normally, i pull a boat (about 3,400 pounds) a few miles to the launch, a two-axle traile with a 24hp tractor a few miles, but nothing over 4,000 lbs in general. This weekend, picked up a new TT in Pochatoula, La (unloaded weight about 6,800 lbs). On the way over there, barely burned 1/8 of a tank for 129. 4 mile distance (overhead said 19. 2 mpg).



On the way back, holly 'l love to drink fuel' batman!!! I kept the speed around 67-70 and the thing drink fuel like my ex-wife drank Vodka!! Pulled into driveway, and it's a tick below half a tank. Suggestion's on how to improve this mileage??? For what its worth, the trailer is a 2009 Puma 30FQSS. While i didn't buy it here, this link has good exterior pics. Not the most areodynamic trailer, but man, i expected a little better fuel mileage. Puma 30FQSS Travel Trailer RV at Cheyenne Camping Center



I have an Equalizer 4-point sway control hitch, and I'm wondering if i need to tweak that, and maybe get a little better mileage? Truck rode like a Cadilac before this trailer, but now, the thing bounces like crazy. Left / Right sway isn't that bad, and the front end bounce dampens out after 3 or 4 oscillations. Rear end of truck still appears to sit a little high after hitched up which is why i'm thinking i need to adjust. I can take a pic if anyone thinks it may need adjusting. I'm a noob with this setup so i don't mind being called a noob

 

[domehead]

How many miles do you have on the truck and is it manual or Auto, 4X4 or 2WDR. Any codes.



Beside those quieastions I have a 2009 3500 and the MPG with 19,280 was 10. 5 and with 17,040 the MPG went to 11. 5. The MPG has increase from 14 to 16. 5 after the truck passed the 8,000 mile mark

 

[B.G. Smith]

First, if your fuel gage and overhead MPG accuracy are like mine and most others you can't determine anywhere near what mileage you are getting form them. I get barely 10 pulling a 32"8" 5th wheel which iis in the 12,000 lb. area. But with towing, speed is a big factor on mileage, the faster you go the more you burn. With the equalizer hitch adjusted correctly, your truck should have the same front to rear level as it does without the trailer hooked up. Sounds like you have the bars pulled up a little too much. Good luck and have fun, If you are like me you won't have to pay for the fuel until you get home and are sitting in the recliner with the AC on. bg

 

[Chief USA]

In most cases the maximum efficient air speed for a truck, SUV, or other high wind drag vehicle is approximately 45 mph or similarly in this speed range. Try slowing down to around 50 mph.



Remember wind resistance is mathematically squared as the air speed doubles. Slowing down 15 to 20 mph can in many cases make a dramatic difference.



I get the best fuel economy in my truck at around 45 mph. As I increase my speed the fuel economy drops like a simonized piano. At 75 mph, my fuel economy drops to around 12 to 14 mpg.



Are you using a good fuel additive that boost cetane value? This may help some if the truck is stock. I am using the Amalgamated fuel additive. It claims to raise cetane value 6 points with the TDR summer and winter formula's.



I agree as already mentioned, stubby pencil checking your fuel mileage.

 

[DHuffman]

I would start with actually calculating your mileage... then I would compare that to what other guys on this board are getting.

 

[CYauch]

Thanks for the replies. Responses (in no particular order )

1. Odometer reading right now is at 8,300, and i figured that as i get more miles on it it should get better and better. I just didn't expect it to be this bad starting out. It's a 4x2, Automatic, no codes. Don't know my gearing as the only thing on the sticker is 11. 50 gear ratio. Unloaded, at 75 mph i'm turing between 1900 - 2000 RPM's.

2. Being that i am a software engineer, i wrote my own program that tracks fuel / mileage costs, but also modifications, maintenance, etc, etc. So, i've been able to reconcile the difference between what the overhead display says and what my actual mpg's are. Yes, i've come to the conclusion the overhead display with useless, but the report's kicked out of my system show that the percent difference is starting to flatline a little, so by glancing at the overhead, i can now estimate what my real mpg's are. As for towing mpg's, this is the first time with a long haul heavy tow, so i don't have a solid baseline yet to compare against for that category.

3. Speed. Getting up to speed seemed a chore, but then again, still feeling this 6. 7 out. with my 5. 9, i just romped the gas until at speed, then backed off. course, smoked from all hell. i know these engines are tough, but can u mash the snot **** out of it till desired speed? Thing gets loud as heck when i do Doing the gradual acceleration seems to take forever.

4. Speed (again). I kept speed around 67 - 70. Seemed to do great at 75 also, but that was way to fast. wanted to see how it handled at that speed though. might try kicking down to 63 - 65 when i make another trip in a week or so. That slow, i feel like i'm gonna cause a 300 car pileup

5. No additives, but will look into that.

6. Have to update my software, but will start tracking towing miles and break that data out in a seperate report.

I've seen some trucks with the air scoop on the roof of their trucks. Does that really help, and aren't those geared more for 5th wheels?

 

[B.G. Smith]

That 11. 5 is the diameter of the ring gear, you probably have 3. 73:1 gear ratio from looking at you rpms. I have takjed to a few folks with the wings on the truck, most say the big advantage is thart they keep the bugs off the front of the trailer, some have claimed a 1 mpg improvement. Sometimes I think they would be worth the price just top keep the bugs off. I fully agree with you on the driving speed, if you drive under 60 around here you will get run over plus the truck runs much better up around 1900/2000 rpm. Hope your mileage does improve, I haven't had that experience. bg

 

[domehead]

It should improve as you get few more miles on it. But it will not be the dame as the old truck. As CHIEF USA state your MPG will go up as you speed comes down, but if you are like most of us you need to get there running the posted speed limit.



You should not have alot of noise coming out of that engine.

 

[WMonroe]

What rpm's were your running at while towing? If it was down around 1600 in 6th gear try bumping it down into 5th mileage might come up since the engine won't be lugging.

Will

 

[JDiepstra]

You want better mileage, remove your emissions equipment.

 

[CYauch]

What rpm's were your running at while towing? If it was down around 1600 in 6th gear try bumping it down into 5th mileage might come up since the engine won't be lugging.

Will

Will pay attention to that when i make my next run. I know i looked at the tach, but for the life of me, can't remember what the number was. Between Hammond and Slidell, La. i was more worried about getting run over. Fricking traffic was jam packed for some reason.

 

[CYauch]

You want better mileage, remove your emissions equipment.

On my list of things to do. Wanted to wait till i hit 10,000 miles before i started taking that stuff off. That way, i would have a good baseline on mpg's with it so i can do a good compare without it.

 

[CUMMINZ]

I have an early 07. 5... With about 31k on it. I tow heavy and have the AZ flash which is the best flash I have experienced. The overhead is very responsive and within 5. to 1. 0mpg ontrack with hand calculations. It is very obvious to me that running on flat ground is much better than even slight hills up and down. Both trips to CO. and back to NC I get around 9. 0 - 9. 5mpg. I added an MP8 the first trip which was a waste of money for towing mileage. I towed my first trip this weekend to the coast (250) miles with the tuner I am using now and got 10. 5mpg set on 90hp with timing added. On the return home empty set the same way I got 15. 5mpg. That is the best readings I have ever gotten. Shortly I will make that return trip empty and return towing with tuner set on 60hp with timing. I expect better both ways.

 

[icman95]

The thing isn't even broken in yet at 8300 miles. On my 5. 9 I think my fuel mileage kept getting better until about 20k, so give it some time. Also, as stated above, your emissions equipment robs you of mpgs, unlike a 5. 9. So already, you're behind the 8 ball. I may have missed it, but did you acutally list what your hand calculated towing mileage was? If you came back with anything between 9 and 11 mpg, I wouldn't be surprised. After all, you're pulling a barn shaped object behind you. If you said you were getting 5-8mpg, I might be concerned, but anything over that is withing normal range.



Pulling my 5er with my 2001 I get 10. 5 at about 60-65 mph. In the quicker states at 70-75 mph I was getting about 9. 5 or so. The worst I ever had was 8. 3 mpg, but that was a bit faster than I should have been going. Heavy towing has a heavy price, but I think you'll see your mileage come up as the miles go on and as you figure out what is most comfortable for you.

 

[CYauch]

The thing isn't even broken in yet at 8300 miles. On my 5. 9 I think my fuel mileage kept getting better until about 20k, so give it some time. Also, as stated above, your emissions equipment robs you of mpgs, unlike a 5. 9. So already, you're behind the 8 ball. I may have missed it, but did you acutally list what your hand calculated towing mileage was? If you came back with anything between 9 and 11 mpg, I wouldn't be surprised. After all, you're pulling a barn shaped object behind you. If you said you were getting 5-8mpg, I might be concerned, but anything over that is withing normal range.



Pulling my 5er with my 2001 I get 10. 5 at about 60-65 mph. In the quicker states at 70-75 mph I was getting about 9. 5 or so. The worst I ever had was 8. 3 mpg, but that was a bit faster than I should have been going. Heavy towing has a heavy price, but I think you'll see your mileage come up as the miles go on and as you figure out what is most comfortable for you.

As of now, the overhead says 12. 6 but i know that's not accurate. Without a load, my overhead and hand calcs (done via the software i wrote) differ, on average, but 1. 5 - 2 mpg. Now, I haven't done a full fuel run towing this rig yet, but at 12. 6 that tells me if i hand calc a full fuel load, it would put my roughly in the mid to low 10's, which is within the range everyone else seems to be getting. I guess i thought it would be a little better, but then again, i keep forgetting about this emission's crap on the engine. Can't afford both the DPF / EGR delete and the Smarty ME, so I guess i need to think about what i want Santa to bring first before i deploy to the desert. Course, could wait till i get back then get both i guess :-laf Thanks for the info!

 

[CYauch]

I have an early 07. 5... With about 31k on it. I tow heavy and have the AZ flash which is the best flash I have experienced. The overhead is very responsive and within 5. to 1. 0mpg ontrack with hand calculations. It is very obvious to me that running on flat ground is much better than even slight hills up and down. Both trips to CO. and back to NC I get around 9. 0 - 9. 5mpg. I added an MP8 the first trip which was a waste of money for towing mileage. I towed my first trip this weekend to the coast (250) miles with the tuner I am using now and got 10. 5mpg set on 90hp with timing added. On the return home empty set the same way I got 15. 5mpg. That is the best readings I have ever gotten. Shortly I will make that return trip empty and return towing with tuner set on 60hp with timing. I expect better both ways.

Looking at your site, looks like you have the DPF delete? If i opt for the Smarty now and the DPF / EGR delete later, will i gain anything? I understand i may not see only a little improvement, if any at all, without the deletes, but i also use the truck as a daily driver. Anything what would help with in and around driving would be a plus.

 

[gsbrockman]

Some more Towing Fuel Economy Figures.........

All truck info is in signature; I had the ECM updated to reflect my "old" LT285/70R17 Firestone Destination A/T's. I now run some 20x9 Ultra Grinders wrapped in some LT305/60R20 Wrangler SR/A's. I now have to multiply my odometer readings by 1. 0683 to compensate for the 20's.



Anyhow, my truck now runs 1,750 rpm at 75 mph, as verified by my Garmin.



I contract haul some on the side; this past Friday I hauled a 1988 Airstream Excella triple axle travel trailer (34 ft and around 6900 lbs) from Hebron, OH to Berea, KY. I left out with a full tank (only had 17 miles driven out of it) and went 278. 3 miles and averaged 17. 652 mpg with an average mph of 61. 84(Juice w/Attitude on #1). Within 10 miles of my destination, I re-fueled and then hooked up. I drove 288. 9 miles and averaged 12. 862 mpg with an average mph of 56. 64 (much lower mph due to an accident delay) Juice w/Attitude on #2. I also have the H&S DPF Delete, too.



That ol' Airstream tri-axle pulled like a dream... ... I had a standard solid ball mount with 6" drop (no weight distribution hitch) and no swaying and tracked as good as a new one, I'm sure. I was actually apprehensive of the weight and the fact it was a Class IV style hitch. The 6. 7L and 68RFE and 3. 73 gears are a great combination IMO.



Greg



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[AH64ID]

Well without the hand calc for the tank its hard to say exatly where you were. . But I would expect your in the 9-11 range towing a barn door at 67-70, just a factor of the frontal area.

With more miles on the truck you may get better mpgs... . but nothing HUGE...

Best way to increase mileage with a TT is to slow down.


As far as the bounyness... you just have to play with the equalizer. I have the same hitch setup and it took me a few tows but I am dialed in and its the best WD setup on the market. One thing I noticed with our trucks is the rear springs are stiff enough that 3-400lbs of tounge weight will lift the front of the truck before it starts to lower the rear, so you need more WD than you would think for the weight. . . but it will transfer the weight back to the front and you won't get the bouncy...

 

[mpaulson]

Someone mentioned fuel additives, I wouldn't do that with this truck unless you remove all the exaust system filters. I didn't notice any milage change when I deleted all the emisions junk. But I did get a drop in egt. by about 150 degrees which helps when you want to keep your foot in it. I average around 10 mpg with a 30' tt, deck on the truck with quads, generator, two canoes,kyak, dog kennel etc. and I cruise around 70 to 75 mph. I've learned to ignor the cost of fuel and enjoy the trip. At the end of the day, whats the few extra bucks to enjoy yourself and not feel like a slug on the road.

 

[SBeretz]

I don't think weight really changes as much as speed does. I pull a large fifth wheel and if I stay around 60-63 my mileage will stay up around 12. If I push it to 67-70 (don't drive that fast anymore), it kinda dunks under 10 pretty quickly. I can pull heavy or light and it stays about the same, but changing speeds really alters the mileage. I would think at first glance, your truck is fine, just needs more towing miles. It will get there. Don't mess with it yet, I bet it will continue to get better. Don't worry about hurting it, run it how you want, the engine needs to turn to make good, solid power. Scotty