how to increase miliage when towing

[jkust]

Re: how to increase miliage when towing

Mine has the 4 cyl mode but it rarely comes on when towing and is disabled if you actually put the truck in tow haul mode.

Well my GM's are both SUV's so are missing a few of the items i'd liked to have had. The GM trucks had this stuff though. No Tow/haul mode, no 4cylinder mode indicator and no Transmission temp readout. Since I absolutly can't discern when the engines switch from 8 cyl to 4cyl mode, i'm really just guessing. I've always understood that the Chrysler products just simply get bad mileage. That's the complaint of the many chrysler/jeep owners's I know as well.

 

[oldjeep]

Re: how to increase miliage when towing

Well my GM's are both SUV's so are missing a few of the items i'd liked to have had. The GM trucks had this stuff though. No Tow/haul mode, no 4cylinder mode indicator and no Transmission temp readout. Since I absolutly can't discern when the engines switch from 8 cyl to 4cyl mode, i'm really just guessing. I've always understood that the Chrysler products just simply get bad mileage. That's the complaint of the many chrysler/jeep owners's I know as well.

The newer hemis get good milage - as long as you keep your foot out of it. I can get an honest 21mpg freeway milage from a crewcab truck that weighs just under 6000lbs.

 

[H20Rat]

Re: how to increase miliage when towing

Speed, or lack of it is probably the best way to increase economy. The faster you go the more air you are pushing.

that is one factor in it, but not always the most important. When I tow with my car, mileage is the worst at 60 mph. Why you ask? My car is a manual, and I at 60 mph I'm only turning around 2400 rpm in 5th (on a 2.0l 4 cylinder). That is fine for normal driving, but doesn't cut it with 2000# of boat behind. I'm forced to rev it up and run in 4th gear at 60 mph, which puts me around 3600 rpm. (and also kicks the ECU into open loop fueling most of the time, so i'm dumping gas out the exhaust pipe) 5th gear at 70 mph keeps it at a high enough rpm to have enough torque, and low enough not to dump gas out.

 

[joewithaboat]

Re: how to increase miliage when towing

I got an old vacuum gauge out in the garage from back when I could still work on engines with a dwell meter, timing light and vacuum gauge. Just run a hose from the intake somewhere? ain't got no carb anymore.

Yea any vacuum source on the engine side of the the throttle blade(s) should work. I have found that sometimes your sweet spot will be at a higher speed than you would think with OD and highway gears if so equipped. Towing there might not be a good idea. Might be better turning off the OD or running in D. Not sure how your vehicle is equipped.

 

[roscoe]

Re: how to increase miliage when towing

LOL - you ever tried getting close to the back of an 18 wheeler? The air swirls back there and really tosses even a pickup around.

You are not getting close enough.

I don't recommend you drive there, but there is a hole if you get close enough.

 

[bigdee]

Re: how to increase miliage when towing

Increase you acceleration & deceleration ramp time. The law of physics says there is a defined amount of energy in a gallon of fuel. Since it takes the same amount of energy regardless of whether it is a 4 cylinder or V8 the mileage will still be about the same. Not much left to do except adjust driving habits.

 

[joewithaboat]

Re: how to increase miliage when towing

Increase you acceleration & deceleration ramp time. The law of physics says there is a defined amount of energy in a gallon of fuel. Since it takes the same amount of energy regardless of whether it is a 4 cylinder or V8 the mileage will still be about the same. Not much left to do except adjust driving habits.

So how do engine efficiencies keep getting better? More power from the same displacement with more mpg, as the size of a gallon of gas remains the same.

 

[jkust]

Re: how to increase miliage when towing

So how do engine efficiencies keep getting better? More power from the same displacement with more mpg, as the size of a gallon of gas remains the same.

Watch Top Gear UK and see them laugh at the low hp we (Americans) get from large displacement petrol engines.

 

[Flynny]

Re: how to increase miliage when towing

So how do engine efficiencies keep getting better? More power from the same displacement with more mpg, as the size of a gallon of gas remains the same.

Better efficiency. There are dozens of ways to make an engine harness the power in gas more effectively.

And the post before you was sort of right, larger displacement engines will get lower MPGs because they use more gas during idle and probably in general.


What the world needs is a hybrid that can tow. Prius with a 5000 pound trailer anyone?

 

[QC]

Re: how to increase miliage when towing

To further on Flynny's post:

The law of physics says there is a defined amount of energy in a gallon of fuel. Since it takes the same amount of energy regardless of whether it is a 4 cylinder or V8 the mileage will still be about the same. Not much left to do except adjust driving habits.

This is kind of true with a diesel, not as much with an Otto cycle engine (gasoline). In both cases (diesel and Otto) the larger reciprocating mass of the larger engine alone requires more fuel for the same output if all else was equal. Generally speaking it takes a little more fuel for each pound of stuff you are spinning, cranks, cams, pistons, rods, etc. Just one example.

 

[joewithaboat]

Re: how to increase miliage when towing

Watch Top Gear UK and see them laugh at the low hp we (Americans) get from large displacement petrol engines.

Yea, we still kick there butts around the race track... they can laugh all they want.

Dollar for dollar have been taking it to them lately. The Caddy and Corvette have pounded them for last few years.

Heck the 2011 Mustang GT beat the new v8 M3 BMW in an all out performance comparison.You could buy 2 Mustangs for the price of an M3.

 

[joewithaboat]

Re: how to increase miliage when towing

Better efficiency. There are dozens of ways to make an engine harness the power in gas more effectively.

Yes I understand this...
I was sarcastically posting because the post before mine implied there is only so much energy you can transfer to the ground from a gallon of gasoline. There are MANY things that affect this.

 

[NYBo]

Re: how to increase miliage when towing

No offense, the wing might help but it is UGLY.

It's ugly and it WON'T help. It's designed for towing a large boxy trailer, not a boat.

 

[bigdee]

Re: how to increase miliage when towing

So how do engine efficiencies keep getting better? More power from the same displacement with more mpg, as the size of a gallon of gas remains the same.

Engine efficiencies have pretty much peaked to the limit...decreasing weight will increase efficiency but that is hard to do with a boat behind you! There is only 49 thermal horsepower in a gallon of gas and about 60% of that is lost when it's burned through an engine.
An automotive engine will produce about 15 HP hours on a gallon of gas that's 15 HP for a period of one hour. You cannot move a tow vehicle and boat with 15 hp.
There is not an engine making 300 hp that will ever get more than 5 or 6 mpg but there is 300hp engines USING 15 hp to get 25 mpg! In summary it is load and the amount of horsepower being used that determines fuel mileage.

 

[joewithaboat]

Re: how to increase miliage when towing

Engine efficiencies have pretty much peaked to the limit...decreasing weight will increase efficiency but that is hard to do with a boat behind you! There is only 49 thermal horsepower in a gallon of gas and about 60% of that is lost when it's burned through an engine.
An automotive engine will produce about 15 HP hours on a gallon of gas that's 15 HP for a period of one hour. You cannot move a tow vehicle and boat with 15 hp.
There is not an engine making 300 hp that will ever get more than 5 or 6 mpg but there is 300hp engines USING 15 hp to get 25 mpg! In summary it is load and the amount of horsepower being used that determines fuel mileage.

Not sure where you are getting your numbers...

Apparently you haven't looked at the new CAFE standards coming up in the future. So you think they will meet them by cutting weight only?:facepalm:

All kinds of small things will add up to the gains needed. Variable valve timing, direct injection, and cylinder management will be the biggest part of it. Probably lots of turbo's as well.

I promise you that when my cruise is set on 70mph and Im getting 28 mpg its making a lot more than 15 hp!!! It takes more than 15 hp just to spin the accessories

 

[bgc]

Re: how to increase miliage when towing

I found driving slower helps a lot.......

That’s right I’m the guy with the F350 dually towing a 15’ Starcraft in the right lane doing 60 mph……..saves fuel and it’s a 6.0(engine could blow at any moment)

 

[Georgesalmon]

Re: how to increase miliage when towing

I can pull the boat and trailer around the yard with my John Deere lawnmower. 8hp

 

[Georgesalmon]

Re: how to increase miliage when towing

Thanks, gonna try that.

 

[BlueLightSpecial]

Re: how to increase miliage when towing

ok, getting back to the OP, I have read on a Dodge Ram forum, numerous times, about guys with the half ton rams installing 4.56 gears. Expensive, especially if you have 4WD. I have a 2008 Quad Cab Hemi, 4X4 w/ 3.92 gears. My boat only gets towed 1/4 mile to the launch, so I cant compare with a boat. However, last time I tracked MPG, I had a bed full (heaping) of fire wood, pulling a 6x12 utility trailer (675lb, unladen) with an atv (approx 800lb), camping gear, 3 coolers, grill, etc and 3 adults in the cab. I averaged 14 mpg on the way up, and averaged 16 mpg on the way back. Obviously the combination was lighter on the way back. No firewood, no beer, soda, ice, food, etc. I was in tow/haul mode, which shuts off the multi-displacement. The route is winding and very hilly. Many big truck safety stops before decending, and truck climbing lanes going up. I am happy with those numbers. I dont know how much of an improvement 4.56's will do, but I bet the highway mileage would suffer a bit. I plan on keeping track on this years trip, since I have added exhaust, and K&N intake.

 

[bgc]

Re: how to increase miliage when towing

I can pull the boat and trailer around the yard with my John Deere lawnmower. 8hp

There is your solution George! Use the Deere!