Towing without overdrive

[Thomas G.]

Originally Posted by gmw photos

Very true. I would suspect that the OEM's would prefer manual gearboxes simply go away. An automatic takes most of the driver skill part of the equation out of play.
..........

Manual transmissions have long been offered freely in trucks, but the market share drops and drops as fewer people can drive one. Even if dad can drive one, mom or the kids can't, so they buy an automatic. Many cars don't offer a manual option anymore because the sales volume is too low to pay for the tooling. The good news is that automatics are getting more efficient.

[KevinScamps]

The prevailing wind is west to east across the plains, so that probably has a lot to do with it. Also the plains are sloped downhill, so getting back you did significantly less up hill. You may still get some benefit from the towing mode. I doubt that it is 20%.

Originally Posted by cpaharley2008

Just returned from a marathon drive to attend a rally in Nebraska this week and wanted to make some observations. I drove 2800 miles over a period of 8 nights, left on a Sunday night and arrived in Nebraska, Tuesday at noon, left there on Saturday, noon and arrived home tonite at 9 pm. Took the northern way out and the southern way back thru 8 states.
I drove a Dodge Ram 1500 with the Hemi engine towing the 19' Escape with the Andersen hitch. The hitch performed flawlessly, particularly in the plain states with 20-30 mph winds. My trailer weighs around 3400 lbs loaded.
I drove with the trans mission in normal drive on the way out and checked my mileage at every fillip. I was getting between 10.5-11.5 mpg consistently with the engine cruising around 2400rpm under load and 1800rpm cruising. I used mid range and E-90 gas mid range. There were strong headwinds going out and returning.
My return trip I engaged my "Tow Mode" which locks out the overdrive and changes the shift points. Surprising I averaged 11.5-13.5 mpg on the return trip. Other than Missouri in lieu of Iowa, I went thru the same states. I noticed the rpm stayed at 2200 under load and would occasionally drop back to 1800 while cruising.I also noticed it did not shift into the higher rpm range as often as the trip going.
This 200 rpm difference gave me a 20% increase in my mileage, which in my case was about $100 savings.
I wonder if anyone else has done a comparison of the two towing modes, with or without the overdrive. My owner's manual says that you should use the tow mode while towing.

[cpaharley2008]

I'll try the experiment next time which will be a north/south direction.

[floyd]

Originally Posted by cpaharley2008

Because automatics make up about 80% of vehicles produced.

At least in the U.S. where people buy according to color and style...Not substance!

[rabbit]

Hmmm, Continental Divide effect. An alternative explanation.

jack

[honda03842]

Our tow vehicle is 9 years old, has a manual transmission and the original clutch. We are now on one of ourhilliest adventures. Yesterday we drove the cape race road, about 24 miles of severe gravel hills. Today we met a guy in the park with a Nissan truck who asked us what did we do about the hill on the Cape Race road....we drove up it of course. Go Honda.

The only issue is backing up hills when it's almost necessary to slip the clutch

[Perry J]

Norm, how many miles do you think you've towed with your Honda Norm??
I agree you can't beat a Honda or Toyota.
I was in bakersfield yesterday and thought of you and Ginny as I went through the In n Out Burger drive through yesterday.

John

[Jared J]

I just did about 1600 miles. I had tow mode off, overdrive on for the drive north, and tow mode on, overdrive off for the trip south. Mileage was within a few tenths either way. The quality of each tank of gas seemed to change it more than anything (damn you and your mileage killing moonshine, iowa). However, it kicked from fifth down to either third or fourth and unlocking the torque converter quite a few times on the way up. It also hunted on hills, making me downshift. On the way back, it never shifted out of fourth, and the torque converter stayed locked. I'm sticking to tow mode with overdrive off.

I averaged 12-12.5mpg (2004 nissan titan, scamp 19'), doing 70-80. It only gets 17 on its own, so I'm happy.

[Brian B-P]

Originally Posted by cpaharley2008

I'm surprised they have not improved the mechanical cruise control with a computerized system that eliminates those down shifts and passing gear upshifts while in cruise mode.

Modern vehicles use an electronic connection of accelerator pedal to engine, rather than the old mechanical cable. This means that the cruise control function is just code in the engine computer.

I find this means much smoother and nicer cruise control, but letting it maintain speed while towing in hills still means too much downshifting and high power application in our Sienna.

[Jon Vermilye]

I'm not sure how you could get the information that the hill you are about to hit is a small one, so let the vehicle slow down rather than downshift, or know when you are just about to hit the peak of the hill, so again, no need to downshift, just let it slow down a couple of miles per hour.

Maybe when they reach the point where cars are suppose to drive themselves there will be enough sensors to do the trick, but my foot seems to work better in hilly country than the cruise control, at least when towing. I have noticed that it works better in my RAV4 than it did in my previous vehicle, a 2003 Town & Country.

[Brian B-P]

Originally Posted by Jon Vermilye

I'm not sure how you could get the information that the hill you are about to hit is a small one, so let the vehicle slow down rather than downshift, or know when you are just about to hit the peak of the hill, so again, no need to downshift, just let it slow down a couple of miles per hour.

Cruise control is a classic feedback-type control system situation, so the usual control loop tuning parameters apply... and it is not necessary to know how steep or long the hill might be. The system can be adjusted to less aggressively maintain the set speed.

Originally Posted by Jon Vermilye

Maybe when they reach the point where cars are suppose to drive themselves there will be enough sensors to do the trick, but my foot seems to work better in hilly country than the cruise control, at least when towing.

Although knowing what's coming up isn't necessary, it does help.

Originally Posted by Jon Vermilye

I have noticed that it works better in my RAV4 than it did in my previous vehicle, a 2003 Town & Country.

I'm not surprised; this may be a mechanical versus electronic throttle linkage difference.

[Radar1]

I have a gauge that shows instant MPG on my Dakota 4.7 V-8 and can be reset easily to check average MPG over any distance. Dodge recommends towing normally without the overdrive locked out on my model, unless you are going up and down hills that cause the transmission to shift a lot. On the times that I can leave the transmission in overdrive, I get better mileage in overdrive than if the overdrive is locked out. I sometimes experiment on the same trip and road/wind conditions and it's always the same, better mileage for me if I use overdrive. Example: If I am getting 16.2 in overdrive, and then try the same road with overdrive locked out for a few miles, then the mileage drops to about 15.1.
If the hills or headwind cause the transmission to shift a lot, then I lock the overdrive out.
Guess every rig is different.

[honda03842]

PerryJ,

We haven't kept track of the exact tow mileage but we 've been towing for 6 years for 7-11 motns a year and just passed 191,000 miles on the odometer. Towing miles have included 2 loops of the USA, a cross labrador andpresently about 4,000 miles in Newfoundland.

On this trip we've averaged 21.4 miles per gallon. Lots of steep hills, dirt roads and wind. Ginny thinks Cape Race was the windiest place we've been though I thinke Port Orford, OR wins.

A nice part of Nfld is very limited traffic.

Working our waynorth to look for an iceberg.

[honda03842]

PERRYJ

In and Out, love to see one in Nfld. We did eat cod tongues and fell in love with tea biscuits, their bread and eat alot more seafood.

As to absolut towing miles I would guess the order of 50,000.