Towing with and without Tow/Haul Mode with Powerboose and gas mileage

[Hullguy]

Tow/Haul mode does use the transmission to assist with braking

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[Jeff1024]

Tow/Haul mode does use the transmission to assist with braking

Yup, but sometimes I dont think the 3.5 has enough displacement to make much of a difference. Never driven the 5.0 but I have to assume its a bit better.

 

[Hullguy]

Yup, but sometimes I dont think the 3.5 has enough displacement to make much of a difference. Never driven the 5.0 but I have to assume its a bit better.

I found it worked well in the Smoky Mountains pulling a 7000 lbs trailer.
i had to change my tow vehicle to a GMC 2500 due to getting a heavier trailer, ( we kept the 150 PB as well), with a 6.5 liter gas engine. The 150 did a better job with braking.

 

[NMMIKE]

Our TT is 22 foot, 5500 lbs wet, tandem axles. We use tow mode, lock out 9 and 10 and the engine braking works great. We live in SW and tow during summer months when temps are hot,,,,, using tow mode and locking out 9 and 10 help keep the engine and tranny temps from getting too high, works well.

 

[Vater]

I towed a small camper, (16ft-3500lbs) around 3000 miles a few months back. A few times I forgot to put my Powerboost back into Tow/Haul mode. I noticed that the gas mileage was better when I was not in Tow mode. I'm guessing it is because the truck didn't appear to use the electric motor. I'm wondering if this is the reason.

Also, if I am driving on flat straightaways and not in hilly areas, does it make sense to stay out of tow/haul mode and get the better mileage? I really didn't notice a difference in modes except going downhill where my transmission stayed in lower gears.

I monitor EG temps with a Data Monster on my PB. I find that when using normal mode and the trans is running in an overdrive gear up inclines with cruise control on, the tendency at holding speed is for the turbos to run up boost without down shifting. This causes EGT’s to run up seriously high, too high for sustained periods at over 1650 to + 1700 F. Those temps are too high when sustained for aluminum pistons as well as the turbos and catalytic converters itself says most places on acceptable EGTs with gas motors. For that reason alone, I will often run in tow haul and/or lock out the 3 overdrive gears, increasing engine RPM and gas usage, but keeping dangerously high over temps out of the motor combustion chambers and exhaust/turbo systems

 

[Ricksc]

On my 3.5 I found tow/haul works better for me going into manual mode so I can get best results on down hill grades. It will hold the rpm I want and if I touch the brakes it won’t down shit again

 

[Atlee]

When I'm towing my 5500# GVWR TT, I always lock out the overdrive gears (10, 9, 8) and usually use Tow/Haul Mode.

I have found that locking out those gears greatly reduced the use of the turbos. I figure the more the turbos spin, the more gas is used, and it probably generates more heat.

When I'm in stop and go traffic, I will usually switch back to normal mode. This allows the ICE to shut down when stopped and when moving at a slow speed.

 

[roadPilot]

Tow/Haul mode keeps the engine/trans in the better part of the torque curve for towing/hauling. It will allow the engine to reach higher RPMs before shifting. It will also downshift sooner to let the engine help with slowing down. This is most prominent when in areas that have more elevation changes.

 

[LD50]

The info below was something I previously posted in a similar thread. Another thing I see a lot of is people deciding to use tow/haul based on weight alone, especially those lighter travel trailers. Once you're moving, frontal area and wind drag needs to be the biggest consideration. I can reproduce the same results below by pulling my unloaded aluminum trailer and leaving the ramp up so it acts like a big sail instead of folded over flat on the trailer.

Today I was pulling a UTV on a utility trailer for about 120 miles. Roughly half of that trip is on a stretch of flat interstate, all headed in the same direction. The biggest hills are overpasses crossing other roadways. The trailer and UTV weigh about 3500 pounds and probably have a moderate or lower wind drag. Since the entire stretch is all in the same direction and the light wind was constant, it shouldn't be a factor in what I observed.

i decided to reset the trip meter and observe different readings over two stretches of 15 miles with the cruise set on 65. On the first one, I let the truck run in 10th gear. I had to move from tow mode to normal mode because tow mode held the truck in 8th. During this test, I observed the boost to remain constant between about 3 and 8 pounds. On the second 15 mile stretch, I left the truck in normal mode and locked out gears 9 and 10. No boost significant enough to read on the dash gauge except when going up an overpass and then it would only get to about 2 psi. After doing both runs, I switched the truck back to tow mode where it remained in 8th gear. I only had about 10 miles on this run because the road changed directions 90 degrees and the wind would have skewed the results. Over those 10 miles, I got pretty much identical results as in 8th gear in normal mode, as expected. I just wanted to confirm.

Here is what I saw from the metrics I was monitoring.

10th gear (1,600 rpm)
Mileage - 12.7
Engine temp - 204-209
Cylinder head temp - 230-235
EGT - 1500-1550

8th gear (2,200 rpm)
Mileage 14.3
Engine temp - 194-198
Cylinder head temp - 216-221
EGT - 1300-1350

Not exactly scientific but it matches my previous observations.

 

[Jmitchelltfo]

The info below was something I previously posted in a similar thread. Another thing I see a lot of is people deciding to use tow/haul based on weight alone, especially those lighter travel trailers. Once you're moving, frontal area and wind drag needs to be the biggest consideration. I can reproduce the same results below by pulling my unloaded aluminum trailer and leaving the ramp up so it acts like a big sail instead of folded over flat on the trailer.

Today I was pulling a UTV on a utility trailer for about 120 miles. Roughly half of that trip is on a stretch of flat interstate, all headed in the same direction. The biggest hills are overpasses crossing other roadways. The trailer and UTV weigh about 3500 pounds and probably have a moderate or lower wind drag. Since the entire stretch is all in the same direction and the light wind was constant, it shouldn't be a factor in what I observed.

i decided to reset the trip meter and observe different readings over two stretches of 15 miles with the cruise set on 65. On the first one, I let the truck run in 10th gear. I had to move from tow mode to normal mode because tow mode held the truck in 8th. During this test, I observed the boost to remain constant between about 3 and 8 pounds. On the second 15 mile stretch, I left the truck in normal mode and locked out gears 9 and 10. No boost significant enough to read on the dash gauge except when going up an overpass and then it would only get to about 2 psi. After doing both runs, I switched the truck back to tow mode where it remained in 8th gear. I only had about 10 miles on this run because the road changed directions 90 degrees and the wind would have skewed the results. Over those 10 miles, I got pretty much identical results as in 8th gear in normal mode, as expected. I just wanted to confirm.

Here is what I saw from the metrics I was monitoring.

10th gear (1,600 rpm)
Mileage - 12.7
Engine temp - 204-209
Cylinder head temp - 230-235
EGT - 1500-1550

8th gear (2,200 rpm)
Mileage 14.3
Engine temp - 194-198
Cylinder head temp - 216-221
EGT - 1300-1350

Not exactly scientific but it matches my previous observations.

That is exactly what I would expect. Mine acts the same way unloaded on hilly drives (I'm only monitoring coolant temp and current MPG's on my MX2 since I haven't done the Forscan work yet)

These motors want to rev when they are working.......but the software wants the boost to compensate for some reason.

With so many F150's on the road, I wonder how many people just set the cruise and let it eat when they tow heavy?

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