Real world towing MPG with Ford 5.0L V8?

[Bill and Earline]

Ram
Chrysler TorqueFlite 8 (8HP70) Transmission Specs & Ratios

Here are the ratios in the 8-speed ZF as used by Ram, including a couple of "overdrive" gears.

Bill

[steve dunham]

We are more concerned with having a vehicle that tows well across a wide spectrum of towing conditions than with gas mileage . When on a trip I keep track of fuel purchases , more for credit card security than for calculating fuel mileage . If we decide to make a trip then we just live with the fact that we can't totally control fuel costs. When we spent 3 weeks in Canada last fall , fuel was more expensive than the US but what are the alternatives , you either pay the cost or stay where your at.
Sometimes it seems that the over fixation on gas mileage leads some to choose a vehicle that is not the best candidate for a tow vehicle.
I am not denying that fuel economy is a consideration but it should not rank above towing capacity , payload , braking ability , tongue wt ETC ETC.

[Jim Bennett]

As fuel is the single biggest cost to RVing for us, fuel economy is of importance. Capacity to do the job at hand is of course a must too.

[Loren & Cathy]

Originally Posted by steve dunham

I am not denying that fuel economy is a consideration but it should not rank above towing capacity , payload , braking ability , tongue wt ETC ETC.

I couldn't agree more and as for the gas, what it takes is what it takes. But then smart folks tow light fiberglass trailers. Loren

[freespirit]

Thanks Brian for putting together the rear axle ratio info...

[War Eagle]

My 1999 SuperDuty F-250 with the 7.3L PowerStroke diesel engine and 6-speed manual overdrive transmission can get 20 mpg all day long doing 60 mph in 6th gear overdrive at 2,000 rpm - but I get passed by everything else on the interstate. When I go over 2K rpm to edge up to 65-70 mph, fuel mileage drops noticeably. I'd love to have one more "double overdrive" gear so I could do 65-70 mph at 2,000 rpm and still get 20 mpg. I'm certain the 7.3's torque could handle an extra "double overdrive" gear. But in the end, it is what it is....

[Santiago]

Originally Posted by steve dunham

Sometimes it seems that the over fixation on gas mileage leads some to choose a vehicle that is not the best candidate for a tow vehicle. I am not denying that fuel economy is a consideration but it should not rank above towing capacity , payload , braking ability , tongue wt ETC ETC.

Hello Steve,

I think all posters here are concerned with towing dynamics and safety on the road. They seem to mention use of full size trucks coupled to a lighweight trailer that any full size pick up truck configuration can handle with ease and safety. I trust your comments were directed to the person thinking of using a small car or car based tow vehicle.

What more horsepower buys you is quicker acceleration and faster speeds up very high mountain passes. Some of us are willing to trade that level of towing performance for fuel efficiency ( both towing and in daily use at home ) which translates to more money to enjoy travel and less left at the gas station. It's a personal choice but braking, towing dynamics and overall safety is not compromised when trailer weight is what it is with Escape trailers.

Now if you tow same trailer with a small fuel efficent automobile, yes you now have big problem. A full size pickup truck, I don't think so.

I for one am conscious of travel fuel cost just like any other cost. Am willing to give up what is not critical to me, speeding up mountains, to having more money to spend on other fun and interesting aspects of road travel.

Ideally, I would love to tow with a Ram 2500/3500 with the optional Cummins diesel, I love diesels by the way. We compromised on the 1500 gasoline V6 8sp and its working out for us.

[Brian B-P]

Originally Posted by War Eagle

Do any of the current 8 and 10 speed automatic transmissions out there have more than one over-drive gear?

Yes, all current transmissions with 8 or more gears - and probably every 6-speed and 7-speed made as well - have more than one overdrive gear. I think the ZF 8-speed has two, the Ford 10-speed has three, and the ZF 9-speed has four. But it really doesn't matter, because "overdrive" just means that the transmission output is faster than the input. If all of the transmission gears are "taller" (numerically low, more overdrive gears), the final drive ratio just has to be higher (more reduction) to get the desired overall drive ratio.

Long ago, some cars had an extra transmission after the main transmission, which provided an overdrive ratio... and that led to people thinking of overdrive as fundamentally different, rather than just another gear ratio.

Originally Posted by War Eagle

Or are all those extra gears just starting lower and/or narrowing the gaps in under-drive to help optimize engine RPMs?

I think this is a good question... but this isn't really about overdrives; it's about range. For example if two transmissions both have a 1:1 top gear (to make the example easy) and one has a 4:1 first gear while the other has a 5:1 first gear, then the one with the 5:1 first gear covers a wider range of ratios. If they have the same number of gears, the steps between gears (engine speed change when you shift) will be bigger for the wider-range transmission.

It doesn't matter how many of the gear ratios are overdrive; just how many there are and how they're spaced.

So the answer to the question is "both": the new transmissions with more ratios usually have both a wider range than the fewer-geared predecessors (so you can have a lower first or higher top or both), and the still between gear ratios the steps are smaller. Apparently Ford's replacement of the current 6-speed (6R80) with their new 10-speed (10R80) is primarily to provide closer steps for more optimal engine speed through the road speed range, and only secondarily to extend to higher overall gearing in top gear or lower overall gearing in first gear (plus various other improvements unrelated to the number of gear ratios).

Specifically for Ford, comparing the 6R80 and 10R80 the 10-speed adds one higher top gear, and has a lower first gear (greater range), but the range covered by 6 speeds of the old transmission are covered by almost 8 speeds of the new one (closer spacing).

[Brian B-P]

Originally Posted by War Eagle

My 1999 SuperDuty F-250 with the 7.3L PowerStroke diesel engine and 6-speed manual overdrive transmission can get 20 mpg all day long doing 60 mph in 6th gear overdrive at 2,000 rpm - but I get passed by everything else on the interstate. When I go over 2K rpm to edge up to 65-70 mph, fuel mileage drops noticeably.

Yeah, that's much more engine speed than needed with that engine when not climbing... even at 60 mph. At 2000 rpm that engine is two-thirds of the way up its speed range, and can put out over 160 horsepower. It's like driving a current Ford 5.0 L gas V8 at 4000 rpm. You could just use a taller final drive, but then there's that problem of getting moving without a low enough bottom gear... although if you're not towing much (by F-250 standards) that might be fine.

[War Eagle]

Perspective (check my math on this):
Let's say you live in Miami Florida, and you're going to make the 7,000 mile round-trip to Chilliwack to pick up your new Escape trailer. You have a choice of two different tow vehicles for the round trip:
Vehicle A averages 18 mpg round trip (388.8 gallons consumed over 7,000 miles).
Vehicle B averages 16 mpg round trip (437.5 gallons consumed over 7,000 miles).
That's a difference of 48.7 gallons of fuel consumed over the 7,000 mile round trip.
Say gas averages $2.25/gallon for the trip, that's a difference of about $110 in fuel for the trip between the two vehicles. (Did I calculate that right?). So, is the $110 difference in fuel a big deal for a 7,000 mile trip? Is there anything about Vehicle B (smoother ride, more comfortable seats, etc., etc.) that makes it worth the $110 higher fuel cost for the trip? I guess that's for everyone to decide for themselves given their options (or not)....

[cpaharley2008]

That example will not work. On my trip in September to get Prairie Schooner, I averaged close to 20 mpg going to Chilliwack 3000 miles out and that average dropped to 13 towing on the return trip 6000 miles total. Thus I used 150 gallons empty and over the entire trip 450 gallons, thus I used twice the amount of gas (300 gallons) returning and towing than going out..thus I was getting 10 mpg returning. I must admit though to exceeding the 55 mph somewhat to make that 1800 miles from Chilliwack to Mississippi Rally in 3 days.

[Brian B-P]

Originally Posted by War Eagle

Perspective (check my math on this):
Let's say you live in Miami Florida, and you're going to make the 7,000 mile round-trip to Chilliwack to pick up your new Escape trailer. You have a choice of two different tow vehicles for the round trip:
Vehicle A averages 18 mpg round trip (388.8 gallons consumed over 7,000 miles).
Vehicle B averages 16 mpg round trip (437.5 gallons consumed over 7,000 miles).
That's a difference of 48.7 gallons of fuel consumed over the 7,000 mile round trip.
Say gas averages $2.25/gallon for the trip, that's a difference of about $110 in fuel for the trip between the two vehicles. (Did I calculate that right?). So, is the $110 difference in fuel a big deal for a 7,000 mile trip?...

I didn't actually check your math, but it looks reasonable.

My only concern with the validity of the example is that very few vehicles are getting as high as 16 miles/USgal while towing, let alone 18. If those really are realistic mileage values for two tow vehicle alternatives, then the math is right, the logic works, and I agree that the extra fuel is probably not a big deal for many owners if there is a meaningful benefit to go with it.

[Brian B-P]

Originally Posted by cpaharley2008

That example will not work. On my trip in September to get Prairie Schooner, I averaged close to 20 mpg going to Chilliwack 3000 miles out and that average dropped to 13 towing on the return trip 6000 miles total. Thus I used 150 gallons empty and over the entire trip 450 gallons, thus I used twice the amount of gas (300 gallons) returning and towing than going out..thus I was getting 10 mpg returning. I must admit though to exceeding the 55 mph somewhat to make that 1800 miles from Chilliwack to Mississippi Rally in 3 days.

Okay, so you need to compare (for instance)

(fuel used @ 24 mpg going out) + (fuel used at 18 mpg coming back) for tow vehicle A

to

(fuel used @ 22 mpg going out) + (fuel used at 16 mpg coming back) for tow vehicle B

So the total fuel in for both tow vehicles would be less than the example as originally posted, but the logic is the same: the incremental fuel cost (given these fuel economy values) may be reasonable.

[War Eagle]

I didn't really want to get into algebra or calculus (or whatever math would be required) with the previous example, but I think most people get the point. Just to go out on another limb, the 7,000 mile trip would probably take a good 10 days of driving (driving 12 hours/day averaging around 60 mph, and no I'm not going to factor in a higher speed driving to Chilliwack not pulling a camper and a slower speed returning while pulling a camper, let's just go with generalities, here). So spreading that potential savings of $110 in fuel cost out over the 10 days of driving is $11/day while on the road. Divide that across three meals per day for the two of us while on the road (I'm not making that long of a trip without my wife along side as chief navigator), and the difference is barely enough to up-size your coffee or supersize your fries at each meal. But then again, I do like my coffee and fries. Just saying....

[War Eagle]

Originally Posted by Brian B-P

... My only concern with the validity of the example is that very few vehicles are getting as high as 16 miles/USgal while towing, let alone 18.

Point of clarification, my example was 16 and 18 mpg averages for the ENTIRE 7,000 mile trip, not just for the return towing portion. So, for example, the 16 mpg average over the 7,000 mile trip could represent 20 mpg for the 3,500 miles going to Chilliwack without a camper and 12 mpg for the 3,500 mile return trip with a camper in tow. Again, the numbers were made up (but probably not all that far off someone's reality) to fuel (pun intended) discussion regarding the relative importance of drive train components as they relate to fuel economy and money saved (or not) for other creature comforts along the journey - like more coffee and french fries... (or more popcorn)

[Brian B-P]

Originally Posted by War Eagle

Point of clarification, my example was 16 and 18 mpg averages for the ENTIRE 7,000 mile trip, not just for the return towing portion. So, for example, the 16 mpg average over the 7,000 mile trip could represent 20 mpg for the 3,500 miles going to Chilliwack without a camper and 12 mpg for the 3,500 mile return trip with a camper in tow

That makes sense.

[Bill and Earline]

Originally Posted by War Eagle

My 1999 SuperDuty F-250 with the 7.3L PowerStroke diesel engine and 6-speed manual overdrive transmission can get 20 mpg all day long doing 60 mph in 6th gear overdrive at 2,000 rpm - but I get passed by everything else on the interstate. When I go over 2K rpm to edge up to 65-70 mph, fuel mileage drops noticeably. I'd love to have one more "double overdrive" gear so I could do 65-70 mph at 2,000 rpm and still get 20 mpg. I'm certain the 7.3's torque could handle an extra "double overdrive" gear. But in the end, it is what it is....

WarEagle,
Don't forget the good ole boys way to change the final drive ratio on your F-250------taller tires. That might get you at the rpms you want to be at 65mph. You should still have plenty of low end power, especially with the granny first gear that manual 6-speed has.
Bill

[War Eagle]

Originally Posted by Bill and Earline

WarEagle, Don't forget the good ole boys way to change the final drive ratio on your F-250------taller tires. That might get you at the rpms you want to be at 65mph. You should still have plenty of low end power, especially with the granny first gear that manual 6-speed has.Bill

Bill, Good idea, but with the heavy duty suspension, my wife already almost needs a step ladder to climb in. Speaking of the manual 6, it's a trip to put the transfer case in 4L and the 6 speed in "L". You can rev the engine to 2,000 RPM and still walk faster than the truck is traveling. I need Brian to calculate that final drive ratio (or just look in the owner's manual)...

[Brian B-P]

Originally Posted by War Eagle

... Speaking of the manual 6, it's a trip to put the transfer case in 4L and the 6 speed in "L". You can rev the engine to 2,000 RPM and still walk faster than the truck is traveling.

If we can believe the Pickup Wiki, that's a 5.79:1 (!) first gear, 2.72 transfer case low speed ratio, and 3.73:1 final drive, for 58.74: 1 overall - what the off-roaders call the "crawl ratio". With the standard LT235/85R16 tires and so 636 wheel revolutions per mile, 2000 rpm yields 3.2 mph... yep, walking speed.

Those tires are no longer used on pickups (16" wheels are gone), but the current 245/75R17 equivalent is the same height. Usefully taller tires wouldn't be an available size for any F-250, so speedo correction could be an issue.

I think this truck is better suited to towing 6-ton industrial loads than an Escape... but of course that's why the new F-150!

[War Eagle]

Originally Posted by Brian B-P

... 3.2 mph... yep, walking speed.

Thanks for going through the calculations, Brian. Still running factory 16" rims and tire size (Toyo Open Country). When I bought the truck new back in 1999, there was still an option for a hand cable throttle so you could set engine RPM by hand (old-school cruse control) - even though the truck trim came with cruse control. And you really could set the hand throttle and get out and walk along side the truck as it poked along, if that's what you wanted to do. I should have gotten it. It would be quite the conversation piece in this day and age.