towing? its not this hard
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Junior User
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towing? its not this hard
my 97 f-150 with a 4.6 is struggling with 4X8 enclosed trailer with maybe a 400 pound load...the trailer is light duty so its not a terribly heavy load all the way around but 75 mph shouldn't be this difficult...i am running it with the overdrive off and it doesn't have a trans cooler but it really shouldn't be that hesitant should it?
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Empty weight on a normal 4x8 enclosed trailer is about 750 lbs. You stated a load of 400 lbs. So your at about 1150 lbs.
Now, the wind resistance on these trailers is tremendous at 75 mph.
Should you be able to tow this reasonably well - Sure. But you don't say how many miles are on your truck either.
Given a 4.6 with lots of miles and lower than new compression. Given a rear end ratio of 3.08 or 3.31. If your trying to pull any kind of hills, it is definetly going to know that trailer is back there at 75 mph.
Also, you might check your trailer tires and bearings. You might also want to check your cats and make sure they are flowing good. Have you noticed a decrease in fuel economy lately (when not towing)?
Now, the wind resistance on these trailers is tremendous at 75 mph.
Should you be able to tow this reasonably well - Sure. But you don't say how many miles are on your truck either.
Given a 4.6 with lots of miles and lower than new compression. Given a rear end ratio of 3.08 or 3.31. If your trying to pull any kind of hills, it is definetly going to know that trailer is back there at 75 mph.
Also, you might check your trailer tires and bearings. You might also want to check your cats and make sure they are flowing good. Have you noticed a decrease in fuel economy lately (when not towing)?
Fleet Mechanic
Joined: Sep 2003
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Yup, check the sticker. For 1997, the standard ratio was 3.08. Optional was 3.55. The towing package had 3.55. I've towed a 4 x 8 box trailer, OD off, into a headwind. Didn't do 75MPH though, maybe 65 or so. I have the 4.6L with towing package.
Back in 1998 or so, there were people complaining about their '97 4.6L that at highway speed on hills it was a bit gutless. No complaints from the 3.55 axle ratio crowd. It really makes a difference.
Back in 1998 or so, there were people complaining about their '97 4.6L that at highway speed on hills it was a bit gutless. No complaints from the 3.55 axle ratio crowd. It really makes a difference.
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Junior User
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yea i had wondered about that but i didn't think it would be anywhere near that low...that would explain a lot! i guess thats ok for people who use a truck as a car but not for me...what kind of fuel mileage do you get with that much difference in gearing?
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cause i was in a 70 mph zone and it was late and i was ready to be home...haha i know not a good reason but still...i've not noticed a decrease in fuel economy at all lately and the truck has 112k miles on it so its not brand new but not exactly worn out either?
Fleet Mechanic
Joined: Sep 2003
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I need to correct the trailer size I mentioned above. It wasn't 4 x 8, it was double axle 5 x 10 or 6 x 12, it was wider than the truck.
Non-towing MPG with 3.55 axle ratio - With my '97 (157" wheelbase, longest chassis, see my sig, tow package) I think I got something like 17 MPG, but that included some suburban driving on the 30 gallon tank, the rest was interstate. Doing 70 - 75 MPH. That was a long time ago. Have used V6 minivan, and now a new Escape for trips when no towing is needed.
Non-towing MPG with 3.55 axle ratio - With my '97 (157" wheelbase, longest chassis, see my sig, tow package) I think I got something like 17 MPG, but that included some suburban driving on the 30 gallon tank, the rest was interstate. Doing 70 - 75 MPH. That was a long time ago. Have used V6 minivan, and now a new Escape for trips when no towing is needed.
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Most 5x10 are single axle. 6x12 are tandem axle. A 6x12 tandem axle trailer weights in at 2200 to 2300 lbs empty. + your 400 lbs of stuff. The weight load again is only part of the issue. The real issue is the wind resistance. Plus if your tires were underinflated on the trailer (and a lot of them are) that will not help either.
The problem with the 4.6 is not hp but it is low on torque compared to the 5.4. Torque is what you need.
97 models:
4.6 Torque 265 @ 4000 RPM
5.4 Torque 335 @ 3000 RPM
And at 75 mph with the overdrive off you were probably under 3000 rpms so you were in the 225 ft-lbs torque range if I had to guess.
The problem with the 4.6 is not hp but it is low on torque compared to the 5.4. Torque is what you need.
97 models:
4.6 Torque 265 @ 4000 RPM
5.4 Torque 335 @ 3000 RPM
And at 75 mph with the overdrive off you were probably under 3000 rpms so you were in the 225 ft-lbs torque range if I had to guess.
Fleet Mechanic
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thabble the O/P had the 4 x 8 w/400 lbs. I had the 6 x 12 
I agree it's all about wind resistance for this issue.
FWI, my '97 4.6L listed 210 HP, 290 Ft.Lbs. torque. at rating RPM's
When I ordered my truck in early '96 and delivered in summer of that year, there was no 5.4L yet. I'm not complaining, have had zero engine problems with the 4.6L. I've missed all the spark plug and COPS excitement of the 5.4L.
I agree it's all about wind resistance for this issue.
FWI, my '97 4.6L listed 210 HP, 290 Ft.Lbs. torque. at rating RPM's
When I ordered my truck in early '96 and delivered in summer of that year, there was no 5.4L yet. I'm not complaining, have had zero engine problems with the 4.6L. I've missed all the spark plug and COPS excitement of the 5.4L.
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i realize torque is the issue but i was pushing 3000-3400 rpm so it was drastically under power...i had overdrive off so she was running in 3rd gear...and i only get 17 mpg with my 3:08 gears so i may as well go up to a 3:55 and pull a lot better...would you recommend having a trans cooler put on too...what would be the benifits?
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If you plan to tow this trailer much at all, I would definetly add a tranny cooler if there is not one already. Look behind the bumper in front of the A/C condensor. There may already be one there.
3:55 gears would definetly help but you have to ask, how much do I tow this trailer at highway speeds? If once a year, not worth the investment. If every week, get another truck. In between, it may be worth the investment.
I am really surpised you were getting 17 mpg towing that trailer at 75 mph. I would have guessed no more than 12.
3:55 gears would definetly help but you have to ask, how much do I tow this trailer at highway speeds? If once a year, not worth the investment. If every week, get another truck. In between, it may be worth the investment.
I am really surpised you were getting 17 mpg towing that trailer at 75 mph. I would have guessed no more than 12.
