Grades and RPM
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Grades and RPM
I have a 05 SuperCrew 2WD with the 5.4. I am towing a short (16ft) trailer that is about 6500 lbs loaded. It feels extremely stable at highway speeds, even in strong winds. Im very happy with the manners...
My problem is pulling grades. Should I treat this motor more like a V6 and keep it up in the rpm range pulling hills or slow down closer to where the peak torque is? Working the 5.4 hard at 4000 RPM at 1/3 throttle pulling long grades isnt pushing the motor that hard at all is it?
My problem is pulling grades. Should I treat this motor more like a V6 and keep it up in the rpm range pulling hills or slow down closer to where the peak torque is? Working the 5.4 hard at 4000 RPM at 1/3 throttle pulling long grades isnt pushing the motor that hard at all is it?
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Originally Posted by gregghealy
I have a 05 SuperCrew 2WD with the 5.4. I am towing a short (16ft) trailer that is about 6500 lbs loaded. It feels extremely stable at highway speeds, even in strong winds. Im very happy with the manners...
My problem is pulling grades. Should I treat this motor more like a V6 and keep it up in the rpm range pulling hills or slow down closer to where the peak torque is? Working the 5.4 hard at 4000 RPM at 1/3 throttle pulling long grades isnt pushing the motor that hard at all is it?
My problem is pulling grades. Should I treat this motor more like a V6 and keep it up in the rpm range pulling hills or slow down closer to where the peak torque is? Working the 5.4 hard at 4000 RPM at 1/3 throttle pulling long grades isnt pushing the motor that hard at all is it?
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Post Fiend
Joined: Jun 2001
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From: Running Springs CA
I like to run an engine near peak torque, but there is nothing wrong with revving it more to get extra power for a few minutes at a time to pull a grade, thats what it was designed for. I took a loaded F-350 rental truck pulling a trailer over the "grapevine" (I-5 south of Bakersfield, 4000ft climb) in second gear at 55mph. No tach, but the 460 seemed to be wound up pretty good. The engine did not overheat or otherwise complain.
Jim
Jim
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From: So Cal
I like to downshift a gear before I get bogged down. Once you bog your engine down, you will be stuck at high RPMS and going slow.
Once you get to know your engine, you will know when to shift down before the engine bogs.
Don't know your engine, but running at between 3,000 and 4,000 RPM seems to work fine with my 460. If I bog down, the engine then downshifts too far and then I get to run at more than 4,000RPM with no real power, pedal to the metal and screaming all the way.
Your gearing is probably a bit light for the weight trailer you are hauling, but chosing the right gear to downshift to can make up for that. Don't go with the giant weenie tires either, that just makes the gearing worse
Good Luck,
Jim Henderson
Once you get to know your engine, you will know when to shift down before the engine bogs.
Don't know your engine, but running at between 3,000 and 4,000 RPM seems to work fine with my 460. If I bog down, the engine then downshifts too far and then I get to run at more than 4,000RPM with no real power, pedal to the metal and screaming all the way.
Your gearing is probably a bit light for the weight trailer you are hauling, but chosing the right gear to downshift to can make up for that. Don't go with the giant weenie tires either, that just makes the gearing worse
Good Luck,
Jim Henderson
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Originally Posted by mistercmk
We would cruise at 4k in our expedition with the 5.4 when going through the mountains, and she runs like a top. Thats what they are designed to do, work.
I am really happy with the way the F150 tows 6000 lbs in this case.
Thanks,
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WHen I started towing about 30 years ago I used to tow a 4 horse trailer (between about 7500 to 8500lbs depending on horse size and I had a 72 GMC 3/4 ton with w 4.10 and a 4 spped and I never had to downshift on hills nor lost speed. Afte 9 years with it, I rplace it with a used 79 J20 with a 360 and towed with that unitl I got out of horses about 10 years ago. Never had to downshift towing with it either because that engine had great low end torque too and deep axle gears, I used to get about 11 MPG towing with it. Today truck weigh more have taller tires and taller gears and less low speed torque yet with higher tow ratings (for sales) and a group of towers is evolving to accept frequent down shift to make up for it. Not me, If I had a TV that would not tow my load up most hills in drive, I would either regear it or get one the would and have none of this constant second gear nonsense.
Last edited by The SnoMan; Nov 18, 2005 at 03:49 PM.
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From: North Dakota
I agree, I need second every now and again when towing with a GCWR of 17k with my F250 and the V10 and I think even going to 4.10s would make enough difference to keep me outa second, but if I changed gears I would just go ahead and go to 4.30s since the mileage and RPM is a very minimal difference from 4.10s. Now if I could only figure out how to justify a $1600 gear change to the better half.
Don't worry about towing grades at 3-4k rpms, the OHC engines are happy up there and its much easier on the trany than lugging it. I don't even hesitate when coming to a hill to lay into it right away and down shift to 2nd and run up the hill at 70mph at 4200 rpms. It's become sweet music to my ears and I actually enjoy seeing hills in the headview so I can show inferior trucks how to make it to the top with 17klbs working against you, lol.
Don't worry about towing grades at 3-4k rpms, the OHC engines are happy up there and its much easier on the trany than lugging it. I don't even hesitate when coming to a hill to lay into it right away and down shift to 2nd and run up the hill at 70mph at 4200 rpms. It's become sweet music to my ears and I actually enjoy seeing hills in the headview so I can show inferior trucks how to make it to the top with 17klbs working against you, lol.
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Originally Posted by SLE
I agree, I need second every now and again when towing with a GCWR of 17k with my F250 and the V10 and I think even going to 4.10s would make enough difference to keep me outa second, but if I changed gears I would just go ahead and go to 4.30s since the mileage and RPM is a very minimal difference from 4.10s. Now if I could only figure out how to justify a $1600 gear change to the better half.
Don't worry about towing grades at 3-4k rpms, the OHC engines are happy up there and its much easier on the trany than lugging it. I don't even hesitate when coming to a hill to lay into it right away and down shift to 2nd and run up the hill at 70mph at 4200 rpms. It's become sweet music to my ears and I actually enjoy seeing hills in the headview so I can show inferior trucks how to make it to the top with 17klbs working against you, lol.
Don't worry about towing grades at 3-4k rpms, the OHC engines are happy up there and its much easier on the trany than lugging it. I don't even hesitate when coming to a hill to lay into it right away and down shift to 2nd and run up the hill at 70mph at 4200 rpms. It's become sweet music to my ears and I actually enjoy seeing hills in the headview so I can show inferior trucks how to make it to the top with 17klbs working against you, lol.
Fleet Owner
Joined: Mar 2003
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From: Blue Hill Township
Originally Posted by gregghealy
This is what I figured I just wanted to make sure. What kind of load/trailer were you pulling through the mountains? There is tons of pedal left up the steepest grade I hit. My dad always told me it was better to work a motor than lug it.
I am really happy with the way the F150 tows 6000 lbs in this case.
Thanks,
I am really happy with the way the F150 tows 6000 lbs in this case.
Thanks,
Elder User
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Originally Posted by mistercmk
We tow a 3000lb pop up behind out expedition with the family and all the luggage in the back. Granted its not as heavy as your trailer, but it still does really well in the mountains.
"Mifflin Clay"
Joined: Jul 2005
Posts: 3,177
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From: Mifflin, PA
Guess I'm a little confused - every one concerned about hitting 2nd gear?
I Have an '05 F250, 5.4 with 3.73 rer, 4X4, with Torqueshift & Tow/haul mode.
Now, pulling a 7000+ Lb. TT, I usually don't use T/H unless I'm starting out on an uphill grade. Once I'm going down the highway, if I see a moderate to good size hill comming up, I hit the T/H button, the rpm's jump up about 2-300 more, and I will even accelerate slightly as I start the hill. If it's a really long and farly steep grade, the tranny will downshift ONCE, putting me in 3rd, jumping the rpm up another 1000 or so, to about 35-3800, perhaps 4 grand depending on how fast I am taking the hill. If there is still a lot of hill the speed may drop a little, or I can give it some more throttle to maintain. Don't ever recall it downshifting again, which would put me in 2nd.
What am I missing here? Am I counting wrong?
I Have an '05 F250, 5.4 with 3.73 rer, 4X4, with Torqueshift & Tow/haul mode.
Now, pulling a 7000+ Lb. TT, I usually don't use T/H unless I'm starting out on an uphill grade. Once I'm going down the highway, if I see a moderate to good size hill comming up, I hit the T/H button, the rpm's jump up about 2-300 more, and I will even accelerate slightly as I start the hill. If it's a really long and farly steep grade, the tranny will downshift ONCE, putting me in 3rd, jumping the rpm up another 1000 or so, to about 35-3800, perhaps 4 grand depending on how fast I am taking the hill. If there is still a lot of hill the speed may drop a little, or I can give it some more throttle to maintain. Don't ever recall it downshifting again, which would put me in 2nd.
What am I missing here? Am I counting wrong?
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Originally Posted by alchymist
Guess I'm a little confused - every one concerned about hitting 2nd gear?
I Have an '05 F250, 5.4 with 3.73 rer, 4X4, with Torqueshift & Tow/haul mode.
Now, pulling a 7000+ Lb. TT, I usually don't use T/H unless I'm starting out on an uphill grade. Once I'm going down the highway, if I see a moderate to good size hill comming up, I hit the T/H button, the rpm's jump up about 2-300 more, and I will even accelerate slightly as I start the hill. If it's a really long and farly steep grade, the tranny will downshift ONCE, putting me in 3rd, jumping the rpm up another 1000 or so, to about 35-3800, perhaps 4 grand depending on how fast I am taking the hill. If there is still a lot of hill the speed may drop a little, or I can give it some more throttle to maintain. Don't ever recall it downshifting again, which would put me in 2nd.
What am I missing here? Am I counting wrong?
I Have an '05 F250, 5.4 with 3.73 rer, 4X4, with Torqueshift & Tow/haul mode.
Now, pulling a 7000+ Lb. TT, I usually don't use T/H unless I'm starting out on an uphill grade. Once I'm going down the highway, if I see a moderate to good size hill comming up, I hit the T/H button, the rpm's jump up about 2-300 more, and I will even accelerate slightly as I start the hill. If it's a really long and farly steep grade, the tranny will downshift ONCE, putting me in 3rd, jumping the rpm up another 1000 or so, to about 35-3800, perhaps 4 grand depending on how fast I am taking the hill. If there is still a lot of hill the speed may drop a little, or I can give it some more throttle to maintain. Don't ever recall it downshifting again, which would put me in 2nd.
What am I missing here? Am I counting wrong?
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Last edited by The SnoMan; Nov 18, 2005 at 07:55 PM.
"Mifflin Clay"
Joined: Jul 2005
Posts: 3,177
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From: Mifflin, PA
Originally Posted by The SnoMan
You are counting wrong because to do 3500 to 3800 in 3rd with 3.73's, you would have to be going 86 to 93 MPH!!! See link below to calculate RPMs.
Click Here
Click Here
I may be slightly off on the rpms, but not much; so you're saying that the 5 speed auto downshifts from 4th to 2nd under load?
Last edited by alchymist; Nov 18, 2005 at 07:57 PM.