Really - how does your 450 pull? - Diesel Forum

guardrail22 · 10-16-2009, 09:24 PM

The guy with the 8x8 pulls 2500# overweight with no problem.

At the Hershey RV show the Horizon RV guy is pulling 24000# thru the rockies no problem with a 550.

My F450 has to pull 18000# and on an uphill it slows often and slows painfully when pulling in regen mode.

I usually run around 62mph with the cruise set. Load is a Carriage 5th wheel.

jasonlisan · 10-16-2009, 10:00 PM

I live in Colorado & most of the towing I do is in the mountains & trust me I'm not doing 80 up the hills, I probably average 50-55mph when I'm towing the TH (Raptor w/small trailer behind, total of 17,000lbs) going up the passes. The only gripe I have is that I can't get over 20psi boost if the EGT's are too high.

chuck_s_jr · 10-16-2009, 11:48 PM

I have no problem with my 19000 lbs toy hauler going over the mountains going to south for the winter and to the east coast. that 55 to 65 with no problems.

Stalwart · 10-17-2009, 10:45 AM

Yes, my truck does pull at 35,000+ very nicely and I almost never use full throttle but I do have a '08 Job 1 w/4.88 rear gears. Running down the road with barn of a truck behind I was seeing a constant 30+ lb of boost.

I never see a regen when towing heavy, any hill is acting as a passive regen. In addition, I've had a cracked DPF since the first month, the first heavy tow killed it further so now I can see black smoke every time I mash the throttle.

guardrail22 · 10-17-2009, 06:37 PM

my insight regularly pegs at 100% engine load on interstate hills.

30+ lbs manifold pressure common. 1300+ Texh

davydee · 10-18-2009, 08:04 AM

Guardrail, could it be perception? We slow down pretty well towing the two lane climbs around Shenandoah NP, and our toughest pull was Tenton pass west of Jakson, WY. We didn't set any speed records on any of these - climbing at or below speed limit. However, we followed a Monaco from PA to West Yellowstone, MT with mostly interstate driving. We out-pulled it on most long climbs - seeing 50 to 55. Like you, we generally tow slightly above 60, and we're around 28,000 to 28,500 GCW.

guardrail22 · 10-20-2009, 10:26 PM

Could be but stop and think about it.

The F450 is rated to pull 24000# with 430 rear axle now. I pull 18000#. Theoretically that means I'm at 67% of capacity.

In my mind that means I should be able to hold speed on virtually any nominal road grade. But thats not whats happening.

True the only way to really tell is to take five rigs to the foot of Saluda grade on I26 in NC and have everyone drive each to the top and back down.

Just trying to scope everyones thoughts.

davydee · 10-21-2009, 09:49 AM

Quote:

Originally Posted by guardrail22

Could be but stop and think about it.

The F450 is rated to pull 24000# with 430 rear axle now. I pull 18000#. Theoretically that means I'm at 67% of capacity.

Interesting & good point. Now, to go completely off topic: We're don't have near the toys for the truck as you do. We cross the scales right at 10,000 lbs for the truck solo, but loaded and ready for towing. You're probably above that. Add the 18,000 lb trailer and you're at least as heavy and probably heavier than we are. I know you're measuring tow capacity, but would % of GCWR capacity be a better rating to measure? I'm about 85% GCWR. That's the heaviest % of GCWR of any tow vehicle we've ever towed with. Consequently, I wasn't expecting to set any speed records up hill.

Now back to that perception: Since I wasn't expecting any improvements and in fact anticipating we'd be slower, I sense we tow fine. However, you may drive our rig and think it stinks!

BeatMarti · 10-21-2009, 01:51 PM

Just a little food for thought:

It is hard to calculate how well the truck should climb. For example, if we take a sustained 10% grade (such as the Teton pass west of Jackson, WY) for 1 mile and we drive it at 60MPH at a combined gross vehicle weight of 20,000 pounds, we move that weight 8.8 feet per seconds vertically, resulting in 176,000 foot/pounds per second or 320 Horsepower. Piece of cake...? Well.....
Based on this, with my rig I should be able to drive that pass at 60MPH without a problem. Turns out, the best I've ever done was 45 MPH end speed (with less than 32 degree ambient temp). When it is warmer out, I don't do better than around 35MPH (end speed). That is pretty dismal considering our theoretical numbers above.
The problem is that it is very difficult to determine how much the friction and wind resistance add in terms of foot/pounds per second.
My rig is a Job 1 F-550. If I put my scanner on record and drive that same segment, I am realizing 350 to 400 HP based on torque @ RPM numbers (torque * RPM / 5252) at least as long as the EGT (EGRT) remains below 1400. So, it actually performs just fine - in fact better than advertised!

guardrail22 · 10-21-2009, 08:42 PM

mine weighs right at 10000# full of fuel with me standing off the scale to the left.

trailer is at high 17000#

CaptSkup · 10-22-2009, 01:32 PM

When my truck was about 6 months old and had maybe 4,000 miles on it, I hitched up the 43 foot, 22,000lb(empty) Teton Scottsdale fiver and headed from Maryland to Casper, Wyoming to get some warranty work done before the sale. I traveled solo, holding speed right at 60mph. Climbing I-70 in Pa I encountered 7% grades and the truck held the cruise control engaged 60mph. I stopped at a truck stop and ran the combo onto the Cat scales. Ticket showed combined weight at 32,500lbs with over 9,000lbs on the rear axle. I got about 8-9mpg average for the long trip. Truck performed flawlessly. Only issue the whole way was almost running out of fuel out on I-80, still hard then to get Ultra Low. Luckily I was carrying 10 gallons in the bed, had to refuel. Now here is something odd, this summer while on a weekend getaway out in W.Virginia, I had the overheat warning come on. This was with my 12,000lbs Sunline hitched up, driving a slow paced 55mph. Plus got regen notice, regen lasted a long time, too. Got to get it into the dealer for a checkup.
I would really like to compare the towing ability difference between a 4.88 and a 4.30 truck, both at max GCWR to see how Ford kept the rating the same for both trucks.

BeatMarti · 10-22-2009, 01:46 PM

Quote:

Originally Posted by CaptSkup

When my truck was about 6 months old and had maybe 4,000 miles on it, I hitched up the 43 foot, 22,000lb(empty) Teton Scottsdale fiver and headed from Maryland to Casper, Wyoming to get some warranty work done before the sale. I traveled solo, holding speed right at 60mph. Climbing I-70 in Pa I encountered 7% grades and the truck held the cruise control engaged 60mph. I stopped at a truck stop and ran the combo onto the Cat scales. Ticket showed combined weight at 32,500lbs with over 9,000lbs on the rear axle. I got about 8-9mpg average for the long trip. Truck performed flawlessly. Only issue the whole way was almost running out of fuel out on I-80, still hard then to get Ultra Low. Luckily I was carrying 10 gallons in the bed, had to refuel. Now here is something odd, this summer while on a weekend getaway out in W.Virginia, I had the overheat warning come on. This was with my 12,000lbs Sunline hitched up, driving a slow paced 55mph. Plus got regen notice, regen lasted a long time, too. Got to get it into the dealer for a checkup.
I would really like to compare the towing ability difference between a 4.88 and a 4.30 truck, both at max GCWR to see how Ford kept the rating the same for both trucks.

32.5K pounds over a 7% grade at 60MPH is very impressive! Not counting wind and rolling resistance (which should be a lot given the configuration and speed) your engine had to generate 364HP to do that. In reality, unless you had significant tail wind, your engine probably had to generate upwards to 450 or more HP. WOW - did you have a chip on it?

CaptSkup · 10-22-2009, 03:11 PM

Nope, no chip. Don't know about wind conditions, didn't notice the trees swaying much. Truck is stock. Rolling resistance, hmm. Did have twelve tires rolling.

lari2001 · 10-22-2009, 03:56 PM

I didn't think horsepower had very much to do with pulling power on steep hills, I always thought that was torque, i know you need some HP to help build momentum but I didn't think it was the determining factor in this case. There seems to be so many variables here, your truck might have not had as much momentum before climbing as his did, I know when I see a steep hill coming I get on it a little bit to build momentum to carry me as far as it can, and your trailer may have more drag then his, depending on how it's loaded makes a difference too, not much but it does.

**gypsybill** · 10-22-2009, 04:58 PM

I just got back to AL from Knoxville via Nashville pulling my new 5er... never got a chance to scale it, but factory #s say 14.5k empty and I had added a washer/dryer, 80lbs of propane and sundry other things that probably brought the weight to ~15 to 15.5k. The only times I felt like the truck was working hard is if I let the rpm fall below 2100 in overdrive/cruise on. Some of the longer climbs in TN had me dropping out of OD if I didn't catch it in time... overall I averaged about 8.9 mpg and ran 2100 rpm (62-63mph) for the entire trip home... EGts rarely got above 1100 unless it was in regen (about once a tank or once every 400 miles) and even then I was able to keep them below 1300 by backing off a bit on the go peddle a bit... all in all I am happy with the way it tows..