Ecodiesel towing test. Suspension sag, mpg, power, and cooling

[RangerGress]

Laramie Crew Cab, 2WD, 1290 capacity per door sticker. 24' enclosed trailer, ~7200lbs. Tongue weight ~800lbs. Conventional spring suspension assisted by Airlift 1000 airbags (rear).

#ad


#ad


Rear end sag.
Height from fender to wheel, inches.
Unloaded, Rear 12 5/8, Front 10 11/16
Trailer hitched up, Rear 9 5/16, Front 11 9/16
Put 40psi in airbags, trailer still on Rear 11 1/2, Front 10 5/8
Took trailer off, 40psi, Rear 12 7/8, Front 10 3/4
Trailer back on, hitch "tilted" forward 2", weight distro bars on, Rear 11 5/8, Front 10 7/8
#ad


I'm working on moving the hitch ball 2" closer to the reciever. This shortens the lever arm the trailer has to move the truck around. This is significant both for truck F/R weighting also for sway. Moving the ball 2" closer means moving the hitch 2" deeper into the hitch receiver. This requires drilling a 5/8" hole in the solid steel hitch for the hitch receiver pin. I spent a bunch of time on this today but all I did was learn that Harbor Freight drill bits are only fine until you come up against solid steel. I got about halfway thru before my drill bit was useless so I'll have to buy some better drill bits and work on that later in the week.

Lessons learned

-800lbs drops rear end 3+ inches and raises front almost an inch. That's a lot.

-40psi airbags changed droop significantly. Rear goes up almost 2". Front down about an inch.

-With no trailer, 40psi airbags don't change ride height much.

-Moving the hitch forward (towards truck) 2" and putting on weight distro bars pretty darn tight changed ride height by only ~1/8". Therefore weight distro bars don't effectively counter rear sag. Note tho that weight distro bars shift do more weight when the rig porpoises so they still fight that pretty well.

-Towing mpg. Went for a 25mi test tow on a flat freeway at 64mph. 14.1mpg. For perspective, my 2000 F-250 diesel would have gotten 13-13.5. My old 2006 F-150 5.4l would have gotten 7mpg.

Lessons learned. I had hoped to get an honest 15-16mpg so this was disappointing. The diesel in the F-250 is regarded as one of the finest diesel engines ever put into a pickup and clearly it's a hard standard to beat. Gas engines suck towing heavy loads. It looks like I ended up with a very comfortable truck that gets great mileage when used as a DD, but isn't much of an improvement towing my trailer.

Towing heat issues. It was 85deg ambient during the above test. Both my coolant and oil got pretty darn hot. Coolant 224deg, oil 237deg. I did not expect this because 64mph on flat terrain didn't seem to stress the engine at all. It's the coolant temp that got my attention. I think I'm going to reduce the concentration of anti-freeze from 50% to 25%, and see how I might optimize air flow for the radiator. Antifreeze has lousy heat xfer specs, so you don't want to use any more of it then you need to. In Savannah, GA it only barely hits freezing a couple times/yr so 50/50 antifreeze is way overkill.

I also want to check if the radiator is adequately shrouded,and I might get a different grill. Radiator shrouds ensure that all air that hits the grill has no choice but to go thru the radiator. The blingly Laramie grill looks it might be blocking a fair amount of air.

Misc. Engine has all sorts of power. Just wish it had all sorts of cooling. Trailer brake controller works well. Since the freeway was flat, I did not engage Tow Mode.

 

[SnoKing]

"The (2000) diesel in the F-250 is regarded as one of the finest diesel engines ever put into a *FORD* pickup and clearly it's a hard standard to beat."

Sorry, I just had to! SNOKING

 

[RikDavis]

Sounds like you need evenmore tension on the weight distribution bars. You should be able to get about 1/2 the rear end drop back and also see the front height go lower

 

[Ozymandias]

Dont be afraid about your water- and oiltemperatures, this is standard for this engine, the newer the engine the hotter it works. My Renault 40Ton Truck has almost 260°F as permanent Oil Temperature, I was shocked when I see that first time but mechanic told me that this is normal working temperature.

You can also expect that the mpg will raise a little whit the engine break in time. Need some time for it.

 

[NIsaacs]

What are your rear axle gears? Flat freeway or not, I think tow/haul would be in order, the weight and wind resistance is significant. Also at 64 mph 8th gear might not be as efficient as 7th. With only 25 miles towing it would be hard to get a good fuel milage test. I think it's premature to be disappointed, 14.1 is not that bad.

Nick

 

[RangerGress]

I did not engage Tow Mode. I didn't see the use in it since on a flat surface and constant speed there'd be no reason for the truck to be hunting for the right gear. As it was, the truck chose 7th on it's own, not 8th.

My rear end is 3.55. I thought long and hard about the higher tow rating with the 3.92, but in the end I decided that 3.92 was fine for an owner in the mountains but in coastal GA, 3.55 was fine. Within reason the transmission computer will set the rpm to whatever it wants no matter what the rear end gearing.

The reviews that specifically addressed towing painted a pretty compelling picture of better towing mpg. I was expecting 25-30% better than my F-250. The next big tow is in 10days tho...7hrs roundtrip, so I'll know soon enough.

 

[Bob4x4]

I would not change your coolant ratio,remember it is also a lubricant for the water pump.Your new engine is not only MUCH smaller than your old Ford but it's first design criteria is ultra low emmissions.If your main goal is MPG drop the road speed,10 mph will make a significant improvement while pulling a box

 

[HookMeUp]

Looking at your pictures your hitch setup is wrong. You need to tilt the head back more, the bars shouldn't be against the trailer frame like that. The bars need to be under the frame rails. Just my 2 cents.

 

[AH64ID]

The engine is new, mileage will go up. It also looks like you are within a few pounds of your max tow rating as it is. I am finding the max tow rating to be 7,700 on the Crew Caw 5'7" box Laramie. Depending on your weight, stuff in the truck, hitch weight, airbags weight, etc you could be over the max tow rating/GCWR. Based on the OEM weights you have 7915 lbs to spare for driver/passengers/trailer/mods/options/cargo. The 3.92's would have given you an extra 1,000lbs.

Most engines have a minimum %age of coolant you can run to prevent corrosion. The engine in my MY05 needs 44% minimum, so you may want to check on that.

I also wouldn't worry about it, they where designed to run hot for emissions, and fuel economy. Running cooler will cause lower power, and fuel economy.

I agree with SNOKING, the 7.3 PSD was the best diesel ever put into a Ford... but that's where it stops. Your 2000 F-250 didn't have near the emissions to comply with and could potentially have been more fuel efficient. You got 2x the fuel economy of a gas engine, be jumping for joy.

I am assuming the truck is pretty new, and low on mileage. Don't forget about the initial towing Cautions.

• Do not tow a trailer at all during the first 500 miles
(805 km) the new vehicle is driven. The engine, axle
or other parts could be damaged.
• Then, during the first 500 miles (805 km) that a
trailer is towed, do not drive over 50 mph (80 km/h)
and do not make starts at full throttle. This helps
the engine and other parts of the vehicle wear in at
the heavier loads.

 

[sag2]

Couple of observations. This truck isn't your 2000 F-250, or your 2006. It is so much nicer of a truck in many ways. It is luxurious, nice looking, quiet, comfortable, and has 10 times the safety and security features of both of them combined. Had you purchased a Heavy Duty Ram, the mileage towing that trailer would not have been much over 10 mpg. So you got a 30-40% improvement over a new competitive diesel offering (regardless of brand).
And looking at your hitch set up, the ball needs to be angled back toward the trailer. There should be an adjustment bolt or shims on the back side of the head between the bar mounts (just below the ball).

 

[RikDavis]

Couple of observations. This truck isn't your 2000 F-250, or your 2006. It is so much nicer of a truck in many ways. It is luxurious, nice looking, quiet, comfortable, and has 10 times the safety and security features of both of them combined. Had you purchased a Heavy Duty Ram, the mileage towing that trailer would not have been much over 10 mpg. So you got a 30-40% improvement over a new competitive diesel offering (regardless of brand).
And looking at your hitch set up, the ball needs to be angled back toward the trailer. There should be an adjustment bolt or shims on the back side of the head between the bar mounts (just below the ball).

I hadn't looked at the pictures. The post above is correct. The head needs to be flat, to tilted slightly rearward so you can properly tension the bars. I like to have about 6 links between the bar and the bracket.

Many years ago Reese did a demo using an Olds Toranodo front wheel drive. It was possible to remove the rear wheels with the bars under tension and have the whole set up level.
You don't want to be that extreme of course but you should be able to get 1.5 to 2 inches of the rear sag back and the lift on the front should settle back so the headlights aren't looking for owls.

 

[AH64ID]

I just looked at the photos, wow that hitch head needs adjusted. The ball needs to be aft about 2", so that the bars point down when sitting static and not pointing up.

 

[crispyboy]

Looked at your other pictures and the weight distribution set-up is all wrong. The spring bars are not doing anything. Tilt the head down. The bars should have enough tension for a slight arc and you probably wouldn't have needed the air bags.

 

[RangerGress]

Lol, a lotta hate on the weight distro bars. I spent a fair amount of Sunday morning fooling with the hitch. The pic was taken at an intermediate step, as I experimented with how to get the ball as close to the truck as possible. The intent was to move the ball up 1" and also to reduce the lever arm that the trailer has to move the truck up/down and left/right. Having never tilted the hitch before, I didn't spot at the time is what has caught your eye, tilting the ball also tilts the WD bars. Ultimately I decided that I could go another hole down on the hitch, and tilt the ball back enough that it didn't mess up the WD bars. I ran out of time tho 'cause I'd promised #1 son that I'd take him to the rifle range.

Tonight I'll drop and straighten the hitch, and also complete the drilling the 5/8" hole that will allow me to put the hitch 2" deeper into the receiver. In between running the kids to and from the soccer field, that is.

 

[RikDavis]

I wouldn't be too concerned about moving the hitch head forward to reduce the lever arm. When you get some tension on the bars it will all work for you. As Crispyboy said, you should see a little arch to them.
If they are to hard to pull up use your tongue jack to raise the back of the truck and the trailer (when hooked together) and it will be much easier, then when you lower it the tension will increase.
Once you find your settings the next hook up will be easier.
Keep us posted


As an aside, I like my hitch head back far enough that I can drop the tailgate with out hitting the jack post

 

[SnoKing]

^^ Hitch head should be vertical! SNOKING

 

[RangerGress]

Understood.

I always set up my WD bars tight has heck with the trailer foot.

On the old F-250 I didn't care much about the distance between the ball and the truck's rear axles, but that truck was a lot heavier then this Ram 1500. Also, I figure that shortening the ball-axle distance isn't just about sway, but the shorter lever arm will also have an effect on truck front vs. rear axle rear weight dist. I figure anything I can do to better distribute the weight on this 1/2ton truck is worth considering.

Years ago I towed a 5000lb trailer each month with a BMW X5, a truck with a fairly short wheelbase. One of the things that made the X5 a surprisingly competent lightduty tow vehicle was the short distance between ball and rear axle.

 

[AH64ID]

I run an 18" shank on my WDH, with the proper setup on the bars it's not any difference than the 12" shank would be. Be careful bringing the trailer further foreword with the tailgate, the reason I run the extended length is so I can drop the tailgate all the time, regardless of trailer angle.

The little bit you gain from moving the ball foreword is probably causing more issues than it's helping.

 

[RangerGress]

I run an 18" shank on my WDH, with the proper setup on the bars it's not any difference than the 12" shank would be. Be careful bringing the trailer further foreword with the tailgate, the reason I run the extended length is so I can drop the tailgate all the time, regardless of trailer angle.

The little bit you gain from moving the ball foreword is probably causing more issues than it's helping.

It might not feel different but the physics says it has to be. Especially for sway.

I think with a 2" reduction in shank, I'm going to clear the tailgate by a couple mm. Not all my ideas work out tho. My "good idea" failure rate is such that one more failure won't cause emotional hardship. One can't just "not try" things just because success is a little haphazard.

 

[AH64ID]

A properly loaded trailer shouldn't sway anyhow.