Towing Limits of 7.3 Powerstroke

[adamis]

As my wife and I look at making the transition from a Truck Camper to a 5th wheel, the question about the suitability of our truck for the job comes into question. Someday a new truck with all the bells and whistles (and the quietness) might be on the table but not immediately.

My current truck is an early 1999 F350 Dually Quad Cab Long Bed 2WD. I've pulled my fully loaded 5k lb Truck Camper plus ~3k lb cargo trailer without any issues. I bought the truck off a guy who used it to haul his drag race car around in a 32ft goose neck trailer. I think he liked to work on the truck almost as much as the race car. Lots of "extras" all over the place. On a recent 3000 mile road trip I had a fuel injector go bad so I took the opportunity to dump about $8k into the engine, to include bigger injectors, bigger turbo, new up pipes, new HPOP and Hydra Tuner. The tranny has the 6.0 oil cooler mod and a Banks Torque Converter and Shift computer installed. Stock the truck made ~20lbs of boost, I'm now pushing 30lbs+ and haven't really tested the limits yet (nor do I plan to). My mechanic (who used to drag race 7.3s) guesstimated the HP to be in the realm of ~400 to 450hp. I am not going to dyno it but seat of the pants dyno I don't doubt it is far off from his guestimate.

Getting back to the towing part... I know the towing limit of my truck is right around the 13k lb range. I'm looking in trailers that are in the 12k to 13k range (and expect about another 1k lb in weight once packed. Pin weight for trailers in this range looks to be in the 2500lb range which is half of what my camper weighs when loaded so I think I'm not concerned about that.

My question really isn't about whether I will have the power to tow it (or the legality of it) but rather the handling / braking aspect. I already have a brake controller but might update it to something more modern. I'm thinking about specing the trailer with disc brakes to give more stopping power.

Does anyone else have experience towing heavy trailers with the 7.3 and if so, do you have an recommendations on what to do or not to do as far as mods and upgrades?

[cummins2014]

4x4ord wrote:
Your upgrades .... exhaust brake, turbo, additional power and transmission, plus the fact that you've got a dually should allow you to very easily handle a 13k 5ver. I would consider a 13k 5ver a light trailer. If you have a gear that will put your engine at an rpm where it makes 400 HP @ 55 mph you will be able to maintain that 55 mph up a 7% grade towing 13k lbs.

I agree ,but if you have dealt much towing fairly heavy with a 7.3 the ETG's are the limiting factor. I dealt with it nearly the whole time I owned that truck ,nearly 16 years . A stock 7.3 just doesn't have it for a heavier fifth wheel , unless you do some mods. I did a few ,and it did help, but the ETG's were the limiting factor, as said it had it there ,but the ETG's would climb up over 1200 degrees ,and I had to get out of the throttle.

Back when the 7.3 was very popular ,and new, ETG's were always a subject on the forums . Water injection, bigger intercoolers etc to deal with it.

[Cummins12V98]

If the op's truck stops just fine now with a TC and small trailer it will do better with a 5er.

[cummins2014]

Cummins12V98 wrote:
Truck stops the Truck, Trailer stops the Trailer.

I can agree if you got disc brakes , drum brakes help ,but the truck IMO does some of the work .

[Wadcutter]

I had a 99.5 F-350 SRW, crew cab, 4X4, 8 ft bed with the 7.3. I didn't have near the upgrades you've done. I ran a small programmer which gave me a little boost in HP and torque. I did the programmer mainly to get better shifting as it tweaked the shift points. I did not have an exhaust brake.
The last 5er I pulled was a 40 ft which loaded maxed at 14,500. Never had a problem pulling. Made numerous trips thru the Rockies. Pulled some pretty good hills and never had a problem. Even with SRW it was very stable in any wind direction. Without the exhaust brake I had watch downhill runs but that would have been the case with any truck. I never had the 6.0 cooler. All stock except for the low grade programmer.
The 7.3 was a good engine. A local truck mechanic friend kept trying to get me to really hot rod it saying it was near bullet proof and could really be turned up. It did all I needed without hot rodding it.

[4x4ord]

Your upgrades .... exhaust brake, turbo, additional power and transmission, plus the fact that you've got a dually should allow you to very easily handle a 13k 5ver. I would consider a 13k 5ver a light trailer. If you have a gear that will put your engine at an rpm where it makes 400 HP @ 55 mph you will be able to maintain that 55 mph up a 7% grade towing 13k lbs.

[Cummins12V98]

Truck stops the Truck, Trailer stops the Trailer.

[adamis]

Thanks, that is exactly the type of info I was looking for. Yes, I do have the Banks Exhaust brake already and use it all the time with the current setup. It has been a fantastic tool in the toolbox for handling the mountains.

EGTs since the Turbo Upgrade have been very good. Truck hardly breaks a sweat pulling the 9000lbs of Camper and Trailer now. I do believe the 5th wheel will test it more but like you, before the upgrades I've done the 35mph in second gear without much issue. Maybe I will be able to maintain 45 or 55mph with what I have now which would be just fine.

If the disc brakes are that much of a difference, I will make that a priority. Stopping that much inertia is really my largest concern for sure.

[cummins2014]

adamis wrote:
As my wife and I look at making the transition from a Truck Camper to a 5th wheel, the question about the suitability of our truck for the job comes into question. Someday a new truck with all the bells and whistles (and the quietness) might be on the table but not immediately.

My current truck is an early 1999 F350 Dually Quad Cab Long Bed 2WD. I've pulled my fully loaded 5k lb Truck Camper plus ~3k lb cargo trailer without any issues. I bought the truck off a guy who used it to haul his drag race car around in a 32ft goose neck trailer. I think he liked to work on the truck almost as much as the race car. Lots of "extras" all over the place. On a recent 3000 mile road trip I had a fuel injector go bad so I took the opportunity to dump about $8k into the engine, to include bigger injectors, bigger turbo, new up pipes, new HPOP and Hydra Tuner. The tranny has the 6.0 oil cooler mod and a Banks Torque Converter and Shift computer installed. Stock the truck made ~20lbs of boost, I'm now pushing 30lbs+ and haven't really tested the limits yet (nor do I plan to). My mechanic (who used to drag race 7.3s) guesstimated the HP to be in the realm of ~400 to 450hp. I am not going to dyno it but seat of the pants dyno I don't doubt it is far off from his guestimate.

Getting back to the towing part... I know the towing limit of my truck is right around the 13k lb range. I'm looking in trailers that are in the 12k to 13k range (and expect about another 1k lb in weight once packed. Pin weight for trailers in this range looks to be in the 2500lb range which is half of what my camper weighs when loaded so I think I'm not concerned about that.

My question really isn't about whether I will have the power to tow it (or the legality of it) but rather the handling / braking aspect. I already have a brake controller but might update it to something more modern. I'm thinking about specing the trailer with disc brakes to give more stopping power.

Does anyone else have experience towing heavy trailers with the 7.3 and if so, do you have an recommendations on what to do or not to do as far as mods and upgrades?

Towed a 15,500 GVWR fifth wheel for about 6 years, probably just over 13K loaded, with no where near the upgrades you have with the early 99 7.3 350 SRW, I bought it new., it did a fair job , not enough power in the mountains. does not sound like you will have that problem if you can keep the ETG's down .

The big issue for me besides the lack of power on steep grades ,was no exhaust brake. That would be something to invest in if you haven't already ,and tow much in the mountains . Disc brakes on a fifth wheel is night ,and day different then the drum brakes . My present fifth wheel has disc brakes , and along with a great exhaust brake these newer Ram cummins have ,no concerns in the mountains power wise ,and being able to stop easily .

I did a few things to my 7.3 ,4" turbo back, 6.0 tranny cooler ,along with the 6.0 intercooler . AIS intake , DP tuner . No upgrade on injectors ,or turbo. My biggest problem was the ETG's. If I would of went to a bigger intercooler to keep the ETG's 1200 or below it had more to give, but I just lived with that 30-35 mph on steep grades in second gear, and just watched my pyrometer . But having it for nearly 16 years it was time for a new one .

Being you have a dually ,I can't see where there will be any handling problem , my 350 SRW did fine in that regard. I think you are set for what you want to do.