What are you guys towing with your trucks and how does it handle the weight?
I have been towing with mine a bit this past weekend And I am not impressed. truck and empty deckover equipment trailer(12,500). Truck, and loaded trailer come sin at 20,000lbs Hard time keeping speed limit on highway hills(loaded or not)

 

What gears do you have ?

20k is a heavy pull if you're stock

 

Yeah, which truck. Your tall tires of your shortbed kinda hinder loaded performance.
My superduty psd work truck with exhaust and DP tuner hauls 20k easy.
Any chance for a boost leak. Do you have gauges. Low boost high egt or abnormal smoke or anything like that.
Your hpop may not be putting out enough pressure which reduces power in the upper end and when demanding the hp in towing situations.

 

I pulled about 22k with mine through Northern California through oregon. There are some long nasty grades through there. Dropped the beast into fourth @ 2800 rpms and she never dropped below 55mph. They can pull, trust me

 

the pic in my signature is 31,000 lbs. truck trailer and hay. I tow that load from delta Colorado to Chino Valley Arizona. it is all up hill, some 7-8% grades. on the long grades I get down to 30 mph, but I still have to wait at the top for my father who is towing with a dodge cummins 3.000 lbs lighter trailer and 100 less bales

 

97 CCSB, Dually, 4.10, 5speed, 35" tires(@65mph I am running 2200rpm in OD)

DP tuner on 60hp tow tune
6637 air filter
3" DP and 4" exhaust

 

Have you checked for Uppipe and boost leaks?

 

I run the DP 60 tow tune as well. My truck is a little better from the factory with a little better hpop and ecu, but its negligible. But a weak hpop or worn injectors make a huge difference.
Did you put an intercooler on your truck.
My 265s and 373 are a little lower effective gear ratio than your 410 and 35s I'm guessing. Your 5spd should make up for that (my auto sucks up a lot of power).

 

Up-pipes are clean and no boost leaks


Yes, I have an I/C and thought I had a boost leak. Swapped a factory NON-I/C spider back on halfway thru my trip and saw the same boost numbers

 

Ive been towing a race drift car and car trailer alot theses couple weeks. the biggest thing that keeps me slow is my egts. running my tow tune throws me up to 1000+ just gettin on the the on ramp. Im not hauling nearly as much as you guys but if i keep an eyes on my egts i cruse right in the hammer lane at 75

 

I know towing with 10k could be a struggle at times with just a chipped truck for me personally. The old girl really didn't come alive in the towing department till I put the new sticks in.

 

You can run 1,200 ALLL DAY LONG and not have any issues.
You can go above that but only for short bursts

 

My egts were at 1100* in 4th at about 2700-2800rpms. With my foot to the floor. Total weight of truck and trailer was about 22k. Stayed right at 55mph. 29psi boost running y 80hp tow tune.

 

your trying to move 20k with heavier taller tires bringing your 4.10's up to a 3.73 range.not ideal for that much weight when a 4.30 would be much better.
you should at least go with 4.56 ring and pinion.that will just bring her back to the 4.10 range gearing she once had with 235/85/16 (srw.)
a set of 4.88's would bring you down to a good towing/performance gear for 20k lb towing with those big tires and get her where she should be at the 4.30 range and pull real strong.a gear set to match the level of truck you built imho.it's not as if she's a dd.it's your devoted towing machine.id set her right up proper as such.
with your wide variety of trucks,you don't have to settle with compromises like the most of us do.you can set up each truck for their ideal use.

 

OBS trucks really have small injectors in them from the factory. My 97 work trucks was terribly slow until I put a chip in it, along with the supporting mods. At 250,000 miles, I put in a set of mini-swamps (150cc) injectors, and it REALLY WOKE THAT TRUCK UP! In fact, with the chip removed, it ran quite well! I don't have any hot tunes in it, nor do I have any gauges in it, but at 390,000 miles, it's still going strong! Transmissions, that's a different story,,,,,,,,,,,,,,,,, Really wish it had a manual.