Ok long story short, we bought a new to us fifth wheel this spring, weighs in about 10k empty. So rough guess were between 11 and 12k loaded.(old was 10k loaded) I’ve been planning to delete my 6.7 all winter once towing season got here. Now though I’m debating dumping it to dump the payment and extra insurance we pay on it. I figure it’s about $1500 to delete so if I took this same $1500 and invested in the 7.3 what should I do to make it tow the 12000 pounds. I’ve never been happy with the way this particular 7.3 tows. I don’t know if it’s the ZF6 or something else. Truck has all new injectors along with a Garrett 38r ball bearing turbo and a 4” exhaust. Other wise stock. Obviously we wanna tune the truck and get an air intake. Anything else that will help me pull this kind of weight pleasently? May be tough going back to pulling heavy with the 7.3 after pulling with the 6.7 but I can’t bring myself to sell the old girl and hate having the extra truck kicking around.

 

I opted for the "400 HP mod" on my 7.3, and the towing was fine for my taste - I live in the mountains.

Bigger turbo, air intake, and exhaust is a great start. You installed new injectors? Not bigger injectors with tunes? Once you power up to 400 HP, that rear suspension protests, so I had to add traction bars. That really helped to smooth out the shifts with stock power as well. There's a list of mods to make you happier with the 7.3L, but I don't think you'll get there with stock injectors and a chip.

When all was said and done - I put about $20,000 worth of upgrades into my truck. Tires & rims, engine, suspension, gauges, transmission, electronics, software, cosmetics, noise abatement, etc.... It had all the features of a 6.7, almost as much power, but not the ride or the quiet. Saying that, it was quiet enough to hold a conversation in the cab without raising our voices. I did it all at my pace, paying as I went - so there was never a time where I was paying interest or upside-down on value. If I had a hard month, I just wouldn't upgrade that month and save money. You can't do that with a loan. I made an error in not putting a rider on the truck, so I have to go through some hoops to get my investment back after a rollover... but I'll be close.

 

Tugly, I’ve followed your mods and unfortunate accident. I choose the stock injectors when I replaced because my previous trucks I’ve never been unhappy with the way they pulled and didn’t figure I’d need the oversized injectors. I think some of my issues is the lack of air intake and the muffler that’s on my current exhaust is very restrictive even though it’s a 4 inch. I do have gauges already to monitor everything. I don’t need it to be a race truck when we pull I just would like it to not feel like I have to run it to the floor every time I wanna get going and work it to death. Like I said this is the first ZF6 so maybe that’s my issue but I’ve been pulling with this truck for two years so would think I have that figured out. Plus the older 7.3 ZF5’s I had I don’t remember the manual playing in to that.

 

I see you already have the turbo and exhaust. An S&B intake will provide all the clean air you need while keeping the noise down in the cab. A chip with good tunes will be a big improvement but if you want to pull like a 6.7 you'll need bigger injectors. 160/80 or 180/80 single shots will get you there. If you still have the EBPV, you can use that with a decel tune as an exhaust brake. As Tugly said, traction bars are a good idea.

 

Add another dimension in your “Time is Money Valuation “

on one hand you can spend the $1500 a month 6.7 payment on modifying your 7.3 to make it an equal to the newer truck or.

you can leave the 7.3 stockish and just slow down and figure the $1500 you are saving is going towards the additional time it takes you to tow your heavy trailer. For the few additional hours you will be adding to a road trip by slowing down to 7.3 speed you will have $1500 in your bank account to spend when you get to your destination.

 

The 38r was nice in it's time but there are much better options that add power over a wider range. The 38r (which I have) comes on real nice over 2000 RPM but any
lower it drops off. Adding some mild injectors, the 30% nozzles have shown to be better on torque because of atomization but do limit on ovrall
volume. Do some reading to make your choice. I woulndt go crazy on power as that will just cost more $$ for clutches.

As some have said, you will probably just have to slow down.. Is that 7.3 a dual rear wheel? With that pin weight I would think it was desirable.

 

Here is the thing, I have a 2000 F-250 with a ZF6 transmission and did pull a 12,000 lbs 5th through mountains. Real mountains in CO, MT, TN, etc... I have stock AD injectors with 250,000 miles on them...

You can shoot for the moon with a missile and spend tons of money, or you can shoot at a bulls-eye target at 500 yards with a high powered rifle and attain your goals. First, you need to describe to us what is happening with your ZF6 that is not playing well into your towing or driving experience. Maybe you are shifting at the wrong RPM, maybe you are letting up on the accelerator a bit too soon before pushing in on the clutch, maybe you have a hydraulic issue that is eluding you, no idea.

What I do know is there are people out there with a ZF6 truck that tow heavy loads all day long with no issues at all, I am one of those people. There are several more right here on the FTE that are always willing to lend a hand. I had to have a video sent to me to learn how to drive this thing because it was my first diesel manual transmission... You are asking for help now, so you are not ashamed or too proud to ask for help. Let's get that issue fixed first, or at the same time as the other parts of your issue.

Pirate4x4_camo is right... You will not get your 20 year old 7.3L powered truck to the same towing experience as your 6.7L is, unless you spent silly amounts of money... I have ~$14,000-$15,000 total (including purchase price) into my truck total and I could pull your 12,000 lbs load all over the country and wherever I wanted no problem. Slow down, take your time, it isn't a race...

So, after you have figured out the ZF6, then slowed down, if you are still not happy with what you have going on in your towing world, this is what I would do.

1. Get more air into the system with an intake, be it S&B, AIS, 6637, AFE, etc, and re-evaluate.
2. Get a Hydra tuner with your choice of tunes from PHP, 1023, Jelibuilt, SDK, etc, and re-evaluate.
3. Install a T4/SXE kit and sell your take off parts to recoup the money and re-evaluate.
4. Install 200/30, 180/80 or 160/80 injectors and re-evaluate.
5. Install PMF or OUO traction bars and re-evaluate.
6. Install air bags of your choice and re-evaluate.
7. Install a quality clutch like a South Bend HD or whatever you find that will suit your needs and re-evaluate.
8. Sell the 7.3 diesel and find a new truck with cooled seats that the bank will let you drive around as long as you pay them to rent their truck each month. The problem with that though is that anything made by humans can and will break. If anyone thinks that the newer trucks (gas or diesel) do not have issues, jump over to the respective forum and spent a bit of time there. Jump over to YouTube and see the countless videos about issues with NEW trucks. The difference is that our trucks we can work on and every issue has been ID'd and remedied 100's of times.

Again, I tow with tired *** 250,000 mile stock AD injectors all day long and have no power issues what so ever. I am not winning any races and do 65 MPH down the interstate instead of 80+ MPH with a trailer like some of the jackasses out there. I have been using 1023 light tow and daily driver tunes on the Hydra, but recently switched to the PHP 65 HP performance tune for ****s and giggles. The SXE will take just about anything you throw at it.

Since you do have a ZF6 manual transmission, controlling your descent speeds with it is easy enough and the EBPV is not required.

If you are not familiar with the SXE turbo, here is my adventure to finding out it was the right call for me. https://www.ford-trucks.com/forums/1...been-made.html

Also, my install video to show you that it truly is bolt on parts.



FIRST AND FOREMOST, DO NOT JUMP INTO ANY PURCHASES OR DECISIONS UNTIL YOU HAVE SET A GOAL AND A PLAN TO ACHIEVE THAT GOAL!

 

Simply getting some decent tuning and a good intake will make a very noticeable difference in power. I dont think removing the muffler on a 4" exhaust will affect performance with stock injectors, but the intake will.

The 7.3 needs to rev "high" to make good power. You'll want to stay 2500+rpms on the steep hills. These old beasts just dont make the low-end torque that the new ones do, but will run 3k rpm all day without complaining.

My 7.3 has intake and exhaust, but has stock turbo and injectors. I've been running the canned php tuning that comes with the hydra and the difference is still night and day between stock and tuned.

I'd recommend getting a php hydra and re-evaluating from there. Whether you're happy with the new found power or still want more, you wont regret it. If you dont have an egt gauge already, I highly recommend getting one, especially since you have a zf6.

 

Whether your foot's to the floor on a stocker or half throttle after mods, if you're accelerating at the same pace you working it just as hard so ignore the pedal position and let your gauges tell you when you're working it too hard.

 

First, IF you decide to delete your 6.7, KEEP everything you delete. It’s cheaper to put it back on than buy it again. The Dealership will make you pay for it one way or another. A good friend owns a GMC Dealership, he gives that advice to anyone interested in deleting their truck.

‘Now, to your 7.3L depending on what gearing you’re running that plays a role in how good yours pulls. I recently pulled a trailer with my truck, GVCW was 22,620lbs, truck weight was 8200#, trailer was 14,420 and pin weight 2,340 running 4.10’s and PHP 45 hp tow tunes never took the transmission out of OD, EGT’s were at 1100 anytime I was on the throttle and keep in mind that’s at 6800’ of elevation. I don’t think I’d want to go up any steep winding Passes with that kind of weight but it’s good to know that the truck I built handles that kind of weight... I think you’ll spend more money on the 7.3L than necessary considering you have a 6.7L that will do everything you want it too. Romantic as the 7.3L is why spend more money when you already have a truck that will tow that weight...

 

Good points.. How much can you get for the 7.3 towards paying off the 6.7?

 

ditto this.

doesnt matter what truck or engine you have, moving 12,000 pound from the bottom of the hill to the top takes the same amount of energy, Watch you trans temp gauge ( you installed a real gauge right ? ) your EGT and don’t exceed RPM redline, other then that your truck doesn’t care how hard you ring it’s neck.

 

I would delete the 6.7 regardless. It should net you a couple MPG and probably some power. Just save the stock stuff just in case. If you like towing with the 6.7 better then sell the 7.3. Certainly they are much easier to make big power with.

 

what ? Wait a second, what parts are you talking about deleting that is going to improve MPG ?

and if you don’t mind explain to me how deleting them decreases the fuel burn rate or extracts more power from the fuel that is being burnt. I am confused and appreciate the clarification

 

EGR and DPF extracts more power through cleaner burn, lower back pressure, and no DPF regen cycle dumping fuel into the exhaust.