Max Tow/Daily driver

rhorsers · Aug 27, 2017

Finally picked up an early 99 4 door dually to make my full time tow rig. Looking for recommendations to make it a towing powerhouse and part time daily driver. Its an early 99, 6 speed with 3.73 gearing. 4X4. What injector and turbo combination does everyone recommend? Going dual disc southbend and want to max it out with best power and efficiency with minimal internal mods. Head studs is about as far as I want to go for internal mods. What is the best combo for 6 speed 3.73 gearing? Thanks for the help. Any ideas are welcome.

powerlifter405 · Sep 6, 2017

IIRC anything much more in CFM than the GTP38R valve springs are suggested.

The consensus is tuning is a huge factor. There are plenty of guys w/ big turbos and injectors in the 300cc-ish range that tow.

Best bang for the buck simplicity from what I gather is good tunes, factory single shots and GTP38R. Singles give a decent bump in hp/torque, the GTP38R is bolt on, add tuning and you're done. It's all about how much you are willing to spend and how much time you are willing to invest to get what you want. And I want to say anything smaller than the 250s should be doable on the factory HPOP.

This a ball park figure from Swamps for a reliable set up and for ease of install he suggested the GTP38R. Fwiw, KC is now offering BB setups so something for the 7.3 might be viable. I had the 38R on my 02 6spd and found it was more responsive compared to the factory journal setup.

200/200's max out @ 550rwhp
238/200's max out @ 600rwhp
250/200's max out @ 675rwhp
300/200's max out @ 725rwhp

At the end of the day how much money and how much time? Only you can answer that. Once you do, call Swamps or Warren for quotes.

Good luck

IdahoF350 · Sep 7, 2017

Fellow E99 guy, E99 being what it is, you've got your work cut out for you. E99 specific turbos and support parts like bellowed up pipes make the L99 or T4 conversion economical for us. If you can swing the conversion to L99 parts, the latest KC38R 366 looks to be where it's at for a stock appearance bolt on tow turbo, if you're in a non-emissions area, a T4 swap and S666SXE is what the latest KC unit is based off of. The stock HPOP on our trucks is lower volume so it can't maintain pressure as well. That means a pump change or careful injector choice. I've seen a lot of guys swear by 238/100s, making them a definite possibility to me, I'm personally torn between the simplicity of 160/30s and performance potential of 200/80s, with the 200/80s taking less oil than the stock ABs and a seemingly perfect match for the latest KC38R 366, this is the setup I'm looking to replace my D66 and AB codes with. You'll want to update to a later PCM from a 2000-2001 to make tuning easier.

Now, if you really want the truck to be a whole lot better, you'll do what I did and rip the E99 axles, steering, suspension, and brakes out from under the truck and swap it over to '05+ steering, suspension, axles, brakes, wheels and tires. You can find 4.10 and 4.30 geared axles that will make better use of the power and put less strain on the engine, clutch, transmission and everything else. The biggest benefits are turning radius, stopping distance, ride quality, and most importantly, component life, the newer stuff is just simply superior in almost every way, and as an added bonus, the truck sits as high as a leveled leaf spring truck from the coil swap making 33-35" tire fitment a breeze.

I had the ZF6 and a South Bend single behind my 6.0L, I miss having the manual at times, other times, I just wish we had a more modern 6-spd auto behind the 7.3L in place of the outdated 4R100.

JDelaney · Sep 7, 2017

160-30s, a T4 kit, Adrenaline HPOP. and a BW 364.5 SXE are a fantastic towing combo.

powerlifter405 · Sep 7, 2017

IdahoF350 said:
Now, if you really want the truck to be a whole lot better, you'll do what I did and rip the E99 axles, steering, suspension, and brakes out from under the truck and swap it over to '05+ steering, suspension, axles, brakes, wheels and tires. You can find 4.10 and 4.30 geared axles that will make better use of the power and put less strain on the engine, clutch, transmission and everything else. The biggest benefits are turning radius, stopping distance, ride quality, and most importantly, component life, the newer stuff is just simply superior in almost every way, and as an added bonus, the truck sits as high as a leveled leaf spring truck from the coil swap making 33-35" tire fitment a breeze.

I had the ZF6 and a South Bend single behind my 6.0L, I miss having the manual at times, other times, I just wish we had a more modern 6-spd auto behind the 7.3L in place of the outdated 4R100.

Aside from the engine question the above is a very doable and worth while conversion if you plan on keeping this truck. I got my 05 and it wasn't running, w/ the intent of swapping suspension and interior out of my 99. A FICM relay later the wife made a decision for me and here we are BUT I miss my 7.3/6spd combo and the 05 conversion would have been a worthwhile task.

rhorsers · Sep 17, 2017

Update. Found out this is a late 99 with build date 3/99. Plan on swapping the S366SXE from my 01 to this truck and going 238/100s unless someone has better advice with only doing valve springs, pushrods, and head studs. Good information for the 05 front suspension swap as I plan on keeping this truck until it just will not go at all or cant get parts. Is there any benefit to the KC38R 366 over the SXE? I will be needing something different for my 01. Maybe KC38R or 364.5 SXE.