So after selling my 7.3, I moved on to a 12 valve powered super duty. I am not new to the diesel world, but am new to the cummins world. The truck is a very strong runner no doubt, but after towing my buddies 2500 behind it, it left me wanting more. The truck is currently setup with the following:

98 12 Valve (Originally Ups Truck (175hp Tag))
66mm BW Turbo (Supposed upgraded internals)
191 Delivery Valves
4k Gov Springs
Arp Studs
60lb Valve Springs
100# Plate
21* Timing
Comptec Push Rods
Airdog 150
370 Injectors (Was told not Marine)

Now to start off, the truck is pretty dang quick unloaded. My issue I have with it is, it smokes like a pig (Which I expected) until it boosts up, and as soon as I hit overdrive, if I am not totally in the pedal, the turbo will surge. When towing, the truck does alright going through the gears, until I hit overdrive on the interstate. It was a smokey pig as soon as it shifted into OD, and seems to lack power up there very much. I understand ~9k behind it is no easy task to ask of it, but my buddies relatively stock 12v pulls better than this does. Am I asking too much of it, or is there anything I can do to set up in order to tow a little better? I have considered playing with the plate, and housing to see if I can get myself anywhere, but haven't tried yet. The truck is also setup with the factory 5r110, but runs a pcs standalone controller. I also considered throwing a laptop on it and seeing what the shift points were set at.

Thanks guys,
any help is appreciated!

Chase

 

Turbo is Non-Wastegated, which leads me to believe it could be overboosting. I believe they are rated to 49 PSI.

I have been doing some research on the 370's and that's what I have gathered. The PO assured me they were the correct pattern, but even that doesn't seem to be helping much. I am somewhat in the market for something different due to that. For some odd reason the PO didnt have any gauges in the truck. I am ordering some today, and was about to order EGT, Boost, and I guess Fuel Pressure. I was unsure as to what to order for the 3rd but from the information I have been gathering, that seems to be the one I need to order!

He is running 3.55's, and I have 3.73's, but he is 2wd, and I am 4. Both extended cab long bed's. '

What is a good rough starting point for the AFC housing? Also, what is a ballpark turbo size for a 370, and what is a less dirty comparable injector?


Thanks a million guys.

 

Welcome to the cummins world and cummins swap world. Firstly especially for towing the 66 is your main problem. Do you happen to know what turbine size is? Regardless you need something more like a 62/65/14 or so and not a heck of a lot bigger to tow. That also contributes to the smoke because the truck will need around 2200 to be efficient. Secondly as you didn't mention, I sure hope it has studs. As for gauges boost, pyro, and trans temp for the auto. I also hope it has been built somewhat or won't handle that power level too long. 370's are 5x12 and have the incorrect pattern, as you stated they may have been corrected. If you have the funds to do so I would swap the 66 for a good name brand 62 or maybe a 63mm turbo, Ed makes good custom stuff, I believe the killer b is a 63 or may be a 62, htt also makes a good product and many 62 sizes avalible. If power is a bit more important then towing a 63/68/14 may be a good middle ground or even a 64/68/14 which I believe does exist. You'd need a bit better insight than myn on the best tow turbo. As for injectors just a quality set of 5x12s from sdx which is a very popular reputable brand. And finally for tuning it's all dependant on the truck and set up, moving the plate back will help control higher rpm egts and smoke. As for the housing maybe start I'm the middle with the star wheel about middle, get into the throttle and see how it smoke and when, if it's instant the housing and pre boost screw will need some adjusting. Once you've gotten the pre boost figured out fine tune the housing a bit and then work on the star wheel which is the desired full fuel to boost availability. You may find you need a tighter spring set. Also with the 66 this will be hard to tune. One final thing if you happen to like the 66 and have money to spare and can install it without issues, a cam like the 188/220 from Hamilton or colt will really wake the truck up and make the 66 much more responsive. But that's all up to you. Hopefully some other guys will chime in and add to what I've said.

 

That was my initial thought, the turbo being too large. I do not know the turbine size, but can ask the PO what it is. I will look into the SDX injectors, as well as a slightly smaller turbo. I know for a fact the truck was built to be a dd/redlight queen, and it does a very good job of that. If possible, I would like to keep the 66, but I am not dead set on doing so by any means. Thank you for your insight!

 

And yes, it is studded.

 

So something along the lines of a killer B would suffice?

Killer "B" Turbo Kit - Dodge 1994-2002 5.9L

 

I would like more info on what tire / gear ?

I have a 87 F250 with the 7.3 IDI and 4 spd.. i hauled a Excursion 11K and it did awesome .. so a cummins should be a rocket ..

My 12v hauled 6K like it wasnt even there .. ( Till i had to stop ) ... LOL


Tire/wheel/ AFC tuning can make a huge difference .. if your getting too much fuel before boost you need to screw in the Smoke screw to tighten it up and allow more boost before fuel comes in ...

 

Cooper AT3's, in 285 flavor. 3:73 Gears..

I can vouch for the pulling with a 7.3, as my e99 pulled like a dream. I will mess with the smoke screw a bit! Thanks!

 

Sounds like you have a good combo on the gear and tire ...

I love my AT3's .. 315/75/16's .. 3.55 gears .. run the **** out of it on the freeway all day and still get 20 mpg .. LOL.

 

The killer would be a perfect compromise, with some tuning I could imagine it would tow fairly well. And just make sure you have correct spray pattern injectors. The investment in new ones might be worth it. What kind of rpm do you see at 60mph? The closer to about 1900 the better. Like I said about keeping the 66, a cam would fix it up a bit. How much I couldn't say but a 188/220 is supposed to spool 64-66 mm chargers like they are much smaller. Everything else in your sig seems like a well built truck. Minus the gauge part, sounds like plain old laziness. And could easily have caused damage if the original owner was an idiot. That would be my first fix, followed by what to do with the charger. Then get to tuning.