Cummins NTC-350

Quick pulling question for you guys with big rigs and standard gearboxes. I want to try my cab over out on some pulls next year. I'm not super hotrodded either but What do you guys run for rears? What gears do you hit going down the track? How many shifts?
 
Ha ha how many shifts!!! The answer to that would be ZERO! Unless you have an 18 speed then i don't know if I'd even do that, be hard on the driveline.

Well the first time I pulled my truck it was a completely stock 855, 350 hp. I pulled in 3rd gear, differentials locked. My truck has 38,000 rears with 4.11 gear ratio and 22R10.00 rubber pretty worn down at 60 psi of air. I couldn't tell you at which rpm I leave the line at as my tach doesn't work, I go by sound, but 2,000 is where I'd like to be. I get the Rs up let the clutch out, try to slip as little as possible then drive with the throttle by feel.

Now that I have a little more power I pull in 4th gear at 40 psi in the tires. If I leave with the right amount of RPMs I have to be careful off the line to not make it hop, but it will spin out at the other end.
 
Ok fair enough. I though I heard shifts in your runs that you just posted up. I didn't think there supposed to be lol.

I'm set up with 11r22.5s, 40,000 rears 4.33s. 13spd. 430hp C12. But I'd think about juicing it up the electronics and putting my Billet GT47 on it. Not sure what it would make then but it'd be more I'm sure.

What gear would you suggest on that? Still 4th?
 
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It might sound like shifts because I had to pedal it twice to keep it from hopping not that track before it would hook up.

Umm... An electronics motor is a bit different than my my handicap motor. If you have a power box and a charger your prolly making a fair amount if power. What do you have for a trans? I'm guessing you can get 5th out if it. You'll know if it can't hold 5th by 100 foot.
 
I'd say try 4th the first time or two, if you think it can hold 5th after that go for it. Then it's just playing with tire pressure until you find that fine line between to much or to little traction. And that will also change between tracks.
 
So something I was thinking about today. I called the shop that rebuilt my pump to get another button. He sent me a 0 button, so we're gonna see how it goes today. But anyways I got to asking him what else I could do for fuel modifications, and we got talking about a bigger gear drive pump. I asked the question, " Does a bigger gear drive make more pressure or simply flow more fuel than my pump currently?" His reply was, "It will increase your pressure but will ultimately providing a bigger quantity of fuel."

So this got me thinking, when changing button sizes, are we effectively adding a bigger quantity of fuel with gained pressure as a result? Or is this pump putting out the same volume of fuel, no matter which button you use, the button just controls the pressure?

Also, there is a guy that runs a KTA in our club that obviously is pretty much unbeatable, especially now that he has learned how to drive his truck. But just before every pull he jumps out of the cab, crawls up inside the wheel well on the left side and does something. My only thought is that he has a pressure regulator on his return line that he is adjusting. This has got to obviously help these PT fuel systems does it not? Worth looking into?
 
PT = pressure time. A certain amount of fuel pressure injected for a certain amount of time = x amount of power.

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You need to have some injectors built first, being as you havent even gotten the ball out of the throttle shaft yet you are not at the max capability of the pump, and trust me when I say that there is a point that too much pressure will hurt performance with your stock injectors, I saw this in my T600.
 
Well maybe I have got to much pressure going to the rail. I have taken the ball out of the throttle shaft am I am 7 turns out from where it was after being rebuilt. As far as injector work the shop that I had rebuild my pump said that the only thing I had left to do to my injectors it to take the orifice screw out of them behind the screens.
 
There is plenty that can be done besides just removing that screw, call diesel controls.
 
I'll have to give diesel controls a call. We have plenty of time to get a game plan under way.
 
I called diesel controls today. Talked to Jim if I remember correctly. He said my injectors are currently only putting out 204-206 cc's. for $75/ injector he can get them to flow a little over 300 cc's. He thought that added fuel plus a big HT60 would be a decent set up.

He also said that he has never seen a 0 button from Cummins. They are all homemade, and if not machined perfectly flat there will be some leak by causing a loss of rail pressure. The 0 button that I put in Saturday looked machined and like it was from Cummins but i don't know for sure.
 
IF you go that route you will need a bigger gear pump to keep up with them, I would let them set your pumnp up as well to match the injectors, they can also set it up too 2700rpm under power as well, thats about the limit on the stock springs before they will start to float.

You might start looking into a valve spring upgrade, I would say the dual springs off of a 903 would be the way to go, but if you use those the injector hold down wont fit inbetween them. You could possibly try and find the springs and retainers off of a late model big cam 4, they are a single spring but will take more than the old single spring then you could turn some more rpm to it.
 
Picking up an HT60 I bought from a member here on CompD. I think I am going to take the orifice screw out of my injectors myself and send my pump off to have the big gear drive put on it.

Does any one know if an N14 exhaust manifold will fit on to an NTC. I believe the early mechanical N14's still had individual heads. Not so sure about the later electronic motors though. Anyone know about this?
 
N14's have 3 individual heads. So 2 holes per head.

Honestly the N14 manifolds are the fugliest thing I have ever seen, check with PDI on a manifold if I were you!
 
Has to be an early N14 to have a manifold that matches the bolt pattern, the later ones have bolts that are at the top and bottom instead of on the sides. I don't think there is much difference between the early N14 and later big cam manifolds.
 
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