More Power

Has anyone turned up the 250 Cummins or know how to, I think they would be easy to turbo charge since the 855 uses the HT3B turbo and the block and heads are basicly the same, You could maybe add an injector pump and injectors from a 444 Cummins or something simmilar, I know a button can be added to the injector pump to get more fuel but I don't know how much more, Pittsburgh power can easily get 700 horsepower from the 855 Cummins , Has any body tried any of this to get more power

You can add a turbo, but don't bump up the fuel too much.
The 250 doesn't have oil cooled pistons like it's big brothers.
35-40 hp is all I would reccomend, and only if you add a pyrometer, keep exhaust gas temps around 800- 900 degrees F.
Custom intake will have to be made, no hood clearence for cross-over pipe to intake manifold. Good news, plenty of room to route 3' tubing around front of motor next to t-stat housing.
An easy install if all exhaust components from donor engine are used.
I did mine a few years back, no issues.

How exactly did you turn up the fuel, and thanks for all info I appreciate it

On the NH250 Cummins, the fuel pump is adjusted/calibrated with shims under a spring plunger device. As I understand it this is to adjust two things, the governor and the fuel delivery rate.

Here is some info that may help you change the fuel pump button (I think its actually called an 'idle plunger' or something). What this does is increase the fuel rail pressure.
(Cummins calls this pump/injector system the 'pt' this stands for 'pressure-time' Really the external pump is just a big ,fancy pressure regulator ) More fuel pressure = more fuel.
Turning up the pump is not that hard to do but I can't recall the specifics because its been over a decade since I did this. A few hand tools are all thats required to pop the cap off the end of the pump then a socket and needle nose pliers to pull the stuff out. The 'buttons' are stamped with a number on the groove where it is narrower and the lower the number, the more fuel pressure. The numbers go up in a weird sequence if I can recall --> alternating between the increase of 2, then 3, then repeat --> like 5, 7, 10, 12, 15, etc. Depending on how far you want to go,On the big motors, 350's, and 400's guys used to take whatever they had and drop the number by 10 or 15 and it was pretty safe, I'd just drop one size on a 250.
If the exhaust temp stays low on a hard pull, then maybe I' drop another size.

Just be sure to have a pyro , be sure to warm it up properly because that extra fuel will score a liner much quicker when not warmed. Do not lug the engine - drop a gear soon as there is enough rpm room to do so.


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thanks for the replies, good info.