NHC-250 turbo

Has anyone here ever tryed to install a turbo on a 800 series 250 Cummins?Just curious,thinking of this on my 816.

It would work. Don't go over 7psi with it unless you have a pyro and some software to help out with the math.

i was told by a cummins wench turner that you have to change the cam,timing, fuel pump settings and a a few more things to turn a 250 into a 290(250 with a turbo) and be VERY carefull about ovet tacking, so with the info i gave up the turboing idea of my 250, instead it will get a 10 od trans

i was told by a cummins wench turner that you have to change the cam,timing, fuel pump settings and a a few more things to turn a 250 into a 290(250 with a turbo) and be VERY carefull about over tacking, so with the info i gave up the turboing idea of my 250, instead it will get a 10 od trans

As a general rule, N/A Diesels don't turbo well in terms of cost return other than emissions work. Similar engines with really efficient turbochargers are designed that way from the initial day.

Sure, you can tag a puffer on anything and run it. Rodders do it all the time, but they are not really concerned with longevity.

Properly implemented turbos will greatly increase HP, torque, and mileage. But is comes with a price, and that is engineering design.

i.e. take the Benz 3 liter Diesel. The turbo manifold will fit the N/A motor, and man will it go. For about a week.

Stick a 5-ton turbo (multifuel) and injectors on a duece. Man will it go. For about a week.

Swapping the engine is usually a better route for most than trying to refit something that will ultimately cause you grief.

If done anyway, invest in a good pyrometer to monitor EGT and a boost gage to monitor manifold pressure. Realize where your maximum operating points are before you exceed them.

Unlike current Diesels overseen by microprocessors controlling everything from cam timing to firing injectors and monitoring parameters safely, your motor is still a mechanically controlled device with a limited set of variables.

You will no longer have that cushion of "ignorant" reliability your truck comes with. You have turned it into something fragile in the hands of an inattentive operator.

Always remember you can't polish a turd, and your M35 will never be on par with a new Kenworth road tractor for highway speed.

A stock truck will have enough power to break things easily in any situation of abuse.



dg

Well stated Sir!

DG, read your post twice and agreed with it both times.

G744 said:

Stick a 5-ton turbo (multifuel) and injectors on a duece. Man will it go. For about a week.




dg

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Would that be a Non turbo duece?

I know a guy who has a Cummins with a turbo from a road tractor for sale. It was recently rebuilt and runs great. I think he wants $1500 for it. I could get it to NC for $200 for you.

Crazy M, the turbo is only in operation when needed. If you are sitting at idle and just rev up the engine to 2,000 rpm or more, there is no real power involved to do this and there wil be no boost, very little fuel is used and there is plenty of air, so no turbo "needed".

The turbo boost comes in when the engine is loaded down and more fuel is delivered by the governor in response to your accelerator pedal position.

If you install a turbo with a lot of capability, you also have to "turn up" the fuel delivery on the governor (injection pump) if you want to make that power available. If you don't turn up the fuel, the fancy turbo will not deliver anyway.

This is where the pyrometer comes in, you have to watch that EGT and not exceed that critical 1,200 deg F in the exhaust manifold.

The 5-ton multis were set up with different pistons, injectors and also with more fuel available to let them deliver 200 HP or so when needed.

Fuel delivery settings:

LDT-465-1C 64lb/hr
LDS-465-1 80lb/hr
LDS-465-2 90lb/hr

What DG is saying is that if you turn up the fuel and let the engine run under full load with a big fancy turbo, pressures and temperatures will blow the engine apart in short order if the engine itself isn't built for it.

I'm sure there are other ways to explain it, but this is how I understand it.

as i stated before , to make a 250 into a 290 takes a lot more then juse adding a turbo

Hmmmm I didnt know there was a difference between the 5 ton and the duece motors

Pistons. Piston cooling nozzles. Radiator capacity. Timing. Turbo. Injectors. Fuel pump. Air cleaner capacity. All are different between G742 and G744 engines.

A number of dueces inherit 5-ton multifuel engines, with marginally better performance. The main problems are overheating under load, and airflow problems thru the air cleaner.

Sorry guy, there is just no easy way to make a duece more powerful without damaging things in the long run. Sure, technically it can be done, but it will just about double the price of the truck.

dg

I know a guy who has a Cummins with a turbo from a road tractor for sale.

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The problem is the 855 CI block (which this most assuredly is) won't fit under the hood of either the M39 or 800-series trucks...too tall. I've seen it done, looks really odd with a channel cut into the hood. The same problem exists when putting a Jake brake on the Cummins 250.

dg

73m819 you do not have to change anything besides fuel and injectors. I run a compound turbo setup on my m818 and make 35 psi.

And you don't need to cut the hood just reposition a couple things.

This is a 12 year old thread.

98G said:

This is a 12 year old thread.

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Classic! Love dead thread revivals. It shows site stamina, how well the search function works, I guess. ........and you guys thought it was taking me a long time to do my engine/trans swap.

caleb0613 said:

73m819 you do not have to change anything besides fuel and injectors. I run a compound turbo setup on my m818 and make 35 psi.

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Welcome caled0613, and don’t mind those guys, I think they may have missed lunch today...Post up some pictures of your truck and turbos, would love to see it!

We've all been bit by the ancient thread. I know I've done it. The site suggests related threads, and doesn't look at the date. You see something interesting, reply, and GOTCHA!

LMAO!