What turbo for nhc 250

[my blood flows OD]

Im just curious what turbos guys are running on there nhc 250's?
and what donor trucks Your turbo came off.
Ihave a turbo off a 7.3 power stroke. Is this a good option? I have the skills required to make the crossover tube I just don't know enough about selecting the right size turbo.

 

[red]

Way too small of a turbo. For reference a Holset hx50 is considered a BIG turbo for the 7.3, it's too small for the nhc250. It's a 14 liter engine.

Holset HT3B is a common turbo from the other Cummins 855 engines. Hx60 can be made to work but it will spool up a bit late for the 250 in stock form.

 

[simp5782]

Way too small of a turbo. For reference a Holset hx50 is considered a BIG turbo for the 7.3, it's too small for the nhc250. It's a 14 liter engine.

Holset HT3B is a common turbo from the other Cummins 855 engines. Hx60 can be made to work but it will spool up a bit late for the 250 in stock form.

These puppies are lonely. $1200 shipped. TT setup off a 6.4 powerstroke. 42lbs of boost.

Sent from my SM-G935P using Tapatalk

 

[my blood flows OD]

So what is the best turbo to use and what trucks are they commonly found in?

 

[98G]

So what is the best turbo to use and what trucks are they commonly found in?

Why reinvent the wheel? Have a look at what is used on the factory turbo equipped 855s and go from there...

I've got an M818 that the previous owner put a turbo on. I am EXTREMELY HAPPY with the performance. I'll have a look tomorrow and see just what it is.

(Shame on me for not knowing. Let me quote Barman "if you didn't build it, you can't call it yours!" )

 

[red]

1970's-1990's heavy duty trucks. Peterbilt, KW, Freightliner, etc all had them. It's not like the light duty market where Ford/Chevy/Toyota etc all have just their engines.

Turbos that came on the 855 series Cummins engines are commonly the Holset HT3B, HT4B, HX60, and some other models from Garrett and wcuhillbilly is running a Schweizer turbo (check out his thread 'm816 jakes and turbo'). Supposedly the HX55 came on some of the lower power models but I haven't seen one. I am planning to test out the HX55 next year on my wrecker, see if it spools up low on the RPM range to help with the wide gearing gaps of the transmission.

 

[my blood flows OD]

Thanks red, tons of good info.
are the turbo clearly marked or easily identifiable as to what model they are?

 

[simp5782]

All of them have tags on them. Brand, model number, and serial # unless it is missing then that's up to you.

 

[98G]

Here you go -

 

[98G]

The thing abut putting a turbo on an NH250 is the lack of oil squirters. It seems to me that it's an invitation to a melted piston. The risk:benefit seems slanted in favor of risk.

A pyrometer is an absolute must. Knowing when to let off it is a must.

All that being said, OH-MY-GAWD it makes a difference. Even with the 16.00s on this truck it practically sprints up the hills at highway speed, and takes off from a stoplight as well as the redtruck, all while howling like a banshee... if you like a deuce with a whistler you'll really like this....

 

[my blood flows OD]

Can anyone identify that turbo?

 

[red]

Can anyone identify that turbo?

Looks like a Holset HT3B but can't read the tag to verify

 

[98G]

The tag isn't any more legible in person.

 

[74M35A2]

You can also size it the other way around. Turbos are sized by air mass flow, which is a direct correlation to hp, so, they can be sized by target hp essentially. This can be plotted on a compressor map, to put the turbo at a specific efficiency area on the map. It is not as difficult as it sounds. If you are starting out with no turbo, this may be a better way to size accordingly to what you want.

Just another option to do this. Probably still easier to simply grab a turbo off an old 300hp 855 and be done with it. Or the entire engine itself for that matter, and if doing that, go for the old 400hp one!

 

[l3oss]

Thanks for starting this thread. I to had the same questions. I read the thread thus far and went and explored a bit on google and came across this chart someone else had entered onto a diesel bombers turbo thread. Maybe it might be useful to someone here ....

Turbo---CFM----Racing HP-----Daily HP inducer
HX35----574------420----------330------ 56
TP38 767
HX40----763------560----------440------60
T66-----800-------560----------440-----66
GTP38R 897
B1------900-------630----------495
H2E-----868------700----------550
HX50----1000-----700-----------550-----63,67
HX55----1050------735----------578-----67
HT3B----1085------770----------605-----76
GT42----1302----------------------------75
T76-----1350------945----------743------76
HT60----1400------980----------770
B2,s400-1500------1050---------825-----75
GT47------------------------------------80
HX60----1550------1085---------853
TV81----1600----------------------------85
T88-----1750-------1225--------963-----88
HT4B----1800------1260---------990
Big Brother-1900----1330--------1045-----87
T91------2000------1400--------1100-----91
HC5A/HX82-2450----1715--------1348
T100------2600-----1820--------1430-----100
T105-----2900------2030--------1595------105