Cummins NHS-275 Supercharged Engine for American Truck Simulator
This mod adds a 1968 Supercharged Cummins NHS-275 engine to the game!
About The Engine
The NHS-275 is the supercharged version of the NH-220, and is a 12L inline 6 diesel engine.
It makes 275HP (205kw) and 745 lb-ft (1010 Nm) of torque.
It was found in OTR trucks, Marine, Generator, and Fire Pump applications.
The supercharger is a roots style blower and is gear driven at 1.8 times the engine RPM.
This supercharger was somewhat prone to failure if not maintained and driven correctly.
The 275 was nicknamed "Two-Six Bits", and was known for sometimes producing
a small conical flame from the exhaust stack while under load.
The distinctive sound comes from the nearly flat cam profile, which caused the valves to "pop" open and closed.
About The Mod
You will find four horsepower options for this engine in all vanilla trucks and many modded ones too.
The first one is based on official specs (as best as I could find),
outputs realistic power for this engine.
I highly recommend you try this version out.
1. 275HP and 745 lb-ft.
The next three versions are made-up and never really existed.
These are here for people who like the way the engine sounds
but don't want to give up the power they are used to.
2. 550 HP and 1,512 lb-ft.
3. 675 HP and 1,855 lb-ft.
4. 825 HP and 2,267 lb-ft.
Driving Habits
Just like the NH-220, you're going to want to rev the snot out of this engine.
You have a narrower torque band in this engine,
so try to keep your RPM at or above 1500 at all times.
Here are a few guidelines for cruising and shifting:
- Cruising RPM: 1800-1850
- Unloaded Upshift RPM: 1850-1900
- Loaded Upshift RPM: 2100
- Unloaded Downshift RPM: 1400-1500
- Loaded Downshift RPM: 1600-1700
For transmissions, bring as many gears as you can.
You'll need them in order to keep the engine in its power band.
I would recommend at least a 10 speed, preferrably a 13 or 18.
Supported Trucks
Vanilla:
- Kenworth T680
- Kenworth W900
- Peterbilt 389
- Peterbilt 579
Modded:
- Ford F150 Raptor 2017
- Freightliner Argosy
- Freightliner Cascadia 2018
- Freightliner Columbia
- Freightliner Classic XL
- Freightliner Coronado
- Freightliner FLB
- Freightliner FLD
- International 9800
- International 9900
- Kenworth 521
- Kenworth K200 (RTA)
- Kenworth Needle Nose
- Kenworth T610 (GTM)
- Kenworth T800 (GTM)
- Kenworth T800 2016 (ModSaver)
- Kenworth W900A
- Kenworth W900B (GTM)
- Kenworth W900L "Big Bob Edition"
- KRAZ 64431 AZOV
- Mack B61
- Mack R Series (Harven)
- Mack RS700l
- Mack Rubber Duck
- Mack Superliner
- Mack Titan
- Mack Ultraliner
- Peterbilt 281
- Peterbilt 357
- Peterbilt 359
- Peterbilt 389 (Viper2)
- Peterbilt 567 (GTM)
- Scot A2HD
- Ural Next
- Volvo VNL670 (Aradeth)
- Volvo VNR
- Western Star 4900
Changelog
2018-08-13
- Initial Release
- Automatic Transmission Tuning
Credits:
1. Many of the exterior sounds come from this video: https://www.youtube.com/watch?v=pKuvwHioZCI
Supercharged Cummins 275 "two-six bits"working with cone of fire out the stack
2. Many of the interior sounds come from this video: https://www.youtube.com/watch?v=AQoKzOyj1M0
220 Cummins backdrop manifold with straight pipe in a 1962 freightliner cabover
3. I borrowed a few sounds from Kriechbaum's N14c engine mod - specifically one of the "no fuel"
sounds which I blended with one of my own, and the Jake Brake sound, because
I haven't been able to find a good clean recording of a jake form an NHS-275.
The N14c is in the same engine family, just about 40 years later.
