Creating an engine's specs (Dev's Needed)

Im trying to create the a bus engine's specs. The bus engine is a Cummins ISB 6.7L Turbo I want the torque curve to look like the picture below and have the same 800 lb-ft @ 1,500 rpm, 350hp




The transmission is a NV4500 2001, I have the gearing set to the specs outlined in red in the picture below.



Although I have everything setup right, my engine only produces 640 lb-ft @ 1,500 rpm and 162hp as you can see in the picture below.



How do I get it to work?

 

you do need to artificialy inflate your figures to account for crankshaft friction.

 

Ok thanks! Is there a way to lower crank shaft friction in the jbeam file or should I just add more torque to compensate? Also am I doing everything right by copying real life gear ratios to the transmission section of the jbeam or are there other things to consider?

 

real life ratios in transmission.

Dont want to reduce friction, bump up torque values manually until it lines up

 

If I see this right you used the lb-ft numbers while the engine jbeam file is in nm if I remember correctly. Try converting the numbers to nm to see if it improves.

Edit: the app also shows nm, so it does seem like there's a rather large loss in power from the engine to the wheels. You should still convert it though.

 

Ok thanks guys! I converted to nm and it got me much closer to the 350 hp needed, I'll have to up it slightly until I can hit 350 hp like sixseixseven said. Also the bus reaches a max speed of about 60 mph and i'm reading that a school bus usually maxes out around 50-70 mph so its looking pretty accurate

Also Side note: I notice that the semi has a turbo charger for its engine, but with it removed the engine is very weak, why do trucks have weak engines and turbos? why not have a powerful engine and skip the turbo

 

Because of the fuel economy. Bigger engines use more fuel than a smaller engine with a turbo that produces the same amount of power. That's why.

 

Easy, off throttle response versus on throttle. Off throttle, aka cruising, you have alot less fuel going into the engine, less boost produced, effectively burning no fuel. Yet put your foot down to get upto highway speeds, turbo kicks in, provides power. Its fuel economy. A 2 litre engine with turbo is far more efficient than a 4 litre engine of same horsepower.

That and diesels themselves, they tend to have a very low horsepower peak and then immediately drop off to producing nearly nothing. Turbo can help aid against that (and as a result leads to the incredibly broad power band of a turbodiesel engine).

 

Good info thanks guys!