Souped up or bigger to begin with?

[pengyou]

I have done a lot of reading about bus/diesel engines. I have noticed that a 6bt can be "modified" to produce almost hp/torque as some of the larger engines. Yes, they all cost lost of $$ and mods as well. What is the difference between a 6bt with mods to let it put out 400 hp and 700 ft lb vs. another engine that can do it without any mods?

The bottom line for me - I have never met a diesel mechanic that could not properly fix a a 6bt. The parts are readily available....etc.

[Rusty]

Trade-offs.

Vehicles are compromises. You can get 1000 Bhp out of a 6BT for a few hours, but you need to be willing to rebuild from the stress of higher RPM and bigger boom in the combustion chamber.

Force air and fuel in to a diesel and you get more power as they don't depend on the stoichiometric balance gasoline does. Bigger turbo and injectors, larger exhaust and ooomph. Higher temperatures to follow, shorter life.

[EastCoastCB]

The modded 6bt won't last as long as its big brother, and when it comes time to rebuild it, its gotta come out of the bus to do so.

[Brad_SwiftFur]

One thing you have to keep in mind is not only engine longevity, but also heat dissipation. The original 5.9 cooling system is only designed to dissipate so much heat. Start cranking that up to 400+ hp and ascending a steep hill, things are going to heat up quickly. This isn't the drag races or tractor pulls, where you have a short run time and cool downs in between. You need a cooling system capable of cooling a much higher load. At what point does it become a better choice to buy a bus with a larger engine and properly engineered cooling system in the first place?

[Njsurf73]

As stated above... Higher hp in a smaller engine is going to wear out faster and possibly fail spectacularly. Just YouTube Cummins drag truck or pull truck... 1000+ hp and they blow all the time.

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[pengyou]

So if I want a 38-40 foot bus that will cruise at 65 mph, I should not choose one that has a 6bt? possibly towing a suzuki sidekick? and how much difference does an engine with a computer?

[Njsurf73]

My 24v 5.9 cruises at 65 all day long. It's a 35ft all American RE. It has to do with the trans/final gearing as much as the engine.

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[pengyou]

What kind of mpg does it get on flat land @ 65 mph?

[Njsurf73]

I did 800 miles on about 80 gallon of diesel. That was cruising anywhere from 50-70 and probably a nice easy 60 most.of the way (took it easy on the first trip)

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[Versatile]

Originally Posted by Brad_SwiftFur

One thing you have to keep in mind is not only engine longevity, but also heat dissipation. The original 5.9 cooling system is only designed to dissipate so much heat. Start cranking that up to 400+ hp and ascending a steep hill, things are going to heat up quickly. This isn't the drag races or tractor pulls, where you have a short run time and cool downs in between. You need a cooling system capable of cooling a much higher load. At what point does it become a better choice to buy a bus with a larger engine and properly engineered cooling system in the first place?

You can do quite few free mods to a 5.9 that won't hurt it a it. Give me a 12 valve with mechanical injection vs electronic any day.