Small Diesel Engines - Natural Aspiration vs Turbo Charged?

[greggyy]

Yep, supercharger.

 

[buickanddeere]

It is easier to make a small engine with the turbo pass the Tier IV emissions .

 

[Fallon]

All turbochargers are superchargers, but no all superchargers are turbochargers. ;-)

 

[Shady oak]

Big trucks use a turbo to have increased torque at low RPM. Up hills at 900-1000 RPM. Cruise at 1300-1400. The first one I drove was a Mack 300 with a 5 speed. When you hit a hill and it started to whistle that's when it really got down and pulled! No need for a 13-18 speed and 2100 RPM.

 

[Industrial Toys]

I thought super chargers were crankshaft driven and had an electric clutch. Not that I ever looked into it.

Not a fan of lifted monster trucks, rolling coal, but some kid was cruising through a gas station parking lot with such a truck and the turbo whine was quite impressive. Like a jet taxi-ing (don't have a clue how to spell that)

 

[welyell]

I thought super chargers were crankshaft driven and had an electric clutch. Not that I ever looked into it.

Not a fan of lifted monster trucks, rolling coal, but some kid was cruising through a gas station parking lot with such a truck and the turbo whine was quite impressive. Like a jet taxi-ing (don't have a clue how to spell that)

Back in my young and dumb days, I put a B&M low profile blower and manifold (supercharger) on a Chevy 350 I built from the block up, had it in my '67 Impala convertible. The engine was running 8:1 compression and with the blower on it, it was a powerhouse - BUT - as I said, young and dumb, this was my only car and even with a dual core radiator, I had to stop on long drives to cool off on overheated engine Often wished I had just left the stock 327 I rebuilt in it when I was 16.

I have never seen a supercharger with an engagement clutch, but then again I quit working on engines many years ago when plastic and computers started showing up under the hood. All of the superchargers in my gearhead days (mid '70s to early '80s) were direct belt drive off the front of the crankshaft.

 

[cba]

All turbochargers are superchargers, but no all superchargers are turbochargers. ;-)

A good description can be found at wikipedia, search for supercharger.

Turbochargers are by far the most fuel efficient superchargers, because they use the otherwise lost waste heat from the exhaust.

All other superchargers consume up to 1/3 of the engine power to drive themselves. They still increase engine power output, but at the expense of fuel efficiency.

Examples:

engine with no supercharger produces 100HP, consumes 20kg fuel per hour, and delivers 100HP at the shaft

same engine with turbo produces 150HP, consumes 20kg fuel per hour, and delivers 150HP at the shaft (or produces 100HP, consumes 12kg/h, and delivers 100HP)

same engine with roots supercharger produces 300HP, consumes 60kg fuel per hour, and delivers 200HP at the shaft (100HP are consumed to drive the supercharger). Note that as this engine has to produce 3 times more power, it will not last very long. It will self destruct if not designed for the extra power and heat.

 

[Industrial Toys]

Are you not adding back pressure to the exhaust? Which would take HP?

I guess I have wasted enough money in my life but never on performance. Buying Accel (sp?) fancy plug wires for my 77 Plymouth Fury Ex Police car was the only thing!

 

[joefromga]

Too fuel dragsters use around 600 hp just to turn the supercharger.

 

[Fallon]

Diesel vs. Gas behave rather differently on the fuel efficiency (regardless of forced induction, which makes things worse). Diesel sprays just enough fuel into the combustion chamber to keep the engine spinning at the RPM set by the governor. A gas engine needs to keep up a fixed (stoichiometric)*fuel/air ratio.

So a diesel can run really lean when loafing at a fixed RPM then dump in as lot more fuel for more power at the same RPM. A gas machine on the other hand is a relatively fixed amount of power & fuel consumption at a given RPM.