Small diesel engine turning supercharger

[APU]

Supercharger guys tell me that inefficiency with roots blowers are due with the throttle demands. Roots blowers are best at fixed RPMs. If all the power requirements are meet without changing RPM then the best efficiency should be achieved. The same load can be pulled with a vehicle with a much smaller displacement, V6 instead of a V10 or V8. when the extra power is no longer nessesary the diesel engine simply won't be started.

Has anyone looked into the shaft RPM of the air conditioning compressor and alternator that works most efficiently ? I can make the pulleys for the system that will put all the components in their "sweet spot".

[drmiller100]

supercharging an engine does not make it more efficient.

but if you believe in your dream, then build it!!! Good luck!

[ecomodded]

twin turbo's all the way !
The reason they use twin turbo's is that one of the turbos is smaller so it has very little turbo lag and one is bigger and pumps larger volumes of air.

[ConnClark]

Originally Posted by mechman600

Adding boost to an engine will never increase the efficiency of the vehicle

Not if its a diesel

[mechman600]

Usually true. But adding boost to a diesel will not necessarily increase efficiency either if it isn't too rich without boost in the first place. It will not necessarily increase power either, unless you fuel it more. I've seen it a million times on the dyno - putting vice-grips on the wastegate line to increase "power" (as if boost is an indication of power) only to see power actually drop slightly.

[redpoint5]

How about an electric super charger? There would be virtually no lag, and it would only spin when the extra air was needed.

[mechman600]

An electric supercharger could control throttling as well. A positive displacement supercharger (ie roots style) not turning would provide plenty of restriction, eliminating the need for a throttle plate. It could be spun up enough at any given time/situation to control manifold vacuum/pressure. Controlling it all would be a challenge. Probably best left to the OEM engineers.

[drmiller100]

run the numbers on how much power it takes to compress the needed air to the boost you want.

Then convert the horsepower to watts. Then divide by 12 volts, and you will see you need thousands of amps to make it work.

Good luck!

[APU]

3800 cc engine, 14.27 psi, 6000 rpm, Eaton m90 supercharger 19.5 hp
convert horsepower to watts 19.5 horsepower = 14541 watts
14541watts/12 volts = 1212 amps

This is the reason I'm looking for an internal combustion solution .

[ecomodded]

Even 2 to 5 lbs boost would add pep, I bet you could make a home brew supercharger that went up to 2 to 5 lbs. My 1.9 turbo diesel uses 15 lbs steady to accelerate hard but in that case I am not running the car economically, but at 2 to 5 lbs I am.