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KnifeEdge_2K1
07-20-2004, 04:15 PM
we all know the A/C uses power from the engine (from crank) which decreases fuel efficiency

if you have a turbo with the shaft driving the A/C then you're gonna loose less fuel efficiency right?

johnnynumfiv
07-20-2004, 05:56 PM
Not really, because the turbo will lack efficency, so the engine would need more gas to make up for the power loss.

Matra et Alpine
07-20-2004, 06:10 PM
we all know the A/C uses power from the engine (from crank) which decreases fuel efficiency

if you have a turbo with the shaft driving the A/C then you're gonna loose less fuel efficiency right?
Interesting idea but the huge inefficiency would make it a no-no.

Look out for more cars adopting electric A/C.
No power drain when not used, no complication - except a bigger alternator - and can run withou the engine :)

KnifeEdge_2K1
07-20-2004, 06:25 PM
Not really, because the turbo will lack efficency, so the engine would need more gas to make up for the power loss.

but it would be less then the A/C we have now which is connected to the crank by means of a belt which is directly taking power from the engine

if you take the energy from the exhaust gasses don't you loose less energy in theory? its like the supercharger vs turbo, but i goess controlling the amount of boost err ... strength of the a/c will be the problem i dunno it was a dumb idea :P

Max Legroom
08-01-2004, 03:44 PM
An interesting idea, but a few things to consider:

A turbo causes backpressure which reduces engine power and efficiency since the exhaust gases can't completely exit the cylinder. A belt driven AC compressor doesn't steal any power from the engine when it's not running because it has a clutch which only engages when you demand cooling, so the pulley is free-wheeling the rest of the time. A turbo presents backpressure all of the time, more when you're making it work by driving a resistance such as a compressor, but the backpressure is still there when you're not cooling.

In addition, a turbo only produces meaningful torque when it's spinning at very high rates, like 100,000 rpm. You can't drive a normal AC compressor at that speed (although you could design a special compressor which would work at those speeds), so you'd need reduction gearing, which would introduce further losses.

Also, when you're sitting at a stop light and the turbo isn't spinning, you're gonna get pretty warm...