HP output with Airco on & off

[MvM]

When I want to drive getting the maximum performance of my car (engine) I always shut off the airco. I remember reading somewhere the airco will draw away about 10-15 HP.
Now someone else told me shutting it off will not make any difference because the power-connection (??) from the engine to the airco will still remain.
Can anyone shed some light on this. The NSX cabin/cockpit tends to heat up pretty quickly even on a moderate day so I usually keep it on all the time.

 

[DutchBlackNsx]

The A/C compressor is a mechanical device connected to the cranckshaft by a belt. The connection between the belt and the compressor is accomplished by a electrically controlled clutch, which is controlled by the A/C unit from the dash.

If you ever have turned the axle of an A/C compressor with your hands, you will know that turning the A/C off will give you better performance.
The NSX A/C compressor is actually a 10 piston compressor, so you'll understand that it will take some power to operate it.

Try driving on a steady RPM, and switch the A/C on and off. You will feel the difference.

Very 'smart' A/C systems will 'know' when you are accelerating, and thus not engaging the clutch. The NSX climate control is pretty good, but not that good.


Dutchy

 

[Chuck]

Originally posted by DutchBlackNsx:
The A/C compressor is a mechanical device connected to the cranckshaft by a belt. The connection between the belt and the compressor is accomplished by a electrically controlled clutch, which is controlled by the A/C unit from the dash.

If you ever have turned the axle of an A/C compressor with your hands, you will know that turning the A/C off will give you better performance.
The NSX A/C compressor is actually a 10 piston compressor, so you'll understand that it will take some power to operate it.

Try driving on a steady RPM, and switch the A/C on and off. You will feel the difference.

Very 'smart' A/C systems will 'know' when you are accelerating, and thus not engaging the clutch. The NSX climate control is pretty good, but not that good.


Dutchy

Dutchy is correct but it doesn't take much intellegence to turn the AC off during acceleration. All you need is a vacuum switch connected to the compressor clutch that opens under loss of vacuum.(acceleration

 

[MvM]

Thanks guys.
Seems that after all I was right about getting more HP to the wheels with the airco shut off.

 

[Soichiro]

Duchy posted:
>>The NSX climate control is pretty good, but not that good.

Actually it's better! The NSX was the first car made where the AC control was integrated into the PCM. The ECU additionally richens the mixture when the compressor is engaged and the car is accelerating to compensate for the lost power of the compressor.

 

[ilya]

I never use my AC and just pulled the belt off. Anyone know if that would yield any benefits? It's always easy to stick the belt back on. I didn't want to remove the compressor and devalue the car so I figured just pulling the belt would add some HP.
Was it a waste?

 

[POWERED by HONDA]

Originally posted by ilya:
I never use my AC and just pulled the belt off. Anyone know if that would yield any benefits? It's always easy to stick the belt back on. I didn't want to remove the compressor and devalue the car so I figured just pulling the belt would add some HP.
Was it a waste?

Isn't it bad to NOT use the AC? I thought in the manual it states to use the AC at least once a week for 10 minutes or more so it can run and lubricate some seals, etc. etc.

 

[gheba_nsx]

I already imagine Ilya running to his nsx and reputting the belt in order to save his AC!!!

 

[nsxtasy]

Originally posted by ilya:
I never use my AC and just pulled the belt off. Anyone know if that would yield any benefits? It's always easy to stick the belt back on. I didn't want to remove the compressor and devalue the car so I figured just pulling the belt would add some HP.
Was it a waste?

Why don't you just run the HVAC system in the AC OFF mode?

 

[ilya]

I pulled the belt off because I figured I would have less parasitic loss. I thought regardless of what you shut off, the belt is part of the system and will run anyway robbing some HP. I didn't think about running the AC every now and then to keep it functional.

That compressor is incredibly expensive. The day it dies is the day I pull it out to cut weight. It will signal the beginning of a slippery slope where I start pulling out other stuff as well. Maybe I should sell it while it's still working fine and get some crack money instead of tossing it once it eventually dies?

 

[DutchBlackNsx]

Removing the belt will not gain any HP.
As said, running the vent with the A/C in the off mode is youre option.

And its true you need to run youre A/C at least once a month to keep it alive.
Thats the reason why overhere in cold Holland a lot of A/C systems die. People use it in the summer for three months, and never use it till the next year (not knowing that it is perfect for defoging the windows).


Dutchy