How much horsepower does it take to run A/C?

[ekpolk]

Originally Posted By: BuickGN
Originally Posted By: 440Magnum
Originally Posted By: qship1996
Variable displacement compressor lasted over 200,000 miles on my Q45. Once you get used to driving a car with one, you will be extremely annoyed driving a car with a cycling compressor due to noticing the differences in acceleration, noise, and vibration changes as the compressor cycles on/off


That was the same argument for EPR valves- no cycling to annoy the driver. But I never notice cycling anyway, even on the lil' under-powered PT Cruiser. Definitely never on one of the 440s

Really? I thought the AC compressor kicking on would nearly stop that torqueless wonder.

Tsk, tsk BGN, one who lives in the glass house of Honda-Acura ownership ought not to be casting torque-stones. . .

 

[1 SX]

Originally Posted By: CharlieJ
I guess when driving a 4-banger the power decrease is much more noticeable compared to a 8 or even a 6 cylinder car with twice the power. My next car needs a bigger engine.

Haha! This made me think, I had a 94 Saturn SL1 1.9L SOHC 85HP, Automatic with p/s. (this was my first Saturn, sold it and bought the Saturn SL2 (1.9L 124HP) Much better, but its still and 4 CYl.)

That car was so slow with the A/C on, From stop lights i would have to WOT it always just to keep up with traffic..

Even the SL2 It was slow with the A/c on, But was nothing like the SL1...

Boy do i love the power of the 6 cyl...

 

[440Magnum]

Originally Posted By: ekpolk
Originally Posted By: BuickGN
Originally Posted By: 440Magnum


That was the same argument for EPR valves- no cycling to annoy the driver. But I never notice cycling anyway, even on the lil' under-powered PT Cruiser. Definitely never on one of the 440s

Really? I thought the AC compressor kicking on would nearly stop that torqueless wonder.

Tsk, tsk BGN, one who lives in the glass house of Honda-Acura ownership ought not to be casting torque-stones. . .


If he was calling the wife's PT 2.4 a Torqueless wonder, well, yeah he shouldn't be throwing torque stones, but... ummm....

he's right

Actually the 2.4 isn't terrible for its size... just needs more size. Or the turbo version.

If he was referring to the 440s, then I *know* he's yanking my chain

 

[Nick R]

Still haven't gotten to do any serious driving with my A/C off. one of these times it will be cool enough to drive around a bit with it off. I prefer A/C over windows down, Heh.

 

[lexus114]

So we still didnt determine how much hp the compressor takes??

 

[BuickGN]

Originally Posted By: 440Magnum
Originally Posted By: ekpolk
Originally Posted By: BuickGN
Originally Posted By: 440Magnum


That was the same argument for EPR valves- no cycling to annoy the driver. But I never notice cycling anyway, even on the lil' under-powered PT Cruiser. Definitely never on one of the 440s

Really? I thought the AC compressor kicking on would nearly stop that torqueless wonder.

Tsk, tsk BGN, one who lives in the glass house of Honda-Acura ownership ought not to be casting torque-stones. . .


If he was calling the wife's PT 2.4 a Torqueless wonder, well, yeah he shouldn't be throwing torque stones, but... ummm....

he's right

Actually the 2.4 isn't terrible for its size... just needs more size. Or the turbo version.

If he was referring to the 440s, then I *know* he's yanking my chain

Yes, that was aimed at the 440s. I apologize, I didn't realize you had the 4 banger in the stable too. I grew up listening to my dad talk about the torque of the 440 he used to drive so it was just a little poke.

Ekpolke, I'm the first to admit the glorified Accord is a torquless wonder, I've nearly been kicked off of acurazine for saying so.

 

[rationull]

Originally Posted By: BuickGN

Ekpolke, I'm the first to admit the glorified Accord is a torquless wonder, I've nearly been kicked off of acurazine for saying so.


BuickGN, it's always amusing to me, as someone whose cars have spread the gap from ~70 hp to ~150 hp, ~80 to ~160 ft*lb) to read your posts referring to the TL's "only" 258 hp and it's "torqueless" motor at what, around 235 ft*lb? This is not meant as a dig btw, I get where you're coming from. I hope to some day have my perspective changed on this issue as well

 

[BuickGN]

Originally Posted By: rationull
Originally Posted By: BuickGN

Ekpolke, I'm the first to admit the glorified Accord is a torquless wonder, I've nearly been kicked off of acurazine for saying so.


BuickGN, it's always amusing to me, as someone whose cars have spread the gap from ~70 hp to ~150 hp, ~80 to ~160 ft*lb) to read your posts referring to the TL's "only" 258 hp and it's "torqueless" motor at what, around 235 ft*lb? This is not meant as a dig btw, I get where you're coming from. I hope to some day have my perspective changed on this issue as well


I'm too hard on the car sometimes. It is faster than the average car but I'm used to a little more. Some of my issue is the way the power is delivered. The peak numbers aren't bad but I wish it had more down low instead of having to rev it past 5,500rpm. According to Acura literature, there's 198lbs available at 1,000rpm. Sure doesn't feel like it. As of now, I can floor it from a redlight with traction control off and barely chirp the tires. It's the only car I've owned that can't take advantage of stickier tires in a drag race.

 

[Tahoe4Life]

Every so often I will see a new Caddy,Beemer or some other high end car with all 4 windows down in this Florida blazing sun where the heat index is at 105 degrees by 11am. To me that makes driver look kind of stupid.

I say stupid since I don't like using the R word.

 

[BuickGN]

Originally Posted By: FORD4LIFE
Every so often I will see a new Caddy,Beemer or some other high end car with all 4 windows down in this Florida blazing sun where the heat index is at 105 degrees by 11am. To me that makes driver look kind of stupid.

I say stupid since I don't like using the R word.


And before you know it, we won't be able to say the S (stupid) word either. What's this place coming to?

 

[Pgmr]

Any of the OBDII gauges (like ScanGauge) that reports HP might be able to give a ballpark figure. With cruise control on level ground, switch the ac on and see how much the hp reading goes up.

I've got a ScanGauge in my truck and will try to remember to test it next time I'm out.

 

[Nick R]

Curiously, I'm starting to think it's not about how much horsepower it takes to run it, but the resistance to revving, and the torque used. It can't technically use more than a couple horsepower, but taking even, being generous- 10 horsepower, is not going to make a car act like it does when the A/C is on. I think the compressor instead has a very very high resistance to speeding up, which is what causes the seeming lack of power. Once it's at speed, they don't seem to have any more effect on performance than, running your headlights. But once you hit the gas, it is like a dog that balks when you pull on its leash, not wanting to come along for the ride.

 

[ekpolk]

Originally Posted By: BuickGN
. . .


And before you know it, we won't be able to say the S (stupid) word either. What's this place coming to? [/quote]

"This place"? By that, I hope you don't mean here! Did you not notice the recent national furor over the use of the R word? For sure, it's not a nice thing to say, but equally surely, it's getting a little scary when you think about how much "oral hygiene" our society is demanding these days (and I'm not talking about brushing your teeth...).

EDIT: And just for the record, the R word is not on "the list". Do not take that as an invite to expand the frontier... Thanks.

 

[Propflux01]

Hmm, first we had the S-word, then the F-word, then the N-word, and now.... The R-word?? Running out of alphabet real quick!

 

[Steve S]

The ECM compensates.

 

[JHZR2]

Originally Posted By: rationull
Originally Posted By: BuickGN

Ekpolke, I'm the first to admit the glorified Accord is a torquless wonder, I've nearly been kicked off of acurazine for saying so.


BuickGN, it's always amusing to me, as someone whose cars have spread the gap from ~70 hp to ~150 hp, ~80 to ~160 ft*lb) to read your posts referring to the TL's "only" 258 hp and it's "torqueless" motor at what, around 235 ft*lb? This is not meant as a dig btw, I get where you're coming from. I hope to some day have my perspective changed on this issue as well


+1. I'm never unhappy with my bmw318i commuter, but it is much less of a heavy car than a TL. The Honda torque profile is annoying though. I'm driving my inlaw's 01 accord, and with just myself and the ac on, the car was unable to go up a steep usvi grade at more than 3 mph! I had to turn off the ac to be able to get moving again.

Then again, the Honda has already required an AT rebuild at 38k, while the Camry of the same vintage still runs strong at-wise at nearly 100k. The camry is v6 and the accord is an I4.

 

[Pgmr]

On my 4.6l F150, the ScanGauge reports:
At idle w/ac off: 6.7 HP
At idle w/ac on: 9.2 HP
HP difference: 2.5

ECU does kick up idle speed a bit when compressor comes on, so I'm not sure if the total 2.5 HP difference is due entirely to load caused by ac.

I did not have a chance to check the difference at highway speeds, but will do so if the little gray cells remind me.

On another note, pretty amazing that a V8 engine is producing less than 10hp at idle.

 

[mechtech2]

Pgmr - The AC will rob more HP at higher speeds.

 

[brianl703]

Originally Posted By: Pgmr

On another note, pretty amazing that a V8 engine is producing less than 10hp at idle.


Not really. Try slowly releasing the clutch while it's at idle (if it's a manual) and notice that the HP numbers go up as the load increases on the engine.

 

[Nick R]

Originally Posted By: Pgmr
On my 4.6l F150, the ScanGauge reports:
At idle w/ac off: 6.7 HP
At idle w/ac on: 9.2 HP
HP difference: 2.5

ECU does kick up idle speed a bit when compressor comes on, so I'm not sure if the total 2.5 HP difference is due entirely to load caused by ac.

I did not have a chance to check the difference at highway speeds, but will do so if the little gray cells remind me.

On another note, pretty amazing that a V8 engine is producing less than 10hp at idle.


That is because the throttle is completely closed at no-load idle. As the previous poster mentioned, when you put load on a car, even at idle, it will open the throttle enough to maintain idle, thus making more power.