Just Curious about AC power loss

[barmanjay]

Does anyone really know on average how much hp/trq loss you have when you turn on your AC?

[DRFT-S13]

Most A/C compressor's cut out at higher RPM to eliminate any drain under heavy acceleration. Most people think it draws hp, when really it doesen't.

[Maxt]

Most air conditioners in cars use about 1-1.3 hp per ton of refrigeration, and most cars have about 2 tons of a/c, some of the bigger vehicles, trucks vans , old caddy's etc had upt 5 tons of a/c, so just average out at about a 3-4 hp loss on most cars, and 5-6 hp for trucks and larger cars. It really gives you an idea of how much effect 4 or so hp has on the way a car feels, or how some really gutless some cars are, I remember driving a rented sunfire to winnipeg, the difference between climbing a hill at a reasonable speed and barely making a hill was whether the a/c was on or not, and being thats its hp loss at the flywheel end its probably like losing 10 hp at the wheels...max

[GTS Jeff]

id say its got to be at least 10 since its very noticeable on small engines when a/c is on. auto ELs top out at 140 with the a/c on :D

[googe]

my sti loses 15 at the wheels, dyno tested.

i was surprised!

[hjr]

just dont turn it on when you want the power. it uses no power when its off and the only area you loosing is that the car may be 50lbs heavier which is negligable on the street.

[hyperwhite]

either citreon or peugeot developed an AC kit for their rally cars that only used 2 hp. i cant remember which one made it but it would be nice to see them hit the roads sometime soon.

[Mckenzie]

I think of it like a turbo: I drive around with the AC on all the time and when I pull up to a vette or something that wants to race I hit the off button (its like turning the turbos on) and I instantly gain like 50hp and I rape the vette or viper or whatever tries to race me. They never know what hit them....






























:nut: ;)

But seriously, its pretty surprising how much power my car loses when the AC is on. I can still climb hills in 6th gear sometimes on the highway but you can defenitaly feel the drain when it is on. There was actually a guy on the Acura Legend forums that took the AC compressor out of his car to gain a few horse from the weight loss (what a tool). :rolleyes:

[Khyron]

I have a small disp turbo car, so launching at a light with the AC on is hugely noticable compared to having it off. I would rather have 2 200 pound people in the back than my ac on if stuck at a light.

Khyron

[Seanith]

yeah it would be interesting to see exactly how much of a loss it is in my car. its so noticeable. if i'm accelerating with it on and i turn it off it feels like a big load was taken off. i rarely use AC though.

[canadiandaytona]

I'm planning on removing mine.
Not so much for weight, but for better airflow over intercooler (a/c rad covering currently)
Plus Its A t-top car In Canada, when Do i Need air conditioning?

[barmanjay]

I think I'm gonna try at Secret Street and see what kind of difference it makes,... mind you I have a 3.1 V6

It would be neat to see what the differences are in the 1/4 times,.... I've raced the last 2 weeks, and I average 16.9, depending on my launch, and reaction time.

[CKY]

just go on a highway and start off driving with your A/C on, after a bit, turn your A/C off, you'll be suprised how much better the car runs, its especially noticeble on weaker cars (like my mom's CRV :whipped: )

[Scat]

Its not just the power loss that the AC compressor creates though, its also the weight. When you think of the added weight of the condensor and compressor, it can be anywhere from 50lbs to 100lbs.

[vincent-h]

Originally posted by googe
my sti loses 15 at the wheels, dyno tested.

i was surprised!


where were you able to dyno your sti!? please let me know thanks! Don't tell me u only dynoed 2 wheels!:eek:

[googe]

Originally posted by vincent-h



where were you able to dyno your sti!? please let me know thanks! Don't tell me u only dynoed 2 wheels!:eek:

oops, guess that is misleading
someone else did the dyno run, not from around here. they posted the results. the statement "my sti" is accurate under the assumption that my car also has similar results, since its the same car :)

no awd dynos anywhere remotely close to here. i think the nearest is in washington.

[vincent-h]

haha damn i thought u either wrecked ur car on a 2wheel dyno or you completely raised my hopes haha

[GTS Jeff]

Originally posted by Scat
Its not just the power loss that the AC compressor creates though, its also the weight. When you think of the added weight of the condensor and compressor, it can be anywhere from 50lbs to 100lbs. it shouldnt weigh any more than 50lbs cuz the condensor is pretty small and the compressor is small too. yes, 50lbs counts, but removing a/c is a lot of work for 50lbs.

[Scat]

Originally posted by GTS Jeff
it shouldnt weigh any more than 50lbs cuz the condensor is pretty small and the compressor is small too. yes, 50lbs counts, but removing a/c is a lot of work for 50lbs.

But on a front engine car with a front weight bias, removing the AC components removes some of this weight from the front wheels, therefore allowing the car to have a weight distribution closer to 50/50.

[GTS Jeff]

Originally posted by Scat


But on a front engine car with a front weight bias, removing the AC components removes some of this weight from the front wheels, therefore allowing the car to have a weight distribution closer to 50/50. which would make like a 2% difference if u are lucky. lets say it takes u 8 hours to remove a/c. u could spend that 8 hours working at a $20/hr job to make $160, which u could spend on something like say a stb. which would make a bigger difference than removing a/c!

[canadiandaytona]

If it takes you 8hrs to remove A/C then you are retarded
(Well I guess it could take longer if you remove internal components from under the dash, but why bother?)

[barmanjay]

Lets say,.... hypothetically,.....

you were able to re-plumb some AC piping to various parts of the engine bay to help as a 'heak sink',.... soak up some of that unneccessary heat, hence, cooler engine, better run,..... mind you this application would only be good for short races.
Turning off the system right before you race.

[GTS Jeff]

Originally posted by canadiandaytona
If it takes you 8hrs to remove A/C then you are retarded
(Well I guess it could take longer if you remove internal components from under the dash, but why bother?) i think ure missing the point/

[canadiandaytona]

No I get you, If your looking for more power don't remove your A/C.
If however, your A/C doesn't work, like mine, Or you never ever use it, then remove it for more power, weight reduction and better cooling.

Right

:thumbsup:

[Scat]

Originally posted by canadiandaytona
No I get you, If your looking for more power don't remove your A/C.
If however, your A/C doesn't work, like mine, Or you never ever use it, then remove it for more power, weight reduction and better cooling.

Right

:thumbsup:

Exactly!
If it doesn't serve a purpose, get rid of it.

[barmanjay]

Just do you know,... I plumbed my ac through my TB heater (which i bypassed). i ran .2-.3 sec faster on the 1/4,... I was amazed,.. The whole top end of my engine stayed relatively cool to touch throughout the night, however,.... my gas mileage has gone down by 20%. I'll be lucky if I get 300kms on this tank,...lol

not sure exactly why,...possibly because the air is slightly cooler because of the TB plumbed with the ac,... and maybe because the top end is cooler,.. i dunno, but i am stunned that I ran faster.

for the last 2 weeks i couldn't, for the life of me, break 16.7,... but last fri,.. I steadily ran 16.5's - 16.6's, and even got a 16.4!

Anyone else has any explanation for this?

[canadiandaytona]

Um.
Cooler intake air charge= more o2=more gas can be ADDED= more power.

[barmanjay]

and what bout the power loss having the ac on?