How much power does your A/C use?

R

Rattlecanpaint

New member
I've got an '06 V8 4runner and with the A/C on when it cycles it seems like it takes 100 HP. I'll be driving down the road with the A/C on and when the compressor cycles the thing acts like you let off the accelerator pedal. Then it cycles back on and it's like a kick in the seat. Any one else notice this problem? It cools great but is annoying as h-e double hockey sticks when cycling.
 
Register to hide this ad
Never noticed either but my guess is it would be a bit more than that. There have been several studies that show that running the a/c will run you a 1-3 mpg decrease in performance.



.
 
Rattlecanpaint said:
I've got an '06 V8 4runner and with the A/C on when it cycles it seems like it takes 100 HP. I'll be driving down the road with the A/C on and when the compressor cycles the thing acts like you let off the accelerator pedal. Then it cycles back on and it's like a kick in the seat. Any one else notice this problem? It cools great but is annoying as h-e double hockey sticks when cycling.
Click to expand...

Yes, all that, but as you will see, the opinions range from that to "I never notice it". Blows my mind.
 
That is not normal. Maybe your a/c compressor is on the verge of seizing up if you are experiencing that much power loss.
 
Neighbor came over last night with his car to ask me to reset his CEL. We started drinking the beer he brought, then made a run for a couple of more 6 packs and a bottle of Don Julio. As we were getting lubed I remembered this thread and we hooked the scan tool up to the 4Runner to see what effect the a/c had on RPMs.

The first screen shot is with the car idling in park and then powering on and off the a/c.

cabowally-albums-wally-picture18988-ac-1.jpg


Car nicely idles at 700 rpms and when the compressor is turned on it drops 100 rpms but the car then immediately compensates by increasing rpms close to 800.

Second screen shot shows the is the same but with the car in gear.

cabowally-albums-wally-picture18989-ac-2.jpg




.
 
Rattlecanpaint said:
I've got an '06 V8 4runner and with the A/C on when it cycles it seems like it takes 100 HP. I'll be driving down the road with the A/C on and when the compressor cycles the thing acts like you let off the accelerator pedal. Then it cycles back on and it's like a kick in the seat. Any one else notice this problem? It cools great but is annoying as h-e double hockey sticks when cycling.
Click to expand...

I experience the same exact thing. Think it's normal. To not notice it you'd have to be driving drunk. It's very, very obvious.

I try to avoid using it on all but the hottest days by lowering the windows and rear hatch window and enjoy the nice breeze.
 
Mine is the same way. The compressor kicks on and the truck falls on it's face. Surprising to me since it's a torquey V8. But it definitely sucks power.

I have a rule that I never turn my A/C on until we hit the 90s outside.
 
Never noticed it on a 4runner...

I'm a relatively late adopter to AC. Living in CO I figured I didn't really need it so all the vehicles I owned from 1979 - 1999 had no AC. I finally got an AC-equipped 2wd Ranger in 1999 and all my vehicles since then have had AC.

To answer the specific question, the only vehicle I ever noticed a power drop using AC is my little DD Mazda Protégé. With only 1.5l engine, I can feel a significant drop in power when I turn on the AC. On the Ranger I noticed a very slight drop in RPM and on my Subaru and the 3 Toyotas I've owned since then (04 Taco, 99 T4R and my current 07 T4R) I haven't noticed a lick of difference with AC on or off.

I used to shun AC because I inherited the belief from my Dad that AC will kill your MPG!" Honestly, I think that stuff comes from the old days when AC compressors weren't nearly as efficient as they are now. Modern cars are all designed to use AC anyway (no vent windows!) and except for the Protégé (which is not only 16 years old, it's also pretty underpowered) I've never noticed any loss of power or increase in fuel usage when using AC.

BTW, one of my most memorable (and miserable!) driving experiences happened in 1993. I had to get from Fort Huachuca in Southeastern AZ, to Fort Bragg, NC, in 2 1/2 days in late July. Driving the Southern US in 100+ temps in a MItsubishi Montero with no AC = definitely NOT fun! I couldn't even listen to the radio because the only way I could be comfortable was using "470" AC: 4 windows down and 70 MPH! :D
 
Last edited:
I really do hope the OP is talking about RPM and not HP, because if you think your AC is using 100HP you have something seriously wrong with your truck! :O
 
I have also noticed it, and would like to add my observation and my opinion:

What feels like power “drop” actually happens when AC cycles “off” not “on” and when you feel like a power boost it actually when AC cycles “on”… you can tested it very easily by just paying attention to what happens when you turn the AC “on” or “off” in the manual mode.
So obviously this is not a “power “issue of the engine or too much drag from AC… it is just simply “issue” with the AC control circuit (more than likely very aggressive attempt to reduce gas mileage by not allowing the engine gradually increase or decrease power based on AC cycling phase and doing that in very abrupt way) … unfortunately Toyota just call it “normal”…
The good news is that I only really can notice it on the flat highway with speed less than 70 mph, no load (like a trailer) and without cruise control; As long as there is any kind of the load added or cruise is on this issue is undetectable.
 
Well seems like it's normal for some and not for others. Maybe it's just something I'll get used to. My 3rd gen would do it too but only after at least an hours drive time since it had adapted to highway driving. (I used to rarely drive highway, though now I do it every day.)
 
Definitely have this going on in my 05 SEV8. A/C clutch kicks in, RPMs drop, then releases and the truck lunges forward unless I'm planted on the brake.
 
My T4R used to surge forward like that thread is describing when my ACC and compressor was on its way out. I recently replaced both because the compressor locked up. But the new one I dont even notice it cycling (probably was a little low on oil before), now that theyre replaced it doesnt surge at all

Although even with the old clutch and compressor I never noticed any appreciable HP loss with the A/C on or off, not in my 4Runner or any other vehicle I have ever owned or driven with the exception of one. That vehicle is my old Jeep with a tired 2.5L on 31" tires, when the A/C is on I have to give the vehicle a little more throttle or slip the clutch a little when taking off from a stop when the A/C is on.

You guys must be very hyper sensitive to your vehicles.
 
MICA4R said:
This is normal behavior by most forum members.
Click to expand...

This is very true, more so for mechanics I think also... my buddy (ex EBMUD mechanic) was driving my 4Runner and we had the radio off and he was like, "you hear that? That sound right?" and I couldn't help but chuckle.

When you love your 4Runner as much as many of the members here do, you get that sort of first baby parent syndrome where the slightest anything makes you think you're kid's dying of some sort of devastating disease.

Also... I don't really notice what its like to drive without the A/C... I only have two settings in my cars... windows down & "Polar Bear Country" as my friends call it. I like the cold. :smow:
 
You must log in or register to reply here.

Members online

Total: 415 (members: 1, guests: 414)

Forum statistics

Threads
278,307
Messages
3,554,054
Members
248,016
Latest member
Advally Service

Share this page

Trending content

Back
Top