AC robbing power..

[Custom88]

I have never driven a vehicle before that is such a slouch once the AC is switched on. It's borderline pathetic the huge difference. I lose close to 5 MPG average and I have to just about redline the engine to accelerate from stops. Even on turns if you don't let the engine downshift to 1st gear it can't even accelerate. I have to have the gas pedal down to the floor just about to even accelerate at all. I just have never had a car that got that dogged down from having the AC on. The outside temperature is 92, and I have the AC set at 69. Do other 3.5 owners experience a huge loss in power? I think the DOHC engine's lack of torque really shows through in these conditions.

[Black02Rora]

Hey Custom88.... don't feel like you are all alone, mine does it too! And if you switch the A/C to the off mode while accelerating, you will feel the difference as the motor goes back to its normal mode. The power is felt with a surge. I don't like that. But all cars do it. I was used to the 3800's torque, but in my Toronado Trofeo the 3800 felt just as sluggish with the A/C on. All cars do this. It's like 2 cylinders are reserved for A/C only. Its a fair trade off for cool air.

[erw38]

Mine feels the same way.......I guess it would since it is predominantly the same engine.

[Marc]

There's usually about a 10% loss in HP with the A/C on.

[macadamiaman]

I don't have this problem at all....?

The car is fine accelerating, gas mileage is 20mpg all summer (winter = 18mpg or less). Could it be because I have a new compressor?

[auroralover]

Although you know the a/c is on, and there is a little power loss, mine is nowhere near what you describe. Might want to get that looked at... Yes, I am talking about my 3.5.

[BNICOV]

It's not just the A/C that's robbing your power, it is so freakin' hot that your engine isn't running at full efficiency. The air going in is very hot and is less dense than colder air (say about 15-20 deg. C or about 60-70 deg. F). Just watch a golf ball go in hot weather, it travels farther than when it is cool outside. My advice is not to thrash your car too much when it is this hot out. Don't expect it to act like it usually does. Back in the day, we hated racing in this heat with our 5.0 mustangs because they were slugs b/c of the hot air.

[MBowen574]

I've read that there's very little difference between the second-gen Aurora 3.5 and 4.0. Thus, I haven't felt any of this with the 4.0. Could it be a problem with your car? I never felt much loss with the Maxima, either, but my mom's old Eighty Eight and my '96 Galant that I have now both lose tons of power with the A/C on. My dad's Xterra doesn't lose any, either. I agree that the outside temp might have alot to do with it.

[BuccaneersFan]

I have never had that much power loss with my 96 and thats even considering the brutal weather down here in Florida, today it was 97 degrees with 95% humidity.

[Marc]

The power loss in my 2001 4.0 with the A/C on is very small. If I want to accelerate fast with the A/C on, it can do that. The only other car that I ever drove that was
not slowed by having the A/C on was the 1972 442
455 that I had before my 2001.

[Aurora40]

It's not that noticeable on my 4.0, nor on the Regal. But it's supremely noticeable on the 200SX. Kicking the compressor off is like hitting a nitrous button or something. It's possible the compressor is the same as the 4.0L compressor, thus it's bigger compared to the motor in the 3.5L.

You might try test-driving another 3.5L if you can, see if it feels the same. If not, maybe your compressor is going or has some other problem?

[stevensolds]

Dan...the 8-cylinder sure would help you in this case.

Mine doesnt do any of that crap with the A/C on. I only time I even used it this summer was in Carlisle, and it did feel a little sluggish from a stop, but flooring it on the highway when doing 80, it accelerated to 100 just as fast as without it.

Why do you think I never run the A/C man??? Its 90 degrees here all the time and I never use it. I would rather wear a sweatband and listen to my exhaust, not to mention free up the extra juice.

[auroralover]

When you get older Steven, comfort is more important than listening to your exhaust and freeing up the juice. I have to have my air on when it is this hot..I can still hear my Flowmasters just fine man...

[stevensolds]

The only way i can hear mufflers with air on is by removing the rear seat.

[Custom88]

age isn't my problem, but I take certain medications that make me real sensitive to heat and humidity. I get sick if I"m in it for too long and get real shaky and weak. I'm only 19 so it's not my age, but medication like I mentioned. anyways, I think the main problem is I just have the temperature set too low.. I'd imagine the compressor runs full time at full power when I have the climate control set to 68 and it's over 90 outside. I"ve been setting it to around 74 lately with recirc on and the power loss is a lot less noticable. BTW steven, I notice no difference at all at WOT either. Know why? The AC compressor turns off at anything over 3/4 throttle to give you maximum power. It's a liability against GM if they didn't. "I couldn't accelerate to avoid being hit because the AC was taking up my power."

Bob, funny part is that there aren't any 3.5's around my area for sale right now. When I was in the market to buy, there were 3.5's all around. Now that I already bought an Aurora there are atleast 7 4.0's within 25 miles of me. Go figure.

[stevensolds]

Ok, that would explain it then. Thats a neat it would kick the compressor when flooring it.

[macadamiaman]

I never use the A/C at anything other than 60º temperature (if I want it warmer, I either open the windows, put the air somewhere else, or lower the fan speed), and my 3.5L has NO sluggishness to it, or at least no noticable sluggish. And I tend to notice those things... (I noticed the uptake with premium gas, for instance)

[Custom88]

I noticed something interesting today since the temperature outside was 97*. The AC didn't seem to take away much power.. until about 5 miles into my drive. After I had driven a little ways and the car was cooled down, that is when I started to lose massive ammounts of power. It almost makes my 220 horsepower engine feel like a 150 horsepower one. I'm used to having no power with the AC on, but what happened today that hasn't happened before was this certain smell. After I got home and got the car in the garage I got a faint smell of burning rubber. Almost like a belt burning. Popped the hood and sniffed around but couldn't tell where it was coming from, except from the passenger side of the engine. burnt rubber... doesn't sound too good, does it?

[stevensolds]

might be throwing the belt

[auroralover]

Sounds like the sepentine belt. Did you check the alignment or condtion of it?

[macadamiaman]

Yeah, definetely too much friction somewhere... something wearing down as a result = something will break... taking so muhc power from the engine to wear whatever it is down means that it'll break soon! Preventative fix!

[Custom88]

the belt appears to be fine. Talked to a dealer about it and they said not to bring it in until something breaks.. They said the AC is supposed to make the engine very noticably 'sluggish.'

[02aurora]

My car does that too.Compared to normal, I feel like i'm driving a Neon when I have the AC on, when it comes to power anyways. That's when you can really enjoy the luxury of these cars.

I drive like grandma moses with the AC on anyways, with how dark the tinting on my windows is, it's funny to watch people drive by me, obviously trying to figure out what kind of car it is. Makes for an entertaining ride.