Reason I ask is because I finally took my RS to Las Vegas this weekend from Santa Barbara. It was 97 degrees on the worlds largest thermometer(spelling) on the way to Vegas, but when I would accelerate up the hills with the AC on any setting, the car didn't sound good. I guess the sound was kind of the same as when you try to accelerate in say 5th gear while you are at only 1500 RPM. Thing is though I would try to accelerate but the car was already doing 65 (approx. 3000 RPM) I am also not talking about full throttle acceleration, I mean I just wanted to keep going at around 75 MPH. I have never really driven stick shift car with AC before so am I suppose to downshift to 4th which would have put me at about 4500 - 5000 RPM (or maybe more) just to keep going 75MPH? I mean those hills are long stretches. I mean I want to be able to drive my car anywhere. I know it's fun in the rain and in the snow, but come on it should also be fun in the heat.

Thanks,

Juan

I would say it's normal dude, 97degrees your running the AC compressor constantaly (almost)
There is ALOT of loss when it comes to running your AC thats why it eats up gas...your working the engine harder.

My old GTi would almost stall when the AC compressor would come on....(yea yea...i know it was a VW)

Wait for some more replys to be sure.

Peas,
AaRoN

Hmmm...There should be no real problem. Even with level 4 AC set on recirculate, the power loss is inconsequential (unless you are racing. http://www.i-club.com/ubb-files/smilies/wink.gif . I mean, what kind of a grade are we talking about? And how much more did you have to hit the gas? Also, in 4th gear at 75 you would be at about 4900 RPM...It's okay, just don't do it for 20 miles straight...

The grades are long I mean you go from 1000 feet to 5000 feet. I wasn't accelerating like you do when you accelerate from an on ramp to get on to a freeway. I just wanted to be able to keep going 75 or 80. I know your AC takes some HP away, but I guess I felt it unusual because the sound made me not want to accelerate even a little bit. And most of the stretches of highway to Vegas are probably 10 miles +. They are steep, but they are spread out over a good distance. I have mainly driven auto's with V6's and they don't sound anywhere like my RS. The V6's were in a 87 Mercury Sable and a 95 Ford Taurus, and those aren't very powerful V6's.

Juan

Sounds like you just aren't used to the way a "4" sounds. Just keep it in 5th and be liberal with the gas! Ignore any "funny" sounds you hear. Just use as much gas as it takes to keep it at the desired speed. http://www.i-club.com/ubb-files/smilies/smile.gif

I know what will help...
hmmmm TURBOOOOO!

When I drove across Montana a few years ago (in my '98 L) I decided it was better to run with the AC off. Every time the compressor kicked on the whole car shuddered. Of course, I was crusing at 95 most of the way (back in the days of 'reasonable but prudent') and the engine was cranking over pretty fast.

Windows open, A/C off, stereo cranked... Ahhh what a life.

The compressor will turn off after 4500 - 5000rpm. It does this to save power. Trust me, you'll be able to smell it when it kicks on again. That, and the vents will start blowing hot air.

Here in Miami, A/C runs all the time. Its not hot, but when its 85 outside and the humidity is the same, you get very tired of sticking to everything.

but when I would accelerate up the hills with the AC on any setting, the car didn't sound good. I guess the sound was kind of the same as when you try to accelerate in say 5th gear while you are at only 1500 RPM
Juan, if you were trying to describe a rattling or knocking sound, that would be detonation. In high heat and high load, the car may require more than 87 octane, so if that's what you were running you might consider upping it during the summer if these type of excursions are normal for you. My car likes premium (only 91 here) in the summer, but then again it's not stock.

The best thing to do would have been to downshift.

I was crusing at 95 most of the way (back in the days of 'reasonable but prudent') and the engine was cranking over pretty fast


Did Montana repeal "reasonable but prudent"?

i never turn on the AC...

Hmmm... could it possibly be an elevation issue? Does the engine sound improve when you turn off the AC? I'm thinking that if you were driving from a low elevation to an extremely high elevation, the ecu may have been having a hard time keeping up with the change in air density.

Jordan

Thanks for all the input.

ColinL - I was using Chevron 87 Octane for the whole trip. And it was kind of like a rattling sound, the only time I have heard a sound like that is when I missed a shift from 2-3 to 2-5, that is why I used the example of trying to accelerate while in 5th gear while at low RPM. I think I will try the 92 Octane gas when I head out on a high heat trip. Also would it be advisable to downshift, and get the RPM's up ~4900 for about 10 miles(the length of the upgrade) I was in 5th and I was already at ~3000 RPM when I would accelerate.

Poseidon - Yes the sound would go away when I turned off the AC. I know the AC takes power away, but I don't want to have to turn off the AC when I go up steep grades, it shouldn't take away that much power, should it?

Thanks,

Juan

A couple of years ago I believe...
It was a sad sad day.