AC is by request only but I really only notice a difference when its first turned on

 

i also have PowerFlex engine bushes... so when the AC is on... in addition to problems you mentoined... the car SHAKES LIKE A MOTHER F&%$ER!!!! very annoying especially that i must turn it on everyday during summer since it like 43 degrees over hear!!

 

A few years back, an Evo VIII on the dyno measured a 25 HP drop when the A/C was engaged.

An episode of Mythbusters disproved the notion that gas mileage is better with the A/C on and windows up than with it off and the drag from open windows. The aerodynamic drag of open windows does not compensate for the power loss of the A/C compressor.

Lee K

 

Yep, if you have a X the compressor turns off, my STi does the same thing. If you don't believe me, turn it on full (not on max, as it seems that it doesn't do it on max) and if you hit the gas enough you'll notice the air get warmer for a bit.

Someday here I'll get my car dyno'd and perhaps I'll try it out with a car that turns the compressor off. I'm sure it is still affected, but not nearly as much.

BTW, here is the full result of that MythBusters:

"Last time around, in "AC vs. Windows Down", the MythBusters concluded that using AC was more efficient than opening your windows to cool down. However, they quickly admit that they were wrong to make such a hasty confirmation. In fact, they find that over 50 mph, you're better off your AC on, but slower than that, open your windows."

So essentially, if you're driving an Evo, leave the AC on (You should be going over 50 most of the time ) The aerodynamic drag from the windows at speeds over 50 is pretty great.

 

Some one told me once that in our car at wot the ac would disengage but I didnt believe him. It would be nice if that was the case though.

 

don't know about mitsu, but toyota's vvti system will do that - as in, turn off the compressor at full throttle, and resumes when you let off. so it does exist, not sure if mitsu does that though.

 

i rarely use the ac, definite difference in power.

 

Definitely sucks leaving from a stop with the ac on. Especially when your on an incline.

 

I know on the VIII's the AC cost a LOT more than 3 or 4 hp. If you put one on the dyno even with the fan and ac off, but put the dial on defrost position (runs the compressor) it costs between 20 and 30 whp. The X may be less than that but the story is still the same. It is a parasitic draw. I'm sure some will think i'm full of it, but I have seen it time and time again on the dyno.

So something to think about... if you leave the selector on defrost when your not running the AC or heat etc.. it's probably costing you power.

 

As far as I have heard around here the Xs do have that same sort of system set up. I know my car does, and if I set it to max AC (rather than just the lowest temp) it doesn't do it anymore.

Like I said, test it out, crank up the AC on a hot day, drive around till it cools down a little, and the go WOT and see if the air coming out gets hot for a bit. Mine does. I'm sure it still robs a decent bit of power, especiallly non-WOT, but it's a pretty cool little feature.

 

Yes AC on. Only to my feet though, but I drive with sandals and hate having sweaty feet during the summer. Power loss is there but it's not like I'm launching from one red light to another.

 

i drive with ac on all the time!

 

the weather stays the same out here in Hawaii, so I rarely use my AC. I just roll down the windows and let the breeze go through the car before I get in. Then once I start driving, everything cools down. Plus people tend to drive shirtless a lot out here so it's not weird for me to do the same

Can't wait to move back to CA though, I miss the winter...

 

Turn it on for 5-10 minutes every couple weeks regardless of whether you want to. The lubrication and rust inhibiting stuff is all in the freon so you need to make sure it circulates every once in a while or the system will go bad. You don't want to know how much it will cost to fix...and it will be hard to sell it with broken AC.

I don't have an X, but that is just general car advice.

 

good to know.