Is the AC still engaged ( when left *on*) at WOT?
I read on another thread for a different car that the AC was turned off at WOT by the ECU.
Reason I asked I just ran a 60-90MPH test but forgot to turn off the AC!

 

So what I did 40-140 with the ac full blast

 

I'm pretty sure most cars turn off the compressor over a certain RPM.

 

It's not rpm but WOT..I found this:

http://forum.miata.net/vb/showpost.p...11&postcount=7

I would be willing to bet that if you actually installed an indicator light to monitor the compressor clutch engagement (as i have done) you will find that, yes, the compresssor drops out at WOT.

I have never seen any A/C equipped car, going all the way back to the '50s, that did not have some means of unloading the compressor either at WOT or under heavy load/acceleration.

It only makes sense. The compressor doesn't run full time anyway, so why would the design engineer not include a feature that dropped off that unnecessary load when the driver is calling for max power.

Bill (state licensed HVAC engineer)

 

yeah, when the throttle is engaged at a certain percentage (I think like 92%) the pcm cuts the compressor off. It's not like you'll ever notice though since you're only at redline for like milliseconds at a time.

 

Not sure about the T/C but on the S/C the A/C would turn off when TPS was 95% or above and A/C would turn back on when TPS was 92% or lower.

 

I only run the AC for like 5 mins anyways... run it for 5 mins, with the system on recirculate... then turn off the AC button but leave the fan and recirc on... it stays cold for like an hour....

 

I think it's when are at 100% Throttle (WOT). I flored it at 4000RPM..*redline* isn't in the equation here..just throttle position (under load).
Found this on the Solstice Forum:

http://www.solsticeforum.com/forum/718474-post3.html

The ECM shuts off the AC compressor under full throttle to make more power available to the wheels. The assumption is that by going full throttle you want maximum acceleration. I can't really imagine spending enough time at full throttle to make lack of AC a serious comfort issue. Why would you want to defeat the function ?

 

Also, on the S/C there was on option in HPTuners where you could disable the A/C at different RPMs as well. That feature was not used in the stock tune, but it could used with HPTuners.


Not when it is 90 -100 it doesn't.

 

Not for nothing, but I've been driving this car every day since I bought it 2 years ago, and I've driven on lots of 90-110 days.... I run the AC for no more than 10 minutes an hour on long drives....

 

Just so you know, when the recirc button is on, the A/C is running as well because you're calling for max cooling.

Try turning off the A/C and recirc buttons and see how long you last. =)

 

That's simply not true.

 

I don't know why you do this. Turning the A/C on and off while driving is what kills the clutch.

 

not entirely true...the clutch cycles when in normal operation

the coils in the AC clutch are what fail, and if left engaged, they fall apart...

 

I guess you just can't win.

 

You're still running the compressor just an FYI

Put your passenger side of your car near a wall, roll down the windows, and turn on just the fan motor with nothing on.

Now click the recirc button, you will hear the compressor.

Period.

 

That's because you are running the compressor in the recirculation mode with the newer gm vehicles. The 5-10 mins of air conditioning you run does not last an hour. It is a default mode so that the windows do not fog up from humidity like a greenhouse affect on a hot day. It is not like a vent back in the old days it is more like defrost which also runs the compressor to keep the windows from steaming up. I worked in the gm hvac for 6 years. And also you do not need air on at all just the recirq button will get cold and stay cold as long as the temp is set to cold then will warm after an hour or so then get cold again after a off and on cycle. A 2004 silverado has this feature even as well as the redlines and solstice among others.

 

Ok, I stand corrected. You guys are a bit more informed than I!

I have a followup question because now I'm curious. With the AC button on, I can feel drag on the motor when the compressor kicks on. With the button off, and recirc still on, that drag goes away completely, which led me to believe the compressor was off...

any input on this?

Ronn, sorry for the threadjack!

 

That drag is from the current drag from the electric fans. They come on automatically with the recirc.

 

come on........

drag that comes with turning the ac button on, and goes away with the ac button off is from fans, that would be on, and running, almost constantly on a 90-100 degree day? Yet I don't feel that drag at all with the AC button off?

 

So I guess we're all in *agreement* that the AC is turned off (*disabled*) when in WOT?

 

Yes.

 

The fans aren't always on when the AC is on. When they do come on with the AC already running, it will drag the car down. If you don't believe it, go unplug the fan relay and see for yourself.

 

Placebo effect.

 

I can feel it if I turn the recirculate button on .... it definitely puts a load on the motor. I can feel it when i turn the defrost on without any buttons pushed.