[rfitzge6@fau.edu]

My ac feels cold when i drive the car under half throttle but anytime i get on it it feels like the ac compressor turns off and just blows warm air. Very annoying i live in fl and i have to drive it easy or it never cools down. Anyone else notice this, is it made like that to give you more power?

[satakal]

Are you ever at WOT more than 10 seconds at a time?
________
LittleRiddle

[rfitzge6@fau.edu]

no but anytime i floor it even for 2 seconds it gets warm and takes 10 seconds to get cold again

[StarrDlux]

yup except mine only takes about 1-2 seconds after you let off to get cool air again? you never own an american car just about every modern chevy does this.

[BMWeber]

BMWs since like the 80s have been shuting off the ac at
WOT

[rfitzge6@fau.edu]

your right mine takes like 3 seconds to get cold again, never had an american car before so i guess this is normal

[rfitzge6@fau.edu]

i also have a x3 and it doesn't do this blows cold air the whole time under full throttle, thats why i thought something was wrong

[sambonator]

Under WOT, the AC compressor shuts down, so this is normal.

[Ryan@Motorwerks]

Originally Posted by rfitzge6@fau.edu

is it made like that to give you more power?

Exactly. We would hate for you to lose to that IS350.

[CASHBY]

Originally Posted by sambonator

Under WOT, the AC compressor shuts down, so this is normal.

Correct... WOT will disengage the AC clutch to limit any more Load on the motor... thus giving a bit more power turning the AC compressor off

Just sucks it takes a second again to blow cold...however pretty normal

[mistermojorizin]

Originally Posted by rfitzge6@fau.edu

i also have a x3 and it doesn't do this blows cold air the whole time under full throttle, thats why i thought something was wrong

its probably not noticeable in the x3 because the x3 doesn't run at 240+ degrees. so sutting the ac, it takes longer for the air to get hot from the engine.

[Craigito]

Normal. And just for the record...the A/C sucks donkey balls on this car. Unfortunately, you have to buy a Ford to get the kick ass AC

[sambonator]

Originally Posted by Charlie@RissRacing

Correct... WOT will disengage the AC clutch to limit any more Load on the motor... thus giving a bit more power turning the AC compressor off

Just sucks it takes a second again to blow cold...however pretty normal

Hey Charlie, long time no chat!

You work for Riss Racing now?

[hotrod182]

Originally Posted by 335e90

Exactly. We would hate for you to lose to that IS350.

Thats right, don't want to lose your cool if that IS350 beats you, so you just lose your cool inside the car only.

[StarrDlux]

overspinning the same reason i disengaged my ls1 a/c quicker. it had a 3500 stall and went from stopped 570wft/lb in about one stuff of a push. too rapid acceleration of an old-skool a/c could throw it through the hood (no joke).

But my audi a4 it has variable compression/displacement a/c with no clutch so it just alters its displacement and runs 100% of the time so its completely transparent.

I assume bmw is the latter but is more aggressive. i never felt this in the audi because the tiny motor needed wot all the time to get going even with 22psi peak. the a/c just rocked out. but i guess when 275ft/lb and 225bhp isn't that much to worry about.

They should just go to electric compressor so we can rock out full time.

[Sniz]

Originally Posted by StarrDlux

overspinning the same reason i disengaged my ls1 a/c quicker. it had a 3500 stall and went from stopped 570wft/lb in about one stuff of a push. too rapid acceleration of an old-skool a/c could throw it through the hood (no joke).

But my audi a4 it has variable compression/displacement a/c with no clutch so it just alters its displacement and runs 100% of the time so its completely transparent.

I assume bmw is the latter but is more aggressive. i never felt this in the audi because the tiny motor needed wot all the time to get going even with 22psi peak. the a/c just rocked out. but i guess when 275ft/lb and 225bhp isn't that much to worry about.

They should just go to electric compressor so we can rock out full time.

never knew air conditioning was worthy of the term "rock out"

[Wires]

Originally Posted by StarrDlux

They should just go to electric compressor so we can rock out full time.

It would suck more power to convert gasoline to electric to run the electric compressor. Not the same as the fans, since they used to have parasitic losses.

[tintivilus]

Originally Posted by Wires

It would suck more power to convert gasoline to electric to run the electric compressor.

Trivially more -- electric alternators and motors are pretty efficient. Thing is, you'd still want to kill the AC at WOT to reduce engine load. It takes (roughly) the same amount of energy to drive the compressor whether it's via a belt or via the alternator.

How the hell hot is it in Florida? I can't imagine how badly the A/C must be loaded (thermally) for the chiller to warm up so quickly after removing power.

[StarrDlux]

whoa whoa. clutch? you are kidding?

Doesn't the prius use an electric air con? or do they have to start their motors to use a/c? that wouldn't seem logical in heavy city (peak mpg) mode?

back to the clutch you are kidding right? audi doesn't use a clutch at all it is continuosly variable compressor not alot different than an alternator. if there's no load there's near-zero parasitic loss.

now i thought the bmw used some sort of variable load alternator that disengages at WOT?

[Wires]

Not sure about BMW, but all the vehicles I've driven before have a electric clutch that engages/disengages the A/C compressor. On my 335 I have no idea, since I can't find it under the hood.

The idea of having a variable load A/C is pretty cool though. You should have a consistent temp coming from the vents.

As for the alternator, the design of it varies the load on the engine based on electrical demand. I don't think that it would disconnect the alternator under WOT. With EFI, you have more strigent voltage requirements for operation, and running the engine at 6000RPM with no power coming in would be short lived.

[skim7x]

Railgun is correct. The compressor disengages on WOT to prevent overspinning... not to save precious 5hp lol