Is this normal? When I'm driving my car on a level road and i have the air (fan setting on 3) and then push in the A/C button and I get a sudden loss of power? Perhaps something is wrong on my car, but as soon as the A/C engages my car actually jolts. I know i'll feel a power loss, but a jolt? is that normal? thanx for the info?

Has anyone ever run a 1/4 mile w/ their A/C on? I wonder what the difference would be.... maybe its time to go back to the track.

 

That's somewhat normal... I try to engage the A/C when the RPMs are under 2K in cruise to minimize the wear on the EM clutch.

 

No difference, the A/C turns itself off at WOT.

 

i'm guess that's true for all generations?

 

Chunger definitley is doing it right.

Once she is going with the A/C on, I don't notice much of a difference at all.

 

Autos will shut off the A/C at WOT - Manuals will shut off the A/C at 4k rpm.

So when is someone gonna invent a reliable electric-driven A/C ??

 

Manuals will also shut off the AC at WOT only, not 4K rpms.

DW

 

Right after the 1st performing electric supercharger

 

yeah, its normal.

 

Actually, I've been reading up on variable valve timing, and BMW is gonna start making cars with electric A/C and power steering. They had to beef up the electrical system to handle the valve solenoids, so they threw all kinds of other stuff on there for good measure.

 

Dunno about WOT - probably does also, but mine shuts off at 4krpm under light pedal pressure and comes back on under 4k.

 

Don't know if you can do it in your area, but on a 5-speed, 4000 rpm in 5th gear is about 100 mph. We all know that a Maxima can easily cruise at 100,120, even 130 mph. I would think that only people in the Midwest have the kind of highways where you could explore this kind of cruising in a somewhat safe manner Try cruising at 105 mph in 5th and the AC will stay on. It does not make sense for it to cutoff like you suggested. Maybe something's up with your car, like maybe you are a bit low on refrigerant and the AC is cutting out at high rpms so as not to self destruct.

OK. I checked my FSM for a 98. It says that the AC clutch remains engaged unless:
main system switch is off
fan is off
ignition is off
outside temps are really low (Perhaps you were driving thru Antarctica?)
refrigerant is low

Oddly enough, it doesn't mention WOT

DW

 

I'm sure there are a few other perks that aren't mentioned in the FSM. Keep in mind that the signal to activate the compressor comes from the ECU and the ECU logic is nowhere to be found in the FSM either.

My 99 shuts down the compressor at WOT, it's easy to discover this perk too. On a hot day, A/C blasting ice cold, from a stand still put your foot to the floor and hold it there. Somewhere in the middle of 3rd gear, your A/C system is starting to blow warm air. (the compressor has been off for a bit) By the time you hit 4th gear your blowing nothing but warm sticky air. My buddies I30 does this as well. As soon as you back off the throttle a bit, the A/C starts to blow cold again.

Actually this logic is probably found in quite a few cars on the road today. When you demand full power, certain power robbing accessories shut down for a brief second or two. The normal day to day driver would never know it happens. We on the other hand discover these things when we push our cars to the limits. It also prolongs your compressors life, I'm sure the compressor wouldn't be happy seeing very high RPM's.

 

I said 4kprm - I didn't say 5th gear. Where did 5th gear come from? No, I never drive that fast - too many cops.

In 2nd and 3rd I'll let the revs creep up to 4k rpm under ligth pressure sometimes - especially if I can see I'm about to slow down again. When I accelerate I will sometimes do that at 50% throttle and let ti rev up to 5500 rather than go WOT up to 3500. Accelerates faster with and is more efficient. Of coure then you see the 4krpm cutoff on teh A/C clutch. Well, you feel it - that little bump followed 10 seconds later with swamp air coming thru the vents.

 

Scruit, I was just giving evidence to support my claim; a manual tranny maxima does not cutoff the AC at 4000 rpm. 4000 rpm in any gear is 4000 rpm. I'm willing to bet that your AC is not quite right.

It's Interesting that you let the car get to 4000 rpm under light throttle. For me, that would be battle mode, so that I could have instantaneous throttle response if I decide to put the hammer down. It looks like you got to 4K rpms and then want maybe 80% power. Normally, I decide to go hard at around 3K rpm and wiz past 4K rpm onto redline

NJMAX - I know that WOT does indeed cut out the AC, I just find it odd that they left it out of the FSM. Maybe it's in another part of the book.

DW

 

Try it. It may do that on yours and you haven't noticed it because you already said you don't run over 4k at light throttle.

I'll try it again on my way home just to confirm - but i'm pretty darned sure I'm right. If I'm not then I'll post again to say I was a dumbass...