Clutch totally different when a/c is on

[Ps3alltheway]

I've owned my 3 for 7 years now and I never understood why my clutch feels different when i turn air conditionning on. I can be shifting smoothly all day but when i put ac, it seems like the friction point is different and i start shifting like a noob. No one else seems to have that issue with their cars.

[Cjcoolen]

I thought I was the only one.. lol 2nd gear sudden bumps for me. Its embarassing.

[Flagrum_3]

Noobs.

[r4BBiT]

It's the same for me with a/c on :-?

[Dubcee]

Same for gen3. I also get the same when more than 1 person sits in the car.

AC draws hp which is going to change how much gas you need to rev match properly. Only solution is a different engine with gobs of power. Or an automatic. :>

[pwdunmore]

Ummmm not really... the amount of HP the AC takes up is nominal compared to how it adds more load the the crank portion of the engine. When the AC clutch is engaged the crank pulley has to spin that extra load.

AC is engaged - Changing gears will cause the rpms to fall in a non linear decent

AC no engaged - rpms fall in a linear pattern because there is no extra load on the crank

Solution - Time you shifts differently when the AC is on

[Milan96]

Ummmm not really... the amount of HP the AC takes up is nominal compared to how it adds more load the the crank portion of the engine. When the AC clutch is engaged the crank pulley has to spin that extra load.

AC is engaged - Changing gears will cause the rpms to fall in a non linear decent

AC no engaged - rpms fall in a linear pattern because there is no extra load on the crank

Solution - Time you shifts differently when the AC is on

Agreed. RPMS drop much faster with the AC on, so shift timing is different. Much harder to be smooth with the AC on. I don't notice my clutch grabbing at a different point with the AC on though...

[Flagrum_3]

Ummmm not really... the amount of HP the AC takes up is nominal compared to how it adds more load the the crank portion of the engine. When the AC clutch is engaged the crank pulley has to spin that extra load.

AC is engaged - Changing gears will cause the rpms to fall in a non linear decent

AC no engaged - rpms fall in a linear pattern because there is no extra load on the crank

Solution - Time you shifts differently when the AC is on


Adding load to the crank equates to more horsepower loss.

[McGuyver_3]

I rarely ever use my AC(generally only in the rain) because I use my windows even on the super hot days. But I have never noticed a difference on any of my cars, no matter the horsepower or people in the car

[pwdunmore]

Adding load to the crank equates to more horsepower loss.

I said there would be nominal losses Flagrum_3 So what's your point?

Rotating mass I was talking about in my post and that is what the OP is feeling.

[Flagrum_3]

I said there would be nominal losses Flagrum_3 So what's your point?

Rotating mass I was talking about in my post and that is what the OP is feeling.

My point was that your comment was contradictory. You stated; "Ummmm not really... the amount of HP the AC takes up is nominal compared to how it adds more load to the crank portion of the engine." -FYI, adding more load to the crank equates directly too using available horsepower, therefore a loss of power and actually a semi-substantial amount with the MZ3s...MS3s drivers may not notice much difference.

_3

[pwdunmore]

My point was that your comment was contradictory. You stated; "Ummmm not really... the amount of HP the AC takes up is nominal compared to how it adds more load to the crank portion of the engine." -FYI, adding more load to the crank equates directly too using available horsepower, therefore a loss of power and actually a semi-substantial amount with the MZ3s...MS3s drivers may not notice much difference.

_3

At low load the HP rating of the MZ3 and MS3 are very similar, so you are saying a lightened fly wheel will give me more HP? Less rotating mass = less HP loss correct?

[Kiewan]

Agreed. RPMS drop much faster with the AC on, so shift timing is different. Much harder to be smooth with the AC on. I don't notice my clutch grabbing at a different point with the AC on though...

Its easier to lose speed while downshifting with AC on for this reason which can be helpful.

Same thing for me, rougher shifting if I am not paying attention with AC on

Side note: Mine has gotten to the point where I turn the AC off on advanced green lights. Noticeable power difference when accelerating. AC is only used on HOT HOT days for this reason.

[Reddie1337]

I fixed this problem easily by getting a speed. Just keep it in boost and shift real fast and you won't find this.

On a real note, AC hogs power, no doubt about it. You will find it makes your shifts rougher because even at idle you can feel the difference of AC being on (at least with aftermarket mounts) the engine has a bigger load on it, unless you account for the difference, you're shifts won't be as smooth.

[Flagrum_3]

Its easier to lose speed while downshifting with AC on for this reason which can be helpful.

Same thing for me, rougher shifting if I am not paying attention with AC on

Side note: Mine has gotten to the point where I turn the AC off on advanced green lights. Noticeable power difference when accelerating. AC is only used on HOT HOT days for this reason.

I remedy the issue by simply shifting at a higher rev point, rev matching on downshifts, and at launch a little goose of the throttle before dropping the clutch helps too. But still feel a loss of power no matter.

_3