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6MT shifting with AC on

Wissam2010-08-18 15:32:14 +0000 #1
I normally shift around 2700-3000 rpm, but I noticed when the AC is on it becomes hard to shift smoothly at these rpms and I would have to go north of3500 rpm to help smooth the shifts out. Are you guys noticing the same thing? I know the AC puts extra load on the engine, but it should not be this noticeable on an engine this size.
Matt@Camber-Toe2010-08-18 15:38:30 +0000 #2
i have noticed that as well...below 3000 rpm the engine drops like a rock and I have to quick shift or blip the gas to keep it from lurching.
wj42010-08-18 16:08:44 +0000 #3
I, too, notice that. But I notice it with other cars as well. I believe when the a/c is on, it's using a lot of juice from the surge compressor that's why.
achien2010-08-18 16:23:49 +0000 #4
Yes, especially if you "Max" out the A/C. I feel the power lost is more apparent when shifting from 1st to 2nd.
Wissam2010-08-18 17:22:50 +0000 #5
Thanks guys for your feedback...
MPoWeRMAN2010-08-18 15:49:56 +0000 #6
especially here in the desert where its 120 in the summer, if I need a little more power off the line, I shut off the ac till I reach speed
TRZ062010-08-18 16:04:52 +0000 #7
You know I never thought I would say this, but with this particular car and this particular auto tranny....

This car is better driving and more user friendly and for the most part faster with the Steptronic. It's almost as if this car was built around that tranny.
bmw0perat0r2010-08-18 17:58:42 +0000 #8
Quote:

Originally Posted by TRZ06

You know I never thought I would say this, but with this particular car and this particular auto tranny....

This car is better driving and more user friendly and for the most part faster with the Steptronic. It's almost as if this car was built around that tranny.

I don't notice the a/c on at all with my steptronic. Shifting is consistantly smooth with or without it on. Engine speeds between shifts do not change. In short - one does not notice any difference in engine power/smoothness.

In my old e36 m3 ...oh yeah, you felt it kick in even while at highway speeds...car would slow for a second when you turned it on, needless to say I rarely used the a/c.
CaptChaos2010-08-18 18:44:14 +0000 #9
Yes, I can tell when the AC is turned on. The revs must drop faster during shifts so this requires more attention to be smooth.
epiphone32010-08-18 17:16:30 +0000 #10
I notice the same thing... I try to keep the AC off as much as possible.
danimal2010-08-18 19:24:21 +0000 #11
Quote:

Originally Posted by epiphone3

I notice the same thing... I try to keep the AC off as much as possible.

+1

They need to make a/c run off the electrical system, not the engine.

-Dan
fdc2010-08-18 20:52:08 +0000 #12
Quote:

Originally Posted by danimal

+1

They need to make a/c run off the electrical system, not the engine.

-Dan

it is much worse ...

in this case the a/c will take the power from the generator that of couse

will take the same power off the engine (becaming harder to spin as you

request more current). Not only, since the generator has a 80%

efficency you will loose ... after this your 'electric' A/c will require a compressor (another electric motor ...).

Attaching the compressor directly to the engine is actually the most

efficent option

fdc

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