woody

One thing that has been bothering me since delivery of my car on May 6th, is that the car seems a bit sluggish (and the gas pedal does not seem fully responsive) when I start moving from a complete stop. This is not always the case, but it does happen quite often and mostly when the car is not fully warmed up. Much has been written on this forum about steptronic not shifting down to 1st gear when coming to a stop and instead starting out in second gear. I have always thought that this has been the cause of the sluggishness and non-responsive gas pedal.

On several occasions over the last few days, I have turned off the climate control system (pushing the round STOP button) and driven around town with the windows open. On each occassion, the sluggishness and hesitation completely disappeared, the gas pedal became much more sensitive and responsive and the car felt much more powerful. I'm almost tempted to drive without air conditioning and to just sweat it out all summer (LOL)

Has anyone else experienced this? Does the climate control system drain that much power from the engine? Can this be the cause of the hesitation and sluggishness?

I'm leaving in a little while for the July 4th weekend, but would be interested in reading about anyone's thoughts on this when I return on July 5th. Thanks.

EBMCS03

I know AC does zip some power but I wouldnt have thought you would have noticed it that much.

The thing is. Step does start off in 2nd many times like you noted yourself but if you step into the gas a little more from a stop the transmission should choose 1st instead of 2nd.

Hehe maybe you should have gotten SMG. I never have a problem of it not starting off in 1st.

vegastrashed

Well, I do notice a difference between having the A/C on and off. And, I turn it off when engaged with some spirited driving.

Doesn't the Step have a Sport button? Have you tried driving with Sport mode engaged and in DS mode. Isn't that the correct mode to be in for a more responsive drive?

znod

If your compressor is running, then you probably would feel some sluggishness given your relatively low HP. Our cars' compressors don't have clutches, and they can be more, or less, on, in degrees, depending on the circumstances. So, sometimes one might experience loss of performance and other times not. In this regard, it apparently takes "an extended period" for the compressor to completely turn off after turning climate control off. So, if I want to ensure no loss of power for some reason, then I turn climate control off as far ahead of time as I can anticipate.

znod

Step has DS on the 545i--biut no sport button. And, yes, that's the place to be for spirited driving, generally speaking.

jet190rs

every car is slower when the ac is on. how slow each car becomes is difficult to determine.

Bimmer32

Some cars, particularly Japanes, have the compress come on and off. Znod, I think the compressor cuts out as soon as you turn your AC off. At least in mine, I don't hear the "extra" burden on the engine when I turn off the AC.

On V8, you may not feel a power loss due to AC, but on 4 and 6 cyclinders you do.

Ricracing

The AC is driven by the cars crankshaft!

The AC consumes power and increases the gas consuption,
as the generator and wather pump but much more.

No matter if it is a 116i or a 550i, but relatively the 550i suffers less.

So if you what to get the most hp of your E60 turn off all electrical devices
and most important, the AC.

PS. BMW is developing electrical wather pumps (in some models it
already is) and a generator system that don't use the crankshaft power.

znod

You may be right about the compressor turning off immediately. That's logical. I got my info from my dealer's Shop Forman, but who knows? Otherwise, my points hold. And, unfortunately, our compressors don't turn off, in any degree, when the car is floored--according to the same guy.