Just like the title says. When the A/C is on, the car bucks when shifting under normal conditions and taking off. I expect a little power loss since it is a 4 cylinder and there is no boost during normal driving, but this is more than just power loss. For a while I have been putting up with it because at times it's barely noticeable plus I used to think it was just me. I would still be putting up with it but it seems to be getting worse especially when outside temps near 100º or higher. I'm wondering if there may be an issue with the compressor clutch. What do you guys think? Anyone here had this issue? Do I have to live with it? Car is 6sp. manual BTW.

Also, I will probably be getting torque arm inserts soon. Will this make matters worse, or do you think maybe the soft POS factory mount is part of the issue?

 

I don't have driveability issues on my 8500-mile 2012 MCS. I hadn't driven without a/c recently until the other morning. Yes, it saps power to some degree, but it's smooth/consistent while driving.

I do have the NM torque arm insert(s), but I installed them the 2nd week I had the car. They're worth having, but I can't comment on how they might affect what you're experiencing other than they do firm up / generally eliminate the engine movement when shifting, so that would seem beneficial. Maybe a danger of band-aid'ing a symptom, though.

I take it this is a new(er) behavior for your car? Oh: but your first full season of hot weather with it, right, since delivery in 9/2011?

 

I've got a 2011 cooper w the 6sp manual and it will buck with the AC on if you let the RPM's drop to low. I have learned to keep the RPM's up a little bit with the w the AC on in hot weather ( I live in AZ so it's HOT 3 months out the year and warm for another 3 ). Mine only does it when starting from a dead stop - as long as your moving ( the 1-2 or 2-3 shift ) your fine.

I just chalk it up to hot air , and the drag of the AC compressor on the engine at low RPM - it needs a little more gas to get the car the moving.

Hope this helps - keep us posted

 

When cruising, it's fine. It even picks up fine when I accelerate. The problem is starting off and shifting in lower gears. It's going to the dealer as soon as it is convenient for me to take it and leave it, but that could be a few months for all I know. I think I remember someone on here saying they had some sort of vibration damper installed by the dealer for the a/c system, does anyone else remember this or know what it could be?

 

Thanks for the input. I plan on getting the torque arm inserts in about a month along with a nice shiny new magnaflow muffler. Hopefully it helps!

 

I have a 2011 MCS and mine was like that too until I switched out my intercooler to a Helix and no more problem.

 

FMIC is way out of my price range right now lol