Hey All,

I'll be participating in a BMW driving school this weekend with my MCS. Where I live, the temps should be around 100 degrees. I had originally intended to spend the day without A/C, but now I might decide not to be so competitive. I know, it's not meant to be a competitive event, but I still want to go as fast as possible.

Regardless, I'm curious how much horsepower the A/C will take away from my MINI. I've heard anecdotally, that a 15 HP loss can be expected as a rule of thumb.

True?

 

10-15 HP sounds normal. In reality, I can't tell a lot of difference in acceleration whether it's off or on. (I didn't say undetectable, but it's not a LOT.) I keep mine on all the time. I drive an 05 MCS/JCW, and I've done some motoring in an 06 MCSa. The MCSa isn't drastically affected either. Try a couple of 0-60 runs both ways and see how much difference it makes.

Rawhyde

 

I'm personally fairly certain my my MCS looses about 162 horses with the AC on...

 

You could keep the AC running until you need to hit the gas, then just flip it off and drop the windows.

 

I was talking to a guy in a body shop that was working on a MCc. He said that he was actually AFRAID when he was merging onto the Highway. It was 100 degrees+ so the a/c was on. He said that he couldn't imagine owning a MCc in KS, mainly because its hard to drive it with the a/c on.

I also taked to a tech at my dealer, and they said that it takes a lot to turn over that AC compressor. The MINI already has a small engine, so there isnt much power to spare.

 

i would say about 30hp

 

While the effect of the AC is much less noticeable on the MCS, I can say for certain that I do everything I can to keep the AC off when driving my MC, especially in city driving.

The best time for the AC to be on is while I'm cruising the expressway and already moving fast!

AC definitely kills performance.

 

Not sure what the HP impact is on an MC seems to be minor on MCs as others have stated. Since you are talking about driving competitive. I would make room for a big jug of your favorite water based drink and sweat it out. You are probably only talking about 20 to 30 mins at a time in the car, I could be wrong on this though.
Not really the same topic but its been pretty well demonstrated from a MPG stand point that you do better at highway speeds with AC on but you take a hit when city driving.
Another slight thing to consider about running laps with AC on is you will build heat quicker and shed less heat due to the load from the condenser being passed on to the radiator and engine compartment. (Probably negligible impact though...)

 

i heard.. the AC can drawn as much as 40% of the cars power, heard this from a guy who races in drifting. he took out his AC on his S15 because of the weight and the lack of usage and power that brings to the car.

 

I hate AC, whenver it is on its like I am pushing around 5 horsepower max, god I cant stand it. Is there any thing to help this terrible problem with the AC on?

 

The cooper owners have spoken. I believe ac for us Coopers takes a good 30hp cause the last month in cali where I live has been like 110 none stop and with the AC, the cooper does not go. I have to drive alot harder, shifting at 5-6k everytime to push the damn car and ive noticed because i gotta drive it harder, im avg. only 24mpg on city driving where before i was always in the high 20's or 30 to 31mpg. Im thinking of cutting my floor bord and yelling Yaba Daba Doo!!!!

 

You all do know it shuts the AC off anyhow when you are at WOT for 3 seconds, right? And when you step out of it it will come back on.

 

How much HP do you lose because of the aero-drag with your windows open?

 

^ yeh, a lot of people say it's better to run the A/C vs open windows
while at higher speeds.

but not sure if this applies to MINI's... im sure it does but it's not the most
aerodynamic looking car.

 

Which means you have to floor it everywhere you go then, not exactly practical in traffic. Personally I've never driven a car that was so affected by the AC as our MCS, it drives like almost 2 different cars. I turn off the AC real quick whenever I need to do something important on the road

 

Not running the AC will take a lot more HP out of *you* if it's 100° out.

 

I don't really notice much of a difference on our mcs, but it was a HUGE difference on the mc

 

about 7% on a MCS according to this old thread (61 posts long, however)

http://www.mini2.com/forum/engine-drivetrain-tuning/33585-air-conditioning-your-fat-friend.html?

 

I would much rather have the AC on and downshift than roast myself to death! (Comming from a MCS owner in the heart of Kansas.) Its not that bad. But we do notice a difference. Not enough to SCARE us!

 

This is my reasoning to always run with the A/C on

 

Being said tongue in cheek....have a large bottle of water, a good size towel and a stack of Depends and don't worry about the AC.

 

I'm not sure if the AC was designed to be on while you rev your engine to redline accellerating through the gears.

Some cars (not sure about the Mini) will shut the AC off when the engine rev's to a certain RPM to give you more power.

Sorry I don't have any real answers. :(

 

You will most likely be required to run with your windows down and sunroof closed. The windows have to be open for passing hand signals and for safety.

 

Don't know if it will really help...but, I've noticed some super-duper air-conditioning coolant in AutoZone recently that claims to lower the air temperature.... and increase HP, by reducing friction losses in the system.

Probably snake oil, but I hope someone tries it and lets us know if it helps.

 

I was wondering when someone would bring that up. That's right, when you tromp on the gas, the AC disengages.

And it's also quite right that your original concern is a moot point: You will probably be required to drive with the windows down and the sunroof (if you have one) closed. So just use your AC while you're waiting to so out.