Does everyones mini do this?
My car runs pretty horrible with the AC on, I would say I lose a good.. 35% of my power, maybe, probably more.

When the AC is on, the car is harder to drive (floods easy) and the throttle is MUCH less responsive.
I honestly can't stand driving it with the AC on, so whenever I have to go some where I arrive sweaty.
Why is this? Why does the AC effect it so dramatically?
This is my first summer with the car, and it might be a rough one..



Also, could it be because of the bpv? I think I need to replace it anyway, I only build 10 psi..
https://www.northamericanmotoring.co...-this-now.html

Or, since I have 84k miles should I just go all out and get it rebuilt, port and polished or whatever..?
opinions?

 

The A/C does take quite a big chunk of power to run! I don't like driving off a stop with it on, it takes longer to go! It's mainly because when the A/C clutch engage, it drag some of the power of the engine! As much as I hate how much I feel the effect of it when it's on, I wouldn't get rid of it :p

 

Yeah haha, that is what I have to do.
When I am stopped at a light I watch for the other light to turn yellow to know to turn off my AC before I have to take off.. heh.

 

I've driven mine 128 miles all with the a/c on in 99 degree weather. 33mpg and no complaints of any kind, let alone of running "pretty horrible." Shrug.

 

Are you talking about your R56?

 

Of course. When you wrote "everyones mini" did you mean 1st gens only?

 

Oh no, thats fine, I was just making sure.
I thought you might have another mini since this is the 1st gen section =]

 

You could be noticing this MINI A/C phenomina more due a poorly fitting BPV plate. With a 15% pulley reduction your boost numbers should be closer to 14-15 lbs. That is where I would start first.

Generally we only use the A/C on hot days, and as we all know the hotter the day ( esp depending on what altitude you are at ) the more power loss we will experience....a combination of the two is noticible but not to the point of having to shut down the A/C just to drive normally.

 

hahah, its sooo horrible with the AC on >< its hard to go from a STOP, i wud always stutter on it. i might have to try ur method and turn it off on a stop =P

 

Yeah, I know that but I lose a LOT of power, pretty much suddenly when I turn off the AC and get it back about a second after I turn the AC off.
I will start by changing the BPV.
I think I want to try the DTBPV, but I am a little afraid I won't like it, I don't know why, I guess it is worth a shot.
and by a poorly fitting BPV plate, do you mean the piece that covers and uncovers? and getting a new BPV would fix it if that was the problem, right?
I know I need a new BPV anyway, so I will get on that soon!
Thanks.

 

haha, its the only way, sounds like we have a similiar issue, mine is really hard to not make it stutter on take off with the AC on, unless I rev it really high, then I still take off SLOW!
I hope the BPV helps, I know it will with the AC off, but I hope it does on as well.

 

if you dont like the dt bpv you'd probably be a first not to

 

Both my MINIs did this.
I hardley ever run AC, unless I want my hair gel to dry.
For spirited runs or traffic jams and track days I always turn it off or even run heater on lowest dial. DTBV did not do nothing for AC power loss.

 

I thought I was the only one running the heater in traffic.

 

In my '03 JCW, due to the tall gearing in first gear, it was difficult to pull away from a stop smoothly - turning off the compressor helped considerably - but eventually I just got used to it and got where I could pull away smoothly without over revving it. No question, you notice the drag of the A/C much more in the early cars, and it really affects the fuel mileage. Mine would drop as much as 3-4 mpg when the weather got really hot and I was using the A/C all the time, but it was a price I was willing to pay to be cool in the car.

In my '09 Clubman S OTOH, you hardly notice whether it's on or off and it doesn't seem to affect the mileage either....

 

I think anyone with a 4cyl notices the loss of power with the air on. I fitted a home made intercooler sprayer, and while sitting at a light hit the mister a few times and can tell a noticeable difference when pulling a way.

 

I did a test of this on a Mustangs dyno - with AC on I noticed a loss.... was done by mistake so did another run to get a proper figure and the difference was 5whp less with the AC running c.f. off I have 211whp so 5whp isnt quite a 35% loss though... perhaps something is wrong with your car then... :(

 

I definitely lose more than 5 hp.
seems like the supercharger takes a really long time to kick in.
I hope the BPV will help, I know I should be losing a little power with teh AC on, but I really really don't think it should be as much as I am.
I am going to order the BPV today, I will post again when I get enough time to get it on there.

 

OP said he was running a 15% pulley and only showing stock boost of 10lbs......that said, a BPV could be the answer to his pressure loss.

As far as a DT BPV helping with acelleration issues when A/C is on ? He should be showing higher numbers of boost with or without the A/C on.

 

I fall into the "don't notice much" catagory, but then again, I am old...really old. Remembering the 4 cyl pigs of the 80's, the Cooper does really well.

Off the line, there is definitely a big difference in the amount of gas you have to give it as well as off the line power. After I am going though, I don't notice anything. This seems totally normal to me.

 

With that in mind I would say its not the AC thats the problem then - hope the BPV sorts it for you

 

I'll find out pretty soon hopefuly, I ordered the DTBPV.
Now I just need to find some time to put it on heh.

 

Had the same problem. Twincharged it, and it wasnt a problem. It's more of a compressor issue then anything.

as for only a 5hp difference with it on, at peak hp you wouldnt notice it as much, but across the curve im sure its a lot more than 5 hp and that you will notice as everyone here is stating.

 

Love that approach; my car feels a bit sluggish... I know, lets twincharge it Love it

 

The biggest difference I notice w/ the A/C on is a very notchy (for lack of a better word) throttle response. Smooth clutch engagment is nearly impossible due to the "all-or-nothing" nature of the throttle response with it on. Otherwise, power-drop is about what I would have expected from an engine this small when off-boost.

I've learned to live with the idea that A/C=daily commuting/leisurely cruising, and harder/sportier driving=sweatty brow and sticky palms. My last car was an early (1.6) Miata... Believe me, the MINI (R53, in my case) is actually not that bad with the A/C on!