1st Gen R53 Cooper S Most liked posts in thread: OK to bypass AC to gain hp?

  1. jiminni

    jiminni Well-Known Member

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    #2 jiminni, Nov 25, 2009
    Most hardcore power junkies and racers remove their a/c's. When the a/c is not running there I still a little drag there, nothing like when it runs though. Adding a pulley without the a/c should have no effect on the s/c. You will
    need to ask someone here, what size belt you will need if you remove the a/c and add a 15% pulley. I have seen it done, but didn't see what size belt they were using.
     
  2. Way Motor Works

    Way Motor Works New Member

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    #3 Way Motor Works, Nov 25, 2009
    When we take the A/C compressor off the race cars we are doing it primarly to save weight. But I put an idler pulley in it's place to keep the belt length correct. I have the Idler pullies here to replace the compressor if you want one, just give me a call.

    WAY
    317.201.8670
     
  3. Steve

    Steve Administrator
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    #4 Steve, Nov 25, 2009
    Makes me wonder...if you're going to remove the A/C compressor anyway, might as well pull the rest of the system as well, right? Unless you're building a real race car it's probably not worth the effort to pull every last wire and cable, but maybe the compressor, evaporator and easy to access lines, etc. On the other hand, I suppose if you're planning to sell the car one day you might want to just replace the heaviest part (compressor) with an idler pulley and leave the rest in place so you can easily put it back together again later.
     
  4. Mintendo DS

    Mintendo DS New Member

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    #5 Mintendo DS, Nov 25, 2009
    So the compressor doesnt draw enough power from the engine to gain any noticable hp if bypassed.:idea:
     
  5. Nathan

    Nathan Founder

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    #6 Nathan, Nov 25, 2009
    A few local track rats have pulled the A/C on their track only MINIs. My thought it is more in weight saving than picking up a few HP. The compressor is fitted with a clutch that allows the pulley to freewheel when the A/C is not on.

    It would be an interesting experiment to dyno the car both before and after to see if there is any real gain.
     
  6. Mintendo DS

    Mintendo DS New Member

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    #7 Mintendo DS, Nov 25, 2009
    Thanks everyone! I think i'll be leaving Charlie as is for the time being. Living in PA, we get a good bit of snow so any extra weight in the front end will be a good thing. Thanks again!
     
  7. Mike

    Mike New Member

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    #8 Mike, Nov 25, 2009
    The compressor clutch is outside of the compressor, so when the clutch is disengaged, the pulley rides on a good set of bearings. The friction is very, very small. The replacement pulley has a lower moment of inertia, though, so theoretically the engine would spin up a tiny bit faster with the replacement pulley in place of the compressor.
     
  8. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    #9 BlimeyCabrio, Nov 25, 2009
    Last edited: Nov 26, 2009
    Take off the belt and spin the compressor pulley - as Dr. Mike says - very low drag. I doubt it really matters as far as drag is concerned. Weight savings of losing the whole cooling system would have a bigger impact.
     
  9. Dr Obnxs

    Dr Obnxs New Member

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    #10 Dr Obnxs, Nov 25, 2009
    If you're serious

    and yank the condensor from in front of the radiator, you'll drop about 1% of the weight of the car from the front wheels (good) and improve air flow through the radiator (good as well).

    But like many have said, pretty much race car only....

    Matt
     
  10. Mintendo DS

    Mintendo DS New Member

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    #11 Mintendo DS, Nov 27, 2009
    My MINI may look it, but its far from a true racecar. 0 track days, 0 autoX, 1 Dragon, and 1000's of local twisties. So until some of those numbers get greater, i think i'll hold on to the AC. Hell, i might even get it fixed.:lol: