Engine Power gains from this....

Discussion in 'SN95 4.6L Mustang Tech' started by Jhussey1280, Jan 30, 2013.

  1. Jhussey1280

    Jhussey1280 Member

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    Hey guys, just pulled the A/C system off of my car and I'm wondering if anyone knows a rough guestimate on how much power may be gained and how much weight is saved over all. The only thing I left on was the core in the dash.

    Thanks.
     
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  2. madspeed

    madspeed Colonel Mustard
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    20 lbs and maybe 5 hp
     
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  3. jcgafford

    jcgafford Advanced Member

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    which amounts to a hot summer and no noticeable power gain. at roughly 6 pounds a gallon you would have been better off keeping the a/c and keeping the tank half full.
     
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  4. madspeed

    madspeed Colonel Mustard
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    correct!
     
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  5. madspeed

    madspeed Colonel Mustard
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    considering the a/c compressor disengages at wot, no real performance gains are made
     
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  6. jcgafford

    jcgafford Advanced Member

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    there is always that hesitation with wot with the a/c on. BUT you can just turn it off to avoid that. and on the way home from the track or after you passed the moron in the left lane doing 60mph you can switch it back on for a comfortable ride.:)
     
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  7. madspeed

    madspeed Colonel Mustard
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    Youre not gonna even have it turned on if youre at the track. The slight hesitation during a streetrace on a closed course or whatever isnt gonna make much dif....Leave it on if you can!
     
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  8. jcgafford

    jcgafford Advanced Member

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    street races are naughty
     
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  9. Jhussey1280

    Jhussey1280 Member

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    Haha well thanks for the answer. I'm not worried about having the A/C but thank you all for the concerns.....
     
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  10. madspeed

    madspeed Colonel Mustard
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    edited LOL :p
     
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  11. Nightfire

    Nightfire Mustang Master

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  12. trinity_gt

    trinity_gt Advanced Member

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    Agree with the above.

    When the compressor is "off" it acts as an idler and consumes virtually no measureable power.

    In removing it you've removed, say, 20lbs (madspeed's #) from the car. A Mustang weighs roughly 3400 pounds with the driver so by removing the A/C components now you're at 3380. If you are still stock and making 215HP, your weight to power ratio went from 15.81 to 15.72; pretty much a rounding error. Don't expect to feel anything in terms of acceleration.

    You've removed 20 pounds, all of it from the nose of the car. This means that the weight distribution has moved marginally backwards. At the curb the car weighs ~3250 lbs and had a distribution of approximately 57/43. This means that 1852 pounds are on the front wheels. With the A/C removed this drops to 1832 pounds. With the total vehicle weight dropping to 3230 this means the weight dist is now 56.7/43.3%. I doubt you'll feel this in daily handling and braking.

    This kind of delete might make sense on a 9- or 10/10ths race car but seems without benefit on a daily.
     
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  13. Jhussey1280

    Jhussey1280 Member

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    Never said my car was a daily driver. I was just asking because I needed the info for something, but thank you.
     
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  14. trinity_gt

    trinity_gt Advanced Member

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    The car in your avatar looks like a daily and you didn't say the car wasn't a daily...
     
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  15. Jhussey1280

    Jhussey1280 Member

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    I also didn't say it was the car in my avatar, but again thank you.
     
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  16. Modular2v

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    Put the ac back on.... You gained zero hp, lost 8lbs of weight and de-valued the car!
     
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  17. 007

    007
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    Its a convertible people. Give the guy a break! I have literally NEVER used my AC.
     
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  18. Jhussey1280

    Jhussey1280 Member

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    All I did was ask for some simple numbers. I didn't ask for anyones opinions on the removal of an A/C system. Thank you 007.
     
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  19. Modular2v

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    I didnt mean anything demeaning by what i said. Its just literally a waste of time and effort to remove the ac on a street car if it works! Even on my car which is setup for 600hp, i would NEVER remove the ac. It simply just doesnt make sense. Why remove it? To pick up hp gain? Well there is none to be gained. The only thing he gained was the loss of cold air when its 100* out! Now, if the car was running 9s and he was trying to shave every ounce of weight off to pick up ET and mph at the track then sure but there are even 9 second cars with ac..... He litrally would have noticed more a difference by removing his spare from the trunk.
     
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  20. bhuff30

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    Said well by someone who has obviously never raced seriously. I yanked the AC on my 88 mustang, and later on the entire heater box.

    A drag car will be taken apart frequently for modifications, repairs, ect. The simpler it is to work on, the better. If you are at the track and break something, time is CRITICAL. Anything that un-necessarily slows you down could cost you the race. Even if you have plenty of time, the AC is just another thing that's in the way anytime you need to pull the engine.

    As for performance, the only benefit as others said is the 20lb weight loss. No measurable hp gain as the compressor switches off near WOT. But what if you pull the AC system, heater, HVAC box, misc. insulation, sway bar, cruise control, washer fluid tank, ECT, you can easily add up to 100lbs or more. Some skinnys, tubular front suspension and you are talking some serious weight loss. And this is weight loss from the FRONT. Ever drag raced? Weight you pull out of the rear of a mustang tends to have no effect on ET because you loose traction more easily. I ran my first 12s pass just before leaving the track once... loaded my tools, spare parts, and other junk in the trunk and made the 12s pass at a lower mph after making about 10 low 13s passes for the night.

    What the OP is doing? I dunno, but it's his car. Maybe he has a master plan. Gotta take one step at a time.

     
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