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Weight reduction = horsepower gain

Discussion in 'General Tech and Maintenance' started by humblegumbo, Jun 26, 2007.

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  1. humblegumbo

    humblegumbo 1595cc's of Mad Fury

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    I am looking for a simple equation. Somewhere out there in the wild world of the interweb I know there is a straight forward equation for converting weight reduction to horsepower gain equivalent.

    What I mean is this: :hmm:
    If I remove one pound of weight from my car, how much HP would I "gain"?

    I'm putting my girlfriend on a serious diet. Last weekend she lost 30 - 40 lbs when I tore out all the underhood A/C components. The new headers and downpipe also helped. I'm looking into lightweight batteries and relocation kits as well. :shades:

    Reasoning? It sure seems cheaper to remove "useless junk" (like A/C) than to increase hp. If I can get a pound for pound hp comparison, I can convert that into dollars. Everyone wants to know hp per dollar.

    Maybe the cheapest way to go faster is to be skinny....
     

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  2. eg6sir

    eg6sir Supa Mod Moderator VIP

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    i've heard for every 10 lbs its like gaining 1hp
     
  3. CRX-YEM

    CRX-YEM Super Moderator Moderator VIP

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    I've often heard that a weight reduction of 100 lbs. should reduce a 1/4 mile time by 0.1 secs
     
  4. CRX-YEM

    CRX-YEM Super Moderator Moderator VIP

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    I think that's a stretch, removing his A/C system would then equate to a 30-40Hp gain.

    I think that your an order of magnitude off on the ratio, 10lbs = 0.1hp gain, which equate to about a 3-4Hp gain which seems much more reasonable
     
  5. phyregod

    phyregod !!YTINASNI

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    Unsprung weight and rotating mass is worth 4 times that. So if you get a set of wheels that is 10 pounds lighter each, you remove 40 pounds from the car, but it will act as though you've removed 160 pounds.
     
  6. eg6sir

    eg6sir Supa Mod Moderator VIP

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    maybe thats what it was.. my mechanic told me that years ago.. he builds hotrod drag cars..
     
  7. humblegumbo

    humblegumbo 1595cc's of Mad Fury

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    I'm serisously no math wiz, but break out your calculator for this one.

    A ten to one ratio would mean that 30-40lbs would be 3-4hp....that does seem reasonable...
     
  8. phyregod

    phyregod !!YTINASNI

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    Thats what he was stating in the first place, except your math is off by one decimal point. 10 pounds = 1hp. so 100 pounds would be 10hp. and his AC system (40ish pounds total) would be like adding 4hp.
     
  9. eg6sir

    eg6sir Supa Mod Moderator VIP

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    i knew i was correct.. :D
     
  10. phyregod

    phyregod !!YTINASNI

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    Its not an exact math, just very rough guestimates.
     
  11. humblegumbo

    humblegumbo 1595cc's of Mad Fury

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    Now, I have heard that. Thank you HOTROD magazine. This applies to everything that the motor turns, which is why a lightweight flywheel would be a nice upgrade.

    That still costs straight cash that my poor bank account can't support. Removing the passenger seat, for example, would be completely free, though. :D

    Does anybody have a source for this rumored 10:1 lbs to hp ratio?
     
  12. eg6sir

    eg6sir Supa Mod Moderator VIP

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    nope.. i'm just going by what i was told by a hotrod builder
     
  13. humblegumbo

    humblegumbo 1595cc's of Mad Fury

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    I won't trust that source unless he has a sweet mullet.
     

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  14. eg6sir

    eg6sir Supa Mod Moderator VIP

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    exactly why i said its like gaining 1hp.. never said you gain 1hp for every 10 lbs
     
  15. jimboburgess

    jimboburgess Go fast, Go Cheap

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    not only would loosing weight help you go faster but turn and stop faster too. the main thing most hondas have going for them is they are light weight, that's why a little b16 eg has a fighting chance against a 350hp monster that weighs sometimes twice as much.

    here's a chart from super honda on free things to remove

    Remove Spare Tire

    Remove Jack

    Remove Floor Mats

    Remove Passenger Seat

    Remove Rear Seats

    Remove Muffler

    Drain Washer Fluid

    Remove Cruise Control

    Remove Speakers

    Remove Radio
     
  16. eg6sir

    eg6sir Supa Mod Moderator VIP

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    mine has teh spare, jack, carpet, rear seats and panels stripped out.. no AC, no PS.. no glove box or gauge cluster bezel.. of course it'll all go back in once the car is painted.. and for shits and giggles i'll pull out the passenger seat and i can really feel a difference in how the car pulls.. which is a lot harder without that seat
     
  17. CRX-YEM

    CRX-YEM Super Moderator Moderator VIP

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    eg6sir , you stand corrected, math > me today, I totally read your post wrong.
     
  18. klyph

    klyph Dismember VIP

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    Actually, it is YOU who stands corrected. Again. Grammar>you as well :p
     
  19. eg6sir

    eg6sir Supa Mod Moderator VIP

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  20. CRX-YEM

    CRX-YEM Super Moderator Moderator VIP

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    god damn it was a long day at work today.
     
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