WRX STI impresses a MODDED 03 Cobra - Page 2
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This is a discussion on WRX STI impresses a MODDED 03 Cobra within the Comparison: WRX vs World forums, part of the Community - Meet other Enthusiasts category; Originally posted by EIonJess With 225whp how much horsepower would you say you were putting out at the crank? I ...

  1. #16
    Registered User WRXin''s Avatar
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    Originally posted by EIonJess
    With 225whp how much horsepower would you say you were putting out at the crank? I was thinking like 275-280???
    I believe it would be a reasonable estimate to add 60 hp to our whp in order to get crank hp for our cars. If you want to get technical, take the 227 stock crank hp, and divide it by the stock 167 whp. You get a multiplier of 1.36. So, you can multiply whp by 1.36, and theoretically that should give you crank hp.
    Fahd

    Floats like a butterfly and stings like when I pee!

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  3. #17
    Registered User LemonHerb's Avatar
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    They did seem like a good group of people you know. Although, I think I would rather them go back to totally underestimateing me so they will go easier on me. The only way im gonna keep up with a cobra is if his parking break is on, and even then he may take me
    -Andrew

  4. #18
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    Originally posted by WRXin'
    I believe it would be a reasonable estimate to add 60 hp to our whp in order to get crank hp for our cars. If you want to get technical, take the 227 stock crank hp, and divide it by the stock 167 whp. You get a multiplier of 1.36. So, you can multiply whp by 1.36, and theoretically that should give you crank hp.

    ACTUALLY, if I'm NOT mistaking a 30%, or whatever driveline loss, is a CONSTANT!

    In other words, if you take a STOCK WRX or ANY car and figure out:

    1. Rate crank HP.
    2. Dyno'd rear HP.

    From that information you get (A) HP loss or (B) Percentage of loss


    Now you mod the hell out of the car. The driveline has NOT changed and thus the constant of loss has not changed.

    Here is the anomoly and both scenarios
    ---------------------------------------
    Car A

    300 Crank HP
    250 RWHP
    50 HP loss or 20% loss in driveline

    You mod car A and now have 300 RWHP.


    1. 300 RWHP + 50 HP loss = 350 CRANK HP

    2. 300 RWHP + 20% loss = 360 CRANK HP


    These two numbers start to get further apart the higher you go in HP. The margin of error gets BIGGER!

    CAR B

    400 HP STock
    350 RWHP stock
    50 HP loss or 14.2% loss

    CAR B MODDED

    460 RWHP

    + 50 HP loss = 510 HP at crank
    x 1.142% loss = 525 HP at crank


    The numbers are close, but I think the driveline loss never changes UNLESS you put gears in it, or change something to decrease the amount of friction loss or reduce the weight of the components. Its a constant.

    They will give you close to the same numbers. The only TRUE way to find crank HP is dyno the engine by itself. But you can estimate so close that its not worth doing that...

    Just FYI... I could be wrong...
    03 EB Expedition
    --------------------
    SOLD!!!
    03 Cobra
    1/4 - 12.05
    MPH - 118.06
    465 RWHP
    485 RWTQ

  5. #19
    Registered User WRXin''s Avatar
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    Originally posted by 03Cobra
    Just FYI... I could be wrong...
    I like your way of thinking What I've stated is by no means an exact science. It's just one of several approaches that one could take to estimating hp. I think both techniques make logical sense, but it's still difficult to come to a conclusive answer by using either one
    Fahd

    Floats like a butterfly and stings like when I pee!

  6. #20
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    Originally posted by WRXin'
    I like your way of thinking What I've stated is by no means an exact science. It's just one of several approaches that one could take to estimating hp. I think both techniques make logical sense, but it's still difficult to come to a conclusive answer by using either one
    True...True...

    Me likey soap box....
    03 EB Expedition
    --------------------
    SOLD!!!
    03 Cobra
    1/4 - 12.05
    MPH - 118.06
    465 RWHP
    485 RWTQ

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