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RE: vehicle weight, HP, and gearing comparison between vehicles

  1. Mar 1, 2013 #1
    Hello all.
    I am now enrolled at VRI at WWU!

    I am working on a sort of independent study project. I am making a V12 out of a pair of motorcycle engines to go into a VW based kit car.

    I have run the IHP formula and come out with 250hp, and 220 lb/ft of torque.

    The car weighs 1800 pounds.

    Ok now, onto the next. I am targeting as close to Lamborghini acceleration as I can.

    What Im looking for is a way to compare the weight, power, and gearing (including final drive ratio) of one vehicle to set the gearing of the other.

    I know adjustments will have to be made for the torque/hp curve peaks. but trying to get a good close ball park and start from there.

    The transmission will be modular and a sequentially shifted unit.

    Any one point me to the proper calculations, or formulas?

    Thanks in advance!

  2. jcsd
  3. Mar 1, 2013 #2

    jack action

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    Science Advisor
    Gold Member

    This acceleration simulator should help you evaluate the performance you can achieve with a given power/weight ratio, tire's friction coefficient and vehicle layout; no matter what type of engine or transmission. (the theory is at the bottom of the page)

    Once you know the target vehicle' speed and the engine rpm for the desired power output, you just need to calculate the proper gear ratio to link the engine to the wheels (formula and link to nice calculator here).
  4. Mar 6, 2013 #3
    Thanks! Ill look into them.

    Im trying to iron out some details on the engine component alignments. There's always something to have to wriggle into place. A V12 has very little room to work with ironically.
  5. Mar 14, 2013 #4
    I have something that can model this for you:


    It took me about 2 years to write. Admittedly, I wasn't working on it flat out, but it's pretty involved.

    What pair of motorcycle engines have you made a V12 out of?
  6. Mar 14, 2013 #5
    kawasaki voyager. Its a work in process, not complete yet.
  7. Mar 14, 2013 #6
    thanks for your replies. but after a recent thread, I'll stop asking questions here
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