horse power/acceleration

[Ord Millar]

Take the acceleration at some point in your curve, call it A, and multiply
by vehicle mass.  This gives the linear force exerted by the rear wheels.
(front wheels?).  F=MA  (it is convinient to measure acceleration here in G,
and mass in lbs).

Torque at the rear wheel is F / (D*2*PI), where D is wheel diameter.  Engine
torque is rear torque / axle ration / transmission ratio + driveline loss.
(keep D in ft for simplicity, loss in ft-lbs)

Engine HP is engine TQ * engine RPM / 5251.  (when TQ is in lbs-ft)

So:  HP = (MA/(D*2*PI)/ratio+loss) * RPM / 5251.

Add in air & rolling resistance, and you're almost there!
-----Original Message-----
From: Jeff W <sierraj at home.com>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Thursday, May 13, 1999 7:35 PM
Subject: horse power/acceleration


>dear sir
>I am writing to you because I am looking for the correct
calculation/formula
>for finding the approximate horse power conversion from vehicle weight and
>acceleration curve.
>    I am presently in Vancouver community college, in Vancouver B.C and my
>instructor (Dave William's) gave me your e-mail address feeling that you
may
>be of some help to me.
>
>vehicle weight + acceleration curve + some other things I don't know=
>approximate HP at RPM.
>thank you!
>Jeff Weinberger
>sierraj at home.com
>
>
>