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Fw: Ugh, stroked and destroked

To: <spridgets@autox.team.net>
Subject: Fw: Ugh, stroked and destroked
Date: Tue, 7 Jan 2003 15:35:53 -0500
i forgot to remove the trailer thingie...duh!
chuck.
----- Original Message -----
Subject: Re: Ugh, stroked and destroked


> long stroke motors are no good for high RPM's either.  they are low rpm
> motors with good bottome end torque.  and exactly opposite for short
stroke
> motors.
> stroking or destroking a motor is a bit of "rocket science" to get what
ever
> it is you are seeking to achieve.  and can get rather expensive if
> components are to be custom manufactured.
> i have a stroked and bored harley 900cc 1970 sportster.  it's now just
over
> 1200cc's.   it's a terror around town but not much fun out on the highway.
> but lots of bottom end !
>
> chuck.
> i just can not leave anything stock.......*wonder why*........   :)
> ----- Original Message -----
> From: <ckotting@wideopenwest.com>
> To: <spridgets@autox.team.net>
> Sent: Tuesday, January 07, 2003 3:28 PM
> Subject: RE: Ugh
>
>
> > Longer connecting rods DO increase compression, but they
> > reduce displacement.  Maybe some ascii art will help:
> >                        ___         ___
> > Combustion chamber ___|   |___ ___|   |___
> >                       |   |       |___|  Piston up
> >                       |   |       | | |
> >                       |   |       | | |
> >                       |   |       | | |
> >                       |___|       | | |
> >          Piston down  | | |       | | |
> >
> > (Assume that the diameter of everything is constant)
> > Swept area of piston = 4
> > Compbustion Chamber with piston up = 2
> > Compression ratio = 4:2 or 2:1
> > Displacement (Piston Sweep + Combustion Chamber) = 6
> >
> > Longer conrod moves "stroke" of piston higher (as you
> > noted):
> >                        ___         ___
> > Combustion chamber ___|   |___ ___|___|___
> >                       |   |       | | |  Piston up
> >                       |   |       | | |
> >                       |   |       | | |
> >                       |___|       | | |
> >                       | | |       | | |
> >          Piston down  | | |       | | |
> >
> > Swept area of piston (still) = 4
> > Compbustion Chamber with piston up = 1
> > Compression ratio = 4:1
> > Displacement (Piston Sweep + Combustion Chamber) = 5
> >
> > Now, nobody increases the conrod length by 1/4 of the
> > stroke, but you get the idea...
> >
> > A longer crank journal (with the same conrod) increases both
> > compression AND displacement (sweep of the piston goes lower
> > down AND comes higher up).  That is why "stroker"
> > crankshafts are usually supplied with matching conrods (a
> > touch shorter than stock to keep the compression from
> > becoming insane).

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