Engine specs for both the R16 and U20 in the owner's manual indicate a max
engine speed of
6000 rom. Given the 19.5% longer stroke of the U20, I'd say there is some room
for a
higher rpm limit in the stock R16, but a stroker R16 using a modified U20 crank
will
probably (all other things being equal) want to stick with that 6k limit.
Mean piston velocity is equal to 2 x n x s, where n = engine speed in
revolutions per
minute (rpm) and s = stroke length. Depending upon the ratio of the length of
the
connecting rod and the radius of the crank throw (l/r), the maximum piston
velocity ranges
from 1.61 to 1.63 times the mean piston velocity. The higher the engine speed,
and
therefore the piston velocity, the higher the accelerative forces at either end
of the
stroke, forces which must be borne by the crank journal, both ends of the
piston rod, the
wristpin and the piston body. Lightweight pistons and stronger, lighter
connecting rods
are generally part of the package when higher engine speed is the goal.
Gary McCormick
Adam Bradley wrote:
> It seems the common choice for a stroked R16 is a slightly modified U20
> crankshaft - or is it the H20? Which begs the question, if it can do a
> certain RPM in the U20, can the crankshaft do the same RPM in an R16?
>
> That is, is the limiting factor of our engine RPM the stroke or
> something else?
>
> Adam
> '70 1600
>
> --- Gary McCormick <svgkm@halley.ca.essd.northgrum.com> wrote:
> > It's an R16 motor that has been assembled with a crankshaft that has
> > a longer stroke (I
> > can't remember the specific crank that is usually used) and, by
> > necessity, shorter
> > connecting rods, to increase displacement. Engine displacement =
> > Cylinder area x stroke
> > length, so increasing the stroke will increase the displacement.
> > There are tradeoffs,
> > though, as a longer stroke is going to limit, or at least reduce,
> > your maximum engine
> > speed.
> >
> > Gary McCormick
> > San Jose, CA
> >
> > Robert.Long@csdinc.com wrote:
> >
> > > Hello list,
> > >
> > > What does "Stroked R16" mean? How does that differ from my stock
> > 67.6 1600?
> > >
> > > Thanks,
> > > Robert
> > > 67.5 1600
> > > 83 280ZX
> > > Albuquerque
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