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March 27, 2005
Well, Dave....
The biggest/best change you can make is
to bring up the compression ratio next time
you have the head off, unless you're taking
it apart for piston/ring replacement.
Taking the head from 21cc down to 19cc should be good for just under 8.5-1
and
were you to go to 8.8-1 pistons next time
around, the combo would be good for
between 9.0-9.3-1 or so. You could take
the head down to 16.4cc but now you're
down to min. thickness for the head
(strength, cooling, head-gasket issues, etc.).
Besides mechanical stuff, better breathing will help. Vizard outlines in hi
s book a few
simple machining steps for the intake manifold or you can spend just under
$200
to replace the stock, less than well flowing design with a Maniflow intake
manifold
available from APT.
Freer flowing K&N filter elements
in the stock filter cans would be helpful
as would total replacement of the stock
cans with a set of K&N round, oval or cone types, aided by "stub stacks" (A
PT or Pierce Manifolds),
The exhaust system is another place to aid
breathing by reducing back pressure. The
1.5" diameter is reasonable for the stock
motor but the addition of a free flow
"absorption" type muffler, as in a Thrush
or Cherry Bomb would be helpful in getting
the gases out more efficently. Either of these will also add to a louder ex
haust note
as well but....it's a great sound!!
Increasing tire pressures above those
recommended by the mfg. will decrease
drag but at some expense in ride quality.
So, depends upon the state of your suspension (shocks, springs, etc) along
with
quality of road surfaces upon which you do
most of your driving.
Decreasing "unsprung weight" by going to
a set of lighter alum wheels is another power "unlocker" as well. The effec
t is
similiar to lightening the flywheel. Car will
handle more "nimbly" as well.
If I think of anything else...I'll yell!! :))
Cap'n Bob
Basic Frog
"Robert E. Shlafer" < PilotRob@... > 36499
Posted on March 27, 2005 07:48 PM
Posted to category(s) Cooling System | Cylinder Head | Engine (external) | Engine (internal) | Exhaust System | Intake System | Interior | Lubrication System | Restoration | Specifications | Suspension & Steering | Technical Info | Transmission | Tuning | Wheels
