Why Should I Install A Stroker
Kit In My Engine?
By: Daymon Stephens
A stroker kit unleashes all the potential of a factory-installed
engine. A stroker kit includes all the internal parts needed to
build up the original block and heads. The longer stroke crankshaft
of the stroker kit, along with changing the connecting rods, gives
us a larger cubic inch engine. The change to the rod length is
needed in order to maintain the proper rod ratio the pistons in
the stroker kit are made specifically for the new stroke and rod
combination usually with several options of compression ratio for
different octane fuels.
"Ok, great, but why do I need a stroker kit?"
When engines are designed at the factory the combinations that
the designers come up with are configured to meet federal regulations
while at the same time giving sufficient power to operate the automobile
that they are to be installed in. For instance if a truck is designed
and rated at say 6500 GVWR then the engineers for that model would
come up with a combination of total horsepower, torque and cubic
inches needed to operate this particular vehicle.
Lets say we have a truck that is set up by Chevrolet with a gear
ratio and drive train that needs 200 horsepower to reliably pull
a load of 6500 lbs at 75 mph (75 being the current speed for most
of the U.S.A) at an rpm of no more than 3500. The factory is not
concerned with how fast the truck gets to 75 mph or if it will
make power or go faster than 75. They are concerned with getting
to 75 with the best fuel mileage at the least cost to them possible.
If they can build an engine that puts out 200 hp at 8.0 to 1 compression
with a .390-.400 lift camshaft in a 350 cu in package that meets
these demands then that is what is built.
The combination in the above example could have easily made 350
horsepower with the appropriate changes to the compression ratio
and or camshaft, but the easiest way to build more reliable power
is with the installation of a stroker kit. Compression ratio and
camshaft changes have their good points as well as bad while changing
the cubic inches can provide more power while retaining the every
day "drivability" of the vehicle.
Moving the compression ratio from 8.0 to 1 up to 9.0 to 1 or higher
instead of installing a stroker kit changes the octane rating of
the fuel that this engine needs in order give reliable performance
without a detonation problem. While most engines will run on pump
gas with a 91 to 93 octane fuel at 9.5 to one compression ratio
the cost of fuel is not going down and with the savings in fuel
costs you can pay for the stroker kit in the long run time and
time again. For the performance enthusiast we will have a stroker
kit designed not only to get the performance gains of the larger
cubic inches but the increase in power from a logical compression
ratio change as well.
Changes to the camshaft profile will greatly change the performance
of an engine but at the cost of impacting the fuel mileage. To
keep this simple, in order to open a valve farther you have to
have a bigger cam lobe to do it. With a bigger cam lobe you are
holding the valve open longer and this extended overlap on the
opening of the intake and exhaust valves is what causes the rough
or lopey idle that is heard in performance style engines.
The best and most reliable way to make more horsepower and torque
is by changing the cubic inches with the installation of a stroker
kit. We have said it for years and I will repeat it here there
is no replacement for displacement. No matter what you are trying
to do, the larger the cubic inches the more power you can make.
We can make 450 horsepower out of a 350 cu in Chevrolet the same
as we can make 450 horsepower out of a 454 big block Chevrolet
the only difference being that the 350 has to be turning 6500-plus
rpm with 12 or so to 1 compression ratio and it is not "streetable."
The 454, on the other hand, can achieve this same power at a 10.0
to 1 ratio with some good aluminum heads and a nice hydraulic roller
camshaft and can be driven on the street with high octane pump
gas. The larger cubic inch engine will last longer and give you
the same results. Remember though, changing from one engine family
to another creates a lot of problems in making everything fit as
the none of the manifolds, brackets, pulleys etc are the same.
The use of a kit allows you to get all the possible cubic inches
out of your factory-installed engine without emissions problems
or loss of fuel mileage. From the truck that needs more torque
for pulling to the all out racing machine that needs the absolute
most cubic inches that can be gotten out of a certain engine family
there is a kit to fit your needs.
About the author: Daymon Stephens owns http://www.RPMMachine.com/?ref=stroker-kit
where they offer more stroker kits and rotating assembly combinations
than anyone else online. Daymon started working on engines in 1985
as a mechanic, and on to becoming a machinist in 1988. He raced
for a couple of years in 1997 and 1998 and still has a passion