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Fuel Injection
Development Program
Offers Injection Customization to enhance performance

We
have adapted
different injection systems for performance in specialized areas.
Shown above is a Motec, multi-piece cross-flow injection for small
block Chevys.
The maximum power that any engine can
produce depends on the quantity of air that moves through it.
Anything that increases the amount of air moving through an engine
at a given speed always offers the possibility of additional
horsepower at that speed. All engine induction systems are
sensitive to intake tuning.
Fuel injected engines with individual
intake runners are particularly sensitive to ram tuning effects.
Relatively long runners have lower resonant frequencies than shorter
runners, just like organ pipes, and they produce the greatest ram
effect at lower engine speeds. That equates to increased low end
torque. Short intake runners enhance an engine's high speed
performance.
The cross sectional area of the intake
runners is also important. For a given amount of airflow, meaning a
given engine displacement and speed, the velocity of the airflow in
the intake runners will proportional to their cross-sectional areas.
The larger the runner area, the lower
the airflow velocity will be. Lower airflow velocities experience
less flow resistance, or drag, within the manifold and thus moves
air into the cylinders for a given vacuum signal. On the other
hand, lower velocity airflows do not produce as great a ram tuning
effect as faster airflows, nor do they carry fuel droplets along as
well as faster airflows.

The cross ram is an example of a
long runner IR (individual runner) system. It allows longer runners,
while maintaining a lower profile. Long runner manifolds increase
engine torque, usually between 3500 to 5000 RPM, and may maintain
torque increases up to 6000 RPM. Upper RPM output usually suffers
when using a longer tuned length IR. Using traditional vertical
injection runners we have documented stack length changes from 1" to
26". Extreme changes in runner length helps demonstrate wave
reflection effects. Shorter IR runners increase top end power at the
expense of low end torque.
Plenum style manifolds generally
provide a broader upper the RPM power band. Impressive top end power
is a hallmark of common plenum manifolds. In the early 1990's Brodix
built a plenum injector called the 'Armadillo'. We were involved in
the nozzle design and location. That injector failed to capture the
sprint car market. It was, however, well ahead of its time. The
lessons learned from the Armadillo are still very relevant today. We
can help you choose the correct system.
Copyright© French Grimes Race
Systems 2004
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