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Why it
Works!
CV carb
The
PowerNow™,
when installed in a CV type of carburetor, seems to
work better than any other application. The reason
why, is because of the way a CV type of carb works
in the first place.
A constant velocity (CV) carb really
works on air pressure, or the difference in air
pressure, which is normally just called vacuum. When
you open the throttle, you are opening a throttle
plate, or butterfly valve. The plate however, is
located between the engine and carb slide, so the
slide still needs to open to let the air from the
atmosphere past the throttle plate and into the
engine.
The difference in air pressure
between the atmosphere and the lack of air pressure
in the engine, cause the slide to open then, and
really feed the air and fuel to the engine. This is
why the PowerNow™
is so effective on these carbs. It works for the
same reason that it works on any slide carb, as seen
in the “how it works” description for the slide
carbs, but also because it needs less of a vacuum to
open the slide.
The difference in air pressure is
greater with the PowerNow™
installed, which means there is more of a vacuum and
the throttle doesn’t need to open as far to get th
slide to respond. And the slide movement responds
much quicker to changes in throttle position.
This isn’t just theory. It is
evidenced and proven with the Superflow 110
flowbench. With the stock Harley CV carb set open at
½ throttle and the incoming air pressure set at 7”
of water, the flow rate measures at 50%. Leave the
flowbench running and just place the
PowerNow™ into
the carb and the air pressure automatically drops to
6.5”. This means it takes this much less pressure to
flow though the carb with the
PowerNow™
in place. Turn the pressure back up to 7”, and the
flow increases to 54%.
There is a 9.5% increase in flow with
the PowerNow™.
More importantly, since the vacuum required is less
with the PowerNow™,
the engine makes more power at a lower throttle
opening and responds much quicker to changes in
throttle position.
Now you can see how the
power now helps. By dividing the throat into an upper
and lower section, you keep the lower half of the
throttle plate from interfering with the good air
stream. This increases the throttle response, the torque
every time you twist the throttle, and fuel mileage. |