Air
Ducting
The final step in getting
the supercharger installed was to address the ducting
feeding the supercharger and between the supercharger
and carburetor hat. We drove the car, blower belt removed,
down to our local exhaust shop and had them weld a short
piece of 3.5" mandrel bent pipe to serve as the high-pressure
duct between the blower outlet and  Exteme
Velocity carb hat. We then need to weld in a connector
for mounting the bypass valve. A bypass valve is operated
by manifold vacuum to bleed off boost pressure. When vacuum
is present the valve is partially to fully open, allowing
pressure to escape. When the engine is underload and or
wide-open throttle vacuum approaches zero and the valve
closes, enabling full boost to be achieved. The bypass
valve function prevents pressure from backing up into
the supercharger vanes upon sudden closure of the throttle
blades. On fuel-injected vehicles the bypass valve should
channel the air back into air inlet duct before the supercharger.
This is due to the mass air meter having already measured
for that amount of air entering the engine. On a carburated
vehicle we can simply dump the air from the bypass valve
into the engine compartment. There is a slight advantage
to this as we are not recirculating air that has been
through the blower and heated back into the blower.
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We used a hole saw to cut in a 3/4" hole into
our crude but functional blower-to-carb pipe. This
will be the bypass valve location. |
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The barbed connector shown was sourced at a local
hardware store. It is a hose union we cut in half.
Weld this up to be leak free otherwise you'll lose
boost. |
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We're using the Bosch bypass valve supplied with
their S-trim supercharger kits. We tee the vacuum
line in to a source of manifold vacuum.
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The bypass valve will vent into the engine compartment,
as we are not concerned with channeling air back
into the inlet duct as on a mass-air EFI engine. |
At the time of this article we were still not completely
decided on how to route the air inlet ducting and
filter. Due to the tight clearance between the blower,
valve cover and shock tower we could not use the
original Vortech "elephant trunk" tubing.
We were able to fabricate a U-bend using 3.5"
(outer diameter) PVC plumbing pipe.
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Ideally we'd like to have a 3.5" mandrell bend
inlet pipe in place of the schedule 80 sewer pipe.
We'll also work on placing the filter in the fenderwell
or in front of the radiator support so it draws
cold air. |
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We believe this K&N filter (RX-4140) with the
"XStream" end cap should provide ample
air flow into the motor. The attaching end is 3.5",
same as the blower inlet. The overall length is
nearly 6". |
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Conclusion
As you can see installing a 5.0L Vortech supercharger
in an early carburated platform is not impossible. In
fact, once you get through the front belt assembly, the
installation is just as easy as the EFI engine the kits
are intended for. There is no engine computer system to
worry ab
What remains now is tuning. We are fully prepared to hit
some hurdles and challenges in this department. So far
the fact the car idles without issue and drives around
just as well as it did naturally aspirated is a good sign.
Stay tuned for Part III where we cover the details of
dialing in the carbed and supercharged 331 engine.
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Getting
Hosed
It's a given when tackling a project
like this that we'll need to shell out
$50 for this?! |
some coin here and there to make it
all work. Nevertheless no one
likes getting a bum deal. One of the more aggravating expenses
we encountered was with silicone connectors and reducers.
We sourced a reducer from turbohoses.com at an astronomical
price of $50 including clamps. Sounded steep for a piece of
silicone hose, but they were local and we were naive. Later
At $8.65 this made sense. |
we needed a 3.5" connector. This
time we came across Turbo Performance Systems, a dealer for
HTS hoses. Their coupler was less than $10 shipped. To be
fair we looked into the price of an HTS reducer as they are
more difficult to manufacturer. It came in at $25, half the
price of what we paid. Lesson learned - shop around.
Turbo Performance Systems
http://www.boostedsystems.com/
770-896-6600 |
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