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Intake
A very popular
upgrade here in the US is the open element air filter. This is
a replacement for the stock airbox. It consists of a bracket that
mounts to the inner fender wall, a K&N filter, and clamps
to attach the filter to the intake hose.
This modification,
on an 8v 4-cylinder VW motor, sacrifices a little bit of the low
end power to give more at the top of the rpm range. It also makes
the exhaust note more "throaty", giving a nice deep
tone (screams when you lay your foot on the throttle). Definitely
a sportier note. It sounds like a race car!
There is another
product by MidKnight Motorsports called the AirBath Passive RamAir
System that restores some of the low-end power lost with the removal
of the stock airbox, but also retains all the gains of the open
element filter system. This essentially is a half-enclosure around
the filter with a downward pipe leading to a air inlet scoop.
This allows a direct cold charge of external air to be directed
into the open element air filter, while still getting air omnidirectionally.
I have personally
used the above setup for over a year in my car. It is a phenominal
system! My advice to everyone: if you use an open element system
in your car...get and AirBath!!! You won't be disappointed.
MidKnight
Motorsport also has another product called the IceBox System which
directs a cold charge into the factory airbox via the inlet scoop
and downpipe much like the AirBath setup. One day I had decided
that I wanted to take the more stealthy approach to motor tuning
and wanted a more quiet tone. I ordered the rest of the parts
and converted my AirBath System to an Icebox System. The tone
is much more quiet, but still sporty, especially under acceleration.
In conjunction with a drop-in K&N filter and the Icebox, there
were still plenty of gain to be had over the stock airbox.
My current
setup is a hybrid setup using a Ractive heatshield filter, an
ABD Big Bore intake, the MidKnight Motorsports AirBath inlet scoop
and piping and a custom connector to tie it all together. The
Ractive filter is also cross-drilled on the fender side of the
filter to keep the MKM AirBath system passive still.
Exhaust
I used to
think that an exhaust needed restriction, but after driving in
Brandon's Cabrio and installing my new Hartmann Motorsports 70mm
(2.8") exhaust and header...I have changed my opinion on
the subject.
It seems to
be a common misconception among VW'ers that the factory manifold
and exhaust are adequate for optimum performance. It's adequate,
but not for getting the full potential from your modifications.
It is also a misconception that you will lose low-end power and
torque using exhausts bigger than 2.5" on a 2.0L 8v motor.
Brandon and I have both proved this incorrect by our dyno
results.
One fact that
can be made from different sized exhausts is the tone and exhaust
noise. Smaller diameter exhaust piping can be noisy if using a
single rear muffler that is not well baffled. On the other hand
they can be quiet by adding a quality rear muffler. And even more
quiet by adding center and forward mufflers or resonators to the
system. Same goes for larger diameter systems. I have 3-mufflers
to keep the 70mm system quiet, but the tone is very deep, bassy
and aggressive sounding. Especially under full-throttle acceleration.
So diameter of the piping affects more of the tone of the exhaust
note versus the actual noise level it makes.
A free-flowing
exhaust and free-flowing intake is a must before seeing a benefit
from adding other upgrades such as camshafts.
Next
- Camshaft
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