Ford AIS Severe Duty Intake Installation for 1999-2003 7.3L Powerstrokes

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The Ford Air Induction System (AIS) fits
your 1999-2003, 7.3L Powerstroke with technology
that is battle tested in “operation Iraqi
Freedom”.   This air filtration system
holds more dust and soot extending filter life along
with filtering more contaminates, all with less
restriction than any other conventional pleated
filters.  This is one of the best add on air intake
systems available for the Ford Powerstroke and because
it is designed specifically for the 7.3L diesel
Super Duty it fits perfectly. 

No doubt any one who is using this systems knows of
its outstanding filtering capability, but may have also
experienced the filter minder on the air box showing
restriction right after installing the unit.  We
have experienced this several times when installing the
AIS and originally thought it was due to the filter
element being restrictive to air flow.  We decided
to conduct a simple test to find out if the AIS filter
element was restricting flow or another cause could be
found for the filter minder pulling down.  First we
reset the filter minder (original unit, not the one that
came with the AIS) and drove the truck 1 block full
throttle.  The filter minder was pulled down a
little more than half way.  Next the AIS filter
element was removed and the same test was done with no
filter at all.  The filter minder pulled down the
same amount.  This indicates that the filter
housing and intake tube are causing significant
resistance to air flow through the

To get more cool air into the AIS
box I decided to use the fender opening
originally used on the early 99 models for air intake
from the drivers side fender.  I wanted to use only
cool outside air and keep the AIS from drawing in air
from under the hoods as many other performance intakes
do.  So an insulated seal would need to be
fabricated to seal the fender opening to the back of the
AIS unit.

It took some doing and experimentation
before coming up with this closed cell foam part that
fits into the fender opening to make a seal to the
fender and also fit the back of the AIS air box. 
This foam piece is longer toward the front of the truck
to accomidate the off set of the back of the AIS in
relationship to the fender opening.  The foam is
rigid enough to hold its shape, but soft enough to
compress to make a seal when the air box is
installed.  Foam sleeve $23.50.

To get the air into the AIS air box,
I located a 3-1/2″ hole centered on the “X” shown
in the photo using a hole saw.  This is the largest
hole that could be sealed without other modifications to
the AIS box and its supports.  

This photo shows the AIS installed
with the fender seal.  I have been running my
system in this configuration for quite some time and it
works very well.  The filter minder never pulls
down at all and the truck gained performance you can
feel seat of the pants.  I have also been comparing
the performance of the modified AIS against several
other performance intakes, some open, some draw air from
the fender and some even draw air from the front and
fender.  None of them so far can match the
performance and filtering of my modified AIS.  We
are now considering offering the foam connecting tube to
our customers who have choosen the Ford AIS and possibly
including it in the AIS systems we sell.

Of course we can never leave well enough
alone.  We have manufactured a prototype filter
element holder to fit the AIS air box that holds a
2-stage foam filter element.  Testing this element
against the Ford paper AIS element shows no noticeable
differences between the two.  The foam element
also does an excellent job of stopping dirt with plenty
of surface area and has the advantage of being washable
for reuse.  At this time we have no plans to
produce this filter holder as the AIS filter elements
are good for extended use, but may consider making it in
the future should there be a demand for

Article by Diesel Power Products,

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