Don <y2kota@y2kota.us> wrote:
: Looking for a small then what I have know air filter. How and/or where
: can I find out the air flow needs of a 4.7L? This is so I can match up
: a air filter. Looking for a smaller K&N cone then I have now so I can
: mount it in the fender or behind the bumper.
This should give you the info you need to calculate the smallest
theoretical filter size for the 4.7:
http://www.knfilters.com/facts.htm#SELECT
The 4.7's HP peak is around 4700 RPM which would require about
64.7 square inches of filtering area.
When you run the numbers, a 5" diameter by 5" length cone is
approximately the smallest size that gives that filtering area.
However, these estimates have been shown to be extremely
conservative. There was an interesting article in the April 2002
Car Craft magazine about a study done by Marlan Davis using a big
block Chrysler. He used many different filters, ranging from
one that could theoretically only support 3.3L up to a filter that
could theoretically support 15.2L. All power pulls were within 4hp
of each other (on a 520hp motor), which was within the margin of
error for the dyno. So, for all practical purposes, all of the
filters made the same power.
Anyway, what it comes down to is you should be able to go smaller
without noticing a power drop unless you go *really* overboard (or
is that "underboard"?) ;-) with it - you will probably need to
clean it more often though. Plus, if you put a smaller filter into
colder air, even if you did get a power drop due to restriction,
the increase in air density may very well offset it. The only
way to be sure would be to give it a try.
--
-Jon-
.-- Jon Steiger ---- jon@dakota-truck.net or jon@jonsteiger.com --.
| 1970 Barracuda - 1990 Dakota 'vert - 1992 Ram 4x4 - 1996 Dakota |
| 1996 Intruder 1400 - 1996 Kolb FireFly - 2001 Ram QC 3500 CTD |
`------------------------------------ http://www.jonsteiger.com --'
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