Re: Air filter size?

From: Don (y2kota@y2kota.us)
Date: Sat Jan 22 2005 - 08:11:29 EST


Thanks for the info! That just what I was looking for!

Don

On Jan 21, 2005, at 5:00 PM, jon@dakota-truck.net wrote:

>
> 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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