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Re: Ram Flo air filters

To: british-cars@autox.team.net
Subject: Re: Ram Flo air filters
From: Marc Sayer <msayer@efn.org>
Date: Mon, 19 Dec 1994 13:31:01 -0800 (PST)
Stay way far away from Ram Flo or any other foam based filters. As the 
foam ages it starts to breakdown into small abrasive particles. These 
particles get sucked down into the engine and I am sure you can see the 
problems with that. Additionaly, unlike the Pipercross or ITG type 
airfilters which flow well when new and clean, the Ram Flow filters flow 
is marginal at best and even when clean presents a restriction. Due to 
the way foam filtration works, as the filter gets dirty, air flow is 
reduced, so even a if your foam filter flows OK when clean it will 
present an ever increasing restriction as it gets dirty. It is 
also too close to the throat of the carb and creates turbulence in the 
carb. The proximity of the filter medium to the carb throat 
has another downside. The filter medium gets wetted by the fuel fog 
standing off the carb (caused by flow reversal at low RPM's and large 
throttle openings primarily). If the car backfires through the carb (this 
is not all that uncommon) the flame front will ignite the gas soaked foam 
and as the foam burns the charred remains will get sucked into the 
engine. Even if the flame goes out instantly the foam will still be 
damaged and you won't even know about it. At best the damage will reduce 
the filter's ability to flow air, causing you car to run rich. At worst 
the fire damage will cause the foam to breakdown more rapidly than normal 
which will lead to the above mentioned abrasive particles getting sucked 
into the engine. Be smart use a K&N filter. And remeber you must use air 
horns of some sort on the carb(s), a full radius shape is best. If the 
filter you are going to use won't let you use air horns you shouldn't use 
that filter. There are good horns that will work with filters as short as 
1.75" thick.

Marc Sayer
Performance Engineering
1070 W. 2nd Ave. 
Eugene OR 97402
(503) 484-0904  Fax 746-0863
msayer@efn.org


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