Daniel Levitin writes:
> Well, it's time to replace my air filters on the old Stromberg
> CD150s, and I thought i'd find out what other people have
> experienced. Do you recommend sticking with the cardboard type, or
> going to the washable foam type? Any difference in air intake?
Attached below is some recent discussion from the British-cars (SOL)
list regarding foam air filters. Hope it helps,
-- T.J. Higgins | tjhiggin(at)ingr.com | (205) 730-7922 Intergraph Corp. | Mapping Sciences Division | Huntsville, AL, USA----- begin included text -----
# Date: Sun, 18 Dec 1994 12:26:06 -0500 # From: TATERRY(at)aol.com # Subject: Ram Flo Air Filters
Can some one give me a reference to an outfit I believe is in Gilroy, Ca., maybe south of there, that sells custom manifolds for Webers and Ram Flo air filters or Ram Flo lookalikes. He appears at Brit swap meets in the Bay Area from time to time.... Many tnx and cheers Terry
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# Date: Mon, 19 Dec 1994 13:31:01 -0800 (PST) # From: Marc Sayer <msayer(at)efn.org> # Subject: Re: Ram Flo air filters
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(at)efn.org
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# Date: Mon, 19 Dec 1994 18:56:59 -0500 # From: Gregory Urban <gurban1(at)gl.umbc.edu> # Subject: Re: Ram Flo air filters
On Mon, 19 Dec 1994, Marc Sayer wrote:
> 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.
I can vouch for this. I had a 65 Corvair Corsa Convertible with a dual-carb set up (Replaced the original 4 1-barrel carbs). These carbs had foam air filters, and the crankcase vented into one of the air filters. Needless to say the filter was soaked in oil. One day the car backfired, and the filter was engulfed in flames. To add insult to injury, the spare tire was located in the engine compartment, and rested on this carb. The flame burned though the tire, which proceeded to blow more air into the flames, feeding them higher and higher. All in all, a good show for about five minutes. When it ended, I started it up and drove it home (all 5 blocks).
Brit content. My 71 TR-6 had been my daily driver for several years, and never left me stranded until one day as I rounded a corner, it just died. No juice at all. Odometer says...71,000.00 Coincidence? Or just Lucas. Neither, bad battery (and probably my fourth alternator in 2 years).
Greg Urban | Always follow the fool, for the fool knows not urban(at)cs.umbc.edu | where he is going, so he follows his heart. gurban1(at)umbc.edu |
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# Date: Tue, 17 Jan 95 10:25:08 GMT # From: Matthew Walker <walkerm(at)prl.philips.co.uk> # Subject: Re: ITG air filters
> > Date: Fri, 13 Jan 95 09:38:58 -0800 > From: "TeriAnn Wakeman" <twakeman(at)apple.com> > Subject: Air filters > > Does anyone have any opinions with ITG air filters? > They are a tripple laye reticulated polyesterr foam type that sits on a semi > rigid fiber glass frame. The inner layer is treated with a fire retardent & > is not supposed to support combustion. > > They have a filter that will fit on a TR3 with a pair of DCOEs & allow you to > keep that air horns on. > > According to their data sheet their filters are used on the following race > teams: General Motors, Mazada, Mercedes, and are recommended by Bertilis, > Cosworth, Crowther, Hasselgren, Huffaker & Loyning. > > Anyone have any experience with these? > > TeriAnn Wakeman Large format photographers look at the world > twakeman(at)apple.com upside down and backwards >
My engine tuner recommends ITG filters, mainly because they 'breathe' through the rear of the case (unlike K&Ns). This (he says) allows you to use longer ram pipes.
Generally speaking these filters flow very well. I have the same filter on my Westfield that Caterham use on their JPE. This flows enough for >250hp.
They flow well, but do they filter? Well, in my Vizard tuning manual, he recommends you hold a foam filter up to a light source and look through it. If you can see lots of light, it will flow well, but will also allow plenty of dirt through. I've done this with my filter and found some light gets through. It's only pin hole size light that you see, which I suppose isn't too bad. It's also recommended to buy the dust retension spray for the ITG filter. I haven't done so yet, but I will let you know what type it is when I get some.
I know Pipercross foam filters come highly recommended (Vizard recommends them), if you can, I would try the Vizard test on Pipercross before buying ITG.
Comments?
Cheers,
Matt
- -- - -------------------------------------------------------------- | Matthew Walker, Philips Research Laboratories, Redhill, | | Surrey, RH1 5HA. G.B. | | Email: walkerm(at)prl.philips.co.uk | | Tel: +44 (01)293 815376 | | Fax: +44 (01)293 815500 | - -------------------------------------------------------------- ----- end included text -----
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