My ‘90 Regal has a Banks Stage III Power Pack. The air cleaner has an impressive (no doubt expensive) cast aluminum lid, and a wet K & N filter surrounding a mysterious (also no doubt expensive) ring which is cemented to the air cleaner base with white silicone, or such.

That ring is 1/2” shorter than the outer filter. The inner & outer surfaces are fine screen or perforated metal, and it appears to have pleated material inside. It transmits light through the upper half inch which shows a lighter color than the lower part (see photo) but not through the darker part. The wet filter fits around it with 1/4” clearance.

Remembering some discussions about relative filter efficiency by knowledgeable members on this site, & considering the hassle factor of periodically cleaning and oiling a wet filter, I thought I’d see if a paper filter could be had to fit, & indeed a standard truck model paper filter is the same height & outer diameter, but 1/4” thicker than the wet filter so it fits snugly around the mysterious ring.

I queried Banks technical assistance as to the reason for the mysterious ring, asking also if there was any technical reason why the paper filter could not be substituted for the wet filter. I received an automated reply from their sales dept., noting I’d be contacted by one of their “helpful Banks Power Consultants as soon as possible,” and warning me that the information was proprietary, & intended for me alone, etc., etc. Hearing nothing more, after a week I replied to the e-mail, only to have that e-mail bounce. I tried their tech. asst. website again, & that query vanished. I don’t think they’re going to reply.

I have my own theories as to why they have this unusual situation, but I’m curious as to what some of you might think.

The air flow path is into & through the outer filter, after which some of it must filter through the mysterious ring, & some must flow over the top because of that 1/2” difference in height.

A picture is said to be worth a thousand words so I have posted some. Unfortunately the titles didn't upload. The top picture is with the wet filter installed, the second is the filter cover, the third has the paper filter installed, the botom photo is the mysterious ring.

Only thing I can think of is noise reduction.

Without baffles at full throttle that make a lot of noise thru the air intake system.

I had the Banks system on my 454 SOB but the air cleaner didn't work/look like yours. Just had a big filter (K&N wet filter) until I replaced it with a standard truck filter. Had the fresh air induction with water rejector mounted to the front grill.

That thing was LOUD at full throttle!!!

It's an activated charcoal filter. It is meant to contain fumes after shut down. It is supposed to self purge on startup. But, I don't remember any charcoal in mine when I removed it to use a shorter air cleaner element.

MWrench may have a point. Come to think of it, this thing is a lot quieter when the secondaries open than other 454s I've had. OTOH the doghouse is insulated well-enough to absorb some of that sound. Maybe it roars like a jet from outside.

No doubt it serves as a flame arrestor, but if that is its only purpose it looks like overkill. IMHO a simple screen would do that job.

And Bill, what was the result when you took yours out, & what kind of a filter did you use then?

The inner & outer screens on the mysterious ring are so fine it's hard to tell if there is anything in there except pleated material. Of course, cataracts & glaucoma may have dimmed my vision enough so that I'm missing fine details.

quote:

Originally posted by olroy:

[QUOTE] Bill, what was the result when you took yours out, & what kind of a filter did you use then?

I removed the stock AC A348C and installed a shorter Baldwin PA2008 with a PA2008 polyester fiber wrap. I replaced the air cleaner top with a shorter one from a 454 pickup. This allows extra air clearance for a higher intake manifold. Since I did the change, I have read tests that indicate AC is at least as good as Baldwin, so I will replace the Baldwin with an AC when my Filter Minder says its time. However, the foam wrap (cleaned yearly) keeps it so clean that the Filter Minder hasn't moved for years. Both, of course, are a ton better than K&N. Citations on request.

I wish I had taken manometer readings when the charcoal screen was installed. I would be curious to see how much restriction there was.


As far as sound reduction, I have never seen anything in acoustic texts re metal mesh cutting sound, but I guess anything in the way will attenuate sound somewhat. At least the higher frequencies. I would suspect that the mass of a cast aluminum top on the air cleaner would make things a trifle quieter, but not sure if you or I could hear the difference. Now yer makin me think of putting a disk of soundproofing on the lid of mine. However, if we follow the lead of automotive engineers, it would seem that adding soundproofing to the underside of the hood and the back side of the firewall is all they think is productive. I am presuming they look at intake noise, as I remember reading that the Olds 98 had XX pounds more soundproofing than the 88, for example. But they still used a sheet metal air cleaner lid. Even my 454 pickup has a big silencer between the air cleaner intake snout and the fender well inlet. But again, just a sheet metal lid on the air cleaner.

For us, this is a non-issue, anyway, as when the secondaries kick in, the surge of power is so thrilling that the adrenalin generated makes us unaware of any increased noise. Pretty soon the thermal clutch fan starts to roar, and that drowns out any carb noise. And I drive with my hearing aids turned off.

That last para. is obviously from someone with a fresh 502, not a tired 454. And how does the NAPA Gold stack up next to the AC & the Baldwin filters?

quote:

Originally posted by olroy:
That last para. is obviously from someone with a fresh 502, not a tired 454.

And a little poetic license, perhaps.

quote:

And how does the NAPA Gold stack up next to the AC & the Baldwin filters?

From memory, the AC comes out on top and the Napa Gold is made by either Wix or Baldwin. Both are good products, used by high mileage fleet operators who keep good records.

On edit: Here is a paste from a Duramax filter test on dieselplace.com:

FILTER EFFICIENCY

AC Delco OE 99.93%
Baldwin 99.72%
No name filter (made for gas engine, 1/3 less pleats) 99.32%
AFE ProGuard 7 (73-10062), panel filter 99.23%
WIX/Napa 99.03%
Purolator 98.73%
Amsoil, new style 98.63%
UNI 97.93%
K&N 96.80%

These are test readings on a Duramax filter, but I would suspect that each manufacturer uses the same element material for all their filters.

All of this might be cutting things a little fine if you stay on paved roads. We do a fair amount of gravel and dirt roads.