Slant Six Forum :: Early Air Filter Housing

My 225 has a 1945 carb, and with minor modification I can make an early (no snorkel) air filter housing fit. Simply because I like the look of it better. However, given the narrow gap around the perimeter of the housing, I worry that it might be somewhat restrictive? It could be modified with holes punched around the bottom part outside of the actual filter, but I’d prefer to avoid that. Any thoughts from you guys?

Any holes would be on the horizontal bottom plate, slightly in from the current concentric gap, and not be visible. They would also be drawing air from the same place as the existing gap.

You could drill holes, but it would be easier to trim the overhang from the bottom plate. Not sure if it would help, but it would open up even more potential airflow.

You made me make some measurements.

ID of top cover 8 13/16" for an area of 60.994 sqin
OD of bottom plate 8 9/16" for an area of 57.583 sqin

Area of opening then equals 3.412 sqin.

or a 1.84" ID square or a 2.08" ID tube.

Quote:

You could drill holes, but it would be easier to trim the overhang from the bottom plate. Not sure if it would help, but it would open up even more potential airflow.

Seems as if that might compromise the rigidity of the part though. The vertical outside rim of the lower plate stiffens it substantially.

Author:	Bob_A [ Mon Oct 05, 2020 8:18 am ]
Post subject:	Early Air Filter Housing
My 225 has a 1945 carb, and with minor modification I can make an early (no snorkel) air filter housing fit. Simply because I like the look of it better. However, given the narrow gap around the perimeter of the housing, I worry that it might be somewhat restrictive? It could be modified with holes punched around the bottom part outside of the actual filter, but I’d prefer to avoid that. Any thoughts from you guys?

Author:	Reed [ Mon Oct 05, 2020 9:12 am ]
Post subject:	Re: Early Air Filter Housing
It will be louder and you will be sucking in hotter underhood air. Using hotter air leads to decreased performance and economy. From a technical standppoint, you would be better served adapting a later style of air cleaner with a snorkel and fabricating a cold air intake. That being said, the factory knew what it was doing when it designed the air cleaner. No way to increase flow in that design of air filter housing unless you start cutting/punching holes, which looks really cheesy if you ask me.

Author:	Jase [ Mon Oct 05, 2020 10:23 am ]
Post subject:	Re: Early Air Filter Housing
Quote: My 225 has a 1945 carb, and with minor modification I can make an early (no snorkel) air filter housing fit. Simply because I like the look of it better. However, given the narrow gap around the perimeter of the housing, I worry that it might be somewhat restrictive? It could be modified with holes punched around the bottom part outside of the actual filter, but I’d prefer to avoid that. Any thoughts from you guys? I would imagine you could fashion a new temporary top out of a piece of sheet metal, aluminum, or any other stiff material. Then drill a hole in it, and install and see if you notice a difference in performance. If that works, I would look into beveling or flaring out the lower edge of the factory air filter top.

Author:	Bob_A [ Tue Oct 06, 2020 8:24 am ]
Post subject:	Re: Early Air Filter Housing
Any holes would be on the horizontal bottom plate, slightly in from the current concentric gap, and not be visible. They would also be drawing air from the same place as the existing gap. But yeah, I’d rather avoid it if for no other reason than laziness

Author:	Reed [ Tue Oct 06, 2020 1:55 pm ]
Post subject:	Re: Early Air Filter Housing
Quote: Any holes would be on the horizontal bottom plate, slightly in from the current concentric gap, and not be visible. They would also be drawing air from the same place as the existing gap. And it would, therefore, be unfiltered. Might as well run no air filter at all.

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Early Air Filter Housing https://www.slantsix.org/forum/viewtopic.php?t=65400	Page 1 of 2

Author:	slantzilla [ Tue Oct 06, 2020 3:54 pm ]
Post subject:	Re: Early Air Filter Housing
If the area of the opening is sufficient to support the flow the engine desires, more holes will do nothing. The only gain might come from making a straighter flow path.

Author:	GregCon [ Tue Oct 06, 2020 5:24 pm ]
Post subject:	Re: Early Air Filter Housing
The early style air cleaner is a wonderful part. It's as righteous and as much part of the Slant 6 as the slanted block itself or the famous curved (mostly) runner intake.

Author:	Bob_A [ Wed Oct 07, 2020 9:21 am ]
Post subject:	Re: Early Air Filter Housing
Any holes would be outside of the actual filter. There is about an inch of concentric area outside of the filtered area, yet inboard of rhe filter housing diameter. All air would still be filtered, and would come from exactly the same area as the original drew it from. Think of an arrangement of holes on the horizontal bottom of the lower plate. Like a telephone dial, or cop car dog dish hubcap. They wouldn’t show at all. And, they may not increase performance, but would absolutely insure that the original design wasn’t able to decrease it either. I’m not looking for performance gains anyway, just a good running old 6 in my daily driver truck.

Author:	Bob_A [ Wed Oct 07, 2020 12:02 pm ]
Post subject:	Re: Early Air Filter Housing
Attachment: File comment: This might explain better. EBE926CF-110C-4110-BE98-997E57A04D68.jpeg [ 64.76 KiB \| Viewed 4386 times ]

Author:	dakight [ Wed Oct 07, 2020 12:09 pm ]
Post subject:	Re: Early Air Filter Housing
You could drill holes, but it would be easier to trim the overhang from the bottom plate. Not sure if it would help, but it would open up even more potential airflow.

Author:	Bob_A [ Wed Oct 07, 2020 2:21 pm ]
Post subject:	Re: Early Air Filter Housing
Quote: You could drill holes, but it would be easier to trim the overhang from the bottom plate. Not sure if it would help, but it would open up even more potential airflow. Seems as if that might compromise the rigidity of the part though. The vertical outside rim of the lower plate stiffens it substantially.

Author:	emsvitil [ Wed Oct 07, 2020 4:41 pm ]
Post subject:	Re: Early Air Filter Housing
You made me make some measurements. ID of top cover 8 13/16" for an area of 60.994 sqin OD of bottom plate 8 9/16" for an area of 57.583 sqin Area of opening then equals 3.412 sqin. or a 1.84" ID square or a 2.08" ID tube.

Author:	Bob_A [ Thu Oct 08, 2020 11:32 am ]
Post subject:	Re: Early Air Filter Housing
Quote: You made me make some measurements. ID of top cover 8 13/16" for an area of 60.994 sqin OD of bottom plate 8 9/16" for an area of 57.583 sqin Area of opening then equals 3.412 sqin. or a 1.84" ID square or a 2.08" ID tube. Thats more than I would have guessed, and probably adequate. Now I’m off to measure a later snorkel top cover..

Author:	dakight [ Fri Oct 09, 2020 11:02 pm ]
Post subject:	Re: Early Air Filter Housing
Quote: Quote: You could drill holes, but it would be easier to trim the overhang from the bottom plate. Not sure if it would help, but it would open up even more potential airflow. Seems as if that might compromise the rigidity of the part though. The vertical outside rim of the lower plate stiffens it substantially. If memory serves, there is a downturned lip just outboard of the filter element that should provide sufficient rigidity. In fact I see it in your drawing as well.

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Author:	ric325v63 [ Sun Jun 19, 2022 10:42 am ]
Post subject:	Re: Early Air Filter Housing
Quote: You made me make some measurements. ID of top cover 8 13/16" for an area of 60.994 sqin OD of bottom plate 8 9/16" for an area of 57.583 sqin Area of opening then equals 3.412 sqin. or a 1.84" ID square or a 2.08" ID tube. Sorry for dredging up an old thread but I'm new to the Slant (only had it 8 days so far) and was concerned about the very narrow ring of air that can get into the early style air cleaner housing. It sure looks like there are less square inches than the carb throat but I guess there is enough air. I like the look of the air cleaner housing, just wanted to make sure I wasn't missing something with the air flow. Thank you. Jon