9" Air Filter Drop Base - How Much Interest?

Bernica · #1 (**permalink**) 08-19-2010, 02:49 PM

I run a turkey pan with an 850 Pro Systems DP. Have been using the 8" Stellings air cleaner with a 1" K&N filter that is, obviously, choking the 482 motor. Boutght a K&N 2.75" x 9" filter and the Extreme 9" top, all of which will fit inside the turkey pan, and should make a huge difference. Now for hood clearance. Can't quite make it without major surgery on the hood opening or lowering the filter. I have searched high and low, and can not find a dropped 9" air cleaner base. I know someone with a metal spinning shop that can make just what I need. He is giving me a price for my "prototype", but would give a break if he can make more. If there is any interest out there, let me know and I'll see what kind of deal I can get.

Thanks,

Michael

Cashburn · #2 (**permalink**) 08-19-2010, 02:56 PM

Wouldn't a drop base on a small diameter air cleaner completely negate the height gained? I mean the base would be dropping around the carb front and rear right over it. I don't see how you are gaining anything here and if it would be possible with the dimensions of the carb?

Bernica · #3 (**permalink**) 08-19-2010, 03:36 PM

I'm just trying to figure out how to get the most airflow to the carb, given the hood height and turkey pan restrictions.

YerDugliness · #4 (**permalink**) 08-19-2010, 04:19 PM

I would be interested in a 9" drop base IF it will work.....I say IF because I have been investigating a method of getting more hood clearance, although for a different reason (I want to change to a higher rise intake manifold) and was told that a 9" drop base would not work b/c it would interfere with a holley carb's float bowls (look at post #10 on the ClubCobra thread posted just below).

My solution was to try to find a way to drop the engine to gain the room I need, you may want to consider that if you find the drop base unworkable. Here is the thread (again, take a look at post #10 for Holley interference information):

Does anyone make motor mounts to lower an engine?

I also posted a thread at the Mustang forum (my drivetrain came from a 1989 Ford Mustang GT), here is that thread, which contains some advice for gaining additional hood clearance, too:

http://www.allfordmustangs.com/forum...tor-1-2-a.html

Like you, I wanted to use a better air cleaner, that's how my whole problem started. I didn't have adequate clearance to use the raised/radiused base that came with the 9" K&N X-Stream Filter assembly, so I used the base that had been on the car....but I really like the K&N base much better, so I'd like to use that.

So.....it looks like the answer to my problem will be to use convertible motor mounts (which will drop the engine 3/4") and a convertible transmission mount (which will drop the transmission 1/2").

You might be able to solve your problem, though, by using a K&N 9" X 2" filter in place of the 9" X 2 3/4" filter that came with the X-Stream filter assembly, there is information in one of my posts regarding the model number. If it will work for you, it would probably be cheaper than helping finance a prototype of the dropped base.

I'll keep my eye on your thread, if the drop base idea works (meaning that it will fit without interference over a Holley carb, preferably one with center-hung floats, which have a different fuel bowl from non-center hung floats), I'd be in for one.

Cheers from Dugly

RodKnock · #5 (**permalink**) 08-19-2010, 04:46 PM

I may not be thinking about the right thing or solution, but the mid-year (C2) Corvette big blocks 1965-1967, maybe the C3 or 3rd Gen too) had a dropped base to clear the big block hood. They make reproductions of this dropped air cleaner base and they all fit Holley's, including my 850 DP and HP 950 carbs, so why couldn't it fit a Cobra?

Bernica · #6 (**permalink**) 08-19-2010, 04:57 PM

RodKnock,
Do you remember if it was a 9" diameter base? I'll start looking into it.
I have looked everywhere and have been told that there is no such thing.
I will post pics soon of what I'm trying to do. Seems so simple. But then again, what has been simple on these cars?

gsharapa · #7 (**permalink**) 08-19-2010, 05:09 PM

I had a dropped base made for the big cobra oval air cleaner on a 427 small block stroker that really worked well. I'm building a 496 KC motor right now and bought a 9 inch setup with turkey pan just like yours. I'm putting a Eldebrock Victor (Single Plane) on the motor but Keith is going to cut the carb base down by a .5 inch so I'm hoping it will all clear. If not I'm in for a drop base if it would work but I also think it's just too small to clear the float bowls.

RodKnock · #8 (**permalink**) 08-19-2010, 05:11 PM

They made a few of them depending on engine, but I would say they're a little bigger than 9". Hopefully, this link works:

http://www.parts123.com/parts123/yb....5AABLQ~Z5Z5Z51

I also have a repro at home.

YerDugliness · #9 (**permalink**) 08-19-2010, 05:35 PM

I suspect Bernica's issue is the same as mine....my 9" K&N X-Stream FilterCharger assembly sits very nicely up within the hood scoop on my Cobra, a 14" would be too wide to fit between the walls of the hood scoop.

Like you, Bernica, I looked high and low for a dropped filter base before I posted here on CC and on the Mustang forum....no 9" drop bases could I find!

Cheers from Dugly

Cashburn · #10 (**permalink**) 08-19-2010, 05:54 PM

You cannot have a drop base that is smaller than the overall carb dimensions.

YerDugliness · #11 (**permalink**) 08-19-2010, 06:04 PM

Quote:

Originally Posted by Cashburn

You cannot have a drop base that is smaller than the overall carb dimensions.

....exactly what I was told:

Quote:

Originally Posted by mikeforte

Hi Dugly,
The drop based 14" air filter assembly is the smallest it can be. The size of a Holley dual feed carb requires a 14" filter assembly for the drop based filter to fit over the carb.

In Bernica's case, the limiting factor might well be what will fit within the turkey pan rather than what will fit between the inner walls of the hood scoop...just figured that one out

.

Cheers from Dugly

YerDugliness · #12 (**permalink**) 08-19-2010, 07:41 PM

Quote:

Originally Posted by Bernica

Now for hood clearance. Can't quite make it without major surgery on the hood opening or lowering the filter.

Depending on how much room you need, here is something that might just work (you'll get .75" reduction in height with this):

http://www.knfilters.com/search/prod...px?Prod=E-3527

Will that be enough?

Cheers from Dugly

Bernica · #13 (**permalink**) 08-20-2010, 11:39 AM

Quote:

Originally Posted by YerDugliness

Depending on how much room you need, here is something that might just work (you'll get .75" reduction in height with this):

http://www.knfilters.com/search/prod...px?Prod=E-3527

Will that be enough?

Cheers from Dugly

Bingo Dugly! I actually ordered #3510 (2") and #2640 (2-1/4"). Your pic in the previous post is right on what I'm trying to do! Still pursuing a flat or slightly lowered base. And, yes, I understand that I can only go as low as the top of the carb, or close anyways.....

Bill Wallace · #14 (**permalink**) 08-20-2010, 12:50 PM

I made my own out of an old piece of 1/8" aluminum that was a bottom cover protector from a dirt bike.

I made a form by using a jig saw to cut a circular hole in a piece of 1 1/2" by 10" board, then used a router with a bullnose bit to route the shape of a flange in the wood. Then I cut a hole in the aluminum that was about an inch smaller in diameter than the hole in the wood. I clamped the outside edge of the aluminum to the outer edge of the wood, then heated the aluminum around the air horn flange with a plumbers "map" (not propane) torch, and slowly beat the aluminum into the shape of the flange routed into the wood. I used the back of a hatchet to hit the aluminum to ensure I had a convex shape and avoid creasing or flattening the aluminum. I used a spray bottle to water down the wood so it would catch on fire.

Then, I used a belt sander to flatten the bottom of the air horn in the aluminum to ensure a tight fit around the top of carb. It looks pretty crude but it works fine.

I use a K&N X top filter and had to trim about 1/8" off the passenger side of the opening through the hood to allow the hood to close over the filter.

YerDugliness · #15 (**permalink**) 08-20-2010, 02:37 PM

Quote:

Originally Posted by Bernica

Bingo Dugly! I actually ordered #3510 (2") and #2640 (2-1/4"). Your pic in the previous post is right on what I'm trying to do! Still pursuing a flat or slightly lowered base. And, yes, I understand that I can only go as low as the top of the carb, or close anyways.....

Shows that great minds think alike, Michael!

I am currently using the flat base that came with a rather inexpensive aftermarket filter....I trimmed down the circular flange so that the underside of the base just barely clears some "bumps" on the side of the Edelbrock carb I am using, but it sure looks to me like the air coming in from the sides needs to make an immediate 90* turn to get into the carb. I'm hoping that the air coming in the X-Stream Filter top will provide some direct in pressure and help with that transition, but with only about 1/8" to 1/4" between the X-Stream Filter top and the underside of the hood scoop, I'm not really sure that there is much air coming in through the top filter.

One thing of which I am sure, though, is that with the 9" X 2 3/4" K&N filter and the X-Stream Filter top, I'm waaaay ahead of the 9" X 1" paper filter that came with the car. I'd still like to be albe to use that nicely raised and radiused base that came with the X-Stream Filter assembly, though.

One thing to watch for.....the #E-3530 filter that came with your X-Stream Filter Charger assembly has an ID of 8" and an OD of 9", but the #E-3510 filter that you'll be replacing it with has the same OD, but an ID of 7.5".....I'm not sure if there will be any interference with the X-Stream Filter top or not, when you get the replacement filters would you mind posting on this thread to let us know if the greater "thickness" of the K&N filter posed any problems (K&N makes 2" tall 9" OD filters in 7", 7.125", 7.5", and 8" ID's)? I'd appreciate it!

Glad this worked out for you!

Cheers from Dugly

Bernica · #16 (**permalink**) 08-20-2010, 06:27 PM

Thanks Dugly!

My metal spinner friend is going to make a 9" FLAT plate with a 5-1/8" hole and 3/16" turned-up lip on the outside, out of material that is thick enough not to bend/warp. I will probably have to make two small relief notches for the float adjustments on my 4150, but not much. That's all I can do. Then, it's just a matter of which filter will fit, noting the comment above about trimming a small amount around the hood scoop opening, which I'm trying to avoid, but may have to do in the interest of airflow. I, too, would like to use the "venturi" type base, but that ain't happening and my Stellings 8"x1" certainly didn't have that. So, they way I see it, with the Extreme top, I'm probably tripling the airflow no matter what, which can't be bad!

BTW, watch the "For Sale" section on this site for a bunch of nice unused K&N filters once I solve this puzzle!!

mdross1 · #17 (**permalink**) 08-21-2010, 02:08 PM

I talked to K&N about my stuffed up 460 with a stock Stellings.My solution was a new hood and grafted a Harwood scoop as low as possible to clear a 3"x14" with Extreme top.This motor now will float the valves before it starves for air.Personally love the look of the Harwood scoop and seeing it full of aircleaner.Besides that I bought the kit and built the car for one reason,and it worked.Always good having a spare hood.

FUNFER2 · #18 (**permalink**) 08-21-2010, 03:30 PM

The problem with dropping the base is, a big drop in cfm.

On the chassis dyno, we tested the Stelling/Helling cleaners, my oval cobra cleaner, typical 14" round and a drop base 14" assembly. Both the Stelling and the drop base choked way too much air. The dropped was the worst, because half of the filter was not above the carb seat, so it was worthless. I'll see if I still have the numbers of the test.

I too would like to find a answer for a drop base as I also have a clearance problem using the Victor single plane manifold, so I to milled down the carb surface 1/2", but I'm not going to harm the motors performance by loosing cfm. Speaking with a few engine builders, the 1/2" will not have much affect, if any, on performance.

Just for knowledge, with the K & N style oval air filter, the worst thing we did was over oil the the filter, thus loosing cfm, a very light coverage was fine. To our surprise, a regular paper filter supplied a little more cfm than the K & N.

When oiled properly, they will trap more debris than the paper, just don't over oil them.

YerDugliness · #19 (**permalink**) 08-21-2010, 03:45 PM

I'm just curious, guys, now that thread drift has taken the discussion to CFM for various filters.

Seeing as K&N makes 9" diameter filters in various thicknesses, would you think that the greater CFM would come from the thicker filters (2") or the thinner filters (1"). There is also a 1.5" to muddy up the waters even more.

It seems to me that the thicker filter, the 2", would have deeper pleats in the filter material, yielding greater filter area. That seems to me to provide an advantage in CFM...anyone have any ideas? For right now it's just one old retired schoolteacher type postulating.....or is that hypothesizing.....or......well, anyway.....

Cheers from Dugly

FUNFER2 · #20 (**permalink**) 08-21-2010, 04:11 PM

Hey Douggie !

Sorry, I didn't mean to change the thread.

We run 2" K & N on the sprint car with no cfm depletion problems but, it's always at top rpm when the injectors (or carb in this case) are fully open and sucking in a lot of air, not at idle or street cruising. I'm sure with a clean filter, you wouldn't have an issue. That would be a nice comparison test on the dyno.