What's with the little aircleaner?

xcop · #1 (**permalink**) 12-11-2011, 04:27 PM

Just bought an SPF and was going over things under the hood, and couldn't help but notice the small aircleaner. This thing has a 427 stroker supposedly rated at 525 to 550 hp, and it has approx. 8'" X 2" round aircleaner on it with the "turkey pan" on top of a Holley double pumper.
I suppose this is correct to the original, but I don't see how they make that much power through that small an airfilter.

TN Shelby Cobra · #2 (**permalink**) 12-11-2011, 04:50 PM

Works for me!! Also for my friends 427 side oiler! Mark

Cobra #3170 · #3 (**permalink**) 12-11-2011, 04:51 PM

Quote:

Originally Posted by xcop

Just bought an SPF and was going over things under the hood, and couldn't help but notice the small aircleaner. This thing has a 427 stroker supposedly rated at 525 to 550 hp, and it has approx. 8'" X 2" round aircleaner on it with the "turkey pan" on top of a Holley double pumper.
I suppose this is correct to the original, but I don't see how they make that much power through that small an airfilter.

You are so right, it drives me nuts when I see a supposedly high performance engine with those little air cleaners. They would be lucky to make 350 HP with that set up. My first engine (a dual 4 medium riser) would not pull 4th past 5500, I had to install taller elements to get enough air to pull past 6000 in 4th. I think some of the guys ran without air cleaners when they raced the single four cars back in the day, but am not positive. Those cars were making in the neighborhood of only 480 HP so maybe they could run with a smaller air cleaner.

gsharapa · #4 (**permalink**) 12-11-2011, 05:36 PM

This works well.... 9 inch by 2.5 or 2.75 K & N, flat base and 9 inch Xtreme top!

Dwight · #5 (**permalink**) 12-11-2011, 05:53 PM

I have a B&B in my shop with a 8" S&H air cleaner on it. 351W with 400 hp. I did the calulation and it was losing 98 hp at 4000 rpms. It would not rev over 4300 in any gear. Changed the air cleaner and now it pulls to 6000 rpms.

Dwight

P.S. I have a S&H air cleaner for sale, make offer.

http://www.secondstrike.com/Technica...leanerHelp.pdf

xcop · #6 (**permalink**) 12-11-2011, 06:12 PM

Gary, can you tell me what kind of aircleaner you have?

RET_COP · #7 (**permalink**) 12-11-2011, 06:28 PM

Dwight, what did you replace it with?

mdross1 · #8 (**permalink**) 12-12-2011, 05:45 AM

Quote:

Originally Posted by xcop

Just bought an SPF and was going over things under the hood, and couldn't help but notice the small aircleaner. This thing has a 427 stroker supposedly rated at 525 to 550 hp, and it has approx. 8'" X 2" round aircleaner on it with the "turkey pan" on top of a Holley double pumper.
I suppose this is correct to the original, but I don't see how they make that much power through that small an airfilter.

Your thinking is on the money.While trying to dial in the 585 hp 460 in my car with the small Stelling air cleaner,knew out of the gate it was too small. A call to K&N set me straight.Ordered a new hood to be cut installed a modified Harwood scoop,now have a 3"x14"with Extreme Top, happens to sit in the middle of the scoop.Performance is the way it should be,the motor no longer lays over for lack of air.

SPF1061 · #9 (**permalink**) 12-12-2011, 06:44 AM

Quote:

Originally Posted by TN Shelby Cobra

Works for me!! Also for my friends 427 side oiler! Mark

TN Shelby Cobra,
If you put your car on a chassis dyno and did a pull with that intake setup, followed by a pull with a big NASCAR style filter, you would see exactly how well it's working for you. Just sayin'.

RACER X #99 · #10 (**permalink**) 12-12-2011, 07:01 AM

Those little Stellings were the original setup for street Cobras today they are car show air filters.
Makes no sense in building a big cube engine with all the go fast parts and then chocking it just because it looks "correct".

TN Shelby Cobra · #11 (**permalink**) 12-12-2011, 07:06 AM

Quote:

Originally Posted by SPF1061

TN Shelby Cobra,
If you put your car on a chassis dyno and did a pull with that intake setup, followed by a pull with a big NASCAR style filter, you would see exactly how well it's working for you. Just sayin'.

Don't really care! Fast enough like it is!

Hotfingrs · #12 (**permalink**) 12-12-2011, 11:08 AM

Gary's air filter is a K&N with an Xtreme top from K&N. I've got the same filter and top, and on the dyno made the same horsepower, with or without the filter, so it does work.

undy · #13 (**permalink**) 12-12-2011, 11:42 AM

That's why a lot of "600 hp" engines built by reputable builders dyno 400 hp at the wheels.

I did quite a bit of chassis dyno time to develop a filter set-up for me. In fact, it put 8 more rwhp down with the filter than without one. Some air staightening is a good thing, as long as the filter's adequate.

Tommy · #14 (**permalink**) 12-12-2011, 01:09 PM

Quote:

Originally Posted by TN Shelby Cobra

Don't really care! Fast enough like it is!

With no disrespect intended, I think that says more about the driver's expectations than the engine's performance.

RET_COP · #15 (**permalink**) 12-12-2011, 01:56 PM

K & N just told me that my red gauze 11 7/8 x 8 3/8 oval flows only 387 cfm ! yikes !!.
I have no room for anything else. I like what mdross1 did and I have thought about this, but it's not in my plans for now.
Those Edelbrock triangle foam filters claim 1000cfm. Does anyone have any positive information on this. Maybe use some flame retardant spray.
Get this, they also said that on a 14 x 3 round red gauze filter, the difference between the extreme top and a capped top is 200cfm
Lou

xcop · #16 (**permalink**) 12-12-2011, 02:14 PM

Thanks, Jack. I ordered a 9" top for mine. It has a K&N element in the Stellings housing, that is about 8 1/2". I hope this top will mesh all the way around, and make a decent set-up. If not, I guess I'll ditch the pan and go with an oval cleaner.
I bought a set of stainless pipes from Madmax, so the "out end" should be opened up, and this should open up the "in end"

Tim Brewer · #17 (**permalink**) 12-12-2011, 07:32 PM

I was told that if on a dyno, a big cube engine might suffer pulling air through an 8" filter. But when driving at speed, the turkey pan becomes pressurized and the engine gets all the air it needs. Thoughts?

Pete Munroe · #18 (**permalink**) 12-12-2011, 09:47 PM

Lots of good data on various types and sizes of air filters on the Superformance Newsletter..."Second Strike" May 17th, 2005

It has actual data to compare filters as to media...foam, paper, oiled fabric, diameter and height, and "style", round vs. oval.

Hope you can find the Superformance Letter. I TRIED to load the pdf. Can't. Forum limit is 39 kb and the pdf file is a massive 196kb.

As to the "best flowing set up" ? A round, 14" X 3", seems to hit the knee of the curve for air flow...less is worse, more isn't much better. You can juggle the media.

BUT the 8" S&H filters are VERY period correct and cool...especially on dual fours. If you need really need more flow...take them off ! Enjoy your track weekend...replace them for the street.

Pete

enigma57 · #19 (**permalink**) 12-14-2011, 02:05 AM

Very interesting thread!

I have found the chart above to be very helpful. You can calculate the required filtration area from this chart in sq. in. and apply it to filter element(s) of any shape or configuration.

Bear in mind that this chart is based upon a 14" diameter round air cleaner fitted with a new (clean) filter element. On street driven applications, I generally size mine at 135% to 150% of equivalent sq. in. filtration area to allow for the gradual in service buildup of dirt trapped by the filter element.

My current project is a vintage car having a relatively low hood line and Weber carbs as do many of the Cobras here. Not wishing to modify the hood nor external appearance of this car...... I am building an air box enclosing the carbs, supplied via 2 ducts taking cool air from behind the grille, ahead of the radiator. Will install appropriately sized flat filter elements at the points of air entry.

My engine displaces 427 cu.in. and I have designed it to peak at relatively low redline of 6,000 RPMs. As you can see, the chart indicates a 14" dia. filter 3.5" in height having approximately 154 sq. in. filtration area. Allowing for decrease of effective flow capacity in service as the filter traps dirt...... 135% of 154 sq.in. would be 208 sq. in. and 150% would be 231 sq. in. So I will locate a couple of late model flat filter elements having a total area between them equivalent to between 208 and 231 sq. in.

FWIW...... A pair of square filter elements, each measuring 10.75" X 10.75" (or equivalent dimensions in rectangular or round shapes) will net 231 sq. in.

Hope this gives you some ideas.

Best regards,

Harry

undy · #20 (**permalink**) 12-14-2011, 12:18 PM

Quote:

Originally Posted by Tim Brewer

I was told that if on a dyno, a big cube engine might suffer pulling air through an 8" filter. But when driving at speed, the turkey pan becomes pressurized and the engine gets all the air it needs. Thoughts?

Uh... not really. The difference at speed would be negligible. The real benefit would be the cold air.