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Intake scoop


Jackal

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This photo has been on the Birkin Australia web site for a few years:

 

http://www.birkin.com.au/image/2091/motorsport3

 

http://www.birkin.com.au/image/2092/motorsport4

 

You may contacting Birkin Australia for info:

 

http://www.birkin.com.au/birkin-dealers.php

Edited by xcarguy
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This photo has been on the Birkin Australia web site for a few years:

 

http://www.birkin.com.au/image/2091/motorsport3

 

http://www.birkin.com.au/image/2092/motorsport4

 

You may contacting Birkin Australia for info:

 

http://www.birkin.com.au/birkin-dealers.php

 

 

Thank you! I appreciate the help. :hurray:

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At 100 mph, a well designed intake scoop will add .19 psi to the manifold pressure. At sea level, that's 1.3% more power, so scoops are only really useful above that speed. It's usually more useful on cars such as ours to ensure the intake air is not heated, for example by being behind the radiator.

If you can keep the charge air 10C cooler, it adds 3.7% power. (For you nerds, I assumed 283/273 K)

 

Of course, that scoop in the photo would do both. Looks cool, too. :)

Dan

Edited by NVP66S
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Those double inlets are NACA ducts, that when designed correctly, add minimal resistance to the air flow. My son-in-law who designs and builds UAV's (drones) for the military tried to describe how to design them in layman terms. Wasn't layman enough for me but there was something about opposing vortices cancelin each other out...blah, blah, blah. His plane's radiators are all cooled by NACA ducts so that he can use an aerodynamic nose piece to greatly reduce drag which gives his drones more time to "hunt".

 

Tom

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My Westfield has a huge hood scope but scoop

is only effective if you have a functional exit.

 

. . . . . :iagree::iagree::iagree:

 

Once I started doing track events, I noticed 'hood venting' during high speed runs at the rear of the hood where the hood lip mates up with the scuttle; this issue has been beat to death on the Stalker forum, but thought I'd through it on the table here. To initially overcome this issue, I simply taped up the hood scoop opening which resulted in no hood venting. However, it did result in a slight increase in operating temps on track, but not to the point of overheating. The tape also had a nasty habit of separating itself from the car under speed (see video link below). This led to several hood mods (see link below) and a few test hops (some still pending) to find a two-fold fix; a) stop the hood venting (primary) and b) maintain additional under hood airflow (secondary). The end result was a hood with:

 

• a dual NACA vent just forward of the hood scoop opening to allow for additional under hood airflow (works great);

 

• the hood scoop opening blocked off (closed off to the relative wind); and

 

• a reverse NACA vent, two louvered vents and row of small round vents located in the rear of the scoop . . . all for the purpose of air evacuation.

 

 

http://www471.pair.com/stalkerv/gallery2/main.php?g2_itemId=26697

IMG_0007.jpg

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Most 'store-bought' NACA ducts are but poor imitations. The S-shaped longitudinal edges should be sharp-edged. An early proposed application was for side inlets to a single jet engine in the aircraft fuselage, where the sharp edged S-shaped sides initiated a pair of vortices that ingested the boundary layer and allowed the duct to draw in free-stream air for the jet engine. The NACA-ducts in the rear quarter windows of NASCAR cup cars (did I say that?) are closer to the original concept than anything I have seen on USA7s or Locost USA sites.

 

Most commercial moulded 'NACA ducts' are little more than vents allowing the entry of high-pressure air. Using a NACA duct of any description as an exhaust does not recognise the principles of the original design concept: it would be simpler and cheaper just to cut a rectangular hole for an exhaust and install a small spoiler ahead of it.

 

If you are after references to NACA duct geometry, an early one is Frick et al., "An Experimental Investigation of NACA Submerged Duct Entrances, " naca-acr-5i20, October 1945. I found my copy as a pdf through Google.

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The intake scoop as shown by the OP harkens back decades. This scoop reminds me of the standard intake on a '77 March Formula Atlantic as shown here. If you are not familiar with Atlantics, at that time they were powered by a 1.6L TwinCam Ford Cosworth BDA, i.e. similar to what many of us have in our modern 7 interpretations.

 

The scoop would be fairly easy to fabricate from fiberglass. March made theirs as two halves (sliced as top & bottom halves) and then simply seamed them together with a strip of "fiberglass tape"; you can see the seam in the pic linked above. The scoop attached to an aluminum plate with (4) dzus fasteners, 2 each on the top and bottom halves. The aluminum plate was screwed to the weber carbs.

 

The foam sock was also simply made. A sheet of nearly 1" thick foam was cut such that when rolled it would form a cone with a glued together seam; during a season of racing and frequent cleanings the glue would fail and the sock replaced with new.

 

It's important to vent the airbox... March fiberglassed a section of aluminum tubing into the back of the airbox, maybe an inch in diameter, through which high pressure air could escape. The filter sock was simply tie wrapped to this tube; it was fun getting large hands back into the back of the scoop to attach the sock.

 

I'm a little fuzzy about the details of how the sock was attached to the front of the airbox... if I remember correctly, the filter sock was simply pinched between the airbox and an inner ring that formed to the contour of the air box inlet; the inner ring was attached to the air box with a couple of small screws.

 

Anyway, it would be a doable DIY project if one was sufficiently motivated. The aluminum backing plate could be easily formed over a wood buck. The airbox could be shaped from rigid foam from which one could make a 2 piece fiberglass mold...

 

I've thought that one would look good on my Superformance S1... and given the extreme heat under the bonnet, it'd probably be a nice performance improvement as a result of cooler air to the intake, but I have a motivation problem.

Edited by dhubbard422
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Okay, Duane,

 

Any word yet from down under?

 

:bigear: . . . . . . . :lurk:

 

Well this exploded into some good theory and conversation. I felt a bit silly starting the topic, but I don't anymore.

 

A Bryn contacted me and mentioned that this was a formula Ford piece that they still may be able to track down. I'll keep everyone updated as to what I find.

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  • 2 weeks later...
Okay, Duane,

 

Any word yet from down under?

 

:bigear: . . . . . . . :lurk:

 

 

Well, I got to my desk this morning and heard back from Birkin Australia. Unfortunately they only have one left and it seems to be in very poor condition. I didn't get much more detail, but I asked if it was salvagable in my reply.

 

Bryn also pointed me the direction of BirkinPerformanceCars.com, who has apparently purchased Birkin SA. Apparently this group plans on injecting some time money and effort into the brand, and Bryn suggested I contact them directly.

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Well, I got to my desk this morning and heard back from Birkin Australia. Unfortunately they only have one left and it seems to be in very poor condition. I didn't get much more detail, but I asked if it was salvagable in my reply . . . .

 

Update, please, when you get a reply . . . . . . . . . :lurk:

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Update, please, when you get a reply . . . . . . . . . :lurk:

 

 

Will do. I'm assuming there is interest on your side to get one as well?

 

I also emailed Dean at BirkinPerformanceCars.com, and we'll see what comes back on both accounts. I'll update when I have more.

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For your zetec, you'd want a formula continental piece:

 

You may want to try contacting van diemen or any of the reputable FC engine builders.

 

Awesome!! That opened the door to a bunch of links. Thank you for the help.

 

I was also playing around with the idea of making my own. I found a few links but the process looks simple enough.

http://www.westsystem.com/ss/the-lost-foam-method-of-composite-fabrication/

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