Big $$$ for Wayne and this product idea

[DAVIDM]

Dear Wayne,
The first problem is the two piece tattered and torn grating that serves as a screen in the intake of my whale tail. (86 Carrera) It is some sort of fiber or plastic held in place by 8 screws and it is falling apart.
The second problem is the price that Porsche wants. Over $200 per side.
The money making solution for you is to have somebody make a few of these in a proper fashion and sell them from your web site.

I paid $75 for 2 ea. 18" X 18" pieces of "perforated sheet" metal. This price is the same if you buy the full 3' X 10' sheet. (www.mcnichols.com) You could get six intakes out of this sheet. McNichols has the stuff in aluminum, steel, or stainless with about 50 different sizes and hole patterns. I bought steel and will paint them either black or the color of the car. Stainless might seem a little "ricer" but it wouldn't look bad.
I simply made a paper pattern from my old one. I cut the two pieces to match the pattern with an abrasive metal cutting disc, clamped the edges between two pieces of wood in the Workmate and hammered the edges down. The sides are rough but no one sees them so they are OK. A proper metal shop could stamp and bend them in about 10 minutes each.
Maybe $15 in materials if you included screws and washers. $50 in machine work. $5 in packaging. $10 in paint (black only). Suggested selling price would be $229.95 and you are still less than 50% of Porsche price. 60% to 70% gross profit margin with no more than 12 in inventory. Sell one a month and you have a low turnover high profit item that is far superior in quality and durability to what is available in the marketplace.

You knew there had to be more than one reason to keep this bulletin board operating didn't you. All these great ideas from your customers. You'll be rich. RICH beyond you're wildest dreams. I only want a small, very small royalty on each set you sell. If you could see your way clear to prepay my royalties on the first batch before Christmas, it would be greatly appreciated.

Pics of the material, my rough handmade set, and my set dry fitted before painting are included.

David
P.S. This is what happens when one's wife has to fly home on Thanksgiving to tend the recovering mother-in-law with the new metal knee, and one has to work on Friday, and all one's other friends and relatives leave town.

[Jack Olsen]

I've hear you shouldn't have less than 1/4-inch openings, as it restricts airflow.

[island911]

Originally posted by JackOlsen
I've hear you shouldn't have less than 1/4-inch openings, as it restricts airflow.

Get rid of small holes. . . Take out the air filter too, then.

I'm kidding, of course.
The point being, hole size has little to do with restricting airflow.
The "open area", or lack of, does.

I would choose something other than perf for this . . . and certainly not stainless.
As Jack points out, it looks restrictive . ..and likely is. It has a cool look to it perhaps, but is maybe only 40-50% open area. Thats gotta suck

What do those tails have from the factory? . . .

[k9handler]

Airflow restriction would appear to be a slight flaw...simply choose a sheet with larger openings. I like the effort and give you a thumbs up!

[Chuck Moreland]

He's got two panels 18"x18". So if it is 50% open area, then he has an equivelant opening of 18"x18".

That's plenty big. It's probably larger than the opening on a non-tail decklid after factoring the grid.

[island911]

Good Point, Chuck. Lots more area.

For comparison, I went and measured the open area in the SC grill. Looks like ~13in² open. (I put the calipers to a couple openings and mupltiplied by # of openings; so beware, the error maybe high)

18in² then is better. (18in² assuming it's not blocked by other stucture, and is 50%OA, not 40ish%)

Still, if I were doing this, I would use something lighter, with higher OA than is possible with round perf.

[Eric Coffey]

Just guessing here, but maybe a more "open" (tubular) mesh would be more appropriate than a perf. sheet. Like something from these guys: www.twpinc.com

Although, unless you are trying to "feed" an intercooler, it may not be that big of a concern (again, just guessing).

[Eric Coffey]

Here's some pics of a few examples from the www.twpinc.com site:

[makaio]

The bottom most one in your picture looks best Eric.

I really like the idea and the look.

But as others have pointed out, it has a lot of air restriction. Normal household window screen will cut air flow by 25-50%, depending on how tight the squares are.

I think if you used a material with openings twice as large ( 4 times more airflow) you would be in buisness.

[Eric Coffey]

Yeah, those were the only pics the web site had. However, they manufacture mesh out of all sorts of material, in many different configurations/dimensions from around 30%OA to 80%OA.
Still, the question I have is: How critical is airflow from the rear deck lid grill anyway? Take cars with factory A/C for instance. Wouldn't the huge condenser prevent just as much, if not more airflow? Also, I have seen a few German "tuner" companies (TechArt, Strosek, etc.) replace the deck lid grilles with solid pieces like this:



Any thoughts?

[masraum]

Eric, that picture looks like a 993. If that's the case the cooling air, I believe is drawn in throught the bottom of the car and expelled through the grill (better aerodynamics). That may be part of the reason why the solid grill is possible on a 964. Without something else going on it would surely be death to a pre 89 911.

[DAVIDM]

The McNichols catalogue lists the open area for each material. The material I used is 46% open area. Only two other hole patterns had higher open areas, but I rejected those because the holes were almost twice as big. Big enought to let stuff through with only 5% greater open area.

The original material is slotted, rectangular holes approximately 1mm X 2mm. The intervening material is slightly wider than 1mm. This results in something less than 50% open area. If one chooses to calculate the tears, gaps and holes it would probably be around 75% open area.

I picked the material that would most closely approximate the factory original.

At the right speed this stuff might whistle. Or maybe a large contingent of flutes. Or maybe a big turbo whine.

David