Originally Posted by Tom M'Guinn

Don't know, but by placing it after the intercooler it should be able to measure more airflow, since cooler air takes less space. Seems like a clever way to extend the air measuring range of the barn door...

Originally Posted by adrial

The factory setup has it sucking in ambient temperature air from the fender ... how could the air post-IC be any cooler?

Originally Posted by adrial

The factory setup has it sucking in ambient temperature air from the fender ... how could the air post-IC be any cooler?

Originally Posted by jasonlp

There's one big limiting factor, where the snorkel meets the airbox is the biggest restriction point in the airbox system. It's almost not worth it unless that bottleneck is delt with.

Originally Posted by kevincnc

Jason my friend I have to call you out on this. How did you figure that the biggest restriction was there? Here's what I did just now: Wrapped a thin wire around the end of the snorkel where it enters the airbox, twisted it tight, and cut it off. The wire measured 11" long. That's about the equivalent of a 3-1/2" circle. Subtract .25" for a .125" wall thickness, and you get an equivalent of a 3.25" diameter pipe. Being squished into a flat triangle doesn't help, but I can't imagine that it hurts too much.

The round part of the snorkel is only about 2.2" ID. So,

2.2" diameter = 3.8 in^2
3.25" diameter = 8.3 in^2

Someone check my math please, but if it's right that's a huge difference. It seems to make sense that the German company pointed out by Voith in this thread makes an 80mm (3.15") snorkel.
https://rennlist.com/forums/944-turb...air-box-2.html

I am re-motivated to make one

Originally Posted by Tom M'Guinn

I'm sure Porsche designed it to flow somewhere near the snorkel's capacity, but measuring the perimeter of the opening isn't an ideal way to confirm. A 4 inch diameter round tube will measure about 12.5 inches around and have a cross-sectional area of about 12.5 square inches. On the other hand, a rectangle that measures 1/4 inch by 6 inches will also measure 12.5 inches around, but will have a cross sectional area of only 1.5 square inches -- i.e. the tube has over 8 times as much area even though the length around the outside is exactly the same.

The actual opening looks to be roughly the shape of a right triangle of about 1.5" x 5.75" x 6". That means the tape would measure about 13.25 inches around, or close to the 14" you measured when you add in the wall thickness. The area of a right triagle is equal to the base (1.5) times height (5.75) divided by 2. All of that means the cross-sectional area of the opening is roughly (1.5' x 5.75")/2 or about 4.3 square inches. A round tube with 4.3" inches of cross-sectional area would measure just about 2.3" in diameter, which is pretty close to the 2.2 inches you measured for the round part of the snorkel. Crazy german engineers...

I defer to someone smarter as to whether triangle-shaped and circle-shaped openings flow the same amount of air if they have the same cross-sectional area. They didn't teach is that in geometry class...