Air intake methods for 13b
Absolute Power is Awesome
Joined: Mar 2001
Posts: 1,973
Likes: 5
From: Issaquah, WA
Just to elaborate. You're not seeing the flow go compressible around butterfly valves, you're seeing flow separation and restriction but it's still behaving as incompressible.
A pressure difference is what motivates fluids to move, just like voltage drives current through wires. There are two types of pressure in incompressible flow, static and dynamic. The dynamic pressure is due to the energy of the flowing fluid. The static pressure is the motivating force behind the fluid motion.
If you hold your hand in front of a hose with a spray nozzle, you are bringing the moving fluid to a stop. The force you feel on your hand is caused by the dynamic pressure, and when it's stopped, it added to the ambient static pressure is called stagnation pressure.
A pressure difference is what motivates fluids to move, just like voltage drives current through wires. There are two types of pressure in incompressible flow, static and dynamic. The dynamic pressure is due to the energy of the flowing fluid. The static pressure is the motivating force behind the fluid motion.
If you hold your hand in front of a hose with a spray nozzle, you are bringing the moving fluid to a stop. The force you feel on your hand is caused by the dynamic pressure, and when it's stopped, it added to the ambient static pressure is called stagnation pressure.
84SE-EGI helpy-helperton
Joined: Oct 2002
Posts: 3,584
Likes: 542
From: Phoenix, AZ
HadaGSL-SE - this was all hand-fabbed to work after giving it some thought. If you look at my previous pictures, you'll see that part of the rubber 'dam' section at the rear of the headlight lid had to be cut away to allow a path for the air to flow.
Once this section is cut, you have to cut your rubber dam so that it fits the new metal section, and then take your rubber air pipe from the stock intake (in front of the radiator) and turn it 180 degrees. Cut it to fit the stock plastic airpipe, and then fabricate the plastic airpipe to fit into the section that you cut out from before. I used a single screw to hold the plastic pipe in place, but when the hood is down, it holds it all in-line perfectly.
I preferred to use the stock AFM and airbox design because I wasn't willing to 'test-pilot' performance mods having to do with filtration and airflow velocity (as you see hashed out here by Purple82 and Pimpncuba). Instead, I used a free-flowing K&N filter and made my own Ram-Air design which is both functional and cool-looking, if I may say so.
When it rains heavily, I put the headlights up so that the NACA duct is blocked from oncoming airflow - this helps to keep rain from soaking the filter and I've had it this way for about a year now and several major rainstorms without any problems at all. I live in AZ, however, so the rain isn't a factor about 99% of the time. HTH,
Once this section is cut, you have to cut your rubber dam so that it fits the new metal section, and then take your rubber air pipe from the stock intake (in front of the radiator) and turn it 180 degrees. Cut it to fit the stock plastic airpipe, and then fabricate the plastic airpipe to fit into the section that you cut out from before. I used a single screw to hold the plastic pipe in place, but when the hood is down, it holds it all in-line perfectly.
I preferred to use the stock AFM and airbox design because I wasn't willing to 'test-pilot' performance mods having to do with filtration and airflow velocity (as you see hashed out here by Purple82 and Pimpncuba). Instead, I used a free-flowing K&N filter and made my own Ram-Air design which is both functional and cool-looking, if I may say so.
When it rains heavily, I put the headlights up so that the NACA duct is blocked from oncoming airflow - this helps to keep rain from soaking the filter and I've had it this way for about a year now and several major rainstorms without any problems at all. I live in AZ, however, so the rain isn't a factor about 99% of the time. HTH,
