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WRX ram-air scoop

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11K views 12 replies 8 participants last post by  Lengthwise32  
#1 ·
Image


First off: This is no way an attack on the picture or person who made it. It is done very well and professionally.

I came across this diagram in another post and wanted to clarify that the shape of the WRX intake is not a ram-air scoop. I degree in mechanical engineering and we studied ram-air intakes in my fluid dynamics class. I didn't put this in engine mod section because it's not a mod, just an FYI for the community.

Although the intake isn't ram-air, it is awesome that the WRX was designed with a real cold air intake to pull air from outside of the engine from the front of the car just under the hood. Which is a great addition to the stock WRX.

A true ram-air intake has an increasing cross-sectional area, not a decreasing one. The larger cross-section slows down the air, decreasing it's dynamic pressure, and increasing it's static pressure getting denser air into the engine.

A good explanation can be found here: Ram-air intake - Wikipedia, the free encyclopedia

An example is here as shown on pro stock drag cars. Notice the smaller opening before the intake opens up to create a true ram-air effect.
-Chris
Image
 
#3 ·
According to the encyclopedia a ram-air intake is any intake design which uses the dynamic air pressure created by vehicle motion to increase the static air pressure inside of the intake manifold on an engine, thus allowing a greater massflow through the engine.......blah blah blah
 
#4 ·
Yup. Even if someone designed one for our cars, our WRX's don't go appreciably fast enough to benefit.

Nonetheless, I don't know why people knock our stock intake, it is a cold-air intake after all.
 
#7 ·
I've always dreamed of designing an intake for the WRX that utilizes the scoop.

It would be something with a rotated setup and an FMIC. Then I would make some insulation/ducting for the former TMIC area and fab up a smooth intake tract from the scoop to the turbo inlet.

The scoop would have a flap that you could shut, via a ****pit cable that would allow you to close it in case it started raining. It would then pull air from a hole opened in the duct.

It might be out of the realm of possibilty, but it would be fun to try.

IBthatideawillneverworkblahblahblah
 
#8 ·
our ram air is the turbo. that little scoop under the hood is nothing more than an inlet to the air box. Id say its function is to direct cool air in more so than to act as a ram air scoop. After all our turbo is sucking in air fast enough to negate any ram air benefits.
 
#11 ·
The turbo is doing more than enough to make any ram air not useful in a turbocharged car. I could see a well build true ram air slightly cutting down on the work the turbo has to do sucking air but not enough to make any difference.

I think its there just to make sure cold air is sucked it.
 
#12 ·
I'm also a degreed M.E., and catch myself pointing out mislabeled techy doodads, whether it's about cars, computers, guns, or whatever.

Having said that, the graphic in question has been around for LONG time on several Subie forums, and has helped huge numbers of people to understand the exhaust layout of their 2002-2005 WRX. I think we can agree that the label being "Ram Air Scoop" rather than "Air Scoop" really makes little difference in this situation. :)
 
#13 ·
Good to meet you, and I totally agree. That's why I started out w/ the first line of my post praising the diagram.

So many other message boards piss on each other and I wanted to be professional in my response. :)