legacycentral bbs

http://www.youtube.com/watch?v=_JwXdkjiMVw

This video is useful for more than just an intercooler design, but I figure it's what most of you would care about most.

Towards the end, you can see the hood being tuft tested. Tough to see, but it looks like the air is actually going forward in the area of the stock hood scoop location (which the test car lacks). From this, I'd say the best ideas for TMIC efficiency are either a cowl induction set up or a scoop that starts at the hood leading edge and follows back to the original opening to pick up the high pressure air in front, something like a Pontiac. Another, high drag, dumb-looking option, would be to have a high-rise set up in the original location to pick up cleaner air in the higher airstream.

Disclaimer: I am not an aerodynamicist, but I play one on the internet.

Yeah with the horrible video quality and it was lagging really bad, not sure if that was my internet or the video but I think it was the video, but it was hard to see anything.

Still pics I've seen on ecomodder are much better. I used them to figure out lower drag, higher efficiency radiator ducting.

Tough to see, but it looks like the air is actually going forward in the area of the stock hood scoop location (which the test car lacks). From this, I'd say the best ideas for TMIC efficiency are either a cowl induction set up or a scoop that starts at the hood leading edge and follows back to the original opening to pick up the high pressure air in front, something like a Pontiac.

I read somewhere (likely here) where the stock SS/TW scoop was changed to act like cowl induction...I'll have to find it.

Since the stock hood scoop is relatively small and only feeds the chimney, I wonder if the original design was more form over function? Or to give the Subie designers credit, intentional to 'exhaust' the turbo's heat, not cool it?

The WRX scoop's higher profile would grab the air you mention?

Td

Since there was no intercooler originally, I think someone determined it was probably just a vent for the turbo heat, which the tuft testing seems to corroborate. I don't think the WRX scoop would grab air as efficiently as the eye would think since it's pulling from a turbulent low pressure zone. A higher-rise set up might get some of the higher speed air out of the turbulence, but a scoop extending to the hood leading edge should get high pressure air without as much drag.

thread from the dead.

I believe you saw the video wrong because all of the end of the video is of the trunk. great video though. this shows the eddy that forms on the back window. I am studying fluid mechanics right now and I find this really interesting. Here in colorado it is pretty easy to find a ridge with constant wind so I might have to try this.
-Max

That's the wrong video. IIRC, the guy posted a couple of them, with one distinctly showing the hood from the leading edge back. I must have screwed up when I posted that link originally and now I can't seem to find the right one. Interwebs fail for me.

the scoop works for me. i have a intercooler pipe siting right under the factory scoop cover (under hood black thing). when i get off the hwy, the pipe is frozen just in that one spot. when i take that black cover right off, everthing stays cold under the hood scoop.

i think the oem scoop does a great job and still does not make to much drag, my impreza hood looked like it was going to rip off on the hwy.

also in that video that car has no wing, so with those string things does it look good or bad ? i want to get rid of the wing.

What you're looking at is a tuft test. Whichever way the strings are moving is what the airflow is doing. If they're flapping around, they're in a turbulent zone. Ideally, you want the strings flush against the body.

It's not that you're not getting air into the scoop, just that, (if I could find the right damn video!) you could see that there isn't clean, high pressure airflow going into it.