I could not find the thread that I had read last night, which stated that most big name Japanese tuners did not utilize wind tunnel testing, and only aero sold parts from the name's sake. Here is a link to C-west's wind tunnel test results, as well as a vid of the tunnel test and Tsukuba time attack.

I found a video of Amemiya's wind tunnel testing on their 2005 GT car, as well as Mugen and a few other tuners, but I can't seem to locate it here at work. Anyhow, enjoy

http://www.c-westusa.com/labs/fudo1_rx7spec.asp

Chris~

 

I'll give C-West credit, at least it appears they did some testing. It should be noted, though, that the vast majority of improvement in downforce is in the rear, due to the addition of the wing-- a fairly easy concept. Very minor gains were made in lift reduction, which is mostly due to the lower front lip of the bumper.

However, I'm extremely skeptical of the time improvement they show at Tsukuba (at least that's what is implied in the ad)-- or at least aerodynamics playing any part in it. Tsukuba is a very tight and overall slower speed circuit; the front straight is barely a quarter-mile long (if that), and most of the turns are pretty tight, with speeds barely exceeding the 60-70 mph range, far too low for aerodynamics to play any meaningful role in lap times. And especially a near-2-second drop in lap times at Tsukuba; that track rewards slow-speed handling and aggressive braking more than anything else.

 

that's pretty cool. I know RE-Amemiya does the same with their products.

 

Linky no worky.

 

It's not a direct link to a video. Click on the link...it's a webpage. Here's the direct link:

WMP: http://www.c-west.co.jp/labs/movie/fudo_rx7.asx
RA: http://www.c-west.co.jp/labs/movie/fudo_rx7.ram

 

Not to argue w/ you, but the video shows they tested it w/ and w/o the wing in the windtunnel. I do remember reading somewhere on their website (and this was mentioned in a past thread) that they only windtunnel tested upto 90mph or so? This was before the DRFT kit tho I believe.

Oh and the video's interesting...I'm curious why the little wind direction indicators were flapping all oevr the place, instead of being matted down against the body of the car?

 

good observation

 

And your point being?

What I'm saying is that if you look at the wind tunnel figures listed on the page, the vast majority of the downforce increase is due to the attached wing on the rear. Not a whole lot of aerodynamic R&D goes into slapping a wing onto a rear deck.
That was probably the limit of the wind tunnel they used. If you look closely in the video, the fan isn't all that big. To generate serious wind velocities, you need a pretty damn big fan assembly, like the one that was posted in a thread a while back. Nonetheless, a lot of the properties observed at 90mph apply at 190 mph.
The reason is the laminar boundary layer becomes turbulent as it flows over the curvature of the body surfaces. It's part of the reason any object has some aerodynamic drag over its surface.

 

Ya. From what I see, they at least put a little more effort than some other companies out there with kits of comparable price range. They also frequent races with their Aero parts, mainly the Super Taikyu series, which is an endurance race similar to the 24 hours at Thunder Hill.

This part I agree with as well (mainly the 2 second lap difference), as I know aero plays an integral part when speeds get above 70-ish, but Tsukuba is, like you said, a low speed course, with only the back straight being the longest section. I could see something like a 1/2 second difference to possibly a second, but 2 off the ticker is a little far fetched.

None-the less, I do see where the engine cooling capacity would be increased with the larger openings in the front fascia, as well as heat evacuation from the vented hood.