IW STi Forum banner

401 - 420 of 1193 Posts

·
Premium Member
Joined
·
2,612 Posts
Discussion Starter #401
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

If you wanted to check performance you could always tape or hot glue small lengths of string/yarn under the car then affix a hero cam under there. That will probably give you a good idea of how the air is flowing over the panels.
I do want to give that a try, but I've got to finish building the sucker first ;) It'd be really nice to see clean airflow coming outta that diffuser...

Dropped the car off at the local subie shop for the coolant leak and axle boot while I am out of town for a client site visit tomorrow. Should be fixed before I get back :)

I'll put the bumper bottom back on and snap a picture of it mounted on the car too. Its going to look looooow :devil: Good thing that stuff is flexible, because its going to scrape on everything...haha
 

·
Registered
Joined
·
479 Posts
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

So my logic may be flawed but if you have the diffuser butted up to the flat bottom with end fences, you can set it to whatever angle you want (while keeping it lower). It doesn't need to be butted up to the bumper does it? I'm thinking of just having the exhaust above (inside) the diffuser. Maybe even have the diffuser extend past the bumper a bit.
 

·
Registered
Joined
·
479 Posts
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

This is kind of what I mean and this is my train of thought for my car.

 

·
Registered
Joined
·
479 Posts
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

I took a screen shot of this ridiculously amazing lotus. This is another example of what I mean.

 

·
Premium Member
Joined
·
2,612 Posts
Discussion Starter #405
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

No it doesn't need to be butted up against the bumper, I just think that looks more low-key :)

Even with the end fences, if you cant just run any angle you want... If i made my diffuser like 20-30 degrees there would be so much flow separation and turbulence that it would be like a parachute and no downforce :(

The pics you posted are diffusers in the 7-10 degree range many people stick to, so they cant come up to the bumper.

Extending the diffuser past the bumper is good though, because the diffuser length is proportional to downforce is generated, so longer is better!
 

·
Registered
Joined
·
479 Posts
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

Thanks for the info! What I was getting at is you could run less of an angle with it not butted up to the bumper :tup:
 

·
Premium Member
Joined
·
2,612 Posts
Discussion Starter #407
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

Thanks for the info! What I was getting at is you could run less of an angle with it not butted up to the bumper :tup:
oh, right. yeah i considered doing that but that wasn't going to look as good and it was going to be harder to securely attach the diffuser... And I figure i'm only a couple degrees more than i probably need to be so its not that big of a deal to me. If I was building a legit race car, I would have done it different for sure.
 

·
Registered
Joined
·
479 Posts
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

Well I guess beauty is in the eye of the beer holder :beer:. I'm quite fond of that look but then again, I like the aggressive race car appeal! I'm excited to see your finished product though, no doubt it'll look great! ;)
 

·
Premium Member
Joined
·
2,612 Posts
Discussion Starter #410 (Edited)
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

weekend update #2

Finished cutting/fitting the passenger side end-fence today. It was a lot harder to fit than the drivers side... Got it on there though. The diffuser is really starting to come together!



When my boy got up from his nap this afternoon, he decided he wanted to help on the car :)


I didnt even direct him to do any of this, he just grabbed tools and started "working" haha


We went out later, so I took a snap from the road


And finally, here is a random pic of the car on a lift from last week. Slightly better shot of the underbody than I normally get...
 

·
Registered
Joined
·
899 Posts
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

Does it just look like it on the pictures or why is the Diffusor off center (using the taillights as a reference).

Looks badass though! :cool::tup:

Seems your mini-me is already on the right tracks :D
 

·
Registered
Joined
·
2,223 Posts
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

Looking good.

There is a thread in nabisco about flat floor. Have a read.
 

·
Premium Member
Joined
·
2,612 Posts
Discussion Starter #413
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

Does it just look like it on the pictures or why is the Diffusor off center (using the taillights as a reference).



Looks badass though! :cool::tup:



Seems your mini-me is already on the right tracks :D

I didn't notice that but it is actually about an inch to far to the right. The pics look much worse than it is... I just followed the edge of the phase 3 panels and apparently i cut a corner on measuring them :(

Oh well its not that bad...
 

·
Registered
Joined
·
99 Posts
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

Looks awesome, I want to copy your flat bottom.
 

·
Premium Member
Joined
·
2,612 Posts
Discussion Starter #417
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

Thanks guys!

I pulled my morroso catch cans apart today since they weren't draining. As I suspected the valves were full sludge... Now they are nice and clean :).

I probably need to make sure im draining them hot so the nastyness doest cake like that...
 

·
Premium Member
Joined
·
2,612 Posts
Discussion Starter #418 (Edited)
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

it was pouring rain all day yesterday, so I had the idea of putting the gopro on the back bumper to see what kind of water/mist patter was coming off the car. Just driving down the highway, there definitly seemed to be more spray/mist in the air than it normally would. Usually I don't see much of the spray up high in the rear view. Today however I saw A LOT of spray in the rear view, enough to cloud the car behind me pretty well!

Here is the video I took (shortened to just the highway part) from the rear bumper. Sadly between the rain drops on the lens and the faint/transparent-ness of the water/mist it is REALLY hard to see much of anything happening with the airflow. If you look carefully between rain drops there appears to be a faint "line" of water spray extending parallel with the diffuser outwards.
https://youtu.be/wpG5lJHVHkc

There also appears to be a lot of water falling off right at the leading edge of the diffuser. This could be airflow separation making the water fall off, or could be a function of the airflow changing in the diffuser and water being heavy... I'm not really sure what that means, and I doubt I'll ever really know. *shrug*

yarn test/video will be coming soon.
 

·
Registered
Joined
·
492 Posts
Re: BlueScooby's 06 STI - Underbody Panels Phase 4 (rear diffuser)

Subscribed! Loving all the progress pics on the underbody panels!, Fantastic work man!
 
401 - 420 of 1193 Posts
Top