Colonel Red Racing 2005 STI Race Car

[Sgt.Gator]

I'm just about ready to start modding my hood for vents and came across this Aussie aero guy. He has an entire series of videos that are pretty good. Aero, suspension, and general race car stuff goodness. Here's his simplified video on hood scoops/vents:

 

[boxkita]

From the Mark Donahue school of racing design, there is a typo at the end of this video. The teams spends millions of rubber ducks on aero. No actual dollars were harmed.

 

[Rhitter]

I'm just about ready to start modding my hood for vents and came across this Aussie aero guy. He has an entire series of videos that are pretty good. Aero, suspension, and general race car stuff goodness. Here's his simplified video on hood scoops/vents:

 

 

Watched that video. Pulled up pictures of the silver eagle to show my wife how you cut up the hood to match what he was talking about. Then made her watch another hour worth of these with me.

 

Overall pretty interesting stuff.

 

This video was pretty good. And drove home the point - "add lightness" End of the video basically showed that aero / downforce on a wrx doesn't make a lot of difference.

[Sgt.Gator]

Watched that video. Pulled up pictures of the silver eagle to show my wife how you cut up the hood to match what he was talking about. Then made her watch another hour worth of these with me.

 

Overall pretty interesting stuff.

 

This video was pretty good. And drove home the point - "add lightness" End of the video basically showed that aero / downforce on a wrx doesn't make a lot of difference.

 

LOL, you're wife is a very understanding woman!

 

Regarding the WRX case study, he doesn't give any details about what aero was done to get the numbers he used. I think he's mostly talking about the kind of aero mods you would see on a street driven WRX. So yes, they aren't going to add a lot of downforce. WRX race car is entirely different. Just look at the awesome cornering speeds modern Time Attack sedans are turning. Remember too that aero is not just about downforce and cornering. It's also about reducing drag and improving cooling if done correctly.

 

I think in this video he drew the Silver Eagle on his white board!

 

BTW, If you haven't been to his consulting website, JKFaero, here's his design for a GT86/FRS/BRZ TIME ATTACK car:

..

Edited January 26, 2017 by Sgt.Gator

[boxkita]

Great line in the wagon aero video "You can set up a car the driver hates, but who cares as long as the car is one second faster?"

 

My street wagon was setup to oversteer at high speed and was pretty dodgy at speed. It would have benefited from a rear wing as well as front splitter among other things. I'm planning to drop the street car values onto the race car as a starting point. Expecting magical lap times, too.

[Rhitter]

Sgt.Gator are you going to have an aero consultation done on your car? Or are the mods pretty straightforward / tried and tested on an 05 STI? Edited January 26, 2017 by Rhitter

[Sgt.Gator]

Sgt.Gator are you going to have an aero consultation done on your car? Or are the mods pretty straightforward / tried and tested on an 05 STI?

 

I have a local AE friend here in Bend. We may start our own aero consultation service. I've been waiting for a 3D scanner that meets all our requirements to be available to do scans, then convert to a 3D model that he can do CFD analysis on. The scanner I planned to buy a year ago turned out to be all market hype with vaporware. There's another one out soon that claims to do what we want, but it wouldn't surprise me if it's vaporware too.

 

Back to your question, most of the mods are well known. Like deleting the monster 2005 STI hood scoop if you have an FMIC. Based on my track testing last year with the wool tufts I also installed an EVO vortex generator above the rear window and added extensions to the rear wing to get it up higher. Knowing what I know now I should probably have used aircraft micro vortex generators instead of the CF Evo style.

 

http://www.aircraftspruce.com/catalog/graphics/05-04457.jpg..Or..http://www.aircraftspruce.com/cache/370-320-/catalog/appages/apmisc/vortex.jpg....or...http://www.aircraftspruce.com/catalog/graphics/05-04662.jpg

 

available at: http://www.aircraftspruce.com/categories/aircraft_parts/ap/menus/ap/aerodynamics_vortex.html

 

I am wondering if there's other places the micro VGs could be useful like the bottom of the rear wing or on a full undertray........hmmmm.

 

I also will be installing a rear trunk lip spoiler. It may seem counterintuitive to use both a wing and a lip spoiler but the study I've read says it makes the wing more efficient and reduces the drag, which is the holy grail to both increase downforce and reduce drag. Pics soon.

[bigBADbenny]

Check out Andrew Brilliant's lip & wing low drag/hi downforce 86 aero on Speedhunters for extra inspiration...

http://www.speedhunters.com/2017/01/hks-gts800-the-tsukuba-record-challenger/

Edited January 31, 2017 by bigBADbenny

[boxkita]

It may seem counterintuitive to use both a wing and a lip spoiler but the study I've read says it makes the wing more efficient and reduces the drag, which is the holy grail to both increase downforce and reduce drag. Pics soon.

 

Kyle.Drives videos for wings and splitters talk about that. It seems counter-intuitive, but the whiteboard logic works out. Who am I to argue with a guy who majored in Race Car Aerodynamics?

[Sgt.Gator]

Check out Andrew Brilliant's lip & wing low drag/hi downforce 86 aero on Speedhunters for extra inspiration...

http://www.speedhunters.com/2017/01/hks-gts800-the-tsukuba-record-challenger/

 

Very cool, and a Subaru BRZ/Toyota 86 too! It's amazing how the time attack guys are advancing the aero on sedans and coupes.

Thanks!

[Sgt.Gator]

It's been awhile so here's some updates:

 

The Dry Sump Tank, Vent Tank, and Cooler are mounted in the trunk. I cut a hole thru the trunk to let the tank hang lower and also easy to access the drain plug in the bottom. Also note the new rear diffuser, an OEM unit. At the front the DS scavenge lines are run, with DEI hose fire sleeves and DEI wrap around the Perrin ELH headers. :

[Sgt.Gator]

Wondering how the DS oil cooler mounted in the trunk is going to get cool air?

I've mounted NACA ducts in the rear bumper directly opposite the factory flow thru vent holes. Normally the flow thru vents duct air out of the trunk and into the space between the bumper and steel body. But now I've reversed that by deleting the oem one way vents and sticking the NACA duct into the hole.

 

The usual practice would have been to put the NACA ducts in the Lexan rear windows with vent hose going thru the firewall between the passenger compartment and the trunk. I did it this way to avoid putting big holes in the firewall. Now the only holes will be for the dry sump lines.

 

The downsides are that they may not suck in enough air in this location or they might suck in too much tire rubber castings and other debris. I will be putting screens over them on the inside to cut down on that. If they don't work I can pretty easily block them off and install them in the traditional place in the windows.

 

How does the air exit? Thru two holes I cut in the trunk lid. I've mounted exhaust fans in the holes at least temporarily. If it turns out I get enough airflow thru the trunk without them I can easily remove them to reduce weight.

 

I also ditched the pull handle trunk and gas cap lid releases, they were unreliable. (The hood release too). For the trunk I used old school spring latches.

[Sgt.Gator]

I installed rear wing risers to get the wing a bit higher. And a vortex generator on the roof. Next will be a Gurney flap on the wing, and a trunk lid lip spoiler. My garage is too cold now to use the double sided 3M tape even if I will be doubling down with sheet metal screws.

 

In the previous post I already showed the new oem rear diffuser. I also ordered new underbody panels.

 

I'm looking forward to round 2 of my aero studies with yarn and GoPro to see how all this affects the airflow over the rear window and wing. I'll probably do that in March at an ORP track club day or the Autocross Club of Central Oregon April 1st track day at ORP.

[Sgt.Gator]

The Chase Bays power steering cooler kit was sorely lacking in several respects. The hose they supplied to go from the resovoir back to the pump ( very low pressure) was not the right size. It was impossible to get to get the hose over their supplied fitting. I actually pushed so hard it split the braided the AN line!

 

A new Push Loc line fixed the problem. Although the same diameter as the AN line, it's internal diameter is slightly larger and being push loc it doesn't have the braid stopping the slight expansion to get it over the fitting bump.

 

But they also supplied an AN fitting on the bottom of the reservoir that didn't have enough bend to get the line going back up to the pump. So i got a new AN fitting there too.

 

Which makes me wonder have they ever done this themselves?

 

I also had to re-do the air filter - intake. Once I mounted the power steering pump the air filter was pushed up and wouldn't stay in the surround. So here's my latest version.

 

I will never do a 3" intake in the stock location again!

 

I ran all the AN lines for the fuel rails (Radium rails). The longer ones have DEI insulation. Mounting the Perrin fuel pressure regulator required fabricating a bracket. And I played around for a long time to come up with a way to mount a fuel pressure gauge where I could see it and it would stay tight.

[Sgt.Gator]

I knocked out the rear suspension update. I'm replacing every suspension bushing in the car with Whiteline and Energy Suspension. The rear is 99% done, I just need one new OEM nut to replace one that got all fuggled up removing it, then the full re-do on the alignment. In this pic you see new trailing arm bushings, new adjustable lateral links, new differential outrigger inserts, new energy suspension sway bar bushings, new whiteline adjustable sway bar links. What you can't see is the Perrin subframe lock down bolt. I don't think the LGTs have a way to do that, at least I don't remember seeing any aftermarket parts to do it to a Legacy.

I also knocked out the power steering bushings replacement.

Next up: The front suspension bushings/Whiteline Caster-Anti-Lift kit/Whiteline tie rods.

Edited February 21, 2017 by Sgt.Gator

[Rhitter]

What's that filter?

[Sgt.Gator]

What's that filter?

 

The vent for the now deleted charcoal canister vapor return line. Amazingly it doesn't stink up the garage with gas fumes. Earlier in this thread I posted links on how to do it.

 

A lot of guys on NASIOC do it on their street cars but I don't advise it for a street car.

[Sgt.Gator]

The Nurburgring 2017 STI is testing. They've done a lot Aero work. The car is nothing like a production car other than general outline. Longer wheelbase, wider track.

 

Great details in this video. I sure wish I knew what he's saying!

 

STI NBR CHALLENGE 2017 シェイクダウン潜入濃厚レポート！！

[fredrik94087]

I love how the canards blend into the fender well for downforce.

 

Different video...OMG look how that hood unlatches at 45 seconds of this video:

Edited March 13, 2017 by fredrik94087

[Sgt.Gator]

The Nurburgring 24 Hour race motor.

 

http://www.subaru-msm.com/2017/img/news/2017NBRSD_2.jpg

[boxkita]

TMIC ftw :-)

[Rhitter]

I am surprised at how stock that looks. Also that they stuck with the TMIC.

[ehsnils]

Considering that the ring is a high speed track I see that aerodynamics is the prime concern for good lap times as power required increases exponentially with the speed. Add to it a lot of fast corners where you really want the car to stick to the ground and not get too much air under it.

 

So it may be the reason for keeping the TMIC.

 

The number of aerodynamic details they have would make any ricer jealous.

 

I also realize that I need to learn Japanese.

[GTEASER]

I like the little NACA duct next to the hood scoop with the piping that shoots fresh air directly at the turbo and dp area. And the plexiglass plate over the upper grille opening.

[Sgt.Gator]

I'm sure they kept the TMIC and the hood scoop because corporate wants the car to look like a Subaru STI. And since they aren't going for huge power in their class rules it makes sense, sort of. The class rules may prohibit them from switching from a TMIC to an FMIC too, I'm not familiar with the exact rules. The TMIC is terrible for aero but at least the new hood scoop is much more aero than the old 2005 like my STI had. (now deleted, pics soon).

 

GTEASER I noticed that NACA duct too. Probably just the right amount of cooling air for the turbo and down past the tranny to help, but not too much to mess up the aero. I may have to copy that idea.

 

The grille block off is interesting too. Would be a cool experiment to compare top speeds with and without and cooling issues.

 

When the video goes underneath you can see they did a lot work putting a flat panel under the car. Another reason the NACA duct to keep the heat down.

Edited March 15, 2017 by Sgt.Gator