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Re: BlueScooby's 06 STI - Redoing the underbody and diffuser. again.

Fortune Auto 510 Review

The RDC installation was finally completed last weekend with a servo replacement from FA so I could finally test out the dampers at different levels of stiffness. First of all, being able to control that from the drivers seat is amazing! But I am thoroughly impressed with the damping of these coils. The FEAL revalves I was using before are pretty close to what these coils are at full stiff, but yet the coilovers seem more compliant (and with a stiffer spring!). Big bumps do not upset the whole car like the FEALs did. I always assumed that was related to the large swaybars, but it appears that is not the case. Right now I'm driving the car at 15 clicks out of 24 and the car seems both planted and a more comfortable ride at the same time. I can't say how these compare with other coilovers of course, but I am very impressed with these compared to my previous setup! :cool:
Ditto going from stock struts with RCE Yellows to RCE T2's.
 

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Re: BlueScooby's 06 STI - Redoing the underbody and diffuser. again.

Quick garage update:

Added a disconnect for the compressor, so I can easily turn it off when not in use:


And I picked up a hose reel on sale this weekend! Now I just need to run some tubing or something up to it. Contemplating going with copper if I can do a decent enough job sweating the joints...
d





Aaaand, an updated pano of the whole garage:
 

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Re: BlueScooby's 06 STI - Redoing the underbody and diffuser. again.

So clean. Too clean. Haha

Sent from my SM-G950F using Tapatalk
 

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Re: BlueScooby's 06 STI - Redoing the underbody and diffuser. again.

Turned out very nice, now come do mine.
 

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Re: BlueScooby's 06 STI - Redoing the underbody and diffuser. again.

So clean. Too clean. Haha

Sent from my SM-G950F using Tapatalk
Turned out very nice, now come do mine.
:lol: Thanks. I probably spend too much time trying to keep it clean but I think its worth it :cool:
 

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Re: BlueScooby's 06 STI - Redoing the underbody and diffuser. again.

Thanks :D

We need pics of your new garage! Throw a lift in there ;)
I've been considering that Oswald brace... but that pic has me questioning. Do you think it would clear the stock dust/dirt caps that go over the strut top?
 

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Re: BlueScooby's 06 STI - Redoing the underbody and diffuser. again.

The Oswald brace is definitely the best one IMO. The carlabs one doesn't connect the shock towers laterally which looks like a potential weakness.

Its funny you say that now, I just got in the revised brackets or the rear towers. I'll upload a pic of them so you can see what he did.

I would think you could email him and have him send you a modified set in your order instead of the basic ones.
 

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Re: BlueScooby's 06 STI - Redoing the underbody and diffuser. again.

The Oswald brace is definitely the best one IMO. The carlabs one doesn't connect the shock towers laterally which looks like a potential weakness.

Its funny you say that now, I just got in the revised brackets or the rear towers. I'll upload a pic of them so you can see what he did.

I would think you could email him and have him send you a modified set in your order instead of the basic ones.
I Installed Oswald brace plus Beatrush floor braces together. They made a huge difference on how the car felt and also reduced understeer too.

I am still running his front and rear braces both. :tup:
 

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Re: BlueScooby's 06 STI - Redoing the underbody and diffuser. again.

Ladies and gentlemen, the level of "nerd" in here is about to go WAY UP.

I finally got to play with Autodesk Inventor and Autodesk CFD and I came up with some results!

Now first off, these are SUPER simplified models. I took the profile outline of the car and traced it out (its a square from the front :lol: ). This is very rudimentary and should be taken with a grain of salt... The pictures below, however, are a slice taken from the center of the car, so its shape is hopefully close enough.

I ran (3) different setups. Stock STI (although with a completely flat floor because it'd be too hard to draw otherwise, so actual drag/lift would be a little worse), Stock height STI with a front lip and rear diffuser, and a lowered (with 1 degree of rake) STI with front lip and diffuser.

Stock:


Stock with added front lip and diffuser:


Lowered (w/ 1 degree rake) with front lip and diffuser:


Now the graphics of the airflow are neat to look at, but there is one particular piece of data I want to focus on here: "TOTAL FY, xx.xxxx, lbf" on the lower left of each picture. Stock shows 74.7lb of lift. Addition of the diffuser and front lip lowers the total lift down to 67.8lb. Lowering the car next makes a huge improvement however, now having a total of (-)7.9lb of lift. In other words, the car went from positive lift, to negative lift (DOWNFORCE)! It may not be much, but I think its pretty stellar either way.

I would like to refine the models further and potentially get a closer representation of what my car is actually doing, but this is an encouraging start.

OH, and check out that green, relatively "high speed", airflow coming up out of the diffuser in the last scenario! No airflow separation there!
 

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Re: BlueScooby's 06 STI - A little CFD Analysis on the car ;)

And now back to your regularly scheduled program...

Got the modified strut tower brackets installed. I apparently didn't measure quite accurate enough, because I still had to add a washer to each stud for it to fit :tdown: If anyone is requesting the same modification on their brackets, use 1.75"-clear for the dimension under the raised leg.

At least Ive got it all back together and complete now.

You can see here that I've JUST got the clearance for the RDC system.




Glad to finally have my rear brace back together and functional :D
 

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Re: BlueScooby's 06 STI - A little CFD Analysis on the car ;)

man yall are a tough crowd...
That cfd, what speed is it at (and did you caluclate various speeds) and can it calculate cornering or is this only to simulate braking/straight line performance, and in that case should you add rake?

Does it differentiate between each axle?
 

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Re: BlueScooby's 06 STI - A little CFD Analysis on the car ;)

That cfd, what speed is it at (and did you caluclate various speeds) and can it calculate cornering or is this only to simulate braking/straight line performance, and in that case should you add rake?

Does it differentiate between each axle?
This was me starting to learn the program so its not very in depth...

I picked 80mph as the speed (arbitrarily) in hopes that it would be fast enough for aero effects to start being noticeable. 60MPH seemed like a more common bench mark (based on next-to-no-research... haha) but I was worried that might not be fast enough. Also 80 is a seemingly better option for "highway speeds" than 60, if we're being real. This was the only speed I tested as I was looking for differences between car profiles not defining the actual performance of one.

This is an "at speed" model in a straight line. I'm not sure if this program has the capability to do an "accelerating" (speed up/slow down/turn) analysis. The way I understand its usage (at least my usage so far) is that you are looking at a particular snap shot in time, and the computer does several iterations of calculations to define the airflow at that point.

I probably could differentiate between axles, if I can figure out how to add spot load areas of interest. That seems probable...

One side note, after completing what I showed above, I was looking around online and found that I can simulate the ground "moving" to get a more realistic model. I hadn't even thought about that, but without it, its like the ground is traveling with the car and proving drag against the air under the car... You can apparently also make the wheels spin, but I think the results of that are going to be far less drastic than the ground moving at speed with the air.



Do you have any experience with CFD? I'm not sure if you're asking out of curiosity or out of expertise. I'd love to learn more if you know some stuff ;)
 
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