CFD analysis of BRZ/FRS rear diffuser
 

:confused0068:

Related links:
http://www.ft86club.com/forums/showt...t=42605&page=9
http://www.ft86club.com/forums/showt...t=34937&page=6

So, as most of you know I have been building and tweaking my rear diffuser model for a few months now. Some experiments with success, others with failure.

I love our automotive community and would rather help foster growth and success from within, instead of looking to outside sources for work, technology and effort. So, I contacted @plucas from Hancha Group, who is not only a part of our community but also an owner and enthusiast of our platform. Hancha builds a couple parts for us and are working on more. They are in the same boat as me, they love what they do and are working to get better.

Anyhow, the moment many people have been waiting for. Hancha uses a 3D model that they are continuing to build more and more detail into. It isn't complete. This data is not 100% fact, it is meant as a function to show where and how my diffuser functions in an environmental simulation. It provide graphical representation which I can back with real world accounts that reinforce the data.

Would I love to be able to get into a wind tunnel? Yes. Would I love to run the model in UNC's engineering computers? Yes. Can I afford any of that shit? No. So if any millionaires have complaints about the testing data, feel free to paypal me some cash, because the government doesn't even want to pay me my check right now.

Without further ado.

http://www.ft86club.com/forums/pictu...pictureid=6290
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@plucas @Gunman @FT-86 SpeedFactory @robispec

About time you posted this. Nicely done

Great stuff. I'm definitely feeling a difference at high speeds with mine.

Question: Is the lift decrease the same thing as downforce or what?

Decrease in lift = downforce.

I know we're enjoying it on track. :)

With the APR wing, the car is amazing.

Great job, Wonderbar. Worth every penny.

I promise I am working on the front end too! Just a little tough with other things going on.

I totally forgot to mention a special thanks to @Gunman. Insight, mentorship and nerding out on race car stuff is much appreciated!

For anyone tracking the car, I suspect a front splitter would help reverse the 9% rearward shift of the Cp, IF you think the aerobalance needs it.

On an FR-S which is looser from the factory, maybe the aeroshift helps balance it?

Any time @Wonderbar , a former boss once told me, "racing isn't a job, it's a lifestyle", and that applies to us in the design office too!

Great stuff!

Thats 108lbs of lift decrease. This may take some clarification from hancha, but is that a decrease from stock? If so, IIRC, thats only about 18lbs of downforce. I seem to remember that stock, there was about 90lbs of lift. I could definitely be wrong though.

I guess it depends on how you look at it. It would still be 108lbs, but if it negated the entirety of the lift over "stock" and created additional force over that, I'd still call it a win personally.

Was this modeled with a stock muffler shape?

The muffler shape or type makes no difference with the diffuser on. The diffuser encloses the entire cavity and covers the entire muffler.