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Aero Master
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observe this picture. outer channel stalls because the rear wheel is not fenced. the wheel is not moving in this picture but if it already stalls at speed in a wind tunnel, think about what would happen if the wheel was moving.
 

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The revised narrowed diffuser will be done tomorrow after I double check some things on my car. I'm sending one out for some track testing (by monday), and sold another which will also get some track time... hopefully soon. The new shop I am working with is extremely cooperative and we should be able to start working on full pans soon.




Who makes this rear diffuser?
 

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Oh my god...

This is fantastic, I won't be able to make the GB since I'm snagging some other ****. but will most certainly be on my car in the near future.

But I won't be hitting the tracks, so this will be taking a backseat for now.
 

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observe this picture. outer channel stalls because the rear wheel is not fenced. the wheel is not moving in this picture but if it already stalls at speed in a wind tunnel, think about what would happen if the wheel was moving.
I will try to write it down, translate it and then paste it here. I can't get the correct words in my mind... This pic help to explain what I tried to in my last post.
 

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I have tufts on mine, but I just need to find a safe way to mount a GoPro and I promise I will have vids showing what the airflow is doing everywhere. Open to suggestions. (suction cup randomly falls off inside the hardtop window after a 20 min track session, but holds still through the session-- wouldn't want it "randomly falling off" when i drive)

I have some tufts on the main/center channel and as in previous posts have shown, it is flowing upwards, meaning it is staying attached to the trailing edge (as you want it to) and minimizing drag... which verifies with my drag/coastdown tests.

A coworker has mentioned they are visibly pointing up and outwards when he was following me one day.
 

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I am curious, getting just the center, how will the aero compare than getting the whole thing?
NuWing, my response would be covered in my review (sorry for the lag). In short, front end is basically an airdam and splitter. I made my own 26" wide diffuser (this one is about 28" wide for the center channel IIRC) that arguably was functioning well.

I added a secondary airdam to the leading edge of splitter to reduce airflow flowing underneath to balance the aero effects at speed with my DIY diffuser and front end aero. (It is easy to produce a functioning splitter). My secondary air dam reduces lift ever so slightly, but was very balanced.

When I finalized mounting this diffuser as shown in previous pictures, the balance became more focused in the rear (rear is more planted than the front now). As a result, I am moving back to revising the front, to add more downforce.

When I had just finished my DIY diffuser, I was even planning on a rear DIY adjustable spoiler, but reduced front downforce via secondary "RWB-style" (as i like to call it) airdam instead. Now with JJ_warhorse's diffuser, the spoiler is pushed further down the line and am needing to redesign the front end for more downforce to regain the balance.

I was testing entirely on all-season tires to reach the limits of mechanical grip much sooner than you would on sticky street tires and worse yet, R-compounds because, let's face it, I am driving a 183k mile 1.6L engine that is bone stock aside from a $30 exhaust. I am hitting 90-95 while an RS-3 equipped 1.8L is hitting 100-105s at Buttonwillow, and all seasons grip will always be much less.

Anyway, I tend to ramble when it comes to aero discussion so I'll end this here. Feel free to ask any other questions, I'd be happy to reply my experience with this.
 

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Fearless ****** of Ghosts
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Sorry if I didn't catch it, but did you try it with and without the piece on either side? I like how it balances the front splitter you have without needing a rear spoiler. This makes me very happy to think I can have a miata with downforce without a high spoiler on a car that I use mostly on the street. Main point in me asking about those side panels is that I want to add as little as possible on my car as to not have a street car that looks too much like it doesn't belong. Silly, I know.
 

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Discussion Starter #311
NuWing: you want the aerodynamic benefit while retaining a nice clean look... that is not silly AT ALL and a part of the reason I designed this diffuser to be modular.

The center sections are by far the most important part. As you get closer to the A-arms and wheels there will be more turbulent air. If you do a proper flat bottom that includes covering the A-arms and fences off the wheel wake ( as hnguyen037 said), the side sections are going to be more beneficial. If not, they are reduced to being more cosmetic and less functional and _may_ be doing some directing and cleaning up of the more turbulent air coming off the a-arms and axles towards the outside of the car. The center section is what is doing the majority of the "work", and it needs clean air from a flat center section extending to the front of the car to do it properly.
In short, if you dont plan on running a pan over your a-arms, deleting the side sections will likely make very little difference. However we don't have the empirical evidence to demonstrate this yet, unless arjay just hasn't gotten around to sharing it...
 

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Thanks for the answer! Guess I will have to get ready for your group buy once announced! Sounds like the center portion will work awesome.
 

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Discussion Starter #314
Thanks! We're getting close... just getting some last things lined up before I start the group buy and start accepting peoples $. I hope to have the GB ready by sunday night.
 
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