Here you go, they come in white or black and flex nicely to the shape of the fender.
Whitecap Nylon Louvered Vents

Here is a pic of them KORACING :: High Quality Automotive Parts - Products,click on the pic to enlarge. Don't pay attention to the 3 full car pics as those are old ones from an earlier tune with a different turbo. The bullet mirrors were removed to install the vents and mirrors were installed back on the doors.

If the panel is fiberglass, just grab a dremel and cut the slats in it, twist the slats to angle up into a louvered position, then glass the corners to hold the slats in that position. Integrated louvers, no add-on pieces. Fiberglass is flexible.

-Ryan

I owned a fiberglass co for 10 yrs in ft laud. and cutting the fiberglass neatly would be hard enough, then twisting it up at an angle would require alot of reglassing underneath to get strength back and then you would have a bunch of finish work to do to make it look nice as the glass fibers would tend to shred loose. For $19 apiece and 5 mins of jig sawing per fender you can have the others installed and they are very functional and look nice.

It can be done, didn't say it was easy ;) If you've got a flat panel to work with, sure, buy pre-fabbed. If it's a curve, good luck finding a pre-made louver that will conform to it.

That is the cool thing about these vents, they flex as you can see on the stock fender which should have the same curve..

My buddy Sean is competing in the Modified class of MC and the series is coming down to the wire, so he asked me what we could do to his car to improve the aero in the rear. I ruled out bigger stuff like a diffuser that would take me multiple days to make, but still think some improvements were made:

We went with redesigned wing endplates (running the square APR/949 units previously) that should increase the efficiency of the wing. This should mean he can run a shallower AOA and probably still get the same net downforce as before, but with much less drag.

Also made dive planes in front of the rear wheels to keep air off the tires.

https://www.miataturbo.net/attachmen...ine=1382398223

http://i175.photobucket.com/albums/w...psd59b5c79.jpg

In the conversation about flat underbodys on page 15 it was suggested to extend the tray past the pinch welds to prevent air from being sucked under. Would it make sense to use an underbody that extends past the pinch welds far enough that you create a feed style skirt at the same time? Seems like two birds with one stone.

https://www.miataturbo.net/attachmen...ine=1383941818

I have the Garage Vary side skirts pictured above and my Flat Underbody goes from side skirt to side skirt.

This looks like a fast racecar.

That sounds like a good alternative to me, thanks!

Hahaha! inorite.

We should all get our aero ideas from hardparkerworld.com.

So a rather definitive report on the aero developments I've been making this season..

Last November at Auto Club Speedway (40+ second straight/banked turn) I was nudging 134 mph with 207 whp on the straight and then scrubbed down to ~130 turning into the banked turn.

This weekend I was cracking 140mph on the straight on low boost (~180whp), and keeping my foot in it turning in, not scrubbing any speed and sustaining 140 through the banking. Bumping up to 205-ish whp gained ~2 mph more on the straight, and I scrubbed back down to 140-141 through the turn. (This is all based on gearing calculator)

Tires are BFG Rivals, last December I was on RS-3s; lateral grip is nearly identical between the two, if not slightly in favor of the RS-3.

Everyone blames the turbo for me winning Super Mod, but I had 200+ whp and RS-3s last year and wasn't winning. I'm still on junk coilovers, still running street tires, and some events I've left it on low-boost to conserve the tired 1.6... my primary focus, and where I've spent my hours this season has been the aero. I think the turbo is just easier to point the finger of blame at ;)

-Ryan

Congrats on the win. I think the fact that you race like every weekend has something to do with it too. *cough-skill* Don't let the car get all the credit.

FTFY

:brain:

FTFM

Compromise

I don't get nearly as much seat time as I would like, usually one day per month. Sometimes I get lucky and can make the second day of a weekend happen as well, but it's not common. This past weekend was a treat - got to drive Friday and Saturday.

Emilio is right, big difference between time trial and racing. I'll be making the switch to proper racing soon to take the next step with my driving development :) Time Trial is Qualifying in racing terms ;)

I do feel my driving has improved since last year, and other factors as well that contributed to a much improved lap time over last year, but for that section of the huge straight, there's few important factors besides aero and horsepower, so looking at that area alone and the significant difference in top speed and cornering speed through the bank, with less power even, it's pretty clear what made that difference.

-Ryan

https://www.miataturbo.net/attachmen...ine=1384287155

To report after going to the track.
Dollars spent: ~$20(bought the material a few months ago)
Hours spent:3
How effective:3
0=slower, 1, no improvement, 2 =slightly better,3= big improvement
Materials: Dibond knock off from local sign shop.
Tracks tested on: ACS
Race/TT class built for: Miata Challenge Modified class.

Going into this track day the wing stayed at -1.0 degrees relative to the ground plane and I kept the 949 air dam on the car.

There was a MASSIVE improvement in rear down force and reduction in drag. I gained a few more MPH going into T1 & T2 (+5 mph according to gps) which allowed me to maintain 120MPH. In turns 5/6 & the back complex before the front straight away I had a lot more under steer compared to the last time I was at the track. I softened the dampening 1 click on the front shocks and the car regained some balance. I suspect the car could stand to have the dampening softened one more click and it will throttle steer nicely again.

Overall the changes were very worth while.

Rokomis, care to post a pic?

Edited the post and added a new one, I didn't want to copy and paste the same pictures ThePass posted.

Started working on my splitter and airdam today. The design is similar to the one I helped Sonny build on his msm except this one is completly suspended by cables. I found that if I ran a cable from far back all the way to the front of the bumper, (3rd pic) it pretty much eliminates any rotation of the splitter. It is pretty stable, supports my weight and quick to remove. Also I left a gap between the bottom of the airdam and the splitter which is filled by the garden edging. Still need to clean up the cut but the benifit is this allows it to flex upward a decent amount.

https://www.miataturbo.net/attachmen...ine=1384752410

https://www.miataturbo.net/attachmen...ine=1384752410

https://www.miataturbo.net/attachmen...ine=1384752410

https://www.miataturbo.net/attachmen...ine=1384752410

I still need to finalize the design of the splitter. Part of that depends on if I can get all this stuff to play nice.

https://www.miataturbo.net/attachmen...ine=1384752410

Dat last pic.

That's pretty amazing.

Where did you find that plastic garden edging? That's exactly what I want, but I've tried every garden/home improvement store around here and can't find it. If you still have the packaging and a brand/part number that I could google/Amazon search, that would be awesome.

Chris's EP dam and splitter are pretty much standard issue around here. Each guy on the team that has a car, and John building mine, have all contributed to it's evolution. Garden edging from Home Depot Motorsports, as are the cables, buckles, hardware, birch ply. If making a splitter, 15/32's to withstand downforce. If it's just an undertray we use the stuff closer to 3/8". Above about 130mph, even the undertray generates significant downforce when it's countersunk behind the air dam so you can't use the super thin plywood without it getting sucked down and scraping.

For the garden edging look in the garden section at home depot. The stuff you want is not kept with the main grouping of lawn edging for some stupid reason. It is usually hidden somewhere near the bricks. There are two different versions I have seen there. One is like what I have and the other has bits connecting the base that you need to cut before you can bend it.

Yes, it's often referred to as paver edging. I haven't found it at Lowes, but have at HD.

THANK YOU FOR THIS. Seached thru pages and pages of garden edge and found nothing that would work. :crx:

So many options once you know what it's called.

No problem. I feel your pain, it wasn't until I came across it accidentally while looking at pavers that I knew what to look for! The only thing that sucked was that the one with the "links" you have to clip off is pretty robust - a PITA to bend, needs to be trimmed for fairly tight radiuses, and is way heavier than it needs to be.

This stuff is about to allude me for the third winter in a row. I have seen it in stock over the summer but I haven't been in car building mode at the time so I have skipped it. During winter tear-down and development, I go looking for it and flame out. Oh well. It should be back on the shelves by the beginning of march which will be plenty of time to make the early events up here and MRLS.

I tried my home depot and lowes and struck out too. I'm tempted to try and find time to run by a home depot while I'm in cali for the 25hr... if I find it in stock for cheap, I'm shipping some home to myself lol. Now that I know it's called "paver edging", it looks like it's pretty readily available online though.

Dimex E-Z Connect 16 ft. Multipurpose No Dig Lawn Edging and Landscape Border Project Kit in Black-1504BK-16C at The Home Depot

Been working on trying to get my simulation to work right. So far I got the program to calculate the coefficient of drag to be .34 (actual .38). However, Autodesk Falcon is not consistent in its results. Either it gives a reasonable value near .34 or something ridiculous with successive trials. As such I have very little confidence in any results. I guess that is what I get for using freeware. The computer in my laboratory has Comsol on it which can do the calculation. Just need to find a time when it is not being used for micromagnetic simulations.

https://www.miataturbo.net/attachmen...ine=1385105564

If that graphic is showing your actual trial resolution you're multiple orders of magnitude too coarse. I found, even just doing the wing in 3d, if it took less than an hour to simulate it would give weird results, that was in cosmos. I would think the whole car ought to take a couple hours unless you're running on some serious hardware.

The resolution is much higher than those vectors when you plot with different methods. Usually the scans take a few hours to get a decent value or I just leave it going overnight.

does anyone have more detailed pictures on how they mounted their APR Gt-250?
getting mine as a christmas present lol

maybe not so soon, as I was just informed that these are no longer available from 949. Looks like I would need to order a custom wind from apr, or explore another option. Any ideas on an optimal yet practical 2d wing for a low hp PT/TT car?

I think the general consensus for practical(affordable) 2D wing is still the COT from eBay.

Affordable, but not an ideal foil profile. The COT wing profile is optimized for speeds a Miata won't achieve unless it's dropped from the stratosphere. I understand the Ciro Design foil is basically the same as the GT250. I might be wrong there.

Brooks Motorsports has some nice looking wings and seem pretty open to custom stuff. Last time I saw one of their wings was a few years ago before the company changed hands, and it was a little rough around the edges but overall pretty nice. The only real complaint I had was a very rough leading edge from the mold parting line, and they've supposedly changed the molds to eliminate that. I don't know anything about the foil profiles they're using, though.

I don't disagree on the optimization, any reason you're stopping production on the GT-250s?

I saw a Brooks wing on a friend's car recently and the leading edge was fairly rough as well.

Demand is light and the cool guy pricing only came with a big order. So I just send folks directly to APR now. When we get around to producing our frame rail mounts, we'll produce some matching foils to complete a PnP kit. Low priority right now though, sorry.

Just finished mounting the new fiberglass front end. It's an E-prod setup, but the fenders are made to mount flush to the door. I was VERY tight on tire clearance and wanted to vent the rear fenders, so I just made some stanchions to hold them out and flex the fender slightly. Thankfully, the fiberglass is so damn thin, it has a good bit of flexibility and doesn't put up much of a fight. Nose and fenders come off in one piece, mounted to a pair of tubular frame rails after I cut most of the front end off.

Makes sense, I know a lot of people they are turned off by anything that involves some effort to DIY. I could see a PnP kit doing much better! I am rocking the GTC-200 & Air Dam you sold for a while, serves my purposes just fine! :bigtu:

Recently checked out a Brooks airfoil, owner said it was from after the change of ownership and while the swan neck element was cool (custom $$$ request by the customer), the finish/quality of the airfoil was not very impressive. Very rough front edge and wavy surface. You could run your hand over it and feel it dip and rise.. customer also wasn't very happy with the finish of the swan neck mounts either (can't remember why) which is a shame for how much they probably cost him.

-Ryan

After trying my gt200 wing from the grey 400whp mx, on the stock(ish) powered red one, my friend had to have a wing too.

Shaved a clean 1.5 sec of pr lap on a 1.48 min lap on our local track(rudskogen , norway)

the wing on the red one is " china special " mounts are 4mm titanium plate(yup.. steel was heavy and he had access to titanium)

legs for the wing are custom made for this setup, and the mounts underneath the wing moved out to match..

Will complement with a frontsplitter similar to the one i have posted aerlier to balance it all out.

hope you guys approve of Einars new aero :)

https://www.miataturbo.net/attachmen...ine=1390746061

https://www.miataturbo.net/attachmen...ine=1390746061

https://www.miataturbo.net/attachmen...ine=1390746061

I like it, did a similar set up with mine. Put my wing a bit higher but unfortunately my uprights bent under the downforce. I remember reading somewhere you should be able to sit on your wing without it shifting. Like you say the front splitter will help balance things. Then you play around with the wing angle.
I managed 1.13G on some bends in the morning. Only managed .99G in the afternoon without the wing after I bent things :( and like you my times were quicker too.

A proper wing/upright setup should be able to take several people sitting on it I would think. 500 pounds is a nice round number, that should be easy enough for a well designed and built setup. Each upright only has to take half of that...

-Ryan

stress testing already done. :)


Attachment 101145

Yeah my uprights will take that. I'd be concerned about that kind of point load on the wing. It'll take the weight as a distributed load though. But my wing isnt designed to go over 100mph, so much drag, hundreds of pounds of drag.

Canards, anyone have info on these that goes beyond basic. I really only ever see non-aerofoil canards, basically just a flat profile sometimes curved a curve. I get 0.6sqft on each side, cant go wider than the rest of the front bodywork, cant extend more than 6" in front of the car. Area is measured by chord X length. 1 end of the canard must be mounted to a surface of the car (IE no front wings). So I can camber, and fatten the shit out of it to get all of the downforce without a real penalty besides drag, which I dont really care about.

Did you ever figure out why your sims were inconsistent? I'm running into that issue now trying to design canards with COSMOS. It wasnt an issue with the wing, the results would change by maybe a fraction of a percent each time, but with the canard its varying by well over 10% I'm assuming its because I have some conditions setup wrong. But I dont have the right version of solidworks anymore to check what I did to make the wing work. Something is seriously buggered anyways since the results seem otherwise wrong and non-aerofoil canards are making more downforce than aerofoil ones at the same AOA with the same amount of camber.

Usually inconsistent results= poor mesh.

To learn the software & validate your results you should start simple with something you can analytically solve with equations "easily". Then you can validate that you are using the system correctly and build complexity from there. Automated meshing tools are not always your friend.

Take this with a grain of salt. I haven't done CFD since college (4 yrs ago), but I do use quite a bit of FEA at work and poor meshes are always a cause of inconsistency.

The guy that made my lightweight hardtop and doors just came out with this for the NB.
97 06 N B Mazda Miata Fiberglass GT Wide Body Kit | eBay

I never really played much more with the software since I got busy with actually working on the car, then breaking just about everything on it at a trackday and subsequent repairs. The problem with the software was probably mesh size. I haven't been to up to date in buying any sort of technology, which is funny since the lab I am in deals with novel computing tech.

This! Mesh quality is one of the most important aspects of quality cfd work. Start with the ahmed model to verify your can run the software correctly and create a decent mesh.

For at least the cfd work I have done, I have found that a mesh under 5 million cells for half car model yields bad results. I usually fall in the range of 10-20 million cells using mesh dependency study depending on the complexity of the model.

I personally know the guy who owns the car in the picture. It is a very nice looking set of body work.

I need to figure out if there's even a way to change this in COSMOS besides just changing the resolution. FEA meshes make sense, cfd meshes are magic.

I would think there would be, but I do know as I do not use that software. I know in most meshing softwares for cfd, you have a lot of control over the mesh. Is that the only software you have access to?

There probably is in COSMOS. I could also use open foam I left like 100gigs open on my desktop's hard drive for a linux partition that I never got around to installing.

I would switch to openfoam as I know it can create a quality mesh and give repeatable results.

Yeah I just need to figure out a linux cad program then so I dont have to keep rebooting.