What's stopping you from mounting the wing up high in clean air? there aren't many rules for street car aero.... It certainly wouldn't be worse than some of the foolishness that has run Pikes Peak.

Anything i put on the front would be removed for street use. I was just tossing the idea of how much grip i could possibly squeeze out of it for track use. Nothing Road Atlanta-ish - Barber's and possible autox only.
A splitter would be ineffective, hence why i was thinking foil.

Anything that involves a radiator that works would be preferable.

Some pictures from the first test day.

It was at a new track so I didn't have any previous times/data to compare.

However it turned in nicely, seemed stable and most important it stayed attached to the car!

My brother should be testing it tomorrow at our normal track, and I might get a chance next week to give it a run also.

Endplates should be on by then, canard design will be happening to. (really just going to copy Ryan's)

Overall, so far happy.

Aero staying attached to the car is always a win ;)
Looks good!

I like the "I give up" point-by in the second pic.

What did you think of Morgan Park Tim?

It was enjoyable.


Some further updates, will be tested tomorrow at a track I'm more familiar with so will have a better idea of the effectiveness.


However my brother did take it out last week and oversteer'd off the track taking a small chuck out. So I am guessing it must be working.

Finally got the Singular end plates installed. Waiting on the Jet Stream headlights to arrive then it will be time to work on ducting some air into the ITB's. Options are limited when the car is also road registered.

https://www.miataturbo.net/attachmen...ine=1442103551Cootha Classic by Eipeip, on Flickr

Hey everyone,I think I know the answer to this already but I have a question regarding how effective (or not effective) this diffuser design is. Just asking for the sake or learning more if I ever design my own.
https://www.miataturbo.net/attachmen...ine=1442710058


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the rear of it isn't as important as the front of the diffuser.

In regards to having a flat floor in front of it? Also should the diffuser be sealed to the bumper? It looks like he's got the bumper cut but there's still the gap between the top of the diffuser and the cut portion of the bumper. I cant imagine that would be optimal?

It can't clean up dirty, turbulent air enough to function, but I was able to get results with a diffuser sealing off the front and rear end of the car, leaving the middle as is. It'd definitely be better with full flat bottom, but I was able to get the tufts flowing the right way :)

EDIT: mine wasn't sealed above the bumper,

When you say sealing off the front was that just using a front splitter? And thinking about it,if you don't have a full flat floor but run a diffuser would having a gap between the bumper and diffuser actually be beneficial? That is if the dirty air underneath the car flows above the diffuser if it's sealed would that just increase the "parachute effect" of the bumper?

To clarify, I had rear flat panels beginning where just behind the seats. Splitter up front. Tuft tested, no guesses.

no need to seal against the bumper on top of the diffuser. That's not the important part of the diffuser.

Good. I was thinking that, depending on how far forward the diffuser went, that opening would help extract cooling air from the diff/gearbox.

So you would think. You have to keep in mind that between the lowest part of the car, even with a diffuser, and the top of the trunk lid is the WAKE of the car. Sometimes the wake is larger and with functional drag-reducing aero, it will be smaller. The wake is turbulent air and so above the diffuser, the airflow doesn't expel differential air as we'd like.

I'm actually surprised I don't see more people using vortex generators in front of the rear window to reduce the size of the wake (and increase the effectiveness of rear wing).

Attached air = good air

In terms of shape and design, the diffuser itself could be perfectly functional. Unfortunately a diffuser is one part to a system. The system requires more elements than the diffuser alone to work. Without a significant amount of the airflow under the car leading to the diffuser smoothed out, it just can't operate as intended.

Recently had the car on the lift and decided to snap a pic of the underside..

https://www.miataturbo.net/attachmen...ine=1442816651

and that, ladies and gentlemen, is what's called DOING IT RIGHT
:D

So with my silly Catfish body on Exocet, I'm going to have a slightly different flat bottom than most factory miatas.

Where most miata flat bottoms step up at the frame rail, my car is going to step down (about ~1") as the edge of the body is lower than the floor pan. This will create a "channel" under the body from front to back, is this good or bad?

I can take a picture next time it's on the lift if this doesn't make sense.

It's good.


Ryan,
Your car looks sticky.

Or maybe it's just my screen.

Ryan... i'm jelly

It looks great,but I am going to be "that guy" and point out that your tires are backwards

Haha, I knew someone would ;) those are just rollers for pushing the car around.

Ryan, how do deal with heat?

From that picture, it looks like transmission won't get any airflow. Same for the diff.

Ryan's diff has a NACA duct inlet.

Yes, hard to see in that pic but there's a big (over 12" long) NACA that feeds air to the diff. The transmission is a bit of an experiment. With an entire flat bottom, the transmission tunnel becomes an air duct - passing air from the higher pressure region in the engine bay to the lower pressure zone above/behind the diffuser, which sounds good enough on paper to pass air over the transmission continually, and hopefully it can move enough air to keep the heat from the exhaust that is running right alongside it in that same enclosed space from severely affecting the transmission. It's rather uncharted water with the Miata though, so the only way to find out if it's adequate or not has been to run it for several years. I haven't seen transmission lifespan dramatically affected, so I'd say unscientifically that it's working.

I'm actually having more trouble with boiling the fuel in the tank than with overheating the tranny or diff :party:

One goal, at least on paper right now, with the new engine config going in will be to move the exhaust out of the transmission tunnel so that heat source is no longer by the drivetrain above the flat floor.

Is there any way to test if they're getting too hot? Maybe if surface temps are xx*? I tried to get baseline surface temps of the diff and trans, never got insanely high readings, but it was a bone stock 1.6L I was testing with. I've had the diff covered for the most part and still didn't run too hot on 95* days at BW.

Sure you can test it - fluid temps are what you want to look at, not housing temps. Super easy to do in the diff by just replacing the drain plug with a threaded adapter and a temp sender for a standard oil temperature gauge.

Transmission could be done similarly but because the drain plug is pointing straight down you'd need to get a bit more creative, or just drill and tap the transmission case for a sender. I just haven't gotten around to doing it. After seeing that I still wasn't prematurely blowing diffs or transmissions with the flat bottom, monitoring their temperature just moved lower on the priority list.

I'll very likely set up the MV7 and Getrag with sensors before they go in, particularly with the trans as it is a $1200 unit, so I'd be less excited to lose one of those compared to a $250 Miata 5 speed.

With your new setup it'd def make sense to monitor the fluid temps. I think it'll be safe to assume if your old setup was fine, than it shouldn't be an issue w/ lower hp levels.

I'm sure Ryan has completely sleeved his exhaust to keep the heat out of the transmission. Look at all of the other work he has done.

You would think so.. I would think that too. But I haven't.. mostly because with a new drivetrain config on the horizon I stopped worrying about it. Most of the work has been on shielding the tunnel to keep heat out of the cabin. IF the new exhaust ends up running down the transmission tunnel, it will definitely be shielded.

I recently discovered this but forgot to post it here. It's the nicest product I've seen for quick and easy exhaust shielding. They have other sizes too.

https://www.pegasusautoracing.com/pr...paign=201509-1

Easy install when new, a bit harder to remove when you take the header out again (since header->right Foot is where you use it).
I have a schredded one somewhere, and this summer I got a burn blister on my ankle...
So it works, when installed :)

Shilds with spacers and air running between the layers work.

For Ryans LFX project, sidepipes or bust (you still lack the side parts + skirts for the floor build anyway). :D

I have nothing on Ryan's awesome build, but I still am very happy with my first foray into aero mods.

Dollars spent: 800-900
Hours spent: 20+
How effective: 3
0=slower, 1, no improvement, 2 =slightly better,3= big improvement
Materials used:
1/2" Birch Plywood
CoT wing with Singular end plates
URL, brand name, material type
Size/thickness of materials:
.060", 3/16" etc
Bracket location:
Splitter mounts near the tow hook location, sub frame to in front of the tires, and at the rear stock undertray bolt holes.
Tracks tested on: Hallett - clockwise
Race/TT class built for: HPDE

Everyone's favorite plywood splitter. Extends 5-6" from the bumper.
https://www.miataturbo.net/attachmen...ine=1443063558


NASCAR CoT wing
https://www.miataturbo.net/attachmen...ine=1443063558

Used at one event so far. Took 2 seconds off Hallet clockwise on my first session with a wet track. Another 2 seconds off my second session. Before adding the wing I have only run clockwise for 2 other sessions (June 2015 & 2016). I figure part of the second 2 seconds is from getting to know the track better and since it was wet on the first session, how about a 3 second improvement with wing and splitter.

:party:

Wow- 2 seconds is sensational. Consider the cost for the return on lap time improvement and it's a bargain.

This thread has so much win. I'd like to see more pics of Ryan's bottom while he's into group sharing. :pitlab:

The one and only set of uprights I've made that are replicas of my own COT setup.
:likecat:

Thank goodness! I was really wondering who on Earth would put that much work into aero, and then run on street tires. Good street tires, maybe. But still street tires!

Neal
(all about the purple crack...)

Some DIY aero pics for you all (more to come):

Front splitter/undertray. Structure is 1" welded aluminum tube. Undertray is 3mm Alupanel. Splitter is 1/2" Russian Birch cut on a CNC router. Quarter turn fasteners are used everywhere on the undertray. The splitter is held on with five 6mm bolts. Brake ducts are 3D printed ABS plastic.


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3d printed brake duct inlets?!?!?. Could you share the file?

Beautiful fab work, but don't expect that frame to last long if you have an off track excursion. I made a splitter support out of 1" square aluminum a couple years ago and it got destroyed the first time I dropped 2 tires over the exit curbing and the outside edge of the splitter dug into the dirt. Your frame work is much nicer than mine, but it mounts to roughly the same locations and will probably break in the same way that mine did.

Also, I dig the slotted dharma holes on the splitter but their orientation scares me, since a very light impact with dirt or a curb will push the splitter back to the "remove" position and it will just fall off the bolt heads. Maybe add 2 more plain round bolt holes, so that you can use the 5 dharma holes for easy install and then lock it in position with 2 more bolts? Or you could just cut a new splitter and change it to 3 dharma and 2 round.

You could also make some of these U-shaped washers.

https://www.miataturbo.net/attachmen...ine=1443198272

Nice. I love the two piece idea using the aluminum panel. The car looks the track part except the show car quality paint. Just finishing up this project or something?

I am excited to finally share my front aero over here after putting the finishing touches on it this week. I am building the car for RTLA and Global Time Attack Street class, so ThePass helped me out to maximize whatever we built for the rule set. According to the rules the splitter cannot extend farther than 5" from your bumper. With that in mind we started by using his old splitter as a template for my new one.

https://www.miataturbo.net/attachmen...ine=1443282880

To make things complicated I wanted the splitter to super easy to remove but also be strong. Ryan came up with a "z" bracket and welded some receiver tabs to the front of the car for attachment points.

https://www.miataturbo.net/attachmen...ine=1443282880

Here is a close up of the mounting point on the front.

https://www.miataturbo.net/attachmen...ine=1443282880

For fun we threw on my street bumper to see how it lined up. It fit surprisingly well with with the GV lip! However, for this splitter we decided to not compromise and also build a EP style air dam on a separate bumper.

https://www.miataturbo.net/attachmen...ine=1443282880

With my "v-mount" set up I also have a bunch of heat exchangers. This made the ducting also a bit of a pain. To make Ryan's life more miserable I wanted to be able to change the car from track use to street use relatively fast. This meant the ducting had to be easily removed as well.

https://www.miataturbo.net/attachmen...ine=1443282880

Things are starting to come into share here, we use the bottom of the splitter as a portion of the ducting and attached the ducting to the mounts for the splitter.

https://www.miataturbo.net/attachmen...ine=1443282880

After a long two days in the shop (~35 hours), here is the finished piece before paint. We fiberglassed the top of the splitter to prevent fluids from soaking and add a little strength. Another piece to the splitter, which I didn't mention, is the plate in the rear. The plate is used to slot into the rear subframe for another connection point.

https://www.miataturbo.net/attachmen...ine=1443282880

Here is a shot with the finished air dam, the splitter is 5" exactly from the bottom of the air dam.

https://www.miataturbo.net/attachmen...ine=1443282880

After after some paint for the splitter and the rest of the car...here is the end result.

https://www.miataturbo.net/attachmen...ine=1443282880

As for the splitter, we made a quick video to show the removal process. Big shout out and thank you to ThePass for helping on this project, it turned out way better than I could have ever managed on my own.

Nice work. Have to be honest though, I don't see that lasting long on track. Rigid mounts are great for pro level cars that have spares and run on smooth tracks. If they have a minor off, pro's are ok with it tearing the car to shit in a sprint race. On a club level car, rigid splitter or air dams are a risk. Drop two wheels and you might grenade that. The first thing those steel tubes will take out is your oil cooler. We stopped using rigid mounts about 7 years ago. Lost some hoses, coolers, fenders and other stuff before we learned to hang the aero so that it cam move upward if it bottoms out and tears off cleanly if you whack the splitter directly into something. Since then, we have had just that happen and were able to get the splitter/undetray back from the corner workers and reinstall it before the next session.

Take note of just how much ground clearance you have under max braking and try to drive accordingly. On our cars, the splitter is usually set up to run 1/2" of the ground at max braking or cornering G's.

To emilio's point. I noticed that even with 1/2"ish ground clearance under braking that the increased AOA and decreased clearance to the ground increased downforce enough to make the splitter flex enough to touch the ground and stall, bounce back up, make downforce again and stall, repeat. Putting some rub strips on the bottom to prevent it from stalling stopped that.

Yup, we noticed that too. We have used small removeable blocks of Delrin and oak on the outer edges of the splitter. Like casters on the tail end of your enclosed trailer for steep driveways.

Actually, the keyholes (dharma holes) are there for that exact reason. I was attempting to create a system where the splitter was more likely to eject in the event of a direct impact. Will it actually work? Who knows, probably not. If it ejects, will it be worse than it would have been had it remained attached? Maybe. I also considered just using smaller fasteners (M4) and hoping they would shear during an impact, which would probably be a quicker and cleaner release than the keyholes.

I rolled this idea around in my head for a while and never really came to a conclusion as to the best way to do it. That's also why I decided to make the undertray and the splitter as separate parts, so that the rigid splitter could be as small as possible and easier to run over if it were to be impacted and ejected. And its why I skipped the turnbuckle style supports that so many people use on the front. The undertray actually tucks under the rear edge of the GV lip, so once the splitter is gone the front edge of the undertray is less likely to catch anything.

All that being said I agree that the aluminum frame will probably be damaged even if the splitter does eject. This is a first attempt, and I learned a lot in the process so there is a good chance I will make some alterations this winter. I could see maybe ditching the rigid attachment members in the front and in the rear corners for something more like a cable or a two piece arm with a hinge the in middle that would allow upward movement of the whole assembly.

I love that video. Awesome fab work and design. I too am wondering what it would do if you were to go off track and dig it into the dirt. It's not going anywhere without a fight!

It's never finished! I have been tinkering with it for 11 years. The car only has 30,000 miles on it, that's the original paint.

I like that idea if the splitter is a simple flat piece with holes in it, but not with the canards/walls attached to the ends of the splitter. You'll end up driving over those and damaging tires when the splitter detaches. And if the splitter stays on the track like mine did, other people might end up running over it too. I had a puny little 1/2" x 1/16" aluminum angle stiffening rib running across the width of my splitter, and 3 of my tires got damaged when my splitter detached.

I used to like the idea of a splitter quickly detaching from the car in an impact, but not after testing that idea in real life. I still feel pretty lucky that none of the 3 cars behind me went off or saw any damage from my splitter coming off.

I know this setup doesn't look as impressive as the beautiful fab work you guys have put into your setups, but it's still functionally my favorite so far. And it's super cheap and easy. The wood "tongue" is wedged into the subframe so that it stays with the car in an impact, but the wood fractures and splinters before damaging any mounting points on the chassis. Emilio uses cables instead of the metal L-brackets that I made and I like that idea even better. My next splitter will be this same thing but with cables.

https://www.miataturbo.net/attachmen...ine=1381343659

https://www.miataturbo.net/attachmen...ine=1381343659

The tongue on the subframe between steering rack mounts is how we do all our splitters and under trays as of around 2011. Makes them easy to remove, supports the weight/load and requires just about zero extra work to dial in. Also, the failure mode is good. Never hurts the car if you smash it into something. For enduros, we would always have a backup made, often the same design for two or more cars. Reduced the numbers of spares needed.

I had many discussions with Ryan about this one, cables vs rigid mount, and ultimately he made the engineering call for a rigid mount. He has had one for a few years now and based on his experiences, and Moti's too, I feel confident in the design. I think there's an argument for both styles of splitter and it's a risk I am willing to accept for now. There is still lots of testing to be done with the aero so I'll be keeping an eye on everything during it's first few outings.

Noted, this splitter will definitely evolve over time with additions like the rub strips and possibly endplates on the splitter.

Thanks, and your's looks great too! I've seen both ThePass and Blackbird (Moti) plowing off into the dirt with their set ups and everything worked out OK. Only time will tell.

Mine is rigid on the back and using 4 carabiners and steel cable (66# rating) i front, it saves it twice actually! Little aluminum bracket mounts to the steering rack bolts, bends and shear off easily with contact...

Emilio knows his stuff... As a bonus, I can remove it quickly and adjust it in few seconds with the turnbuckles. Will post pics this week...

Gonna have to agree to disagree on the solid mount vs. flexi-mount schools of thought for splitters. It's been a long-debated topic on this forum, with plenty of people subscribing to one or the other. Speaking from my own experience, I've been running a solid-mounted splitter (with strong frame) for... years now. Have had lots of big offs, run-ins with boulders at WSIR, full-on splitter dug into the ground at BRP, etc. and zero issues. Ran the same splitter for several seasons, just kept filling in the missing chunks with bondo-glass, only reason I moved on to a new splitter was to make it bigger and badder.

I now run a 2" kevlar strip along the bottom of the leading edge of the new splitter, which has definitely increased the lifespan of the birch from shaving against the ground, but even without that you just fill in the scrapes/gouges with bondo glass between events and keep using the splitter.

Take a walk down the pits of a TUDOR/WEC/etc./etc. race and tally up how many cars have solid fixed splitters with integrated ducting vs. how many have "break away" designs or flexible lines to allow lots of upward flex. I'm not saying the flexible versions can't work when done right - Emilio has a great track record with some precariously loose-mounted splitters, but solid mount is certainly the predominant method in top level cars. Of course the argument is the pros can afford to rebuild it all between races if it breaks, but we're still using birch here, so we're not losing sleep over damaging a splitter if it does happen. Keep in mind also that there are obvious design priority differences between what you need for an enduro car (where priority #1 is to minimize risk of crippling damage) vs. a time attack or HPDE car. Half the aero elements on my car would be designed differently or be non-existant if I was building the car to rub fenders and survive a 25hr race without losing aero balance along the way.

On Sean's setup, which we built to the limits of Time Attack's Street class (5" extension from bumper) we specifically didn't build the frame out to the sides/corners of the splitter because 5" out at the sides is quite a bit of extension and we expect some contact with curbs there, so we left some flex in the sides to accommodate that.

excellent work guys. some of your fab work is really good!!

I've had good luck with a fairly solid-mounted birch plywood splitter on my car after reading pretty much every page of this thread and cribbing ideas from it. The splitter is completely separate from the GV air dam. My first and so far only splitter has survived running through the evil gravel-traps at Laguna Seca twice, a Thunderhill turn 1 excursion, and the curbs at Sonoma Raceway. Nor-Cal tracks have really low curbs.

Most importantly the splitter still flexes upward *just* enough at the front to get it onto the trailer at the end of the day (the driveway is another story but nothing some junk plywood ramps won't fix). The only thing I don't like about the GV air dam is it's kind of a pain in the butt to fabricate intakes for the brake ducting.

In SCCA STL racing, the static height for the splitter has to be >= 3" above the ground. At the Runoffs in 2014 I noticed peoples' splitters whacking the ground only at the Corkscrew at Laguna. So for my application a solid mount is probably safe.

Even so, I picked up a cracked bumper cover off of Craigslist last week for $40 (the one currently on the car is just too nice to be chopped up) and will be building a Crusher-like air dam with a 2" splitter sticking out the front instead over the next month. Emilio posted pictures of one of his cars for Oscar Jackson Jr. a while ago and that is the setup I will be emulating for next year's races. I don't like the way it looks but it's gotta have less drag than my current setup.

Mind you, I'm not that analytical of a driver to notice the difference (never raced the car without one), but splitters and air dams sure do look cool. 1.6's in STL need every little bit of help they can get to overcome a serious horsepower deficit.

https://www.miataturbo.net/attachmen...ine=1443474413

Not to derail this thread, but after watching the Runoffs at Daytona the Miatas in STL didn't look very competitive. It is probably just that track, though. They did seem to do well on the infield.