Aero upgrades for track use

[pmhaddad]

Posted this on the local forum, but I figured posting here might generate good discussion as well.

So I'm mulling over an eventual aero package for the car.

I'm mainly interested in reducing the amount of lift from the underbody at terminal velocity. The first obvious choice is a splitter. Probably not one of those lip spoilers, but one that extends back to the oil pan. I'm going to contact Will at TDR tomorrow to see what sorts of data they can give me on the Extreme or Radical front splitters. Neither of them extend far enough back, but I think its a good start and I can fab something up to go the rest of the way. The Radical is probably the better option because it at least extends back past the radiator.

For reference, the Extreme looks like this:

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/430512_267320483342212_128960713844857_613353_1967 080191_n.jpg

and the Radical looks like this:

http://trackdogracing.com/website/product_photos/radical1.jpg

That should at least help clean up the airflow under the front of the car and generate a few degrees of negative lift. I have no doubt it would be noticeable at say 115mph.

Next up is a diffuser. I found this: http://www.rhdjapan.com/eurou-rear-diffuser-type-1-56563 but I can't find any pics of it on a Miata.

I've also seen Lotus or FD diffusers used. I kind of like the Sanai works diffuser, but I'm not sure I like the way it integrates with the exhaust. I think the eurou is a cleaner solution.

For reference this is what the Sanai Works looks like on an FD:

http://img.photobucket.com/albums/v296/BOP_ROCCO/rear.jpg

I do like how the exhaust is above the diffuser, that really helps, I think the eurou would be like that too. The Lotus diffuser would place the muffler under the diffuser, and you seem to have to hack up your bumper to get it to fit properly.

To finish out at this point I'd just get a Moss ducktail basically like this:

http://www.tougerun.com/v/vspfiles/photos/tr_spoiler_f1.jpg

Purely for looks, but IMO you can't have a diffuser without some sort of spoiler or wing. The CF GT wing is too much of a cop magnet for a DD I think. Plus without FI or a V8 not really sure its worth it. To finish it out, of course I'd get a hardtop.

Basically I'm wondering if anyone has had experience with this sort of thing? I'd be really interested in solid numbers on the lift reduction that you could expect.

Also, Phat if you could point me to some pics with some different RX7 diffusers on Miatas that would be cool, I'm having issues finding ones... Also since you are king of all things JDM I figure you might have some idea of where to look for that sort of thing.

Not looking to jump on it right away, but maybe in the next 12-14 months as money permits. There are a few more important things I need to finish first (seats, hardtop, clutch, flywheel, etc). I'd consider getting the splitter sooner rather than later though....

[morr]

Moti (Blackbird Fabworx) is the man to talk to about aero. I know some other company was posting on CR about mass producing a rear diffuser for NB's.

[Coupeloop]

If you read carefully at TDRs website and product descriptions. the splitters are made to protect your bumper lol
they just contour the bottom edge of the bumper, which does close to nothing besides be a 100$ piece of abs plastic to protect your bumper that you can just make yourself. (you can click the installation instructions and see exactly what you're getting, which isnt much) (also in that second picture of the splitter you posted you can see the floor through the hole of the front lip! :teehee:)
some aftermarket bumpers come with more under panel surface area than those splitters.
I'm not no fluid/aerodynamic scientist but i'm sure you need something with more BODY/surface area to it.

if you want something you can just purchase online...I highly suggest the beatrush or the cobalt underbelly aluminum panels. They replace oem splash guard that is usually already chewed up. and it runs all the way back to the further front LCA bolt.
Anything more extreme than that would probably have to be custom made. Or you can go APR, which you can most likely fabricate some mounting points for it..

here is my beatrush under panel mated with an APR splitter

http://i970.photobucket.com/albums/ae182/windchariot/Miata/IMAG0670.jpg

I still have the project/idea to build a metal frame for the center of the splitter that will mounted to the bumper beam, its sturdy right now, but still flexes a little. from what I've read... you should be able to stand on it. I can actually kinda stand on mine, but then i'd start bending brackets which is why I mentioned building the frame for it.
http://mkimg.carview.co.jp/minkara/blog/000/025/201/772/25201772/p1.jpg

reinforcing kinda like this ish:
http://26.media.tumblr.com/tumblr_m0dysz0HKB1qbnce4o1_500.jpg

[pmhaddad]

You make some excellent points Cody.

In my OP I did mention that to be effective I believed that it should extend to the oil pan. I didn't realize that about the TDR splitters though, thanks for pointing that out! I have thought about the colbolt "skid plate", might investigate that further now.

Do you have some links on that APR splitter? That is a bit extreme for my purposes I think, the N/A miata simply just doesn't generate enough power to make it worth it IMO. I'd be interested in something exactly like that without it extending from the body so far. Maybe 3-4" vs. the 6-7" it looks like yours has.

I really really dig your car btw!

[kung fu jesus]

No splitter needed. Seal off the under the front to the forward edge of the front subframe. Cut out the arcs for the turning radius.

Get a second trunk lid and mount a functional wing to it with the leading edge level to the roofline.

Don't know what to tell you about the rear splitter. FWIW, the hardtop with the rear window removed was effective enough to be banned in SM. Downforce is is key in corners. Too much and you lose speed, too little and the car is too loose.

No one is going to give you numerical research unless you are buying it. It is hard-earned data from testing. Aero is effective at speeds before you are discussing. I can't tell if your priorities are aesthetic or functional.

[pmhaddad]

Functional.

Mechanical grip is more important than aero in this car anyways. You're going to be generating and using much more of it anyhow. My car has really good balance and really good mechanical grip. Doesn't feel loose in the corners, just hooked up.

I like the idea for the front. What material would you use? Just fiberglass?

Someone else suggested a second trunk lid to me as well, its not a bad idea, but based on mechanical grip I just don't think it would really matter. I could be wrong, but it seems sort of counterintuitive to me.

[kung fu jesus]

cheap plastic. maybe corrugated plastic. Something that will take a hit off curbing and not crack or break.

another option, maybe, remove the rear bumper at the track, mount the wing to uprights/stanchions that mount to the studs for the bumper support (which is also the points the rear tow hooks mount to).

[Coupeloop]

Do you have some links on that APR splitter? That is a bit extreme for my purposes I think, the N/A miata simply just doesn't generate enough power to make it worth it IMO. I'd be interested in something exactly like that without it extending from the body so far. Maybe 3-4" vs. the 6-7" it looks like yours has.

I really really dig your car btw!

thanks for the kind words!
as for the splitter...
It actually doesnt protrude as much as it looks. its at most 2 3/4 inches out on the front. Also its from a 350z, i did not particularly picked it, I got the thing for free and threw it on my car lol.
http://i970.photobucket.com/albums/ae182/windchariot/Miata/IMAG0876Medium.jpg

[Phatmiata]

I would say try what Coupeloop has done, with the combo of a BeatRush undertray or similar, and then follow up with some kind of splitter.

If you are worried about drilling holes in your trunklid then you can always buy an extra trunklid and mount a GT-Wing on it, then you can bolt the trunk on for track days, or just take the wing off your car when on the street, whichever is easier.

And believe it or not, something like a Garage Vary lip spoiler will help with downforce, so don't discount it if you just want to get rid of that floaty feeling on the highway.

As for test data, I think only Mazdaspeed did some wind tunnel testing back in 1999 on their aerokits, they did a lot more wind tunnel testing on the RX7, so maybe they just figured they would throw the NB in there as well, don't really know. Ill see what I can find in my magazine/book collection.

[Phatmiata]

Just be hardcore and rock a Voltex wing like Garage Hundred-One has on their blue time attack car.

http://www.voltex.ne.jp/english/index.html

http://farm8.staticflickr.com/7069/6823756056_239945fdb3_z.jpg

Or a how about a full custom Carbon Fiber one from Garage Vary?
(this is Garage Hundred-One's RED Miata "Juan", he is for sale BTW)

http://farm8.staticflickr.com/7181/6821238572_5482523be2_z.jpg

[kung fu jesus]

Looks like the APR wing.

[pmhaddad]

I think the trailing edge is a lot wider than the APR wing...

[atlnb]

As a few others said, the Beatrush panel is a good idea. I have it on my car and I felt a difference. I also just installed a GV lip and felt a bigger difference. In terms of a diffuser, Jet Stream produced one for NA's and NB's so that's basically a plug and play solution. The problem is that you need a panel in the middle connecting the front and the rear to make the most out of the airflow. That I'm pretty sure you would have to fabricate. Aero mirrors are another good choice. IIRC, Emilio said they would save around 10hp at 100 mph. I think I read that on m.net

[Coupeloop]

Just be hardcore and rock a Voltex wing like Garage Hundred-One has on their time attack car.
(this car is for sale BTW)

http://www.voltex.ne.jp/english/index.html


reading the site, only info it gives is that its 1600mm wide. so it could be anything, looks close to an Origin Lab wing with custom mounts. but heck it could be wrong , you can actually find wings sold on ebay being sold on yahoo japan. Usually they want it for the main body piece, and everything else they custom make themselves.

This wing is the same one I have on my car
http://noriyaro.com/wp-content/uploads/2010/12/noriyaro_naoki_nakamura_minami_001.jpg

but back to topic, a big thing you can do that is also FREE (best part) is cut your rear bumper

[Blackbird]

How much power does your car make?
What kind of events are you driving it in? autox? track?

Moti

[pmhaddad]

How much power does your car make?
What kind of events are you driving it in? autox? track?

Moti

Hi Moti - stock power from a 99 1.8 right now. Track events mostly, with a little bit of autox when I can. Priority is the track though.

[urban]

so PMhdad.
you want functional aero , but you want it to be small and not noticeable?
sorry but for aero to work it needs to be big, a trunk lip spoiler will do nothing. a GT wing will .
you really only want the drag reduction though , correct.?
splitter and diffuser.
the flat surface under the car is to reduce turbulent air. the splitter starts at this by reducing the amount of air that creates turbulence. a complete flat surface under the car doesnt work well , cause the trans ,and diff need air to cool.
you can get the effects you want with just a TD splitter and beatrush panel. a GV lip will also. you basically want to push the air around the car ,rather then letting it go through a bunch of holes or under.. the rear diffuser is pretty important. the stock bumper is basically a parachute. if you redirect the air under a splitter , or cut out the bumper to relieve the air build up , it has a pretty large effect on drag. the wheels again. air hitting the rotating tire causes drag. spats on your splitter will redirect it. that rules out the TD splitter.
functional aero for the track changes the cars streetability. and as mild as you seek , the gain might not be alot.

[Phatmiata]

Looks like the APR wing.

Fixed my post, the red Miata has a custom GV wing, the blue one is Voltex, BOTH cars are owned by Garage Hundred-One

[atlnb]

... the flat surface under the car is to reduce turbulent air. the splitter starts at this by reducing the amount of air that creates turbulence. a complete flat surface under the car doesnt work well , cause the trans ,and diff need air to cool...

that's true, but like porsche and cars, they have vents along the length of the car to cool the hot areas under the car to make the most out of it.

Porsche Panamera
http://www.sae.org/servlets/dlymags/dailymag/articleImage.jsp?imgsrc=/dlymagazineimages/8324_9137_ACT.jpg&alttxt=P09_0802_a4.jpg

Honda S2000 (aftermarket)
http://cache.gawker.com/assets/images/12/2009/11/500x_Underbody-Aerodynamics.jpg

Ferrari Enzo
http://cache.gawker.com/assets/images/comment/12/2009/11/eb471c58da57dc68e2498d71286784d7/340x.jpg

Maybach
http://www.kenrockwell.com/mercedes/starfest-2006/images/04/DSC_3919-sl-bottom.jpg

[Phatmiata]

There are a few Miata folks on here that can get you that Beatrush panel too, http://www.laile.co.jp/beatrush/index.html

If you come out to the Wednesday meet you are welcome to swing by my house and I can show you mine, Its not on the car but at least you can get the touchy / feely effect before you lay down cash on one.


http://www.laile.co.jp/cooling/underpanel/img/img_underpanel.gif

[Phatmiata]

There are a few Miata folks on here that can get you that Beatrush panel too, http://www.laile.co.jp/beatrush/index.html

If you come out to the Wednesday meet you are welcome to swing by my house and I can show you mine, Its not on the car but at least you can get the touchy / feely effect before you lay down cash on one.


http://www.laile.co.jp/cooling/underpanel/img/img_underpanel.gif

[Phatmiata]

Here is one on my old Miata, I added the GV front lip as well. I bet if we could get over to V8Roadsters they could fab up something even better and for about the same price, maybe less considering how strong the Yen is right now. ask Bryan "unk577" at the next Wedesday meet, or send him a link here.

Phil, if you want the BeatRush part like in that photo then get with Bill @ http://MiataRoadster.com as he sometimes has 1 or 2 available. Peter Perez in the local club has a ton of BeatRush parts on his 99 Miata, you might ask him if he has this piece?

more pics on my old Cardomain page. http://www.cardomain.com/id/madmx5

http://carphotos.cardomain.com/ride_images/1/534/561/1332780497_large.jpg

[atlnb]

I like how the NA underpans stretches across the entire front bumper. I wonder why they didn't do the same for the NB

http://www.good-win-racing.com/miata/images/items/NBunderpanel.jpg

[pmhaddad]

That beatrush looks like what I really need. I've talked to some track guys and some peeps from the FSAE team where I went to college and they all say that you can do the same thing with corragated plastic. And judging by the cost of the beatrush plus the fact I don't care about being JBM tyte yo, I'd be more likely to just do that.

Also, cutting the rear bumper sounds like a really good idea, but I'm not sure I want to hack my only one up. I'd probably get a spare and do it to the spare. Same thing with a spare trunklid for a GT wing.

Aero mirrors are also something I'd strongly consider, but maybe a little too pricey for a track day beater right now for me. I'm not planning on doing any of this other than maybe something like the beatrush and a GV lip and maybe cutting the bumper anytime super soon.

[urban]

that's true, but like porsche and cars, they have vents along the length of the car to cool the hot areas under the car to make the most out of it.


yeah i mainly brought that up so that no one gets carried away with abs plastic.

[pmhaddad]

http://www.ultimatecarpage.com/images/large/3873/Ford-Falcon--FG01--V8-Supercar_5.jpg

Inspiration for rear bumper...

[atlnb]

yeah i mainly brought that up so that no one gets carried away with abs plastic.

ohhh ok i see

[Blackbird]

Autox and track use with your power level need two different aero packages.
For track use I suggest that you cut your rear bumper, add a front air dam, aero mirrors, fab a spoiler for trunk with low AOA, cut vents in your hood, cut the front fenders at the body line.
Leave the rest alone.

Moti

[pmhaddad]

Autox and track use with your power level need two different aero packages.
For track use I suggest that you cut your rear bumper, add a front air dam, aero mirrors, fab a spoiler for trunk with low AOA, cut vents in your hood, cut the front fenders at the body line.
Leave the rest alone.

Moti

What do you mean by "cut the front fenders at the body line"? Just having trouble picturing what that looks like.

I'm tracing out a floor for the front on carboard before I get some corrugated plastic (or maybe fiberglass?) to make a floor for the front that will extend from the front of the bumper back to the LCA. Its similar to how the beatrush on the NA looks.

How high up the rear bumper should I cut for maximum effect? Can I just trim the under part flat so that it doesn't hook under or does the cut need to come up further and actually remove part of the outside facing section of the bumper?

Thanks!

[kung fu jesus]

PLEASE use a deformable plastic. You do not want to be that guy who leaves shards of plastic all over the track the rest of us collect in our tires or heat exchangers. There will be blood...

[Blackbird]

Note front fender -
2493

Moti

[pmhaddad]

I do believe corrugated plastic is deformable. Maybe I'm wrong about that. I basically want to use the same sort of stuff that the OEM underpanel is made out of. I guess corrugated plastic is the sort of thing they use on election signs, so maybe it isn't deformable enough? Seems like it would be fine though....

Moti - thanks for that, I get it now! That rear bumper looks pretty radical too, that is a lot higher of a cut than what I was envisioning...

[kung fu jesus]

Corrugated plastic is fine, I was referring to fiberglass and endorsing Urban's distaste for ABS plastic.

[Phatmiata]

How about this rear Jet Stream rear Diffuser for NB ?

http://www.jetstream.co.jp/image-nb-road/nb_diffuser/IMG_5949.jpg

http://www.jetstream.co.jp/image-nb-road/nb_diffuser/ad02.jpg

They have a nice downforce wing too!

http://www.jetstream.co.jp/image-nb-road/IMG_6110.jpg

[Phatmiata]

too wild? How about this mild Duck Tail Spoiler for NB

http://www.jetstream.co.jp/image-nb-road/nb-ducktail/PIC_0043.jpg

[stormin'norman]

I love aero and all but I can help but wonder how many of the people rocking it at the track aren't leaving gobs of time on the table elsewhere. Drive the piss out of the car. Learn it. Love it. Embrace it and pass faster things. Then come back to it. The first post in here (non functional items) is a great example of the irreplaceable value of seat time over spending money just to spend money.

[Phatmiata]

I'm sure a lot comes down to driving skills no matter what, all the aero and bolt parts can only take you so far. But like you said once that is down you can get to improving the car some more, and guys like to modify right?!!

anyhow, here is more info on the Jet Stream Parts
http://mazdaroadster.net/showthread.php?2065

[stormin'norman]

and guys like to modify right?!!


This is true. :mrgreen:

[Caoboy]

I want track aero because I'm a poser and want to look badass.

[LOL]

I want track aero because I'm a poser and want to look badass.

+1. True

[Coupeloop]

there is nothing wrong with going fast and looking good at the same time.

http://youtu.be/jtcWy0vWE7Q


when it doesnt look good you have................. spec miata. :?

[I<3flippyheadlights]

So at today's picnic meet thing, I saw a few other GV style lips and after looking at mine, its now bleh. Its been hit and run over too many times; In doing so it looks tired. So to freshen things up I want to be a poser and make an air splitter off my lip. Any ideas or recommendations on how to go about this? (purely for being a poser and no real use except to make the GV stick out again)

[Frenchmanremy]

You could also pull a v-dub crew moment and sticker-bomb it. But then you'll find people reading your bumper in the parking lot when you get back to your car...

[cjsafski]

The wing on my car works surprisingly well for $20 in polycarbonate. At the angle in the picture below it definately seems to help with drag. Fuel mileage for my normal commute went up after I threw it on. On the drive to Laguna Seca the car got 29.5 mpg which is awesome for a car with a roots blower on it. At the track the car seemed more neutral than usual even in the rain. The wing is also adjustable and when angled up like a CSP car the rear definitely seems to stick better.

http://img.photobucket.com/albums/v651/Xekueins/456167_10150624531205658_669370657_9707833_1866310 503_o.jpg

[bokehmon]

^makes sense, you're minimizing the vacuum/ dirty air behind your car, thus... moar faster! :D

I love your hood!

[wannafbody]

I like the look of that wing, can you do a detailed write up on it?

[BlueMotorsport]

yes please ^