custom diffuser in the works
 

I`m never going to get around it if I dont post it here so here it goes. quick napkin sketch of what I`m thinking of fabricating. I`m no aerodynamics wizard, but as Tada san says, best aerodynamics is nothing :) so this mesh style diffuser should allow more airflow instead of acting like a parachute. also, since the exhaust exits are just holes into the mesh, single exit exhaust will actually look good with this diffuser. let me know what you guys think.
https://scontent-a.xx.fbcdn.net/hpho...16327787_n.jpg

thanks,
Andy


UPDATE
3/10/14

NOT the final version, but based on a LOT of measuring I have mocked up something in CAD to get a better visual.
https://scontent-b.xx.fbcdn.net/hpho...74708134_o.jpg
https://scontent-a.xx.fbcdn.net/hpho...63707496_o.jpg
https://scontent-b.xx.fbcdn.net/hpho...37217955_o.jpg

UPDATE 3/14/14
more refined CAD and a quick photoshop of how it would look like:

https://scontent-b.xx.fbcdn.net/hpho...53463965_o.jpg
https://fbcdn-sphotos-b-a.akamaihd.n...59349817_o.jpg

https://scontent-b.xx.fbcdn.net/hpho...71579026_o.jpg
https://scontent-a.xx.fbcdn.net/hpho...96686200_o.jpg
https://scontent-b.xx.fbcdn.net/hpho...55522124_o.jpg

UPDATE 3/27/14
I added two holes with a cap for more downforce. I have no idea if this will work, but F1 has it pretty well explained :)
[ame="https://www.youtube.com/watch?v=YvkFKgBU-8Q"]Renault R30 Innovative Rear Diffuser Explained - YouTube[/ame]

how it looks without the cap
https://fbcdn-sphotos-e-a.akamaihd.n...59099148_o.jpg
with the cap in place
https://scontent-a.xx.fbcdn.net/hpho...36855305_o.jpg
the underside
https://scontent-a.xx.fbcdn.net/hpho...88151401_o.jpg
overall appearance
https://scontent-b.xx.fbcdn.net/hpho...27827853_o.jpg

update 3/29/14

scored a donor rear bumper. gonna start hacking away at it today :)
https://scontent-b-lax.xx.fbcdn.net/...38263965_n.jpg

it fits in the car by the way :)
https://scontent-a-lax.xx.fbcdn.net/...57336580_n.jpg
https://scontent-a-lax.xx.fbcdn.net/...63245131_n.jpg

update 3/30/14
just chop that fool off :)
https://scontent-b-sjc.xx.fbcdn.net/...51169292_n.jpg
https://scontent-a-sjc.xx.fbcdn.net/...50631893_n.jpg

one take away: the diffuser design will have to cover up this ugly area.
https://scontent-a-sjc.xx.fbcdn.net/...89781543_n.jpg

update 4/1/14
what the final could look like now
https://scontent-a.xx.fbcdn.net/hpho...72565030_o.jpg

some napkin sketches
https://fbcdn-sphotos-a-a.akamaihd.n...08039701_n.jpg
https://scontent-a.xx.fbcdn.net/hpho...34461292_n.jpg

update 4/2/14
more exploration...
https://scontent-b.xx.fbcdn.net/hpho...27625652_o.jpg

update 4/3/14
the white bumper goes on the car. gonna start making the mock-up model with foam core to make all the measurements this weekend.
https://scontent-b-sjc.xx.fbcdn.net/...33759238_n.jpg
https://fbcdn-sphotos-h-a.akamaihd.n...03175788_n.jpg
https://scontent-b-sjc.xx.fbcdn.net/...60922532_n.jpg
https://scontent-a-sjc.xx.fbcdn.net/...24902221_n.jpg
https://fbcdn-sphotos-e-a.akamaihd.n...81508180_n.jpg

update 4/6/14
started mocking up the diffuser with foam core. will 3D scan this mock up and clean it up in CAD... just wanted to make sure that everything is fitting well.
https://fbcdn-sphotos-h-a.akamaihd.n...06077466_n.jpg
https://fbcdn-sphotos-c-a.akamaihd.n...19555439_n.jpg

2nd part of the diffuser...
https://fbcdn-sphotos-e-a.akamaihd.n...89234016_n.jpg
https://fbcdn-sphotos-g-a.akamaihd.n...33066135_n.jpg

I think I`m going to cover up the bumper beam and just leave the toe hook spots open. one more step of foam core mock up and then I will scan everything in 3D.

update 04/11/14
final rendering. this is how I`m going to integrate the reverse lights and the fog light.
https://fbcdn-sphotos-c-a.akamaihd.n...26292410_n.jpg


check out my other thread on the functional side vent:
http://www.ft86club.com/forums/showthread.php?t=59345

Reminds me a bit of the setup that one of the members has on here, that I THINK he pirated from a Lotus Elise. Looks good, I really like the idea of replacing the entire rear valence to make once whole, integral unit.

Provided the "mesh" is decent quality, and doesn't look like home depot stuff that has been butchered, the exhaust could look good, but I assume you'd need a custom setup to have it exit that high up?

Also looks like you're planning on a custom reverse light/bar setup as well? Or am I misreading the height/depth of that rendering?

Either way, looks good on paper, would be very interested to see how it comes out.

Cool concept. I'm interested in seeing more renderings

This is the thread he's talking about:
http://www.ft86club.com/forums/showthread.php?t=30149
The guy did use a Lotus diffuser and did need a custom exhaust to exit where he chose to, as well as notching the bumper beam. I plan to do something very similar myself, hope this was helpful.

I do love that one, I just didn't want to mod that much.

I've seen yours in person on Malt's car. Not my style, but very nice.

thanks for all the feedback guys. I plan on sending out an entire bumper with the integrated diffuser if i decide to sell the part. here is take number 2.
https://scontent-b.xx.fbcdn.net/hpho...24569395_n.jpg

i plan on using this part as a part of the diffuser. I guess for the FR-S GT86 guys this part is optional.. I personally dont care for the toyota 2000gt triangle rear fog light.

so... i just ordered this:
http://www.rallysportdirect.com/cata...fg420_1_sd.jpg

looks like this on the STI:
http://www.caradvice.com.au/wp-conte...-3-625x416.jpg

Maybe a single exit option? Some solutions to cover up the unused exhaust port are nice, but a proper single exit diffuser may be a monopoly at this point. Food for thought :) Thanks for the efforts!

Still love my Driveway Labs!

Get compliments on it all the time

Thanks Carl

Apologize for the thread jack

Thoughts on reverse lights? I'm trolling the interwebs trying to find some big dumb diffusers, and the ones that really modify the bumper delete the reverse lights. That's cool and all, but I do drive my car off the track so I'd like some rear visibility.

I've thought of some small 4-LED flood lights, but I don't want to blind anyone behind me at night, even if I would be able to see far better than what the stock lighting provides.

Yea so.. If you read my original post I talked about the single exit option. It's just a matter of drilling one or two holes into the mesh and mounting the trim around the exhaust tips :)

It's hard to see, but if you look at the sketch you can see that the original reverse light is still intact. The only part getting covered up is the triangle part of the reverse light assembly and the white parts are just hidden behind the mesh

Look at the difflow stuff, you might be able to get some styling ideas, or even pick up one of those units and modify it to fit what you want.

thanks for the reference. I`m kind of looking for a more complete design rather than "race car part" look but everything helps!

Sorry, but the sketch doesn't have enough definition/clarity to see what was going on, and when you mentioned that you ordered the fog for the STi, I thought that was what you were going to mount in the center.

Very eager to see how this progresses!:party0030:

seems like the same philosophy on "removing the wall" on the McLaren as well :)
[ame="https://www.youtube.com/watch?v=48LEh-gv85Y"]https://www.youtube.com/watch?v=48LEh-gv85Y[/ame]

Look at any race car, where the rules allow the rear of the car to be opened up. Evacuating the air is good.

another rough draft... good night ppl
https://fbcdn-sphotos-e-a.akamaihd.n...40601651_n.jpg

or...
https://scontent-a.xx.fbcdn.net/hpho...81691344_n.jpg

I think the one with fewer fins looks better.

I think an open-wall mesh would be freakin sweet!

Love the mock ups. Are you contemplating a color-matched panel or something above the reverse lights? May be cool or easier to just use CF or something so you don't have to have so many versions.

I personally like however many fins makes it the most effective. I have an assumption that MOAR IS BETTAR, but I can't back that up. Seems like (from what little I know) you may also do well to put fins on the outside of the exhaust exits, for smoothing the air from the rear wheels.

I see your model has spats on it already; was hoping that this could perhaps wrap around the entire rear and incorporate spats/fins in one piece on the outside. But that may be more race car than you're looking for.

Either way, I really dig it man. The open look, the semi-hidden lights, the mesh and flatbottom mounting. Looks killer.

If you need a test car, let me know!

Interesting design. Would love to see the final product!

this came in the mail :)
https://scontent-a.xx.fbcdn.net/hpho...13982217_n.jpg

Looks great!

will be mocking up the diffuser outlines with foam along with the clay modeling this weekend... been working on the side vent so the diffuser is getting no love at the moment.

CAD updated. leave me feedback guys. thanks.

I'm excited to see it take form. This is a cool project.

Looks good, but a bit unsure on the attachment plans from the CAD update. Can you elaborate?

I love it. How would it install?

I plan on making brackets that will bolt the diffuser onto a chassis portion of the car, similar to something like this:
http://ft86speedfactory.com/images/borladiffuserfrs.jpg

so you would cut out the OEM lower bumper piece?

That diffuser is the Borla unit that mounts to the exhaust.

and also where the diffuser meets the bumper, there will be a lip with a 3M tape that will adhere onto the bumper.

yes you cut into the bumper. If I get enough people interested I could do the work for you and have everything painted and just ship out the entire bumper.. sounds more difficult than just cutting your own bumper though as paint matching alone is a lot of work on its own.

for the fitment, I`m ordering the Invidia Q300 so most of exhaust set up that have similar dimensions will work as I will create brackets that will bolt the diffuser onto the chassis of the car around the muffler, etc...

You are too baller andy

Just the fact that people like @mokinbird87 and @Wonderbar exist, restores my faith in humanity. Love the form, function, imagination, and awesomeness of this. Can't wait to see the final result so I can start saving.

Thanks guys!

Sub'd

I love it. Sign me up if you can make it! Because of my exhaust removing the big / round muffler, I feel like there would be a parachute-effect on the rear bumper. The big / fake black diffuser (stock) looks too wannabe racer with no function. Your concept is great! hope it happens!

i agree good idea, to this date only hole fillers, someone who makes something look OEM off the bat with one hole for the single exhaust folks will be well,,,,,, winning. :)

What about at the front end, where the diffuser "starts" near the diff/rear sway bar? Seems like you could easily tie into the brackets/bolts there for some really solid mounting points. Without those, you'd basically only be anchored at the rear (via band clamps on the pipes and 3M tape on the plastic bumper cover). I'd think that this would cause the long undertray to seriously flex/wobble at speed, since it's sitting out in the wind like a reed on a woodwind instrument basically.

If you already covered this, please disregard. I just didn't see any provisions for those mounts in the CAD mock-ups.

Also; for the rear "fog" and backup lights: it looks like your new reflector will be sitting on top of the existing reverse bar, correct? This also looks like there is a moderate "lip" around the bar where the piece wraps around? I am wondering how this would affect reverse light output/visibility (if at all)? Also, if there will be a way to NOT have the reflector? I blacked out my reverse bar to the same color as the stock bumper so that it blends in, so sticking a bright red reflector back there would stand out a lot :thumbsup:

yup. all mounting points will be considered once i have the diffuser in my hand :) I want this piece to be as functional as possible (without looking too much like a "race car") so how this piece mounts to the car is very crucial.

thanks for the input!