rear underbody plastics

[yodaddyguido]

is anyone working on something like this? i feel like since i added a trd rear lip on my car, my mileage has been affected. our bumper covers seem like parachutes anyways, so i was wondering if anyone has made some sort of underbody panel to get the air around the pocket that is the bumper cover, and been able to kinda utilize the baby diffuser looking fins on the trd rear properly. also, should it cover the exhaust underneath, or be made to channel air over the exhaust and then out the back?

this is for gas mileage more than anything, since its my dd and i just like it clean, smooth, and quiet. suggestions are welcome. and a few tid bits of info. i work in a machine shop, so ive got access to plenty of tooling and w/e i need to actually make something. so if there's a preferred material i should go for when making this thing if no one has done this yet, lemme know. i'll want it to last, but it wont be made of steel for obvious reasons. uhmw, delrin, pvc... aluminum seems a bit like overkill. thanks!

guido

[ROCNYGTS]

I had never thought about this until you posted it. I'm currently getting my TRD rear lip ready to go on my car, and didn't even think about how much drag it's going to cause. I decided to do a quick mock up of something that I think would help quite a bit. Sheet aluminum would definitely be the easiest material to make this out of. Just a couple bends and some hole drilling.

http://www.newcelica.org/photopost/data/500/medium/air_diverter.JPG

I didn't do any kind of measurements for this, just something to give you an idea of how I would do it. You could also cut out a section for the exhaust to fit into if you wanted it to go over that far. For simplicity I would probably just have it end where the exhaust cutout starts on the lip. Let me know what you think.

[bionictony]

aluminum seems to be the cheapest and easiest to work with. something like this would seem good

http://cgi.ebay.com/Carbon-Fiber-Rear-Under-Diffuser-WRX-Impreza-STi-GDB-/120585158474#ht_4728wt_1108

or you can drill holes in you bumper like the civic guys. haha

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=170423059031

[yodaddyguido]

that bumper hole thing... lol geez. couldnt bring myself to do that one. id like to get a nice piece made for the underside, so i guess i just need to get under there with some cardboard and mock some panels up. im hoping shizuma will chime in, because i think he's working with a nice set of custom panels under his, or bt216... i think he's doing the same or something in this realm as well.

[Shizuma]

that bumper hole thing... lol geez. couldnt bring myself to do that one. id like to get a nice piece made for the underside, so i guess i just need to get under there with some cardboard and mock some panels up. im hoping shizuma will chime in, because i think he's working with a nice set of custom panels under his, or bt216... i think he's doing the same or something in this realm as well.

Anything you can do to cover the void between the gas tank and your rear lip is going to reduce drag. This can be very simple and be shaped like a "T" to cover the middle section of the rear and spread out after the rear control arms, or shaped to cover the entire rear and have slots for the rear control arms to operate through. Regardless, you're on the right track. Always, always, always make a mock up or template out of cardboard before you start cutting out metal.

[krnyoshi]

I would pay money if you make a spare. :gap:

[yodaddyguido]

we'll see how much progress i make this summer. getting married soon, and just moved into the new house. its busy, but my free time seems to be spent with the car, so who knows :) shiz do you have any pics of your setup or have any more pointers to get me going?

[Shizuma]

Mine isn't anywhere near complete and probably wouldn't be of much help anyway. I've chopped up a lot of the floor and am not running the exhaust down the bottom of the car anymore. Here's some pics that may help though:

http://i132.photobucket.com/albums/q18/jid2/102_1027.jpg

http://i132.photobucket.com/albums/q18/jid2/102_1028.jpg

[broderp]

Mine isn't anywhere near complete and probably wouldn't be of much help anyway. I've chopped up a lot of the floor and am not running the exhaust down the bottom of the car anymore. Here's some pics that may help though:

http://i132.photobucket.com/albums/q18/jid2/102_1027.jpg

http://i132.photobucket.com/albums/q18/jid2/102_1028.jpg

How is the front edge (side closest to the front of the car) secured from air infiltration when mounted on the car? If air gets in thru the leading edge of this, seems like the trapped air can be worse than the air on the bumper without it.

On a side note, and this may be a silly question, how will this affct the down force on the car? Assumming this works, you will have less drag or resistance of the wind at speed. I'm NOT saying it will generate "lift" as in a plane wing, but will the reduced drag affect the cars adhersion to the road?

[broderp]

To bad no one has a wrecked Celica that can be flipped over upside down and used to make a mold so these parts can be made from a resin or plastic (Vaccum formed)

:wiggle:

[vtjkychan]

if ure going for gas mileage... isn't adding the rear panel = more weight, which reduce gas mileage anyways!?

[edg3h_91]

if ure going for gas mileage... isn't adding the rear panel = more weight, which reduce gas mileage anyways!?

i doubt it the little weight would matter as much, since the panel doesn't have to be heavy as sheetmetal is not all that heavy.. the fact that the rear bumper wont act as a parachute will definately help gas mileage

[vtjkychan]

^ hope so. I have the front under panel and it's quite heavy imo so I thought if the same material is to be made for the rear panel, it would weight either as much or just a lil less.

[broderp]

if ure going for gas mileage... isn't adding the rear panel = more weight, which reduce gas mileage anyways!?

What are you talking, 5-10lbs? (sheet aluminum?) I think the reduced drag would outweight the weight..??

[reguile]

^ No, you're stupid.


lol jk. Yea, I'm sure the reduced drag will improve gas milage alot, and increase performance a little bit, might not be noticeable, esp at low speeds. Can't wait for these panels to be made.

[broderp]

^ No, you're stupid.


lol jk. Yea, I'm sure the reduced drag will improve gas milage alot, and increase performance a little bit, might not be noticeable, esp at low speeds. Can't wait for these panels to be made.

Mamma always said, Stupid is as stupid does..... :gap:

Yeah I'm kind curious as well. I need a front one as well.

[xantonin]

I'm going to have to try and make something...

[Joey03_VVT-I]

^ :headbang:-DO IT!!!

[yodaddyguido]

still workin on it lol...

[Bitter]

how about full body under cladding like the MKII MR-2's had? looked like an insect carapace.

[yodaddyguido]

it'd be nice to have but also a great deal of work making sure air flowed through it properly w/o creating a bigger parachute or odd wind effects... this might seem a little off topic, but i can tie it in with the underbody thing... has anyone incorporated the exhaust outlets into the bumper, kinda like the r8? or even those bigazz lexus sedans with the 'tip' exit pieces that blend with the lower bumper edge?

[Celicasaur]

I'm gonna attempt cooking up one for my car this weekend.

Updates to follow.

[zzt231 gr]

How the hell I missed that thread!I am very interested in reducing high speed lift and drag.

[zzt231 gr]

Updates to follow. :popcorn:

[Celicasaur]

I spent a couple hours investigating and fixing an almighty exhaust leak from the head...and then my lady called me out, so I had to see her instead :o:

Next week maybe :headbang:

[zzt231 gr]

and then my lady called me out, so I had to see her instead Having similar problems occasionally...

[zzt231 gr]

Updates plz??

[Celicasaur]

This weekend if it doesn't rain - I promise :)

I'm gonna go under the car to fit my new wideband sensor, so I'll make a template for the rear undertray as well.

[GSBoek]

What if the lady calls you out again? :chuckles:

[yodaddyguido]

lol^

ive got the massive cardboard pieces home today and the car is up on ramps, so im gonna try and do some work this evening. im debating on making a (set of) panel(s) that goes from the front, where the oem underpanels end, all the way to the back. id like to use a similar plastic to oem, so ive gotta do some shopping with mcmaster-carr for material ideas. anyone good with aerodynamics for underpanels? theres no way to seal the panel, nor would it be a good idea since the exhaust would get sealed in. im thinkin vents along the underside of the exhaust to give it some breathing room, and a few extra exits toward the rear... that and i like the idea of opening up some areas where that black plastic piece is right smack in the middle on the lower part of the rear bumper cover.

[Celicasaur]

What if the lady calls you out again? :chuckles:

Doubtful...we broke up on monday :wtc: she was sooo pwetty.... :sadpace:

[Shizuma]

Doubtful...we broke up on monday :wtc: she was sooo pwetty.... :sadpace:

Does she have a hawt friend?

[zzt231 gr]

ive got the massive cardboard pieces home today and the car is up on ramps, so im gonna try and do some work this evening. im debating on making a (set of) panel(s) that goes from the front, where the oem underpanels end, all the way to the back. id like to use a similar plastic to oem, so ive gotta do some shopping with mcmaster-carr for material ideas. anyone good with aerodynamics for underpanels? theres no way to seal the panel, nor would it be a good idea since the exhaust would get sealed in. im thinkin vents along the underside of the exhaust to give it some breathing room, and a few extra exits toward the rear... that and i like the idea of opening up some areas where that black plastic piece is right smack in the middle on the lower part of the rear bumper cover.

I don't think it is a good idea to cover the exhaust tunnel completely...Maybe a well vented metallic cover would be ok,but I don't remember any of the supercars I've seen in Best Motoring and Hot Version having the exhaust tunnel sealed almost at all...

If you can't seal the rear panels completely for the air entering the upper side of them-witch I think is the only way-you must leave a passage for the air to pass through and get out-we must give it a way out!A good idea is to guide it through the opening you are mentioning-I already cut it for the same reason!Also,especially for the rear body pieces,the best bet would be to give them some degrees of leaning upwards-that works as a diffuser or a spoiler!The fins that we see on many cars-and I mean the functional ones eg.Elise-are for keeping the air turbulence low,thus keeping the cd lower than a rough surface.

Keep up the good work,guys!Too bad I don't have the space and time to make my project,too...

[Thomas]

This afternoon I was looking at a custom rear diffusor mounted underneath a 7th gen celica from a friend of mine! :gap::wiggle:

I'll take pictures next week. Like to hear what you guys think of it.

[zzt231 gr]

Sounds awesome!!!

[Thomas]

This afternoon I was looking at a custom rear diffusor mounted underneath a 7th gen celica from a friend of mine! :gap::wiggle:

I'll take pictures next week. Like to hear what you guys think of it.


The crappy phone picture as promised.

http://i743.photobucket.com/albums/xx78/Blokker/Celica/IMAGE_282.jpg

[Celicasaur]

I wonder if that is actually doing anything....

[Thomas]

I wonder if that is actually doing anything....

I think it does. Now the rear bumper isn't catching so much air anymore. That is all it does I think. We will never know unless we'll put it in a windtunnel..:gap:

[edg3h_91]

those fins are huge!! but awesome work we need more pics !

[Celicasaur]

I think it does. Now the rear bumper isn't catching so much air anymore. That is all it does I think. We will never know unless we'll put it in a windtunnel..:gap:

Or a before/after on the drag strip :gap: (well, that's what i would consider as doing 'something' :o:

[zzt231 gr]

I think it does. Now the rear bumper isn't catching so much air anymore. That is all it does I think. No offense but this think that you have there-which seems to serve almost no function because it doesn't isolates the upper and the lower part of the rear and is too small-only helps in multiplying the parachute effect our rear bumper has!It just forces more air to enter the bumper from the front and add more drag...

[Thomas]

No offense but this think that you have there-which seems to serve almost no function because it doesn't isolates the upper and the lower part of the rear and is too small-only helps in multiplying the parachute effect our rear bumper has!It just forces more air to enter the bumper from the front and add more drag...

What do you mean by isolating the upper and lower part?


I'll be receiving more pics today so that you'll see that not all the air underneath the car will be scooped by the rear bumper. The parachute effect will certainly not be multiplied, on the contrary!

[zzt231 gr]

http://en.wikipedia.org/wiki/Diffuser_%28automotive%29

Check this link for more info!I mean that the air must be guided completely under the diffuser and not above,to gain the maximum out of this.

Let's wait for more pictures...

[Thomas]

http://i743.photobucket.com/albums/xx78/Blokker/Celica/P1000233.jpg
http://i743.photobucket.com/albums/xx78/Blokker/Celica/P1000234.jpg
http://i743.photobucket.com/albums/xx78/Blokker/Celica/P1000237.jpg
http://i743.photobucket.com/albums/xx78/Blokker/Celica/P1000239.jpg

[Shizuma]

^ Looks nice, alumalite wrapped in carbon vinyl?

[Thomas]

^ Looks nice, alumalite wrapped in carbon vinyl?
I'll pass the compliment on to my friend.;)

It isn't aluminium, but a thick kind of plastic.

[ImpulseRED]

if its the stuff OEM headlights are made out of it wont break... lol :P

[yodaddyguido]

its probably delrin or a type of pvc. delrin is pretty resilient. heck, it could be a glass filled type plastic. let us know what it is if you find out. im still debating on what type of material to use for mine. im leaning heavily towards a thin stainless for wear and rust resistance. im going to bring mine a little farther forward as well

[broderp]

http://i743.photobucket.com/albums/xx78/Blokker/Celica/P1000233.jpg
http://i743.photobucket.com/albums/xx78/Blokker/Celica/P1000234.jpg
http://i743.photobucket.com/albums/xx78/Blokker/Celica/P1000237.jpg
http://i743.photobucket.com/albums/xx78/Blokker/Celica/P1000239.jpg

Function before form? Maybe it's me, but this looks aweful. (The rear view from the backside.)

Now if I had a dedicated race machine, and this works, I'd be all over it. For a street car, I'd want something less obtrusive.

The work looks top notch though.

[h8eternal]

what if you were to cut out those reliefs in that grey un painted area on the rear bumper. would that help at all free the trapped air?

[Celicasaur]

^^^ it would certainly help...but probably not as much as one would like :(

[zzt231 gr]

Wow,how the heck I missed the pics!!Looks good to me-compared to a stock ass!And seems to be functional,too!Maybe a true cf construction would look better...Do we have the schematics for this???



what if you were to cut out those reliefs in that grey un painted area on the rear bumper. would that help at all free the trapped air? Also this.It is something I already did.:hitit:

[ImpulseRED]

i'de like to see it trimmed back and flush with the body, or the fins tucked a bit, eaither way i'de rock it :D

[Celicasaur]

Also this.It is something I already did.:hitit:

Any improvement in top end acceleration according to the butt-dyno? :shrugs:

[zzt231 gr]

http://www.newcelica.org/photopost/data/500/DSC012711.JPG

This is my rear aerodynamic setup :rolleyes:

I haven't noticed any improvement in acceleration but,theoretically,I should at least reach some more km/h at top speed...Looks very cool,though!!Now,let's see some rear diffuser hangin there...

[Celicasaur]

Yeah it does look kinda cool :thumbup:

What I'm going to do on mine is simply cut a section out from the middle of the rear bumper and have an aluminium sheet curve upwards into it from the area where the stock muffler sleeps. Fins can then be welded on for maximum rice effect, but that'll be the best way to deal with the issue, methinks.

Of course, it'll be many months now until I actually do this though...ahem...

[zzt231 gr]

^^Maybe I will catch you up first...Anyways,GL when yor time comes!

Do we have the schematics for this??????

[EMSRacerCeli03]

bump ill be working on one this week as well. and get it done hope by wed. lol

[zzt231 gr]

I will start counting days,lol!!!

[EMSRacerCeli03]

k got my template. its going to be like shizuma said. peice that goes just over the fuel tank through the cross members and its going to cover the rest of the bumper. I need to change my exhuast before i finialize the design but ill be using alumalite.

[EMSRacerCeli03]

update: k turkey day and tests with school have kept me pretty busy plus i had to modify my exhuast to move it out of the way for a diffuser :P but had some free time. I have changed things from what i first expected. The diffuser will go to the fuel tank but will go under the frame work and cross members and angle right after the cross members at about 15 degrees to the bumper edge. and i made many vortex fins. does anyone know if how many i put on will make a dif? o yeah and dont make fun of the cardboard template lol. it was just to see lol.
http://c4.ac-images.myspacecdn.com/images02/142/l_e976d9b915994c9fb4f33af03cd0f8a7.jpg
minor measurements to make this rough draft with the fins for looks haha
http://c1.ac-images.myspacecdn.com/images02/127/l_cb12b3369dc04d898bd6ae94fc92d478.jpg
after test fitting it a bit and getting edges cut. pretty good for a first draft.
http://c3.ac-images.myspacecdn.com/images02/127/l_4df46a71223a42e6a231767e1c451326.jpg
under the car. looking good.
http://c1.ac-images.myspacecdn.com/images02/92/l_5e86b40ea5bf4d5cb4d4243f85ad419c.jpg
just cut the final piece (well might change a bit for fitness) i made it out of coroplast. I chose coroplast bc ecomodders swear by it for under panels and full belly plates. its really really light. strong for the way it is, similar to urethane plastic just a but weaker. and its cheap 4X8 sheet for 30 bucks lol. I was going to use alumalite but its super expensive, lowest price for 4X8 was over 250 :O , and really hard to cut and almost impossible to bend. plus i can always make coroplast stronger. but yeah ill test fit the final piece hope this weekend. NOt exactly sure what to use to keep it to the bumper though. guess nuts and bolts? or at least some ganster screws lol.

but yeah let me know what you think. and this piece is 4X5 sq ft peice. about the size of my beatrush front underpanel.

also with all these peices im going to cover more of the underside of the car and maybe some splitters and carnads ill be making soon.

[Celicasaur]

Well done man, that looks pretty good!

Try getting some more under car shots, particularly with it fitted and of the fuel tank/oem muffler area :)

[Hgarden27]

yeah i think it would help but i would use a mesh in its place bc i dont think it would look good with holes in the bumper. but that would help alot

[GSBoek]

^I suppose that was a response to the last post on the first page. :chuckles:

[EMSRacerCeli03]

Well done man, that looks pretty good!

Try getting some more under car shots, particularly with it fitted and of the fuel tank/oem muffler area
ill try to do that. it looks really good though. really clean looking.

[yodaddyguido]

:thumbup: shoot me a pm with info on where to get that ecoplast stuff. sounds like a do-able candidate for material

[EMSRacerCeli03]

well you can get it at sign shops for realativly cheap. but i found pieces in my neighborhood lol. they are all weather, sustainable material. Its not as strong as aluminum or sheet metal in rigidity but i think it would last a long time under the car. Guys over at eco modders have used it for years on end with no fault. maybe a bit of melting from exhuast but im gonig to angle it so it clears most of it and cut where needed.

think corogated plastic. and its coroplast. I really would have used alumalite but i heard its a really hard material to cut bc its so thick (ppl use band saws to cut it). and looked really hard to bend.

[EMSRacerCeli03]

Update
http://c3.ac-images.myspacecdn.com/images02/151/l_71dff51eb35d406eb963c95de5961d06.jpg
http://c3.ac-images.myspacecdn.com/images02/115/l_6f63e94134e54bf19d792cf3c20e65da.jpg
ground shot
http://c2.ac-images.myspacecdn.com/images02/117/l_4b841add4bee4ce190031b6e29c58a81.jpg
ran out of bolts but before i put the nuts on i need some nice washers plus you get to see the angle
http://c2.ac-images.myspacecdn.com/images02/140/l_e9a59357421c4cbb8740ceafdacdaf45.jpg
and some brackets to hold the angle in place.

all this is going to be sprayed with high temp/anti rust material so the bolts and nuts dont rust nor hope it doesnt catch a flame or mostly and probably melt lol. but i made some cuts so it should be all clear of the exhaust.

will be taking pics tomorrow with it on. I got it on tonight and it looked really nice im very pleased :P but i probably wont attach it for a week or so bc im getting a new sway bar so i rather do that first then this lol. but ill get pics for ya. let me know what you think.

o yeah in total i think i have spent 45 bucks. not bad

[ateens4]

why can't it be more fitted or molded to the rear. it looks like it was jsut screwed on. I like the idea, but I'm assuming that theres more coming

[Celicasaur]

I gotta be honest...little jealous right now :o:

[EMSRacerCeli03]

why can't it be more fitted or molded to the rear. it looks like it was jsut screwed on. I like the idea, but I'm assuming that theres more coming
? explain? i molded this to fit any bumper, clearances for the wheels, and exhaust. i think it covers alot. hell after this ill have half the undercarage covered.

[EMSRacerCeli03]

o or maybe you want me to fiberglass. lol screw that lol u can tell you it will fit near perfect and be very stable foe a diffuser.

[EMSRacerCeli03]

This will probably be my final draft so i probably wont update the design from here just getting it on.
Here you go:
http://c1.ac-images.myspacecdn.com/images02/142/l_34619d8f1d864a9eb7ae73e5b263a078.jpg
backing showing all my washers and nuts and haveing them being sprayed.
http://c1.ac-images.myspacecdn.com/images02/144/l_8664bdd16aed4b69a30ccc0a66b4e454.jpg
EMS!!!!!!!!!!! lol but you can see its pretty long piece
http://c2.ac-images.myspacecdn.com/images02/138/l_a99712a24f974bb991357d13f5db55b1.jpg
this is how it sits on the right side bumper and how close it is to the tires lol. its the same on the other side too.
http://c3.ac-images.myspacecdn.com/images02/97/l_43da42f1c8344721b556ed97042453d2.jpg
see it sits really flush with the gas tank. and good thing is that the tank already has three brackets that hold a scrap plastic plate that i can use for mount spots :P
and you can see how i moved the exhaust too. and cut a but to compensate for that.
http://c1.ac-images.myspacecdn.com/images02/149/l_d05385e2ae9e4edea12ad049a489b89c.jpg
good fitment and it sticks out a bit but good if i ever change bumpers later on. but remember its just hanging by the duct tape
http://c2.ac-images.myspacecdn.com/images02/129/l_3f84a67e22ff412aa417f96a31361c21.jpg
an undershot. sorry not so good. these are taken with my phone lol. but trust me its pretty straight and doesnt hit anything.
http://c2.ac-images.myspacecdn.com/images02/72/l_7946947df9a047d28d74e17467357ce9.jpg
again its not mounted all the way hence the space under the car and by the tires and by the exhaust. and yes my tip is crooked lol. and i will need to modify it a bit.

Ok guys i have finals all this coming week and the next. so it will be a while before i put this on (plus getting a rear sway soon :P). so let me know what you think.

[Pocket Rocket]

maybe ceramic coat the exhaust to solve heat issues?

[EMSRacerCeli03]

o it is all the way back coated and i sprayed some high temp paint too. i know it wont be an issue but it will still get hot

[yodaddyguido]

oooooooooh i see what the material is now... nice idea. if i ever get more than 4 minutes of spare time, ill have to see how mine stacks up against yours :wiggle:

[zzt231 gr]

This has turned out better than I hoped!You did a really good job there!Just be sure to have it facing a little upwards from the rear side and don't let any air pass through the upper side of the panel.Can we have the measurements,pleaseeee??:gap:

[EMSRacerCeli03]

yeah it has an angle that goes up past the bumper so no worries and i will try to get measurements but its 4X5 piece that i used well plus the vortex's so probably 4X6

[EMSRacerCeli03]

ok guys i post pics later but i go it on. trimmed it some more so it looks and fits alot better. Took it up to 75 mph and drove it for over 2 hours on the way home. got 45mpg on the trip. my avg hwy was 36-37 so great improvement and city went from 33 to 35 lol. just saying it works.

[bt216]

45mpg!? :eek: wow thats prius good

[Shizuma]

Looks good man, you can strengthen up portions of the diffuser with "L" or "U" aluminum braces.

[EMSRacerCeli03]

45mpg!? wow thats prius good
ha yeah i do crazy stuff like 2way. hypermiller status lol. but yeah i was surprised about the gain but i been around on ecomodders for a while and seen ppl with a nice underbelly gain 10mpg on the highway.

Looks good man, you can strengthen up portions of the diffuser with "L" or "U" aluminum braces.

i used galvanized steel L brackets on everything. i used 6 L brackets on each fin so thats alot lol. Its really stable. On the way back from my trip home (another 2 hour drive) got the same results 43mpg, more uphill back. So good results. And its super stable at high speeds. lol just for my own curiosity i got up to 120 and it felt nice.

[zzt231 gr]

These are very good news,Byron!seems like you did a very good job!Any updated pics yet?

[c3ll]

I think it does. Now the rear bumper isn't catching so much air anymore. That is all it does I think. We will never know unless we'll put it in a windtunnel..:gap:

OR.... hit me with a license for a plugin for cinema 4d that can measure particle (air) movement around 3d models :D

http://img101.imageshack.us/img101/4021/gsports.th.jpg (http://img101.imageshack.us/i/gsports.jpg/)

^ I made her :D

[yodaddyguido]

dang, nice work c3ll. this thread rules :headbang: im gonna head to the local sign place to pick up a sheet of that corugated plastic. i like that material choice! again, awesome job ems

[v3bahumut]

I'm going to have to look into making one for myself. Good work in here.

[EMSRacerCeli03]

ill try to get pics up a bit later. but so far so good. and ask for coroplast if your going to use that lol. sign shops seemed like the best bet

[Jeffro]

very inventive

[KageRyu7]

and these go on sale when?

[Pocket Rocket]

did you put any venting to draw heat from the motor like the beatrush/c-one version? was looking at 1mm ally sheeting - i've already achieved 47mpg on a 2zz wihout this just by observing speed limits and pre-planning.

[Pulsar1]

Very nice I had similar setup on my maxima a few years ago. They certainly can make a difference when thought out and revised. Why they don't come standard on most passenger cars idk. I picked up 5+mph on 75-80mph cruises on the express way. Lower is diffidently better when it comes to making them effective. Mine had to be about 2" higher off the ground than your due to the lack of a rear lip on my car. Do you have that Al front underpanel as well??

[TRlPPlN]

wow def. interested on this. i know for a fact the rear add on lip acts as a parachute as stated.

[pe280ju]

Hi,

I once had a go at this (i gave up), bravo its a really good idea.

Are there any updates ? photos of it fully attached etc

My problem was i feared there would be too much pressure as although the air is going where directed you now have no where for the air that enters the rear wheel openings to go. Im sure you understand, cant seem to articulate exactly.

Regardless, any chance I could get hold of some dimensions ?

[yodaddyguido]

just ordered my 4x8 sheet of coruplast friday. should get it wednesday and get started on it soon. i just started commuting 70 miles roundtrip for school, so im looking to improve the gas mileage seriously now lol. eventually im going to do a total of three panels (i think) to cover the entire underbody.

also, if you happen to have taken down any dimensions or come across any issues when you were mounting/making yours, shoot me a pm or post on here. thanks ems

[EMSRacerCeli03]

yeah sorry to leave you guys hanging ill take pics tomorrow i finally got my camera back.

o yeah and i have a beatrush underpanel too for those asking and ^^^^ i had to just custom mount a few places but all i really did is use the little brackets by the gas tank and heat sheilds.

[pe280ju]

Cheers, so is yours full fitted now ? I have to commute a lot and with price in the U.K being ridiculous this mod would really help. Did you make a note of dimensions ?

[EMSRacerCeli03]

no dimensions yet but here is how it looks on the car.
http://c1.ac-images.myspacecdn.com/images02/152/l_4296d716b5f343ff9400b7f1a98bd344.jpg
http://c1.ac-images.myspacecdn.com/images02/148/l_daa2eb442d484c4182ca3e5a2fb26d3c.jpg

[KageRyu7]

ok this probably a noob question... I understand how the large flat part blocking the air reduces drag, but what purpose do the fins themselves serve? How much would the car benefit with having a fin-less under guard?

[pe280ju]

looks great!

the fins help channel the air

If you ever get the chance please could you get hold of some dimensions. The bumper radius isnt important really, just the rest. Cheers

[yodaddyguido]

snap a few close ups, and did you mention the mounting points at all?

[bt216]

looking good, you gonna make more then one?

[TRlPPlN]

^^^+1

[EMSRacerCeli03]

ha i could make a few since i still have alot of the materials i used but it would proabbly be alot to ship it. and now that i know dimensions i probably could make it out of a different material. But you know what after it snowing here, raining, driving in the dirt and at high speeds (over 85) its still in the same condition as when i put it on with no rips, holes or anything. So keeping it coroplast keeps it light.

and ill post dimensions tomorrow to give you guys a better idea. but the part by the bumper i went by the shape of the trd lip on the rear more than anything.

[SK Ricecooker]

so sexy :applaud:

[yodaddyguido]

any luck dimensioning that part? mine will be installed against a trd rear lip, so ill be stickin close to your dimensions. im just slammed with school and work, so dimensions would be stellar lol

[Entranced]

sounds like I need to get myself some underpanels! :wiggle:

[DNgts01]

did you have that custom made? or was it universal?

[EMSRacerCeli03]

made myself and school has kept me swamped lol i have to take it off the bumper too but ill get you some rough dimensions you can start on. but the curve would be hard to give dimension for but ill try.

[Curt705]

how much for one?

[XBernie]

:drool:
http://i50.tinypic.com/3581d8p.jpg
http://i45.tinypic.com/2l8x30w.jpg

[KageRyu7]

:drool:
http://i50.tinypic.com/3581d8p.jpg
http://i45.tinypic.com/2l8x30w.jpg

yeah...i just might have to make one like that

[XBernie]

Or you can spend 1100 plus shipping from Varis just for the center diffuser LOL

[EMSRacerCeli03]

^^^true it looks nice but not as functional as mine. And for all wondering i could probably make these at a machine shop out of aluminum or out of my coroplast and keep them under 200 for the aluminum and 100 for the coroplast. but shipping could be a issue since its so big. Its 4X5ft.

[zzt231 gr]

Byron,will you give us some under shots??I'd like to see how exactly you hooked it up there...

[EMSRacerCeli03]

thought i posted some.

[zzt231 gr]

I meant I want to see how did you finally mount it to the chassis...I didn't see any!

[EMSRacerCeli03]

man sort of hard with the car so low lol. pretty much i used the mounts for the heat sheilds that are right on the fuel tank. and made a mount right off the back sub frame to hold it from hitting the exhuast. ill try to get pics.

[pe280ju]

sent you a pm buddy

[hoosiergts]

I was at our local Toyota dealer and noticed that the '11 Siennas are coming out with a plastic underbody panel that looks like a diffuser. This is on all models so I'm guessing that there is an engineer out there that is trying to work on the parachute effect. If anything, it does cover up the rear cargo area nicely!

[adosdrummer]

sweet!

[TRlPPlN]

but shipping could be a issue since its so big. Its 4X5ft.
possible that it can be broken down to smaller pieces?

[zzt231 gr]

^^It will have the same functionality,if we divide it in 3 pieces.

[Entranced]

wow that's an ugly kit. :bang:

[pe280ju]

pm'd you ages ago, ever gonna reply ?

[pe280ju]

Hi mate,

Gonna be working on the celica from Saturday so ideally could you take it off like you said over pm. Cheers

[zzt231 gr]

Hi mate,

Gonna be working on the celica from Saturday so ideally could you take it off like you said over pm. Cheers

What do you guys hide from us???:gap:

[Muirner]

Has anyone thought of the effect this may have at 100+ mph? The air is going to flow faster under the bottom now, which should result in downforce right? Which wouldnt be bad... But i'm just wondering if anyone else accounted for this.

[yodaddyguido]

for 99% of us, 100mph doesnt need to be accounted for... lets be realistic here. this is for gas mileage more than anything. if youre doing 100+ consistently with a celica you probably work for MWR and dont care about mileage, plus you most likely didnt make it out of coruplast :wiggle:

[hoosiergts]

Concerning the use of the corroplast, how thick is it that you're using and did you do anything to cover or fill the edges when you cut your pattern out of the sheet? Did you use a heat gun to help mold any curves involved? Is there heat damage from your exhaust on the corroplast? And lastly, did you add any holes to help drain water from above the corroplast? I'd like to build one for myself and these are questions that I have.

[Muirner]

for 99% of us, 100mph doesnt need to be accounted for... lets be realistic here. this is for gas mileage more than anything. if youre doing 100+ consistently with a celica you probably work for MWR and dont care about mileage, plus you most likely didnt make it out of coruplast :wiggle:

I dont work for MWR, but 100MPH can happen. Where i live and drive occasionally the left lane is doing 90-95 it's crazy. So it has to be accounted for in my case. I'm not in the mood to have the ass end get light and do a funny dance at 100...

[zzt231 gr]

Has anyone thought of the effect this may have at 100+ mph? The air is going to flow faster under the bottom now, which should result in downforce right? Which wouldnt be bad... But i'm just wondering if anyone else accounted for this.

This is the main reason most of us want one and the lower Cd,too!The better mileage is a positive side effect.

[yodaddyguido]

I dont work for MWR, but 100MPH can happen. Where i live and drive occasionally the left lane is doing 90-95 it's crazy. So it has to be accounted for in my case. I'm not in the mood to have the ass end get light and do a funny dance at 100...

ok, i can pretty much promise you it wont do any sort of funny dance at 100mph... seriously.

[AZgts]

ok, i can pretty much promise you it wont do any sort of funny dance at 100mph... seriously.

HAHA :chuckles: +1

I do +110 on occasion and its like gliding on ice...

I can only think of one thing that will make you slightly "wobble" when you are drive... gusting cross winds. Think that is about it... ;)

[Muirner]

I do +110 on occasion and its like gliding on ice...

I hope the ass end doesnt step out as easy as ice at that speed. My car is still firmly planted at that speed

[zzt231 gr]

+1 at 250km/h.

[Muirner]

250km/h.

Damn you must be ringing 5th out to the very top as gaining speed in 6th is very slow/hard...

Edit: I dont know if 250 km/h is possible even

[zzt231 gr]

Damn you must be ringing 5th out to the very top as gaining speed in 6th is very slow/hard...

Edit: I dont know if 250 km/h is possible even

I am talking about stock speedometer readings.

I have a PFC,PPE Redliner header,PPE intake,2.5" decat exhaust and some other minor mods.

If you have a good straight,it's doable.But I don't remember which gear I had in...

[yodaddyguido]

this is getting OT

[Entranced]

no more OT. when are these going into production?? :wiggle:

[Celicasaur]

:werd:

Maybe Boosted2.0 should make a limited run of bolt on kits :naughty:

[yodaddyguido]

if i can get mine made up, i might try and go for a sheet metal variant that looks a little bit more like the one on (i think) trannmk's. im still waiting for my celica to get out of the body shop to move forward on my panel.

[zzt231 gr]

:werd:

Maybe Boosted2.0 should make a limited run of bolt on kits :naughty:

Why not??

[2KGTrd]

just started work on my rear diffuser tonight. :)

[KageRyu7]

^--how'd your diffuser come out?

[Koolsilver]

I'm getting interested in making this as well. The question was asked before but never got a good answer, are the fins important for the build. I don't necessarily like the look of them so if I left them out would it be bad or does it not matter too much? Also with the fins and being lowered won't they scrap a lot on speed bumps and what not?

[2KGTrd]

^--how'd your diffuser come out?

Havent finished yet, bc i was trying to catch up in school.
Mine is going to be made out of fiber glass, and cover from the gas tank to the bumper.

[xantonin]

As long as none of these are as ugly as the Scion FR-S diffuser.

[2KGTrd]

mine will look very similar to this.

http://i48.tinypic.com/23s9po4.jpg

[KageRyu7]

^-waiting very patiently for yours to be finished. That's aesthetically what I want.

[zzt231 gr]

mine will look very similar to this.

http://i48.tinypic.com/23s9po4.jpg

Looks very cool!!

[2KGTrd]

anybody know where i can get a couple gallons of resin cheap?

[xantonin]

anybody know where i can get a couple gallons of resin cheap?

Ask your local car audio shop. Preferable one that does custom fabrication work.

[bman365]

Boat supply places, home depot, lowes, paint stores.

I really doubt it will be cheap. The only way to get it cheap is to buy it by the 5 gallons like I do, but I know someone that can get it cheap.

In the stores, it runs about $50 a gallon. I can get it at $90 for 5 gallons.

[TRlPPlN]

any updates :(

[Darksyde]

yes yes...any updates!!!

[Joey03_VVT-I]

:eatpop:-Any updates?

[EMSRacerCeli03]

i re did mine with aluminum but i broke my car so i hadnt had a chance to get it on yet but i refinished mine with a more pronounced angle so the efficency of my diffuser would go up.

[zzt231 gr]

but i broke my car???