it was 18 bucks at home depot. i got the biggest piece they had, i originally planned to cover the whole under of the front, i measured 31''x60'' to fit from side to side of the stock bumper and from the front of the bumper to the crossmember. i was planning on getting two pieces and riveting them together but after i did some cardboard templates i got it to work good i decided to go with the one.



and i did some runs yesterday and without the tray on the freeway with the outside temps close too 100degrees i was a steady 210deg. on the freeway. now with the undertray i barely got it to over 200deg even when i was doing fourth gear pulls. my highest recorded temp was about 203deg and that was after a couple hard pulls.


also i noticed my intake temps at a stand still had dropped from my fan fulling air through the rad and instead of it pulling air from under the car through the rad it pulls it through my fmic now and then through the rad and keeps it cooler while i am at stop lights ect.

over all i am very pleased with it, today i am going to go around with some foam strip and seal off all the nooks and crannys and see if that helps any also.

wow thats awesome, and i didnt realize a sheet that big was so cheap.. usually i see em like over 30 bucks for something that big.


http://i25.tinypic.com/2e55u7p.jpg
http://i31.tinypic.com/6fxp8n.jpg
http://i29.tinypic.com/24o8uba.jpg
http://i30.tinypic.com/ddnjhz.jpg
http://i27.tinypic.com/k0gcw6.jpg

Home Depot FTW!!!!!

i been wanting to make a diffuser for the rear of my car fow a while. the amount of air caught by the rear bumper has a HUGE effect. its like a parachute holding you back.

ever notice those holes cut in the rear bumper of civics. cheap way to release the air. but a flate surface and diffuser works much better!

lol cheap and effective yes... but fashionable or pretty??? FUCK NO lol...

yo thanks for the info. Looks like im gonna have to get more aluminum cause the piece i have ins't gonna be enough for what i plan to do.

And Sen2two, how about getting a rear diffuser from Shine Auto project?

This may have a severe results aerodynamicaly, I would first look into the theory of flat underpanels, and then do testing on a race track, before taking it out on the autobahn...

Riz.

well its a good thing i dont live near the Autobahn lol
from what ive read in car and driver, in a road race your times can drop significantly with the use of undercovers, and splitters
Buuuut, u do have to put in "NACA" ducts to releave high pressure zones

if you read thru this thread the guy does talk about the high pressure zones, i do agree, some research will go a long way
http://ziptied.com/forums/index.php?topic=7879.690

isnt it like 350 bucks? you have a link to it?

https://www.rx7club.com/shineautoproject-161/fc3s-re-amemiya-rear-diffuser-whos-562127/

.... a little googleing would go a long way

^^thanks for that.

yeah, but do you think 350-450 plus 100 shipping is worth that!? not me...

i priced some lexan and wood today. not sure wich one i want to use just yet. it would be just a little over 50 bucks. thats including all the mounting hardware to go with it too...

Awesome thread. Dont have a undertray and been needing to do this.

Yeah, not a very high speedlimit on the highways, huh?

Those have a specific angle aswell though.

Yeah, I've read through that a while back. Awesome threat, I read he was starting work on another car, but there wasn't a topic about that, right?

Riz.

hell around were i live now 60 is speeding lol
i def agree, if the angles are off u can create up force rather then the down force u need
it would def need testing to make sure its done right

idk i didnt see..

The angle of the spliter should be sort of a scoop. It is suppost to act like a velocity stack, speeding the air on the mid section and being released by the rear diffuser.

any followup?

its still working good, i tapped a curb parking last week and bent a little of it but it was easily fixed.