since i was getting frustrated by my stock plastic under panel getting damaged all the time (last time it got nearly ripped off at the track) i decided to make a complete flat panel (not really a diffuser, until i add side channels.. ) and to seal off the underside of the car.

Technosquare suggested that i use a material that i would say is pretty much corrugated aluminum, brand name is called ALUMALITE... its two sandwiched pieces of aluminum with plastic coring for strength. its very light weight (practically the same weight as the plastic undertray that i am replacing) and quite stiff. i think its proper use was sheeting/roofing (?)..

EDITED Aug 22: Alumalite (variation in spelling: Alumilite .. not aluminite like i had previously stated..) is the material name..

get it at:
http://www.montroy.com/


sorta like this:
http://www.rhino-graphics.com/signs/alumilite.html

i got a template out of cardboard and just traced it out, did some measurements underneath the my front bumper and a few pop rivets and rivet nuts later, i got the undertray- nearly level when its installed on the car, and hopefully will create some useful air channeling underneath the car at speed. i made a U channel out of some scrap aluminum lying around at Technosquare, and attached it to the radiator frame for bracing and to reduce vibrations.. this panel sits within 5mm of the front sway bar...

A huge sheet of Alumalite is like $120, which can make two full size undertrays, or even a splitter..so basically this one was $60. using a portable jig-saw and a file is used to cut it.

take a look: comments suggestions welcomed.. and no i did not paint it, once you take off the protective plastic covering, it is gloss black. these are my camera phone picts..

 

Nice. I'm looking at making these in my shop. Where did you buy the Alumilite sheets at? I was looking for something that would be light weight and stiff enough, just like you described.

 

how much dose it weight ? and is there's a noticble difference before and after in handling or on high speed !

 

also with this wouldn't your engine get higher temp since there is no vents on your sheet !!

 

How are you going to change your oil?

Are you guys going to make a little door for oil filter? Or remove the entire under tray everytime you have to change your oil

 

our stock under tray is very sturdy compared to a lot of other cars. only people i see benefiting from this is people with front body kits.

 

I already remove my entire stock underpanel to change my oil/filter.

 

same here ^^ last time i had it changed the lazy bastids at the place spilt a ton of oil on top it and it dripped all over my garage. I was pissed.

Cool piece though looks great.

 

Nice mate im looking into this too. ARC one is just too much $$$$

 

cool. i did the same XD
mine cost 30 dollars and is made out of mid grade ABS plastic. i hate that factory plastic piece! mine gets ripped off in the front too.

 

thanks for the comments.

as for the engine temp comment, i think it would be the same (i've been monitoring it before and after)

since this actually has so side enclosures air can still exit from the sides... as far as oil and water temp, i have an aftermarket oil cooler vented, as well as an ARC-built radiator, and vented hood design to extract upwards. the stock plastic undertray is more 'sealed' than this... we'll find out about track worthiness this weekend... updates with temps then


as for the oil change comment- i have an aftermarket oil pan that came with the turbo kit, i have to remove the undertray anyway, plus it makes the job a whole lot easier-

 

The stock under tray has grooves on it to channel air in a specific direction. I'm not sure how useful this would be when tracking or drag racing the car. I always wondered similar for the ARC piece (if it actually did anything or if it was all for show). If you're extremely serious about the aerodynamics of the car and want the most out of your car, 99% of the aftermarket parts are useless, it seems.

Good looking piece though. Maybe you could provide a template for those who want to make this themselves.

 

Ditto, I couldn't imagine NOT removing it during an oil change. What a mess that would be...

I'm very surprised ARC is still the only company making these (and the cost of that piece is so ). If a company could get one of these out that is well engineered for 100-150 they would still be making 1/2 profit.

 

Good Job!!!!!
No more ripping of the underpanel at 110+
Im not sure about aero properties as far as helping but i dont see how it could hurt either
only rec i would have is to cut some angle strips like ARC

 

cool man really great design I would be interested in a template as well

 

subscribed.

 

as far as air channeling to cooling off specific engine parts, its not a complete seal, such as the stock undertray and/or ARC piece. you can see from the side view that there is some gap, as air flows underneath the car, it'll vent out toward the sides.

most 'diffusers' that are out of this car have a complete seal, and /or higher sides to create a channel, they do not have any vents.. toward the middle.

i really dont believe the ARC piece does much of anything except protect the underside from rocks and look pretty..

 

I'm disappointed, Cheston.

 

 

Not sure I understand either, can you elaborate Andy?