Custom Undertrays

**scheides** · 01-03-2008

Ok, some shit flew up and smacked my motor, and I've driven over enough shyte that I'm enlisting the help of some people here to make a custom under tray for my Evo VIII. Mark (TKRPerformance) says he can cut the metal after we get the templates laid out, and he wants one for his own car (Evo3), so it seems like we can get it done together. I know hughes wants one of these for his Evo IX, so we'll prolly end up doing one for his car too. I'm thinking we'll keep the templates and help out other locals if this goes well. If it falls to shit, then let this serve as a guide on what not to do.

Ok, so first things first, what do we want? Something to cover the bottom of the motor compartment. Why? Two reasons. One: aerodynamics. Any car can benefit from an undertray, the farther it goes back, the better. All high-end sports cars have full belly-pans that cover the entire bottom of the car. Two: protection. One cool thing that I have noticed about the my evo is that it has a lot of extra protection in the form of shielding covering the oil pan, the starter, and the bottom of the tranny. This must come from years of rally experience. Still, it was not enough for my car.

Design: SIMPLE. I want this to be as simple as possible. Buschur is making some cheap ones that basically tuck under the front lip around the entire front of the car, go back to the front of the wheel wells, around the wheel wells, and all the way back past the back of the engine compartment. I want one big solid sheet, and possibly some access panels for the front tow hook and the oil filter.

Materials: several people suggested Discount Steel down on washington, I'll hit them up and see what they got.

Fasteners: I'm eyeing these DZUS/Panex fasteners as seen here and here. These are 1/4 turn quick-release aircraft quality fasteners with D-hooks on the back so you can remove it with your fingers.

I'm open to suggestions, tips, or even if anyone wants to help, let me know. I happen to have a big-ass piece of cardboard in my garage right now for the design of this thing.

turbotalon1g · 01-03-2008

I would like one for my car.

**Kracka** · 01-03-2008

I want one! I would think aluminum or plastic would be the best material since it won't retain heat and be lighter than steel.

**scheides** · 01-03-2008

someone suggested acrylic, I'm gonna see what we can get for how much. I'm thinking aluminum will be the way to go, as it won't be too spensive and will be pretty tough.

Matt D. · 01-03-2008

I just did some searching online and given the prices I think you should stick with something metal.

**JET** · 01-03-2008

Acrylic is pretty brittle, but UHMW works great. Here is a 4'x8' sheet at Grainger. Should be enough for 2 of them.

http://www.grainger.com/Grainger/items/1UWG4

They also have polypropylene much cheaper and I think it would have the flexibility, but I am not as sure.

http://www.grainger.com/Grainger/items/1YYC2

This looks like a good possibility too, but I don't know anything about it.

http://www.grainger.com/Grainger/items/1ZAT5

Matt D. · 01-04-2008

I think black or grey would be a little more appealing.

**Kracka** · 01-04-2008

I want a green one.

I was thinking a big sheet of tag-board would work great for making the template. Its cheap, easy to get, thin, and flexible.

**Halon** · 01-04-2008

I personally used some sheet aluminum on the one I built. Mine isn't a complete undertray though, it's just mainly used to trap air so that it has to go through the radiator. I don't remember the thickness, but it was pretty thin. I got it from Lowe's. Discount Steel would have been a better bet, but Lowe's was 2 minutes from my house.

polishmafia · 01-04-2008

i personally dont have a need for an undertray, but im really curious to see how this works out for you guys. good luck and keep this thread updated.

let me know if you guys need an extra hand.

**scheides** · 01-04-2008

Hughes I like the tagboard idea, any idea where we could get some big enough but cheap enough?

**Halon** · 01-04-2008

I used cardboard to make my templates. Derek used cardboard to make his as well. Worked pretty well for us.

**scheides** · 01-04-2008

The sheet I want to make is pretty big, I'm just worried the cardboard will flex a little too much. I'll give it a try.

**Kracka** · 01-04-2008

Quote:

Originally Posted by scheides

Hughes I like the tagboard idea, any idea where we could get some big enough but cheap enough?

Walmart, we can tape a few together.

**scheides** · 01-04-2008

Fuck walmart.

**Kracka** · 01-04-2008

Quote:

Originally Posted by scheides

Fuck walmart.

Fine, go to Target and spend more

**scheides** · 01-04-2008

I'm thinking we could use some 1" x 1/8" straps to fab up a piece like this. The stock undertray has a part of it like this, it bolts to the center crossmember and then hangs down a bit to offer support for the tray in the middle:

That way its not flappy in the center.

TkrPerformance · 01-04-2008

I have big pieces of cardboard here from all the parts coming on pallets all the time. just use that and some zip ties to hold it up. sense you have the stock tray still we will start with that and make it go all the way back. It will not be to hard to make them

**Goat Blower** · 01-04-2008

I've been thinking about making one for my car as well. I'll probably use 1/8" aluminum sheet with Dzus fasteners for a little extra strength. I want to keep my nose from buckling in at high speeds since I'm planning on trying a standing mile competition this year.

123abc · 01-04-2008

Will over-heating be an issue if one is implemented?