Subaru guys (if there are any here.....)

Hola, What are you guys mounting your rear underbody protection onto and how much of the suspension are you covering? Are you using heavy duty zip ties to attach the trailing end?

I'm designing some soon and need some help. I saw some guys I know just drilled holes into the rear footwells and mounted it that way, but with the flimsy sheetmetal there I'd be afraid of ripping a big ass hole in the car.

Thanks in advance guys

Eli

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Here's how I do it. I weld half inch square tubing to the pinch welded flange along the bottom of the rockers. The square tubing goes along the entire length of the rocker. That reinforces the pinch weld for one, which can otherwise get smashed flat. It also gives you something to attatch the underbody plastic to. I use 3/16" wide head steel rivets (buy an air rivet gun, you'll thank me later) to attatch the plastic. Cover the floor with two sheets of 3/16" thick UHMW, one on each side of the tunnel. 4 or 5 foot by about 2 foot sheets. Pop rivet them to the floor and the square tubing. Trim as necessary to clear exhaust, crossmember access, etc. Make sure the leading edge is well attatched otherwise it will catch and fold over. If necessary, seal gaps at leading edge with a little expanding foam to keep rocks and mud out. You only need to run those panels back as far as the gas tank (where the rear footwell stops) and overlap the gas tank skidplate a little. You also need plastic panels protecting the rear trailing arms or the rocks will wear away at the bushing housing in the rear upright as well as the end of the trailing arm, lateral arms, crossmember, etc. Make a piece of UHMW that spans the length of the trailing arm all the way to end a little past the lower bushing. This piece of plastic will go inside the wheel a bit and make sure you cut it so it spans the gap between the tire and the trailing arm. You will have to do some motching for tire clearance here. This will keep rocks from flying up and hitting the struts. Especially important if you are running DMS struts because the adjusters are especially susceptible to that. Rivet those plastic pieces to the trailing arms like you did the floor protection. You can have that piece overlap the gas tank a little as well.

right now I have my 2x4' uhmw-pe panels held up with sheet metal screws....OK for rallyX, won't hold up for stage rally, so I know I need to upgrade mounting points/hardware.


I was going to use bolts like Eli mentioned, but rivets.....hmmm.



so you can just drill the hole and rivet it right to the car floor, eh?

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Jon Burke - KI6LSW
Blog: http://psgrallywrx.blogspot.com/

Thanks Dave, appreciate the help.

Eli

Dave, what size pop rivets do you recommend? I am very new to this so please excuse the dumb question.

Also, when you weld the square tubing to the rockers, will the stock side skirt still attach or do I trash it? I've been looking for an excuse to trash them anyway....

Pikshurs?

I just drilled 1/2" holes into the footwell as close to the part that goes up to the rear seat as possible and put the largest possible washers onto them. I also threw in a few rivets, zip ties on the trailing arms and finally zip ties on the later links. The codrivers side liked to break the zip tie every stage, so we replaced that one with a stainless steel tie and it's fine now. The overlap from the front sheets is about 3 inches, so the bolt heads are well shielded. Everything else is almost exactly the way Dave described it and it works great.

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I like open light.

gilbrock Wrote:
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> Dave, what size pop rivets do you recommend? I am
> very new to this so please excuse the dumb
> question.

3/16" like I said above. Use steel, aluminum wears away too easily.

>
> Also, when you weld the square tubing to the
> rockers, will the stock side skirt still attach or
> do I trash it? I've been looking for an excuse to
> trash them anyway....
>
>

The square tubing is welded to the inside of the pinch weld so it does not interfere with the skirts. If you want you can let a few inches of plastic hang past the square tubing to protect the side skirts as the rocks will wear them away eventually. You can also ditch the side skirts and and bend the UHMW up around the rocker (a heat gun is helpful) and pop rivet the plastic right to the rock just below the door opening. Helps protect the rocker if you like that kind of look.

eyesoreracing Wrote:
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> Pikshurs?


I don't have any pics, sorry.

Jon Burke Wrote:
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> right now I have my 2x4' uhmw-pe panels held up
> with sheet metal screws....OK for rallyX, won't
> hold up for stage rally, so I know I need to
> upgrade mounting points/hardware.
>

Sheet metal screws have no business being anywhere in a race car, period.

>
> I was going to use bolts like Eli mentioned, but
> rivets.....hmmm.
>
>
>
> so you can just drill the hole and rivet it right
> to the car floor, eh?

Yes.

I'm still new....sorry.

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Jon Burke - KI6LSW
Blog: http://psgrallywrx.blogspot.com/

I weld in 10mm weld nuts into the floor and attach the plastic using stainless steel cap screws (button head). If you don't want to weld, use a air rivnut gun. I'm sure there's a picture somewhere of the underside of my old car.....

Hey Andy, congrats on the victorious debut. Got any glory stories for us?

-Dave

Dang Doivi!

that square stock reinforcement trick is some golden info. I went over to the steel yard amd bought a stick of that stuff right away. Thanks for sharing.

-Al

Nothing too glorious dave. The car had lots of little issues like a water temp of 297...obviously the sensor was off or there was a nasty steam pocket. Since there was no water spitting out of the thing I just continued to flog it...just gambled the motor...nothing major!!

We got a flat and popped a tire off the bead on stage one…then the jack broke as we tried to change the flat…I guess I should have practiced a tire change prior to the first stage!

Besides that the car ran good…it’s pretty damn fast. I had no idea which diff map I was using so hopefully the center diff wasn’t completely open and got burnt out. The fancy controller is stuck in UK customs right now on its way back to Gems for some new maps and health check-up. Hopefully we get it back in time for Idaho!

Did I mention how fast the car was?

Lots of little things to sort out still…launch control…fuel level gauge…coralba…etc etc…..

Hurry up already with that mazdog! I better start my ae86 corolla build soon so we can battle in G2…..

Andrew