Skid Plate for My Bimmer

[brianpgriset]

I posted this up on a BMW forums but thought I would share here:

So I had a run-in with a peice of large road debris on the highway and ripped the corner of my oil pan. Engine was fine, but after the tow and three weeks to collect parts and replace the pan I never wanted to do that again. So I had some steel laying around and decided to fab up a skid plate.

Original plan was to use round tube crossbar tying into the frame rails:

Unfortunatly I was out of round tube and only had square, but I figured I'd go ahead and try to hot bend to the radius I wanted:

It didn't work and buckled as I expected:

No worries, just had to miter it. Not as pretty but still very effective:

Cut flanges from 1/4" plate, two to weld to the frame, two to weld to the cross bar:

Flanges welded and crossbar testfitted:

I decided to add another set of gussets to the frame to help absorb impact loads, so another set of flanges made. This shows how I made them up, welded nuts to the backside, then notched the frame to make the plate fit flush, then weld up.

OK, now on the plate itself, 1/8" thick steel, rough cut to shape:

Welded main crossbar to plate:

To hold the back of the plate I welded two nuts into holes in the subframe:

Gusset bars welded to main bar, and holes being drilled for air slots:

All slots cut, and a quick sand and rattle can prime:

All bolted up:

Could be the strongest e30 skidplate ever!

Still two things to do, 1. paint (color suggestions?) 2. The bolts at teh back stick down a bit more than I like, so I'm going to get some carriage bolts, slot the heads and use a flathead to tighten, the rounded heads shouldn't get caught on anything and will have a lower profile.

 

[brianpgriset]

Oh yeah almost forgot a pick of the carnage!

 

[JC23]

Yeah, them cast pans blow up real good!

Nice fab work on the plate, Brian.

 

[gatewaysysop]

Wow.

Nice carnage pic though. Do you happen to know what it was that you hit? Just curious. Must have been one hell of a mess to clean up in any case.

Kick *** skid plate though, really nice work.

 

[Stuart in MN]

Nice work! BMW had a factory skid plate for the e28 that's still available; I've never checked into it but I wouldn't be surprised if they had one for the e30 as well.

 

[tonydanzah]

that looks really nice, put the one i made for the cts to shame when i ripped out a trans line

 

[bimmertim]

I need to build a plate for my E30 too. I've been looking at a few on E30tech and R3V for ideas, but this is probably one of the better ones I've seen.

I would just steal your plans, but I have an S50 in mine, so the pan sits a little lower.

 

[pro-rallye]

Very cool, great work! I have been thinking about skids for my older Audi and this just sparked my interest again, thanks! For the rear bolts sticking down, maybe a button head allen bolt would work. Might be a little easier to deal with in the future too.

What does that thing weigh?

 

[Wideopentuning]

Nice work!

Give us some details on the car. I spy a couple mods...

 

[Nealcrenshaw]

Nice work! GIT R DONE

 

[Heathens]

Nice work. I need to climb under my car and snap some pics of mine, it has saved me several times, of course its only about a inch off the ground.

 

[Brad54]

As Pro-Rallye said, button-head allen bolts would be the way to deal with those rear bolts.

I like the design detail of the angled slots cut into it.

How much does the whole thing weight? I'm curious if the added weight affects handling at all.

I'm always trying to find a balance between strength and weight, and often think about the old racer's axiom "If you throw it up in the air and it falls to the ground, it's too heavy." Would something like 1/16 or 3/32 have worked? or would milling out one side of the box tubing and making it a stout C-channel design work? (would that even be worth the hassle?)

I love that you took the time to add those slots--really makes it look like a professionally built piece, rather than something someone just threw together. And that's a helluva C-clamp in that picture too!

-Brad

 

[tonydanzah]

As Pro-Rallye said, button-head allen bolts would be the way to deal with those rear bolts.

I like the design detail of the angled slots cut into it.

How much does the whole thing weight? I'm curious if the added weight affects handling at all.

I'm always trying to find a balance between strength and weight, and often think about the old racer's axiom "If you throw it up in the air and it falls to the ground, it's too heavy." Would something like 1/16 or 3/32 have worked? or would milling out one side of the box tubing and making it a stout C-channel design work? (would that even be worth the hassle?)

I love that you took the time to add those slots--really makes it look like a professionally built piece, rather than something someone just threw together. And that's a helluva C-clamp in that picture too!

-Brad

i bet the car handles slightly better now since he added a chassis brace. I would also bet adding that little bit of weight doesn't affect anything, plus it is designed to protect the oil pan.

 

[brianpgriset]

The total weight isn't too bad, maybe 12 to 15 lbs. In my case, the added weight is well worth the benefit. The car isn't a track car or anything, just a toy. I could have used thinner plate, but any thinner and I would've been concerned about it's strength.

The slots took forever but in the end I think well worth it.

The car ins't anything to special (yet). An '89 325i. A few suspension mods, shocks, springs, sways, endlinks, wheels and tires. Stock motor, but before I put the new oil pan on I had a local shop weld on an oil return bung for an upcoming turbo project.

 

[Sick Puppy]

Nice work - just curious, but are OEM sump guards not available for E30's in the states?

 

[mtkst19]

i dig it. If you plan on smacking a lot of stuff, elongate the mounting holes to make it easier to attach the skid plate after you hit stuff. i have cars where the skid plates did their job, but the frame rails or rad supports are so bent up that it is a ***** to get any hole to line up. A little elongation w/ the die grinder goes a long ways. especially if you are in a hurry to remove and reinstall the skid plate between heats/rounds/stages.

 

[DMessin]

Really nice fab work, and I also am a big fan of those E30s!

 

[brianpgriset]

Nice work - just curious, but are OEM sump guards not available for E30's in the states?

They did not come stock on the US spec e30's as far as I know. In addition, they were not terribly robust.

 

[bimmer1980]

nice work! That's an idea I may have to steal for my '87 325is....

 

[bimmertim]

The OEM BMW skid plates are super robust, they just hang really low.

I have a buddy that has the oem one and he has hit some pretty gnarly stuff without issue, but he would hit less stuff if his plate sat closer to the pan like the one you made.

 

[rick carpenter]

Re: Still two things to do, 1. paint (color suggestions?)

Flames!

 

[eborcim]

nice skid guard...now you have something else to offer up to the gods of speed.

 

[montecarlo31]

Didn't see but I'd take a piece of 1" round pipe and cut it about 1/2" or 1/4? and weld it around the bolt so that the rear mounting bolt doesn't shear or damage in the event of another impact.

 

[bchee]

Now that you built it you will probably never run over anything again

 

[tjmonsen5]

E30 owner here as well! Nice job on the skid plate!!
Did it seem too involved to bolt it to the subframe bolts? I wouldnt mind paying for a skidplate if it didnt involve welding my frame rails and subframe. (I dont own a welder)