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Discussion Starter · #1 ·
I am getting ready to make some sort of skid plate and I have questions of course. First off what should I be making this out of? I was thinking of doing steel because I figured it would be easier for me to cut weld etc. What sort of thickness should I be looking at in steel or alum if I decide to use alum. I was thinking of making the skid plate long enough to protect the whole underside of the car cause I figured it would be easier than making two seperate plates one for the engine/trans and one for the gas tank. So I would really appreciate all of your advise and help.

Thanks
 

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>I am getting ready to make some sort of skid plate and I
>have questions of course. First off what should I be making
>this out of? I was thinking of doing steel because I figured
>it would be easier for me to cut weld etc. What sort of
>thickness should I be looking at in steel or alum if I
>decide to use alum. I was thinking of making the skid plate
>long enough to protect the whole underside of the car cause
>I figured it would be easier than making two seperate plates
>one for the engine/trans and one for the gas tank. So I
>would really appreciate all of your advise and help.
>
>Thanks

John V can give the long explaination.

I personally like aluminum. Start at the front bumper with a front bend (so it won't catch, but slide over stuff) to just where my feet are (rocks cut the feet if you don't), then 3/8 plastic to the gas tank where I then had 1/2 inch plastic to cover the tank.

I've had steel in the front. It tends to be heavy, but you can run over pretty much anything the 4wd's put in your way.
 

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I had problems with the engine overheating. I made up 2 guards using leaf springs and then welding steel plates to the springs. This design allowed better circulation, drained better and didn`t collect as much dirt or mud.

I also have used fiberglass , aluminum and carbonfibre. But for the price the leaf type underguards can`t be beat. And considering that I am the second stingiest man in the world ( John V. claims the honor of being first).

Robert VanLane
 

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I'd use aluminum, 3/16" thick. Some will say thicker. If steel, keep it to 1/8" thick; thicker will be grossly heavy.

Make this is in multiple sections; a one piece thing will be soooo hard and heavy to remove and replace at a service. And, It WILL get bent and distorted, and if you have to pull it off, getting it to fit on the car again in the heat of battle will be heck.

Any framework to support this is the most critical part of the design in my opinion. RVL's suggestion is unique! If you use tubing, I'd suggest 0.060 to 0.090 wall, 1" OD tubing.

Use something thinner in the back, and forget any framework back there; this potion is for rock protection, not major smash protection. (One possible placew to really protect: a rear diff housing.) Just screw/bolts it to the car with largish washers. The only expcetion is around the gas tank; you might want this so you can drop it down partially to clean out rocks that get caught between the shield and tank; a sharp rock wedged between will punture the tank if you smack down on it.

My advice, worth every penny of the price paid!
Mark B.
 

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Garrett, first remember its properly call a sump guard, thats what REALLY needs protecting. And to a slightly lesser, only slightly now, the gearbox.
SECOND steel, in and of itself, isn't ALWAYS stronger then Aluminum, all depends on the alloy, see the note about spring steel. Aluminum is always about 1/3 the weight, which means you can go three times thicker of an alloy ALMOST as strong or tough as steel for the same weight and thereby be in total stronger.
Its the idea in aluminum wheels: strength and durability WITHOUT a PENALTY, cause they are often about the same weight as steel.


Note that the idea of a spring steel strip added to a aluminum sump guard is old as the hills, Saab sold one in the 60s for Gp1 and another for Gp2.

You needn't weld anything, you can always think about a design and figure a way to bolt it together.

And as seen from Subie-Gals photo, the leading edge must have support.
And anything longer than about 18" ought to get a traverse support or the plate will just deflect upward and bash stuff anyway.
So better short and stiff and well supported than some wacky floppy thing.

Remember it's supposed to be protecting things from flying rocks and minor boo-boos not making it so your car is INDESTRUCTABLE.

And it should never get in the way of servicing suspension, the thing you are likely to tweak in a minor off.














John Vanlandingham
 

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Garrett,

If you are running events in California, you had better
run a thicker/stronger/larger skid plate than the cars
back east would use.

My skid plate is overkill (5/8" thick steel), weighs a
ton, but gets surprisingly bent-up during eventw with
few waterbars. If you run CRS, you had better think
stout.

Patrick
 

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Sweet Holy Jose, 5/8" steel. How big is that thing. 5/8" steel weighs 26lbs per square foot.

Man, I thought my 3/8" 6061-T6 plate was heavy.
 

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Skid Plate Pics ...

Displayed here is 70 pounds of the StudBug's girth, the repaired Guy Light-built sump protection system that doubles as the light bar mount.

http://www.realautosport.com/pics/SPlate2s.JPG

The mangled alloy on the left is the legacy of bouncing 3000+ pounds of rally car off an immovable upper peninsula boulder at 50mph.

http://www.realautosport.com/pics/SPlate3s.JPG

And a close-up of the point of impact.

http://www.realautosport.com/pics/SPlate4s.JPG

Notice there is NOT a lot of bracing of the uprights. Better for them to absorb some energy twisting and deforming a little.

http://www.realautosport.com/pics/SPlate6s.JPG

Two bolts connect it to the front bumper, six nut/bolts connect angle iron atop the uprights to a brace welded to the 'frame' of the Bug while the rearmost plate bolts to pads welded, drilled and tapped on the front crossmember.

http://www.realautosport.com/pics/SPlate8s.JPG

Call me old-fashioned but that's 70 pounds worth hauling around, so far as I'm concerned.

http://www.realautosport.com/pics/SPlate9s.JPG

Hate to say it, but had we been outfitted with Jamie's plate I'm sure our rally would have ended on LSPR's SS8.

http://www.realautosport.com/pics/Beetle/LSPR/brockway.jpg

We won Saturday's final stages in class with no rear suspension to speak of and the left front corner of the car mangled to hell. Something that could not have happened had the skid plate not absorbed/deflected the biggest part of the shunt the night before.

http://www.realautosport.com/video_clips/lspr2001/mm-stage8-rock.rm

See the hit that just about parked the car on Dillon's door.

Halley ...
http://www.realautosport.com
 

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RE: Skid Plate Pics ...

http://imagehost.auctionwatch.com/bin/viewimage.x/00000000/dellis44/skidbrace.jpg

http://imagehost.auctionwatch.com/bin/imageserver.x/00000000/dellis44/.mids/skidbrace.jpg

" ALT="Image Hosting by auctionwatch.com" ><font size=1>
Click image to view larger version</font></A></center>


<center><font face="Arial, Helvetica, sans-serif" color="#000000" size="2">Low cost image hosting and full service auction management solutions: AuctionWatch</font></center>

http://www.auctionwatch.com/images/cleardot.gif

since you are looking for ideas, this is the skid plat brace that was on my car (VW Rabbit) when I got it. I think it has survived something like 9 rim-of-the-world rallies, anyway it is a tubular brace that bolts to the lower part of the front bumper, then to tabs welded below the accordian "bumper crumple zones" on the body where the bumper "shocks" fit in the body. then at the rear, its located to the large bolts that hold on the front suspension A arms. There are 10 tabs welded to the brace where the fasteners go to attach a 3/16 inch thick aluminum skid plate to the frame. the front lip of the aluminum is just about right under the front bumper, then agles back to about parallel with the ground after the first support bar. Dennis Chizma gets credit for the design and building of it . (someone correct me if I'm wrong) I welded on the forward tow hook tab on, it would be on the passenger side of the car.

hth
David E.
 

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RE: Skid Plate Pics ...

That ricochet blew the light bar off the car and ripped one hood latch out of the body, so we taped the hood to make sure it stayed put. The fangs were something we added when we had burn time after Brockway 1 was cancelled.

Halley ...
http://www.realautosport.com
 

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RE: Skid Plate Pics ...

I can attest to the durability of the StudBug's plate...I had sweep pick up what was left of the light bar, and then returned it to MM later that night. Trust me, about the only thing left on that bar was an HID ballast that was nowhere near the rock, and the bar itself looked like something left over after a building demolition. If it wasn't for the plate, MM could have kissed a championship season podium finish goodbye. That plate may look lightweight, but it's hell for strong.

Now that you've convinced 'em, Mike, might I suggest you refrain from further testing of that particular component? Just a thought...
 

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RE: Skid Plate Pics ...

>Are you sure Guy built this? It looks a bit on the
>lightweight side for his work ............:)

Oh yeah. I've tuned up a thing or three on the car (Aeroquip fuel lines, a mechanical way to drive the odo, replaced those awful Recaros, etc) but the Bug is bumper-to-bumper Light-built. The obviously flimsy skid plate system ;) says a lot about just how structurally solid the basic VW New Beetle is. Those 'strength of the arch' TV ads ain't just whistlin' Dixie and thanks to my experience with the non-seam-welded StudBug I can already tell you what model car I plan for my daughters to begin driving in.

When they're 16.

If I live through their puberties.

Halley ...
http://www.realautosport.com
 

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Discussion Starter · #15 ·
RE: Skid Plate Pics ...

Whoa! I went to order some aluminum today and a 4ftx4ftx3/8 plate cost 250$ weighing in at 90lbs?!?!? The same sized plate in steel cost 134 and supposedly weighs 270lbs? Could this be right? Anyone know of a place in Norcal or online where you can get cheaper prices?
 

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RE: Skid Plate Pics ...

>Whoa! I went to order some aluminum today and a 4ftx4ftx3/8
>plate cost 250$ weighing in at 90lbs?!?!? The same sized
>plate in steel cost 134 and supposedly weighs 270lbs? Could
>this be right? Anyone know of a place in Norcal or online
>where you can get cheaper prices?

whoa dude indeed-arood, dood. According to my handy Materials catalog right here, yeah see it, this one, uh huh, see it says 3/8" right here weighs 5.18 lbs per sq/Ft..16 sq/ft weighs 82.88 lbs, and your price comes in at around $3.00 lb.

That is typical retail price for 6061 dood. look for scrap places, or ask if they have rems or remnants. prices hover around 1.85 to 2 bucks a lb at the joints I know here.

for your planning purposes you may want to note that 1/4 comes in at 3.46 lbs/sq ft, and 5/16 is 4.33 lbs/sq ft.

Think about your design.
why so wide?
why so thick?

3'x 4' in 1/4 would weigh 41.5 lbz and cost $115.
3' x 4' in 5/16 would weigh 52 lbs and cost $144.

1/4" ought to do if there is some support in the middle of the plate, ford has tradionally used a support like a upside down T with little parts welded on to make it like an upside down Y, and this spans crosswise the plate and locates, but is not bolted to the chassi rails..
Light and strong by design, not by simple heftiness.

remember, sump guard, protect the oil pan! And maybe a bit of the trans if it's hanging down..

back to the garage! Make a template in cardboard, look hard. think and trust your eyes.
















John Vanlandingham
 

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Discussion Starter · #18 ·
RE: Skid Plate Pics ...

Ok. Im working on my skidplate and I have a question because im worried about it being overkill :) I used some 3/16 angle iron to make some brackets to attach a squaretube frame which is 1 1/2 inch and then attach 3/16 - 1/4 aluminum plate to that.. So overall I lose almost 2 inches of ground clearence. I still have about 5 inches of ground clearence what I am worried about is the plate being to low and hitting rocks causing me to do some two wheel motion like the stud bug in that clip.. Am I going to be ok with this or should I be worried?

Thanks
 
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