I plan at some point to go back to school. When I do – it will probably be for an engineering degree. Electrical, mechanical, or technical. I figure this degree will be fairly easy to obtain after building and racing a car in one of the toughest motorsports on the planet. I know it will break, but I’m not sure why. Changing: “That’s gonna’ break…” to something like: “Based on the stress load to the cross member, that’s gonna’ break and smash up those bits there…” So much more technical.

I’m in the midst of designing underbody protection for the Neon. Skidplates are an essential crucial part of a good rallycar. Now I actually have some experience in this area. I designed and sold some for the Impreza. The first mistake in designing a skidplate is making it indestructible.

Modern cars get pretty destroyed in accidents these days. Just a 20MPH hit to the front end with crumple the nose of a car. This is done on purpose to absorb the impact of a crash. Skidplates are there to absorb and deflect the impact of rocks and terrain on a car. So taking a giant (3/4″ thick) steel plate and bolting it directly to the front end will take the impact of a giant rock on the road – and force it directly into the chassis. Bending frame goodness.

Take a thinner / lighter aluminum plate. Bolt it to a tubular steel frame and position it 2″ away from the front end you are trying to protect. Now – upon impacting the “giant rock”; The plate has a huge gouge in it, the left part of the steel tubes are crushed, and the plate is now warped and un-repairable. The unibody front end that it was tied to has survived with minimal damage. That’s the idea at least.

An aluminum 3/16″ thick front plate. Tied to spring steel supports that cover most of the front end back to the firewall. A 1/8″ thick aluminum plate from the firewall back to the front seat floor pans. This will be supported by boxed tubing sections bolted to the side sills. From there on I will use plastic. Yes. Plastics do make it possible.

Okay kids, open your engineering notebooks, and take this down. High-Density Polyethylene (HDPE) & Ultra-High Molecular Weight Polyethylene (UHMW). You know that plastic that they make cutting boards out of? Well, it does a good job of keeping sharp rocks out of your gas tank. Great impact resistance, good operating temperature range, and it’s cheap. Like $30 for a 4′ X 4′ sheet of the stuff.

So now I’m making a list of parts and materials I’ll need to buy. I’m sure cutting, sanding, bending, and bolting will be in order. I’m also sure this won’t be the last set of skidplates I build.

Works cited: McMaster-Carr, plastics. McMaster-Carr, Plastic Material Comparisons. Machinist-Materials, Plastics Comparison Table Online Metal, plastics. Special thanks to the guys over at SpecialStage.com for providing the following answer to: “Skidplate Plastic?”