A 8' x 4' sheet of plywood is something like $30. That'll make three splitters.
A 8' x 4' sheet of aluminum is something like $100.

Wood is infinitely easier to cut and work with than aluminum, it just makes a lot of sense to go with wood over aluminum.
I have a friend who had an alumalite splitter on his car... destroyed that by taking some kerbing a bit harder than normal, albeit for faster lap times.

Aluminum and alumalite certainly looks better and can be lighter, but I'm sure most of us aren't pro racing or gifted with a ton of sponsorships

 

You'll find wooden splitters on a lot of racecars, once it scorches and the resins come to the surface it wears very well compared to aluminium for light scuffs, plenty of touring cars still run the under-bumper aero in plywoo, it can flex a long way and come back unlike ally which will bend. Composites and plastics will flex too but at the cost of more wear or more, well, cost.

 

Yup, fixed up a plywood splitter on a Honda Challenge S2000 at VIR this weekend. Plywood took a beating.

 

What I mean is that the edge of the splitter is square and flat. I was thinking about trying to round that off but dont know whether to edge it up or down I think I might try and get some thin sheets of aluminum and cut them to direct air into the brake ducts...might add a little downforce too!

 

Ah doesnt really matter IMO. I rounded mine off so it hurt less when I ran my ankle into it. Thats about it.

 

Wasn't mine, was it?

 

Nope John Oldt. I crewed for him. Did you eat with the HC crew?

 

wood ftw!!!

 

I did. Was parked right across the road

 

Stephen?