Home-made Composite Diffuser

Here is my first vacuum-bagging composite project and its a diffuser for my '90 Reynard FC. I know CF is not acceptable in SCCA club racing but I am only running car in time trials and autocrosses at this time. Weight is approx 9 pounds. I built a plug or buck from 3/4" cabinet quality ply. I used two layers of 10 oz cloth on top and bottom and 1/4" foam core with cutouts for .25x1x2 alum flat stock where mounts will be located. Its quite strong and stiff so I may try building one out of 1/8" foam core with just a single layer of cloth top and bottom to get weight down a few pounds.

First photo of part pulled right off plug.
http://i75.photobucket.com/albums/i3..._151618618.jpg

I had planned to use some 'L' brackets at rear trans cover but strut rods may be all I need since it's also bolted to floor pan.
http://i75.photobucket.com/albums/i3..._223349756.jpg

Nice looking part :beer::beer::thumbsup::thumbsup:

You'll only lose a few ounces by going to a thinner core but you will lose stiffness. When you double the core thickness, stiffness increases around 7x. I suggest keeping the 1/4" core or even going to a 3/8" core, and using a single layer on the top and bottom. You could also use a lighter wood or mdf for your hard points. This should be plenty for autocross. Be sure to squeegee out as much resin as possible without making the fabric too dry.

That looks great!