I Want to Build a Go Fast RC !

[DCastaneda]

Diffusers in the traditional sense may have negligible effect on our little cars but some slightly unorthodox diffuser designs will create a significant difference. You're basically trying to make a relatively flat front end and streamlined rear. A teardrop shape or airfoil of sorts but for ground effect. That combined with some vertical stabs and you're set. This is all very unnecessary to only hit 100mph but to go beyond this point they may be needed or atleast aid in maximizing speed with the power available.

[zeropointbug]

PBO, that's exactly what I'm talking about in the picture, nice streamlined, with channels to hold the low pressure and reduce eddy's. The openings are also something I had in mind, was looking for the term Venturi's, which makes alot of sense.

[SunnyHouTX]

Originally Posted by zeropointbug

... hold the low pressure...

^^^ Very key. Holding the sides of the body steady and not flapping around plays a big part here as well. Actually, something to keep the sides from being sucked in is all that's needed sometimes.