When I was swapping my bumpers I was thinking about how the rear bumper is formed, and how it is concave towards the air from under the car. By having it concave like this it would restrict airflow and slow the car down. Has anyone ever made an insert or something that will fit in the bottom of the rear bumper and direct the air under the car, versus having it act more like a parachute and create more drag? And if so, was anything gained. Thanks.

sorry, i replied but i was mistaken

There are cut-out inserts that you can place into your rear bumper that will act like a diffuser and remove most of the air trapped inside the bumper cover. It's not really all that attractive, but it's effective.

If you get a chance, take a look at the back of the CNNP Racing Neon. It's got what I'm describing on the rear bumper cover.

I don't think that our cars are so aerodynamic that the rear bumper is causing much more excessive drag anyways. Unless you are constantly going 125+, I honestly don't think it would make a difference. For civics, they have those metal cutouts you can put in the rear bumper.

Another thing.. most eclipse are so low to the ground (even stock) that VERY little air actually travels under the car.

yeah damn eclipse so low but doesn't look low grrr... Yeah I wouldn't worry about the rear bumper dragging as much as the front hehe. I wonder which is more aerodynamic the 95 or the 97+ hehe, probably the 95 but you'll probably get more downforce off of the 97+. Want less drag haha get rid of that spoiler and yeah add a diffuser, but like they said 120+ hehe... well maybe 100+

HAHA.. nice Hades. the 'spoiler' on the back of zx2's is for arodynamics and not for downforce :) so I guess it's a diffuser or whatever ya wanna call it.