ok have you ever been drivein down the highway and looked at the back of a GP and watched the bumper kinda shake... like the sides of the bumper?
im thinking the back bumper is cathing a ton of air the way it wraps down and back around liek it does?!
that would be a ton of drag on a car thats racing
now i just gotta figure out a way to fix that

Try getting a piece of plastic to go from the gas tank to the contour of the rear bumper. That should force the turbulence out of the bumper and back down onto the street. Problem: Will that force the vehicle into needing more downforce in the rear? How are you going to get that downforce without needing a shopping cart wing?

oh! and how to handle the heat from your exh. If not taken care of, you will melt your "skidplate".

i just gotta make sure the exaust dosent melt w/e i use...
i was thinking cutting flaps out and putting them on hinges so when the air pressure builds up they blow open as much as they need to and bam no resistace

hmmmmm, louvered bumpers? that WOULD be kinda cool, if you can keep a clean look.

The rear downforce is called "torque". I don't think you'll be going fast enough to notice a huge difference, just like a spoiler.

This idea has been beat up on clubgp.

The bounce you see is broken struts.

The rear bumper is not the parachute you think it is.

A guy (John C) made this already. It didn't net him any gains

does anyone have a link?.....i dont go to club gp like at all so i wouldent know where to look...

Might sound stupid and obviously it's winter... but next year why don't you run it down the track bumperless and compare that time with a run while the bumper is on and just see if you net any gains before putting all the work in a possible meaningless mod and wasting money.

...just a thought!

u totaly just hit the nail on the head! great idea

I won't say it......... but I can't help myself, DURRRRR! LOL j/p man!

well, i know its not the bumper of choice, but i think a se bumper would reduce the supposed drag, wouldnt it?

maybe you should plate everything on the bottom of the car too so its smooth on the bottom lol jpjp

You can't just smooth it all out. You need to take downforce into consideration. If it was smooth flat you could end up creating lift instead of downforce. Race cars like F1, CART, Lemans etc are designed to induce downforce by channelling air not just "smoothing" it out.

The pressure differential in the bumper cover compared to the air flowing past it creates a "bubble" that deflects the air down.

If it produced the amount of aero drag you think it creates GM woulda never designed it that way because of the fact it would hurt the MPGs killing there CAFE numbers.

Some guy ran his down the track bumperless, netted ~0 gains!
Its all on clubgp.