has anyone tryed and tested putting air holes in rear bumper to create less drag, if so is it worth doing. Currently stock rear bumper on eg6

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Weel &raquo;</TD></TR><TR><TD CLASS="quote">has anyone tryed and tested putting air holes in rear bumper to create less drag, if so is it worth doing. Currently stock rear bumper on eg6</TD></TR></TABLE>

Yes, it works.

 

works enough to warrant putting them in, track road race only car.

 

i know this sounds stupid but whats the best way to make them

 

circular hole saw

 

It is definitely effective. Removing the lower-most half of the rear bumper is also effective. Only thing to be aware of, if you're building the car for competition, only H1 allows modification to the rear bumper. If you're just HPDEing, go for it.

 

how does cutting the bottom half compare to adding an underside panel to fill in that area?

 

Johnny Mac or some other aero engineer type would be the one to tell you. I think the bumper cutting thing is just to reduce the "parachute" effect, whereas a diffuser/panel would be doing that in addition to some other things.

 

yeah, my racing rules allow modding the bumper. Just asked as it does look pretty ugly cutting up the bumper

 

The other theory i have heard regarding cutting the holes in the rear bumper is to create more turbulant air coming off the rear of the car to reduce the following cars ability to get a good draft.

 

I'll let you know next year

My H1 legal (H2 illegal) bumper will be off the car and the non modified bumper will go on for 2020... its only a lower half bumper trim BUT i don't think its given me any real advantage. I still have a 1-2mph deficit just prior to the braking zone on all the other cars... the very top of 5th I fall back a smidge. (to be fixed on the dyno next weekend)