[Sven7]

Originally Posted by johnunit

Some of the people laughing at "speed holes" are showing a degree of ignorance of high-level import drag racing. There are tons of VERY fast (think 8-10 second 1/4 mile with FWD) cars out there with so called "speed holes" in the rear bumper. I'd have to imagine that it's a car-by-car thing though. Many cars would probably see losses.


GO-AUTOWORKS.COM Rear Diffusers, Splitters, Front Ends and Carbon components

from the thread below


rear bumper diffuser - 8th Generation Honda Civic Forum

another thread on the topic:

rear bumper holes? - Honda-Tech







There are certainly better solutions, but for CHEAP and within certain rules, it does have benefit.

I don't see anyone proving their theory. Everyone says air catches in the bumper because they don't know about the aero template type things. There's no way the airflow is making a 30* turn upward after the rear axle to catch on the bumper. I'll bet you they're just adding to the turbulent mess down there.

Still, if someone can find ABA or wind tunnel calibrated results I'm open to seeing them. I'm just not yet convinced by street racer logic. If it really worked wouldn't "speed holes" be in the "65+ efficiency mods" in the header of this website? Perhaps they haven't been proven to work...