The Holes!
 

Ok so I'm going to lay this out. I have been researching this for awhile, and really only found one individual that did some testing on the performance end of this. So I decided since my rear bumper was trashed, and I could clean it up with a kit I got from ASP. I know a lot of you are going to say that this is silly and it doesn't work. I do have some graphs to post with this, and I'm currently testing what it will do MPG wise. If it does nothing that is fine because the bumper had a lot going on with it in the bad department.

Ok about the back of a 2002 Honda Civic Si with the bumper removed. It is shaped very odd with respect the way the body allows air to get into the rear bumper. With the holes I cut you can see where air will now leave the underbody and escape straight through the holes. Instead of hitting the bumper and then spilling out.

Ok onto these graphs Green is the run with a bumper with holes in it, and Blue is a bumper without holes. The car was ran up to 112mph(180KPH) which is not far off from what some people get for the north west states. 80MPH being a norm around here. The breakout for speed gained faster doesn't happen until around 66mph. But from an acceleration stand point could mean a lot on the highway if you need to boot scoot and boogie.

Acceleration Graph
https://scontent.fsjc1-3.fna.fbcdn.n...ec&oe=5866B355

Speed Graph
https://scontent.fsjc1-3.fna.fbcdn.n...32&oe=58709AFF


Now i'm not condoning high speeds on the highway, but I will say since doing the holes I have noticed a smoother ride at highway speeds, and a quicker get up getting there. I'm just now waiting to see what happens in the tank department. I had around 125 miles of all highway driving on the tank already when I did the install. This was the round trip plus some to go get the kit. So if I get extra out of this tank after the install it won't be from the highway driving. I drove the car to Montana and got only around 26-28 MPG but I wasn't taking my time either so I choke that up to no good data. But the past two tanks of just city driving has been 28.9 MPG.

So I will leave you with what it looks like and will keep you updated. I got it let the skeptics begin their commentary.

https://scontent.fsjc1-3.fna.fbcdn.n...3a&oe=587CE494
https://scontent.fsjc1-3.fna.fbcdn.n...77&oe=58678A97
https://scontent.fsjc1-3.fna.fbcdn.n...72&oe=586D0DBB

Your test screenshots or that other guy's? It dates to August of 2009.

If you look at newer supercars, the whole back end is ventilated. Maybe add a hexagonal mesh to the openings?

I'd say two trails is less than ideal, but I'm highly interested in what you're doing here.

Those are not my graphs. Someone else's, but with a 3.5 second gain to 112 mph I was convinced. Right now I'm over 200 miles and still a little over half a tank. So I'm guessing I'm going to get good numbers out of this tank.

As for two runs I know I wish he had run more but that's the data he gave.

I do have a ultra gauge on order so I will be able to do my own 0-100 runs and see what I get. I'll just close the holes up and see if I get something similar.

I like how it looks, and if it actually improves your overall performance then that's wonderful. If it also helps with improved FE, then even better.

I'd be interested to see what your results turn out to be... sign me up.

A-B-A For The Win

Yes the look is very aggressive, which I like. Will look really mean When I lower it.

Just an update! I took my son to his therapy today, and like I said a little earlier I was just over half a tank. Well now I'm like a sliver under a half and I'm at 230+ miles. So I have 1/2 a tank to achieve what I have been getting the past two tank of 330. So far looking like a win, but who knows I guess the next two tanks will be the nail in the coffin.

Hoping to see the Ultra Gauge by the end of the week so I can Possibly get Runs in as well.

Consistent and reliable testing methodology is definitely going to require instrumentation. I found I wasn't able to make real lasting changes to my driving habits until I had real-time feedback.

Exactly that is why i ordered the ultra gauge. Almost the same thing as the scan gauge. Just cheaper and I like that it has the obd trouble code detection too. It's like having three things at one. Performance section, fuel stuff, and obd scan ability.

I've seen this in a couple of other places, too. I generally think the better option is to pan over the space that becomes the parachute, but that still leaves you with the big vacuum wake to fill, which this addresses. But with the pan, there's no visible modification. I guess it's a matter of what matters.