I suppose I'm in an argumentative mood. I also guess none of these guys know what they're doing...

 

And there are plenty more examples of reducing aero drag caused by the rear bumper on evos in drag racing.

 

are the diffusers on the jdm rear bumper too small to make any difference? even compared to the usdm bumper?

 

Cut bumper here, zero ragrets. Don't care how much the car will be worth in the future, resale isn't something I consider when I buy a car I plan to keep.

Drag reduction is minimal with a cut bumper, but it makes it waaay easier to crawl under the car and adjust shocks and the rear bar when at the track.

 

yeah... But ZERO cred at the next Cars N Coffee, because it looks funny.

 

Not sure why a 200 dollar plastic rear bumper chop would make someone so butt hurt compared to the hard surfaces many of us have had to cut to get big wheels and tires to work

 

Looks like the answer is cut the bumper only to run an effective splitter.
I can't use my spare tire either, so....

 

I wont disagree, but like weight reduction, drag reduction has a cumulative effect.

 

and there are plenty of this...whats your point?

 

Not one of those is a current day record holder or even competes, and aero development has come a long way.

 

Not to mention your looking at the rear bumper but cant see the rear quarters under those over fenders. Talk about cutting...

 

There are CFD studies out there that show gains are under 1%. The parachute effect isn't nearly as bad as people make it out to be.

Making rear diffusers work well takes either lots of CFD studies and/or lots of testing. Rear diffuser development should be done after a well front aero setup and rear wing are done and proven to work well. In some cases it's easy to make a car go backwards if you throw a whole ton of aero at a car all at once.

 

Never said I was against modifying the body if it was necessary to fit wider wheels or for a purpose, cutting up the rear bumper just isn't necessary. Cars I posted still look like evos, there are no exposed open cuts.

 

First of all, yes you did insinuate that cutting up an evo offended you lol. Second, all of the evos you posted have after market or modified body panels with cut outs to decrease drag and lift. 3rd of all, the advantage of doing so is not solely about drag. There is some weight reduction in removing the spare tire well, and in collaboration with an effective diffuser you can increase downforce. And as Austin pointed out you can access the rear suspension without jacking up the car.

 

You guys:




LOL