So I seen a picture of a civic that had, basically, holes in the back bumper of his or her car...now, I think that looks pretty neat but idk if it does anything at all or is it just...there.
Can someone tell me why they do it or if its suppose to do anything...it's just curiosity. I just hope I don't die.
Answers are appreciated
Thanks (:

 

I'm guessing you're talking about a rear bumper diffuser when it has holes and a metal plate around it, or sometimes they just have holes. It's supposed to be for "race cars" to reduce drag and produce better "air flow". Lol. I personally think it's funny to have it on a daily driven street car. You see it more on drag cars.

 

^^^ like he say, for air flow...

 

So why not use it on a daily, especially if you're trying to get better MPG, better airflow is better airflow, less drag, less restriction... but if you want something that helps out without cutting holes.

OEM Honda diffuser $65.00

 

it's so dumb because 9 times out of 10 the ppl ruining their bumper like that don't have the performance to make it logical...

ruining a rear bumper should be last thing on list to gain time on drag strip...

 

What he said! ***** stupid

 

pssh aint that the truth

 

Now a days they are simply taking off the rear bumper at the race track. The rest of the people are just robots, "monkey see monkey do"... Holes look tacky.

 

Same reason people cut the bottom half of the bumper out. It reduces drag. The theory is that the hollow rear bumper acts like a parachute, creating a heap of unnecessary drag as air gets trapped here instead of flowing underneath. The idea of hole sawing a bunch of portals into it is to reduce the drag by giving the air somewhere to escape.
Absolutely pointless on a street car and would make next to no difference for stock cars tracked anyway unless you are scavenging for milliseconds off laptimes.

 

I would tend to believe that even if you had holes in the bumper if you really wanted to maximize airflow and aerodynamic stability you need a designed diffuser (i.e. specifically chassis designed). Agreed that if you do it for weight reduction then just remove the bumper, race and put it back on then go home.

 

I would tend to believe that you would really want a designed air diffuser as opposed to a bunch of holes in the bumper. Can't see how that would help air flow as much as create pockets where air will just swirl. Oh and add the artarded factor for the 90% that do it for looks.

 

It's suppose to be for racing to help reduce drag and have more airflow