my buddy who is a physics major noticed that my rear bumper has no hole behind it. It only looks like one and he said it'll act as a parachute of types and I should just cut out the "fake hole" indentation. Anyone done this?

 

yeah - but your buddy is full of ****.

Yes, at VERY HIGH SPEEDS, it acts as a parachute - but you shouldn't be going that fast anyway. Get some difusers put in if you're worried that much......

I think there's a piacture of a prelude where a guy cut the holes himself - looks damn good.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TheKingPin &raquo;</TD></TR><TR><TD CLASS="quote">yeah - but your buddy is full of ****.

Yes, at VERY HIGH SPEEDS, it acts as a parachute - but you shouldn't be going that fast anyway. Get some difusers put in if you're worried that much......

I think there's a piacture of a prelude where a guy cut the holes himself - looks damn good. </TD></TR></TABLE>

wrong....that bumper is a giant parachute..and you dont have to be flying for this to apply...i personally dont think that holes in the rear bumper look any good...but they are definitely functional....

 

Oh. My fault.

So it acts as a parachute at like 40mph?.......damn.........

I've seen the difusers - or whatever they're called on an integra - boosted though. Never seen it on a car without boost.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TheKingPin &raquo;</TD></TR><TR><TD CLASS="quote">yeah - but your buddy is full of ****.</TD></TR></TABLE>

Look who's talking ....


I didn't like my parachute, so I did the best I could to make it look ok and not block so much air--



I don't know why the hole isn't cut out from the factory...

 

I would say yours looks damn good also.

 

just take your bumper off, problem solved

hawk what muffler is that?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by prelittlelude &raquo;</TD></TR><TR><TD CLASS="quote">just take your bumper off, problem solved

hawk what muffler is that?</TD></TR></TABLE>

Magnaflow

 

i was thinking of also cutting out that long rectangular indentation on the rear bumper and putting mesh behind it. That would let air through it, would look good, and would match the rest of my mesh.

i was also thinking of designing completely flat underbody panels with possibly a venturi design with rear diffuser. There would be 3 panels (front, mid, rear) and would be constructed of either fiberglass, c/f, or galvanized/stainless steel.

Right now, i'm messing with cardboard to see how it would fit and look. I'm trying to get it so the product would be decently easy to put on/take off (for repairs and such). I also would like to it be fastened to the car by stock bolts so no drilling would be required.

When this school semester is done for the winter and i have a month break (January) i'm going to progress more on this project.

 

btw, hey hawke, why don't you just cut out that little piece in the middle and bottom center of your bumper? (make 2 vertical cuts up to the top of the sides of the holes.) it would make it look better(kind of black widow rearish). i think and it's useless being there anyway.


ot: what's up wit the car emblem?

 

I rally, so I have skid-plates all up under my car. You can use them to your benefit. A simple sheet of aluminium (or carbon, if you're feeling saucy...plastic if you're feeling practical) affixed to your spare tire well with an "inverse" lip (pointing down & away towards the rear bumper) will deflect the air underneath the rear bumper.

One caveat, though...doing so will cause turbulence to form at the bottom of the bumper. This will make your exhaust gases at mid speeds (10-40mph) to swirl up and dirty the living **** out of your bumper.

Unfotunately, I don't have any pics of the last car I had that I did this to. I might be able to photo-chop something for you...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by yOnKiNaToR &raquo;</TD></TR><TR><TD CLASS="quote">
i was also thinking of designing completely flat underbody panels with possibly a venturi design with rear diffuser. There would be 3 panels (front, mid, rear) and would be constructed of either fiberglass, c/f, or galvanized/stainless steel.
</TD></TR></TABLE>

be careful with that...a car that isn't designed for a full diffuser set-up will want to sail away at higher speeds. My co-driver used to race w/ a guy who found that out the hard way while testing his car on a high-speed ring...nothing's sadder looking than an STi after it's been back-flipped...

 

i like it.. gonna cut out that stock indentation..

 

aftermarket bumpers with vents.

(crappy phone pics)



custom grills made by me.

 

Unfortunately, my car will be sporting a Combat rear bumper, like the one above, and it already has a grill in the rear that is great at passing the air. Yes, the air trapped behind the bumper is holding you back enough to justify getting a hole or two in there to relieve the pressure.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sober_John &raquo;</TD></TR><TR><TD CLASS="quote">

be careful with that...a car that isn't designed for a full diffuser set-up will want to sail away at higher speeds. My co-driver used to race w/ a guy who found that out the hard way while testing his car on a high-speed ring...nothing's sadder looking than an STi after it's been back-flipped...</TD></TR></TABLE>


yes, i've been reading up on aerodynamics a little and also came across info kind of like that. that's why i said it was a possibility. i definitely want to make a front panel in front from where the stock splash guard stops until about where the o2 sensor is or a little more. the middle piece would go all the way back to a little before the subframe. the rear would cover the rear subframe and go up at a small degree angle up to the bottom of the bumper. (in my case, to the bottom of the lips).

honestly, i don't expect dramatic results, as i don't drive my car fast enough to get the benefits.

all i'm trying to do is get my car to stop being an airplane wing and producing so much lift. i want more high speed stability. i want a little more speed at the strip too.


sober john: do you have pics of your setup? i have a hard time understanding what you mean by the inverted lip?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by yOnKiNaToR &raquo;</TD></TR><TR><TD CLASS="quote">btw, hey hawke, why don't you just cut out that little piece in the middle and bottom center of your bumper? (make 2 vertical cuts up to the top of the sides of the holes.) it would make it look better(kind of black widow rearish). i think and it's useless being there anyway.


ot: what's up wit the car emblem?</TD></TR></TABLE>

I guess it just kind of outlines the bumper. I have definately thought about cutting more off, but haven't decided on anything. I also have thought about the underbody trays. That would be the right way to do it.

The 'car' emblem makes me laugh...

 

I think a bunch of holes in the rear bumper looks pretty bad. The custom grills look good, although I'm not really into bodywork.
I'd love to see a totally stealth attachment that reduces drag and doesn't lift the car. If anyone comes up with something that works, let me know so I can imitate it.

Dan

 

yeah like someone said I'm just thinking about cutting out the indentation.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by plikit &raquo;</TD></TR><TR><TD CLASS="quote">aftermarket bumpers with vents.

(crappy phone pics)



custom grills made by me.</TD></TR></TABLE>
I don't think its the phone thats crappy

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by maxvtec7500 &raquo;</TD></TR><TR><TD CLASS="quote">
I don't think its the phone thats crappy </TD></TR></TABLE>

At least the guy's out there making his own parts how he wants them.

for being innovative and doing things on your own.

 

omg make it stop

 

question, only prelude's rear bumper acts this way? or all car has their rear bumper act like a parachute? What about some lips? does it help to lower the car?

 

I'm also curious about this. I own a 5th gen with a stock rear bumper. Does it act like a parachute?

 

how fast are you boys going?

Do you really believe your rear bumper is acting like a parachute FFS?

If you want to make a difference, lose the 200lbs of bondo you used to make the bodykit look half decent, and stop dreaming!

Holes in your rear bar....... prolly have the same performance benefits as an exhaust tip spinner!