Rear bumper vents?

[Mike King]

I'm working on my ST sedan conversion and got to looking at the rear bumper. It's not the like ST hatch that curves up underneath almost like a diffuser. The sedan drops almost straight down and it appears it will catch the underneath air like a parachute. Does anyone have ideas about venting the rear bumper cover? The impact bar is very low, leaving a 6-8 inch tall area above it open. I'm considering using a rectangle front grill from a scion or modifying rear bumper vents from a R53 mini cooper. I may also use some custom honeycomb grille and make my own. I'm trying to improve aerodynamics without making it look like a ricer. I bought some flared woofer ports to play with but they would look so ridiculous that I may just use one in my modified airbox only. They are 4" diameter but the flare part is almost 6" so no bueno on that idea.

 

[Lays]

I'm working on my ST sedan conversion and got to looking at the rear bumper. It's not the like ST hatch that curves up underneath almost like a diffuser. The sedan drops almost straight down and it appears it will catch the underneath air like a parachute. Does anyone have ideas about venting the rear bumper cover? The impact bar is very low, leaving a 6-8 inch tall area above it open. I'm considering using a rectangle front grill from a scion or modifying rear bumper vents from a R53 mini cooper. I may also use some custom honeycomb grille and make my own. I'm trying to improve aerodynamics without making it look like a ricer. I bought some flared woofer ports to play with but they would look so ridiculous that I may just use one in my modified airbox only. They are 4" diameter but the flare part is almost 6" so no bueno on that idea.

Have you considered doing what the miata folks do? And just trimming a relief area in the middle?

 

[kevinatfms]

Either bumper cut it or maybe see if you can modify a Verus Engineering diffuser to fit?

The vent holes look so cheesy. Just tacked on. There are plenty of sedan civics in Gridlife and Track Attack that have bumper cuts which look excellent and serve its purpose quite well.

Here is our bumper cut on our Elantra Champ Car. Very subtle but works for exhaust clearance and exhausting air from underneath. Its not a ton that needed to be removed to stop the rear bumper from flapping around. We could probably remove more from the sides to help but this was enough to keep the rear looking clean and our "dad sedan" status on track.

 

[Mike King]

The bumper bar on the sedan is very low, leaving an opening above it at least 4" high, spanning most of the bumper width. I was thinking of cutting that out and putting a honeycomb grille behind it. I also thought about using flared speaker ports. I bought some 4" ones to play around with but they are way to big and goofy looking. Maybe some 2" will look ok.

 

[kevinatfms]

Cut it and paint the beam black. No one will know.

 

[Mike King]

Cut it and paint the beam black. No one will know.

If you look at the front bumper where I replaced the factory grille with honecomb, you can barely see the front bumper. Originally I painted it satin but was too noticeable so I used black BBQ paint which is not quite flat black but it works. I may do the same on the rear but I want my bumper vents to be functional.

 

[kevinatfms]

The bumper cut works and if done right i think looks better than the cut in vents.

Miata's are a perfect example of this. A proper bumper cut on a Miata looks tits.

 

[stadlxr]

i did this to mine. Honey comb delete , allows all the air to flow through the rear grill also makes it functional. Just a grinder and a flap disk is all it took

 

[Mike King]

This is not my car but my bumper is the same. The lower black textured piece is removable so I might try that.

 

[kevinatfms]

Here is a really shitty paint shop hack up of bumper cutting more than just the panel removal.

Have the exhaust come out of there like an ST. Throw a tow hook/strap out back(and one up front) and paint everything else under it black. Would be functional yet start to give off some motorsports vibes(start some motorsports?). If you run some Bilstein dampers and ST or Whiteline springs you will get some color poking out below also(yellow and silver).

If you are trying to stay sleeper-ish then maybe just remove the panel and leave it.

 

[kevinatfms]

Added "exhaust" twin tips.

 

[Mike King]

I removed the lower rear bumper piece. I'm going to paint it black and see how it looks.

 

[Mike King]

The exhaust tips are 11" back from the end of the bumper. Should I have them extended, changed out for different ones, come out the center or one on each side of the cutout? I have a pair of dual oval tips from a cadillac exhaust and a set of active mufflers from an ss camaro but I don't think those would fit due to them being angled. It would be cool if I could because they are closed under vacuum and become wide open when vacuum goes away.

 

[LionsTooth]

Used PlastiDip on mine and love it.



Been thinking about this treatment of awhile...

 

[Mike King]

Looks like you used a holesaw and put some kind of mesh behind it. You wouldn't believe how hard it is to find someone to replace my resonator with a pipe. I used the word "delete" at both Midas and Monroe and you would think I was trying to rob a bank or something. I explained to both that the cat would be untouched but they basically kicked me out the a-holes. I did find an independent shop that will extend the tips out to the edge of the bumper and delete, I mean put a test pipe where the resonator is. Appointment is for a week out this Thursday. Tomorrow is window tint day.

 

[Intuit]

Might be able to cover the gap to block most of the air from entering.

 

[Jabbit]

I like that look above - wondering if that piece drops into the ST rear bumper?

 

[LionsTooth]

Looks like you used a holesaw and put some kind of mesh behind it. You wouldn't believe how hard it is to find someone to replace my resonator with a pipe. I used the word "delete" at both Midas and Monroe and you would think I was trying to rob a bank or something. I explained to both that the cat would be untouched but they basically kicked me out the a-holes. I did find an independent shop that will extend the tips out to the edge of the bumper and delete, I mean put a test pipe where the resonator is. Appointment is for a week out this Thursday. Tomorrow is window tint day.

It's a Photoshop prototype but yes I would use a 2.5-inch hole saw and some stainless, painted mesh. Later this summer...

 

[Mike King]

It's a Photoshop prototype but yes I would use a 2.5-inch hole saw and some stainless, painted mesh. Later this summer...

That area on my sedan is all bumper bar but if I go above it, there is about 4" of space the width of the bumper. It looks like the impact bar should be there but it's below it. I cleaned up the rust and painted the little bit of bumper bar that sticks out the bottom as well as the back of the spart tire well that could be seen from behind. Notice I removed the lower extension panel from the rear bumper. I am having the exhaust done thursday a week from now.

 

[FiestaSTdude]

Can we get some more pictures of this amazing vehicle? Especially interior and engine bay pictures?