That unpainted plastic piece that hides the lower part of the gas tank.

I have and noticed that there is less dust on by rear bumper.

Also, looking at it and the manner that it was attached, it seems that it increases rear drag and lift.

 

How did you remove the two backward screws?

 

If you losen the nearby bolts, you can pull on the bumper until the vailance will slip past the backward bolts.

 

Yeah you can take it off no problem, well a little bending like mentioned above, but its possible to get off.

 

I've been thinking about doing this, for the same reasons you mentioned (drag & lift). Do you have any photos showing how it looks with the skirt removed?

-s-

 

A buddy of mine doesn't have his. The bodyshop lost it when he got it repainted. He doesn't like it off. From a little ways back you can see the gastank if you are following him. I don't think it looks too bad. If it cut down on dust on the back bumper, I would be all for it. It is really noticable on a white FD. I have been meaning to take mine off, sand, and repaint it black. I have overspray on mine. If it looks good w/o it, I'll just leave it off. I will get it done tomorrow and post pics with it off.


I can't comment on the aero aspect of it.

 

Not at this moment.

But it makes the car rear end look a little taller since there is more gap exposed between the ground and the bumper.

It does disrupt the organic lines of the car (probably why Mazda did this in the first place) when removed but the car looks like a "track-prepped" car for some reason.

Of course this portion is purely subjective..........

 

BTW, it's probably not too bad on a dark color car.......

 

Well, I plan to remove mine and install a diffuser that I bought in March.

 

mind if i ask where and how much?

 

ooh, i like the diffuser! judging by the box, i'm gonna guess it wasn't cheap

 

A group buy on NOPISTONS.COM from Chuck Huang at Rotary Extreme.

 

i got the same diffuser from the same group buy.

i dont think theres enough undisrupted air under the car by the time it gets to the rear bumper for that to affect anything, i think all u do by taking it off is let people see ur tank.

 

Did mine just now. It looks fine to me. There are very few cars that will be sitting low enough to get a good view of the gas tank. Here's pics, just because I'm a photo-***** like that.
-s-

 

That's my car he's talking about. What's up Fuman? I didn't realize the skirt was missing until like 2-3 months after i picked up the car. I kinda like the way it looks with it on but mine was faded from the sun. What i really want is the RE-Amemiya Carbon Fiber Diffuser but it won't be anythime soon.

 

In a nutshell....

 

It seems that it would be fairly noticible on a stock ride height. Maybe if your car is lowered...

 

I like it on better than off

 

Remember that drag, lift, and downforce are exponential. I'm not saying it's going to make a difference that is noticeable, but it's definitely not hurting anything. With any luck, you might get a couple more miles per tank of gas, and an extra MPH top speed.

A really good way to see the difference would be to test it out in the rain, drive around with and without your 'skirt on.' The water droplets give a better visual display of what the airflow is doing.

-s-

 

Well, whatever it does, it sure reduced a notable amount of exhaust smell in the cabin when i have my sunroof popped open.

I think when i have the sunroof popped open it must create some sort of vacuum in towards the rear of the trunk.

This must suck some exhaust in and around that area.

 

They're "exponential" only if all the contributing factors are present aerodynamically, and the FD's (or most other production cars, with the exception of a few) undercarriage is full of turbulence-inducing gaps and parts hanging out in the airflow for a diffuser-- or removal of the rear bumper skirt-- to have any appreciable effect.

It will be extremely difficult for someone to see any water droplets through the spray created by the trailing turbulence-- especially from the rear of the car (or even from a car following closely). I doubt you'll be able to tell anything from any droplets that are clinging to the rear bumper due to the aforementioned turbulence.

 

But reducing exhaust smell was my most noticible gain.........

 

Kento, I see your point and agree that the benefits of this would be very small and probably not enough to notice. Those diffusers seem like a big waste of money to me.

The trailing turbulence you mention is exactly what I'm talking about.Removing the skirt (or replacing it with a diffuser for that matter) should cause there to be less turbulence behind the car, even if it's not much less at all. With luck, it might be enough of a difference that you could see less turbulence behind the car when it's raining and there are droplets of water in the air showing that there is less turbulence. It would be such a minimal amount that you would probably need a videocamera so you could compare the two shots. To sum things up:

In theory , it's going to be an improvement (besides the aero savings, I removed almost one full pound of plastic, screws, and metal clips).

In reality, it's going to be such a miniscule improvement that you won't be able to tell the difference, except for the visible gas tank.


BATMAN, what speed is this at? And where the heck is your exhaust pipe dumping? It must not stick out as far back as stock.

-s-

 

Cam at Pettit told me that little rear skirt acts like a parachute at high speed. What I've seen him do is actually attach several small rods to it to bring it closer to the tank.