Civic sedan rear spoiler

[freebeard]

So you mean close of the bottom, underneath the top surface of the spoiler, to prevent air exiting thereby causing a high pressure area that the air stream sees as similar to being a kamm back of 12 degrees?

Pretty much.

I was thinking of a half-tonneau in a pickup truck. It isn't like just having the tailgate up instead of down because there is a recirculation in the front half of the bed that moderates the flow (some how). It could be a sock that fit's over the hoop front and back.

The perforated part would be for rearward visibility, and perforated base plates are a thing so why not?

aerohead and I saw an example at the Darko wind tunnel where a wall of welded wire mesh affected the laminar flow in the tunnel, around a corner.

[Xist]

Take a good profile picture of your car and then put it on the template. I cannot imagine the spoiler would come near the airstream.

Create some spacers from a 2x4!

[D15r]

Originally Posted by Xist

Take a good profile picture of your car and then put it on the template. I cannot imagine the spoiler would come near the airstream.

Create some spacers from a 2x4!

I had to make some from 12mm marine ply just to fit it! And To complicate things This spoiler has to be flush fitted. Makes it all very hard.

[freebeard]

Is it merely fettled or permanently attached? Are there holes drilled yet?

It looks like it could move back about 3" to align with the bumper. Then you have two sides of a box.

It does attach to the lid, doesn't it?

[D15r]

Originally Posted by freebeard

Is it merely fettled or permanently attached? Are there holes drilled yet?

It looks like it could move back about 3" to align with the bumper. Then you have two sides of a box.

It does attach to the lid, doesn't it?

It is permanently attached but not hard to move back, I did think about moving it back further.
I've actually been thinking about using the spoiler as an integral part of a full kaam back.
I'm holding back on extreme aeromods because I live in this car so i don't want to stand out too much. Also my gearing sucks and I can make a huge gain with a vx gearbox if i can find one, so i want to do that mod first.

[freebeard]

K-a-double m. Perhaps you see the problem with putting a Kammback on a car with a trunk. I can't find the original build thread, but 2000neon did this:


http://ecomodder.com/forum/showthread.php/2000-dodge-neon-aero-mods-20741.html#post326693

They haven't posted since 201608, but the thread should still exist. In case you can't make it out, it's a Watts linkage. You can't see the connecting arm in this view. The Kammback swings on a long arc and the decklid swings on a short one.

[ChazInMT]

My guess is this might help you, I doubt it will hurt. Either way I don't see it having much effect on MPG.

Here's how I see it, In this pic we can see your trunk lid is below the Aero Template, which is not good.



By adding the spoiler, it brings it up to being a bit above the line, which is Good. (BTW, I took great care to be sure the spoiler is proportional to the rest of the car, the white civic seemed just like yours but is a better picture to use for analysis)



Now the "Maybe/Maybe Not" point. Since we don't know what effect this will have on the rear corners of the car, we don't know if it really helps, or hurts. If your car were only a 2 dimensional shape on paper, like it is here, this would be a definite improvement. But cars are 3D so it get's real complicated due to the whole "Cars have Sides on them" issue.

I tend to guess that Honda has not designed the sides of the trunk to taper in, so It stands to reason that the non-spoiled car has a sort of deep low over the trunk that the air from the sides wants to climb into, and that's really bad. So by adding the spoiler to lessen the deep low above the trunk, or maybe eliminate it, you'll keep the side air from wanting to climb....which is Excellent.

I'd say the odds are 15% big improvement, 45% small improvement, 30% nothing happens, and 10% small decrease.

So there.

[D15r]

Thanks a lot for your analysis, you saved me the work. Whether it is relevant or not the sides of the spoiler are nicely tapered inwards as the spoiler gains height.

As has been previously mentioned in this thread, I may trial closing in the spoiler. Blocking air from bleeding out the bottom and possibly creating a high pressure zone so that the airstream rides on it and separates at the spoilers rear most edge. Of course I could easily box in the sides with coroplast to prevent of negate the side in spilling in.

Idk much about aeros to be fair so my theory may be off. I have some testing to do, I like to follow the test protocols and get some solid data.

[aerohead]

I don't ordinarily recommend them,but Wheeler Air Tabs were designed to help with notchback issues.The Mitsubishi Lancer Evo is an example of a car which was tested,and found to benefit a little.
Also,the Mercedes-Benz 190 2.3 received a backlight header air deflector and rear wing to help mitigate notchback-related issues.

[D15r]

^air tabs, very cool.
Well my first tank with spoiler on and it is my best tank ever, and I didn't try hard at all. It is too early to say what the spoiler has achieved but at the minimum it doesn't appear to be hurting things. I really like the look of it too so for now it is staying, no regrets so far on this $40 mod.