DIY rear bumper fake vent conversion

MuffinMcFluffin said:

My Si is modern-steel metallic. I guess it's one of those cosmetic changes where I have to decide beforehand whether I think it will improve its look or not. At least it will provide the illusion that the design choice was with a functional intent, even if it does nothing at all.

The other fear I have is if it worsens function, be it performance (like air drag of sorts), engine heat, cabin noise, what about with rain/car washes, etc. Cost is the biggest non-factor for me here if I like it, but if I don't and I have to turn back... well I dunno.

Great for those who are doing it though! Any reason that only the back should be considered to be done and not the front? Though let's be honest, the back is the bigger culprit here.


Also somewhat unrelated, but I myself live in the Bay Area and wouldn't mind finding a trustworthy shop to install a clear bra on my headlights, switch in some new fog light housing, tuck a cable into the dash and tint my windows. Does Garageworks do these things as well (can't tell based on their list of things they do), and is there a chance they can do a same-day thing if I book ahead of time?

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xaviersayys said:

I'm a bit late to this comment but we live right next to each other, and I was looking at Werkshop in South San Francisco. They seem very well trusted from all the Yelp reviews I've read and looking through their pictures it looks as though they can do a lot, from wrapping to bodywork, etc. I'm considering checking them out to get my headlights/fog lights wrapped sometime in the future.

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zroger73 said:

Do you have actual test data to support that? Opening up those spaces would save weight and material. If it would improve fuel efficiency or performance even by the tiniest imaginable amount, don't you think Honda would have done that from the factory? I can't think of anything better for a manufacturer than saving weight, material, and money while gaining performance and fuel efficiency at the same time!

In a worst-case scenario, allowing air to flow through areas not intended could actually create additional drag and decrease efficiency and performance. It may also alter the airflow characteristics in such a way that causes exhaust fumes to be drawn into the vehicle. We'd need a wind tunnel and several hundred thousand dollars worth of test equipment and fluid modeling software to validate these wild guesses.

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pjw7454 said:

Also it allows dirt and water to accumulate in areas that Honda may not have weatherproofed because it was covered. Rust spots may develop especially in the front area where water will get flung into those vents. That’s why I wouldn’t do it.

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Brian17Si said:

Ha! Originally I thought you meant after the conversion. IMO just painting faux vent would look weird. Some people dislike all the black on the bumper. Doing conversion there’s opportunity to reduce black. Cutting out entire vent hole and re-spray the trim color of car. But then I would paint vent trim in front to have unified look.

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DoodleDave said:

I really want to swap with a normal Civic. I have already asked in my regional area forum. I really thought someone with a basic Civic would like a sportier looking front bumper but I guess not. I think I will hold out until Mugen makes parts for the car. If they have a body kit with a more appealing front bumper than I will do that. If not I will buy a new bumper.

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Brian17Si said:

Two words... "parachute effect" it's a thing. I didn't make it up. The average to even spirited driver might not be aware. But the race community is fully aware, embraced, and conquered it. Everyone reading this should've seen race or drag cars with rear bumper holes. Here's a link to a company that sells products they say have been tested. This is what they say...

Rear bumper diffuser

"Whether you drive your car to and from work or only drive a quarter mile at a time you will see remarkable benefits with our new diffuser design. At speed a rear bumper cover can increase overall aero drag and promote lift. Neither of these effects are desirable on any vehicle, and as speed increases the problem becomes more pronounced. Think of your rear bumper as a big air brake. Our diffuser removes the trapped air and lets it flow freely through the bumper cover. Our product promotes higher track speed and gives the driver more stability at those high speeds."

"This product has been tested at the drag strip on a 9 second, 150mph drag Civic. Each diffuser is CNC water jet cut, and features a glossy finish. It measures approximately 4"x45", and comes with easy to read instructions for trouble free install and black painted rivets. For those really fast racers out there you will be happy to know we machined a center hole just for your parachute tube. A secondary benefit for some cars using parachutes is faster parachute deployment due to the larger volume of air exiting out the bumper cover."

- Retrieved from http://www.lighterfaster.com/13163.html

All reply's are appreciated because this topic has been a healthy debate. It's reinforcing more research and knowledge that's extremely beneficial. Info is limited but it seems to be a very important aspect of racing. Hopefully we'll discover the truth behind it, literally. We need people with professional expertise to chime in and shed some facts.

UPDATE: FINDING SOME AMAZING INFORMATION

Spoon rear aero bumper product.
"The newly developed Spoon Rear Aero Bumper was designed based on 15 years of S2000 racing experience. The raised bumper height allows air to escape from behind the wheels thus generating rear downforce. The bumper cutouts allow trapped air to escape for reduced drag and aids rear differential and exhaust cooling."

- Retrieved from http://www.gotuning.com/product_info.php?products_id=1775

Directly from Spoon website...

"Creating down force while reducing drag. These repulsive factors must be balanced at an optimum to produce a truly effective aero part. At Spoon, we combine our knowledge accumulated from all of our years of racing and state-of-the-art CFD (Computational Fluid Dynamics) to develop each of our aero parts for Honda vehicles."

"All proto-type products are tested on the track and validated from multiple perspectives. To achieve the highest cornering performance. Stability under any circumstance. Only the blatantly honest policy to develop an aero part with surpassing performance leads to the highest quality product."

- Retrieved from: http://www.spoonsports.jp/philosophy06.html

Spoon Rear Aero Bumper - S2000 AP1/2

Spoon Sports S Tai Rear Bumper ‑ Honda S2000 AP1 AP2

Spoon s2000 Racing (CUT OUTS LOOK SIMILAR TO SI)

Miscellaneous pics

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Yonder said:

Granted they are tunnels for brake cooling but seeing this may sway the opinion that venting the fronts(or a portion of it) may not be a bad idea. Or if the fake vents bother you that much these may be a good alternative.
https://hpd.honda.com/Articles/Touring/CivicSi

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jasonklor said:

Thanks for the information and examples!

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Learn2turn said:

Hello fellow enthusiasts,

I have the composite solution to this issue. I am the Director of HP Motorsports that was only born on 5/24/19. I welcome all who want to be involved and there will be an early bird price for everything we produce. I am connected with the highest quality composite company using a proprietary method of carbon and hybrid layouts. The first prototypes will be for sale and the first inserts will be RED KEVLAR/CARBON WEAVE.

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Vincent@27WON said:

If we created an easy to install upgrade for this, who all would be interested? A pair of easy to swap and functional pieces?

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