Chin spoiler and tire spats
 

Ive done a TON of searching and lurking around here and other sites and have read the great success stories from running front air dams and the likes. I want to mod my 93 Escort, but I want to make it so it looks like it came from the factory, so no big bumpers or anything. I would love to make a simple chin spoiler and maybe some tire spats to break the wind around the front tires, but after reading up Ive seen alot of back and forth on what would be ideal design wise and what would make things worse. Is there a solid answer as to what I should aim for, or is it pretty much up in the air? Angles, height from the ground, shape ideas to shoot for? I appreciate the wealth of knowledge on this site and hope to be able to add to it myself one day!
Matt

Thanks for posting the question, I'm looking forward to the responses as well.

Here's an article that addresses tire spats. It's specific to that model, but should be useful as a general guide for others as well.

Autospeed Modifying Under-Car Airflow

This is the article I used for modeling my tire spats. I'm happy with them. I made them our of black coroplast and attached them with black duct-tape. Before you wince (too late!) at the duct-tape and coroplast, remember that their color, small size, and placement mean nobody really ever sees the tape or the spat. Fairly stealthy. As for the chin spoiler. A cleanly cut section of black lawn edging was my choice. Whenever I show it to people they cannot guess where it came from (once someone did). Again, somewhat stealthy, though perhaps not totaly an OEM look.

spats
 

On low-drag cars,the wheels and tires can constitute half the drag.
You might consider going beyond spats and consider actual canoe-fairings as you see on aircraft,high-mpg concept cars,university mpg record cars,and university and corporate World Solar Challenge cars.
These devices will pay the largest dividend and are not as elusive,design-wise, on a car-to-car basis.:)

Ive read the Autospeed article a couple times and love the info, funny thing is I like the idea of the stock spats on the Prius LOL.

California, do you have any pics posted up with of your spoiler and spats? Ill do some searching today and see what I can find, but Ide love to see more!
Matt

Here's the chin spoiler, or front air dam. It's a link to a pic in my EM photo album. There is a side shot in the album too. I don't have a shot of the spats, since I took them off recently after one got loose. I want a better attachment strategy now that the rainy season is on me. I think duct tape will work, but I need cleaner surfaces and tighter seals when I apply it.

Here is the pic. The lower grill block has been rebuilt, so that there is just one opening, left of center, directly in front of the radiator and ducted to it. Soon I plan to fill in both upper and lower blocks, fiberglass them, and make smooth surfaces, but I need more time:
http://ecomodder.com/forum/member-ca...ing-airdam.jpg

Hope that helps. I might redo it too. I want the ends to come closer to the front wheel wells. Lawn edging is pretty cheap and I have plenty extra since I had no choice but to buy more than immediately needed, so the cost will be nil.

Excellent, that does look slick!!! I couldnt find any link like you said, but do you have shots of how the spats looks with the front spoiler? I was lookin at using the garden edging, but my buddy has some really light, very durable material at his shop we could use. Its plastic layers with a this layer of aluminum sandwiched in I believe, we could cut, bend and shape it however we please. I might try his stuff but if it doesnt work, garden edging it is.
Matt

California98Civic,
Nice job on the mods.
I would easily take them as being factory if you had not pointed out the changes you had made.

Peter.

Lawn edging, what a great idea!

It is, I've used the larger stuff on my truck. Link in signature below.

Sometimes tire spats that seem as though they would help the Cd count, really don't do much of anything.

When these spats were tested on this '80 Camaro, they didn't do anything for the Cd despite shielding those wheels sticking out into the wind.

http://image.hotrod.com/f/10214175/1...side_spats.jpg

Car Aerodynamics - A2 Wind Tunnel - Wind Camp Tech Theory
Here, Eaker is examining the stock Z28-type side spats, which did not alter the Cd but added 40 pounds of rear downforce. He thought they may be more helpful in yaw but says testing 0 degrees to the airflow gives you 75 percent of the data you'd need at slight yaw. We also tested the Moon discs, which reduced drag by two to four counts. The farther the wheels are from the outer edge of the fender, the less the discs matter. View Related Article


Read more: Chevy Camaro Aerodynamics Side Spats Photo 8

Aerodynamics can be puzzling sometimes. Truly unpredictable !

Very useful article. Thanks. Odd that they don't note a kamm back as a certain aero benefit in their list. The article PaleMelanesian posted has some interesting info on the placing and shaping of the spats, which apparently can make a lot of difference: Autospeed Modifying Under-Car Airflow. Maybe these spats on the camaro might have been shaped differently and had better effects?

Thanks Peter. I'm going to need to rebuild them when I lower the car soon.

Spats certainly do make a difference. I was just showing the unpredictability of aero mods. Personally, I would have bet money ( and lost money ) by looking at the spats on that Camaro.
The area of the wheel sticking out in the wind is enormous ! I would have thought the spats would have dropped the Cd quite a bit.

While we are on the subject of that car, just look at the huge gaping wheel wells around that back tire ! No wheel skirts, yet a .201 !
And stock door handles and misaligned window trim as well !
That car LOOKS like an aero nightmare.

Like that boxy yet sleek old Lexus sedan, whatever that was.

spat
 

Without a wrap-around front airdam as wide as the width of the spat,the approaching air would be colliding with the tire face,spoiling an opportunity for the spat to function.
The Trans Am Firebird used 'leading' streamlining to clean up the flow for this region of the body.

I think ur confused, as was i on first inspection. the spat is on the front side upstream on the rear tires. :thumbup:

I took a crack at some innitial planning and designing last night at a buddies shop. We did a ton of thinking, messed with a few different materials he had layin around and eventually got to work on puttin together a simple "prototype to test out made of aluminum. I didnt want to go too low with the stuff and scrape it all the time so I went 3" below the stock bumper which is enough to cover all the "nastiness" as we call it thats previously left hangin in the wind LOL. We didnt have enough time to finish but the design looks alot like a stock chevy chin spoiler that is only in the front and doesnt wrap around. Im not sure I like it very much but might test it out when we finish and see what happens. Im thinkin I might grab some of that lawn edging and do one more like I wanted, where it wraps all the way around the bumper like the lower chin on the boxy Jettas and Golfs. We messed around with tire spat ideas as well, real simple like the old Prius used to have but will finish the spoiler first. No pics yet, but when I get the bracket together Ill post some up and get yall to critique it!
Matt

rear
 

I guess my reaction would be similar.Aft-body mods cannot function if the air to them is turbulent.
In the absence of an airdam and rocker panel extensions flush with the outside edge of the tires,the flow to the rear spat could be real 'trash',negating its effect.

I'm puzzled because the smooth wheels helped the drag yet the spat did nothing for the drag.

It sounds as if you mean that the front airdam keeps air from colliding with the tire, spoiling an opportunity for the spat to function, yet the wheel covers ( Moon discs ) functioned as they did, so plenty of air was getting to that area.

Without the wheel being even with the outer edge of the spat,the forward face of the spat is being attacked by the airstream.It may have a local Cd as high as 1.11 right there,with full separation,and turbulence following it far down the rocker area.:eek:

Ok, ive still got the first chin spoiler we made, and could finish it up and install it to try out, but now I have a question. What would be better, chin spoiler and tire spats, or do a front underbody tray from the bumper to the front suspension and then some spats along with that? If the tray would be better I wouldnt have to worry about the ground clearance but then again I can make the spoiler a bit higher to deal with it if needed. I appreciate any advice!
Matt

that
 

would that be the '89 LS 400,@ Cd 0.29?

I am dyslexic
 

tru,it just hit me that I was interpreting the airflow from left to right which would make the tail the nose!
Good grief!
My apology to all.
Is this the Camaro with the aluminum nose which is completely sealed?

there's a good reason you're puzzled,it's my stupidity!
 

Cd,I just realized I've been dyslexic on this whole thread.
My brain was interpreting the image with airflow from the left to right.
tru tried to set me right and it went right over my head.
Is this the Camaro with the aluminum nose which extends to almost ground level?
I need to know exactly which car this is.I apologize for the mix-up.( you guys need to keep a close eye on me!).

Im workin on a 93 Escort, not the salt flat camaro, please refer to question asked above and keep posts on topic. :thumbup:
Thanks
Matt

Escort
 

Matt,I would recommend you do the front airdam first.I didn't find a photo of your chin spoiler.Did I miss a link?
Today's NASCAR noses( without the splitter) would be a good example for a nose remodel for healthy airflow if you wanted to take it that far.The lower portion could be a flexible material to deal with curbs and parking hazards.
After that you could appraise your situation and go from there.

Thanks! I didnt take a pic, it was too dark and we never finished it. I believe we will reuse the brackets and run somethin more flexible like what you stated, maybe some garden edging or similar. I got to thinking about the underbody pan, but if you look at the front of my car, there is alot of "ugly" that sticks out below the bottom of the front bumper so my belly pan would have to come down abruptly, then smooth out in order to cover it all up. A front splitter or apron would cover it...then maybe make a pan connected to it? I need new struts for this thing so Im thinkin bout loweing it an inch or two as well down the road.

Heres a picture of the "ugly" under the bumper.

http://img.photobucket.com/albums/v1...ightResto4.jpg

Matt

Perhaps like this:
http://media.scenedaily.com/images/5...r-Nascar-2.jpg

james

That car had a Cd of .29 was tweaked further to .28 and finally .27 in series III trim
Source : Lexus LS400

http://upload.wikimedia.org/wikipedi...00_UCF10_I.jpg

http://upload.wikimedia.org/wikipedi...tone_Pearl.jpg


The next generation LS430 had an even lower Cd of .26, and .25 with optional air suspension, which lowered the car around an inch.

http://images.thecarconnection.com/l...00005822_l.jpg

Despite LOOKING sleeker, the current generation ls460 is also .26
( I suspect the wheels have to do with the higher drag )

Sources :
LS | Detailed Specifications

http://the-grayline.com/wp-content/u...s460-awd-1.jpg

LS430 :

http://carblueprints.info/blueprints...ls430-2003.gif

LS460 :

http://www.the-blueprints.com/bluepr...s460l-2008.png

That's the one ! http://image.hotrod.com/f/10214133/1...front_view.jpg

NO WAY that thing is that sleek! Looka dat hood/windshield junction! :eek:

Yup ! It took me by complete surprise,
Not only does the car have the barn door flat front end, but it has the original misaligned moulding around the windshield, stock unshaved door handles, huge gaps everywhere ( look at the wheel wells ! ), no belly or skirts, etc !
It blew my mind, but it was tested in a wind tunnel by a guy that did the aerodynamics on the EV-1

( How ironic that the car has almost exactly the same Cd as the .19 of the EV-1 )

Ummm... this really needs expert explanation. If that Camaro can accomplish nearly the same Cd as the EV-1 looking like that, and a better number than a 2001 Insight, then... what the hell!

Here is the article : Car Aerodynamics - Hot Rod Magazine

I really think it would be great to invite the fellow that runs the tunnel there to join us for a few questions sometime !
:thumbup:

I wonder if that tunnel would say my Coupe has .19 too? :p

:rolleyes: Still applies guys!

I posted a picture of the actual car in question and ask for any other ideas. I think a chin spoiler california civic's will be the first step, along with ditching the front plate bracket. Tire spats for front and rear tires will also be looked at. My question with the spoiler is, how low should I go. I dont wanna make it rediculously low and scrape it on everything, so would makin it just low enough to cover up the "ugly" under the bumper work?
Matt

The Camaro does apply, in principle.
If you take the chin spoiler alone, then generally lower is better. (See pic of Camaro above) Mine is 2" off the pavement and rubs everywhere. It is wide enough that it does the job of front tire spats as well. It made a large difference for me. I used the lawn edging as shown previously. It lasts about one year if you are rubbing constantly and is much more durable (because it will spring back when bent) than the Aluminum Sandwich.
Get the lawn edging and screw it in and see what happens, cut it down a bit and see how your mpg or coast distance changes, don't overthink this and don't worry about what people think as you expierement. Once you have a result you like, you will be able to live with the look. Everyone that asks me about my rear wheel skirts, I tell them that I think it looks goofy and I don't like the look, they then have a puzzled look, then I tell them it adds 3mpg and they begin to understand...

LOL, very true about the looks deal, but I made a challenge to try and keep it looking OEM, as if it was an option off the showroom floor, or perhaps a tasteful aftermarket mod. I love to test and tweak and test some more so Im all over that...altho I must say, this car already coasta like a mofo...I can even imagine what Ide do if it would go further with less effort LOL. I might try out a couple different setups as well, front underbody pan, front air dam, both etc.
Matt

rocker area
 

Thanks for the photo Cd.Going by the photo,the nose may be 'attacking' the airstream as late as the end of the wrap around airdam.
Even though it has an abrupt corner it's embedded within a favorable pressure regime,forcing attached flow.
Once past the rear edge of the front wheels there should be nothing but turbulence all the way down the rocker panel area,rendering the leading spat inoperative.
Also,since the rear of the Camaro is 'open',air cannot pool within the rear wheel wells as would happen more in the 'production' car,and will dive into the void immediately.
The MOONs do offer a solid surface for the air to flow over.On the Trans AM Firebird I think they were good for a 0.024 drag reduction compared to a stamped steel aspirated wheel.