Aerodynamic modifications to a 2007 Camry SE
 

I made front wheel spats for my 2007 Camry SE out of some mud guards I had laying around. I cut the midguards in half and I attached them using some included fasteners as well as bolts that hold the front undertray in.

The spats made a hole going into the wheel well. I am not sure if closing it off would be beneficial. I will test that when I do AB testing for the wheel spats.

I will be making rear wheel spats with the rest of the material I have.

Interesting. How will you know if they are helping mpg? I see you plan to test. What methods will you use?

On Monday I will do a coast down test at 45 mph. It will actually likely be a BAB test rather than ABA.

Unfortunately, coastdown tests are, in my experience, completely unreliable.

To test the technique, do multiple windows up / windows down coastdowns and ensure that the averaged results show a major increase in drag with the windows down.

There was some snow earlier this week so I was not able to do any testing. I will have to do that later.

I just finished adding the rear wheel spats. It was strange to see that there was a factory spat on the driver side but nothing on the other side! The factory wheel spat did not look very functional-about half of it went past the inside edge of the tire.

I let part of the spat go outside the wheel well. Let me know what you think about that. I think that it would create an air curtain effect. If not, I can always cut that off. Unfortunately I cannot do any ABA testing on these. They aren't very easy to remove.

It’s complicated. I have added spats in front of my rear tires but they do not extend out beyond the body of the car. My coasting distances and tank averages are better than before I started my mods but it is very difficult to tell if the spats are helping or hurting my mpg by themselves. (I have a full under tray that may be helping the most).

It is my understanding that we want the air to stay attached down the sides of the car and detach cleanly at the back end. From the photo, it looks to me like you have added a “Gurney Flap” which is like a small spoiler that may kick the air out around the spinning wheel. I cannot say if this will help reduce aero drag without testing. It may be a good attachment point for a future fender skirt to help clear the lower edge of the tire. I hear you about the spats being difficult to remove for testing. Sometimes a compact ratcheting right angle screwdriver works. I found one cheap at a discount tool chain. You could try some tuft tests to see how turbulent the airflow is. I have seen where Julian will add a tuft taped to the very center of the wheel to see how the air flows across the wheel face.

If there is a high mpg or all electric version of your model of car it is usually safe to copy what the factory has done. FWIW some of the factory spats I have seen are about the size of a playing card, usually much smaller than the size of the front of the tire.

The “air curtains” we discuss here generally have a duct to speed the airflow across something like the front wheels so the flow is more attached down the sides after the wheel opening. Good luck. I hope his helps.

I "assume" gurney flaps in front of the tires help.

My 2015 Mazda3 has them in front of all four tires. I doubt Mazda put them there unless they help fuel economy enough to justify the cost.

I doubt I could discern any mileage degradation if I removed them from my car because of my inadequate ability to test, but I'd bet dollars-to-donuts that Mazda saw an improvement when they designed the car.

The front ones I can definitely test. I still want to do that. I think coastdown testing would be the best method, but I do have a scangauge I could use too. The rear ones would require removing the tire no matter what... there is probably 1 cm in between the tire and the screws. Not to mention I also would need to remove some body paneling to put them back on.

That is good to know that dome cars come with gurney flaps from the factory. Mine hardly stick out at all so I would think that they are beneficial. It would just be a lot of effort to test...

It is worth mentioning that I did see a slight mpg increase my last fillup, which is the first one with my mods. It has been a lot colder lately, so I think I can attribute some of the difference to my mods. I will definitely get around to testing the front ones though, and postung what I find.

Could you post a picture of them? About how far do they stick out from the body?

I'm too dumb to do pictures, but I can say they are not very large at all and certainly do not stick out from the side of the car. I doubt very much you would notice them if you weren't looking specifically for them. In fact, the first time I noticed my car had them was when I read some forum guy was looking for a replacement, since one of his had fallen off his Mazda3. They're only about the width of the tire, and they appear to be positioned to displace that tiny bit of air before it hits the tread.

If Mazda hadn't put them on, I'd say it would be silly to bother installing them. But as I said, I'm certain Mazda recorded some measured improvement with them.

Gurney flaps are on wings. They're called tyre deflectors (tire deflectors in the US).

I will be very surprised if any on-road testing can repeatedly show the results of such a tiny mod on / off.

I also have a terrible time posting photos. I’m not sure why that is so difficult to do on Ecomodder. Without a photo of yours Meteor, I believe we are talking about the same thing which many have called “spats” on this site.

From a different thread, I just learned that we may be using the term “spats” incorrectly going as far back as 2010. The correct term should be “tire “deflectors” so for myself I will drop the term “spats” going forward.

There is a component of lift as the front of the tire is exposed the oncoming air and is forced out to the sides. The mini air dam or “spat” in front of the tire should divert some of the air around the tire more smoothly. Some have suggested that car manufacturers may use them to cut down on noise as well.

I will try to find a link to a photo in another thread.

http://http://s1332.photobucket.com/...juemy.jpg.html

I tried using the mountain sunset button. I can only see a square. Is this because I use Apple?

From this thread.

https://ecomodder.com/forum/showthre...ats-13669.html

FWIW, Julian has tested front tire spats on an early Prius (his version was more like “canoe boat tail spats” at page 6) and found increased lift, instability at speed and reduced mpg.

I would assume that the use of front-of-tire-protuberances, whatever anyone chooses to call them, would have to be designed for and tested on specific vehicles, like other aerodynamic features need to be.

Anyway, I have faith that Mazda put them on my car for some good reason.

I can't prove that, however.

I know of at least one guy who replaced one that went missing on his car.

Faith is blind :-)

Honda Clarity, rear wheels:
https://ecomodder.com/forum/member-v...101-164934.jpg

BMW 3-series, front wheels:
https://ecomodder.com/forum/member-v...101-162448.jpg

Mercedes S-class, front:
https://ecomodder.com/forum/member-v...219-160427.jpg

Toyota Prius, front:
https://ecomodder.com/forum/member-v...219-152556.jpg

GMC Sierra, rear:
https://ecomodder.com/forum/member-v...219-180316.jpg

Honda Accord, front:
https://ecomodder.com/forum/member-v...219-162505.jpg

Toyota Highlander, front:
https://ecomodder.com/forum/member-v...go-2019-33.jpg

Hyundai Sonata, rear:
https://ecomodder.com/forum/member-v...dai-sonata.jpg

Porsche Taycan, rear:
https://ecomodder.com/forum/member-v...che-taycan.jpg

Porsche Taycan, front:
https://ecomodder.com/forum/member-v...-taycan-02.jpg

Chevrolet Suburban, front:
https://ecomodder.com/forum/member-v...t-suburban.jpg

But no Camry. :(

No. But I don't know where you see the square. In the Preview Post window?

You can type [IMG]x[/IMG] or [img]x[[/img] where x is any valid URL and it should display.

Permalink #13 just above the words “I tried”.

Thankfully, others have better skills and have posted some good examples done by car makers

There is plenty of evidence that front wheel deflectors reduce drag. But only by a small amount - eg 1 per cent. As I say, I doubt if it would be measurable by any on-road test.

Not of that generation, no. I wasn't interested in the undersides of cars back then!

Toyota Highlander, front:
https://ecomodder.com/forum/member-v...go-2019-33.jpg

Interesting the Toyota Highlander continues Toyota's philosophy of the inboard hole/holes that I have on my Corolla (a completely different car, large SUV vs small economy car):

http://www.mulsannescorner.com/Ecomo...428_202245.jpg

Believe just about every Toyota has these (interestingly, the Prius does not) in one form or another.

Had these. The new Corolla does not, Camry does not, Sienna does not, Prius, etc. (My third gen Prius had them). I was surprised to see them on the TNGA Highlander, which I think is why I took a picture!

The only other car I can think of offhand with the hole is the Chrysler Pacifica.

Any theory on the function of the inboard slots? That last one isn't so much a slot as an empty frame.

Providing a reliable stream of air for the brakes is as close to an answer as I've determined. Though they seem so ham-fisted. Interesting the current Toyota-crop isn't using them...

I am changing the title of this thread to include all the aerodynamic modifications I make to my Camry. This will be much better than having many different threads for all the stuff I want to do. When I get around to doing some tests I will copy results to the first post.

Those holes in the Toyota wheel spats are very peculiar! If they are for brake cooling, I wish mine came with those... the PO warped one of my brake rotors.

The diversity in OE wheel spats tell me that most designs function fine. The other day I saw a Chevy Malibu that had wheel spats larger than the ones I made that span the entire width of the tires.

A future project I have been thinking of is modifying the spoiler on the Camry to be slanted downward slightly and to have a clean separation edge. This will serve to reduce the wake size (something Julian Edgar talked about in his video about the Mirage). This will be coupled with a full undertray and a rear diffuser that will be angled slightly upwards.

The downwards-angled spoiler extension will work in reducing wake size only if there is attached flow ahead of it. (That's certain on a hatchback roof like the Mirage; it's to be expected but not certain on a 2007 Camry.)

Also, the greater the downwards angle of the extension, the more drag created as the attached airflow wraps around this curve. Therefore, the best trade-off between reduced wake size (reducing drag) and attached airflow around the spoiler (increasing drag) can be found only through testing. For example, throttle-stop testing or mileage over a short, flat, repeatable course at the highest speed possible.

The upwards sloping diffuser will again only be effective in reducing wake size if there is a relatively smooth floor ahead of it, basically to the front of the car. In a car of that age, I'd expect that to require an undertray. Again, though, this is easy to test - pitot tube, tufting (if the car is high enough), even pressure testing.

It would be pretty difficult to test different angles, and probably not something I am going to do because this would require a lot of quality and work to do accurately. I am sure that there is a difference between a 10 degree slope and a 15 degree slope, but not enough to make testing worth it to me.

I will likely slope the spoiler by a conservative 10 degrees, and quantify the change through testing.

I'd never spend money on a spoiler without testing first. Just use plastic sheet and tape to make trial spoilers. Even without throttle stop testing, I could detect (through fuel mileage) changes in drag with different rear spoiler angles on the Roomster shown in the other thread.

(And testing is even more important if it's a lot of work to modify the existing spoiler.)

slotted spats
 

Is it a compromise for brake cooling air?

I can imagine an L-shaped vortex generator directing air to the brake, ...invisibly to the naked eye.