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Old 05-20-2013, 12:50 PM   #1
Idahotom
 
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vortex generators

I've been using them for years, on airplanes. And in fact had some left over from my last installation, and too much time on my hands I guess, so I went ahead and vg'd the aft portion of the roof line on my '08 HB.

The spacing and angles are the same used in aero apps, it has been determined that putting them closer doesn't do any better, but adds more drag. Same with the paired angles, that's all been tested before. So it made it real easy to just use the supplied template and double side carpet tape to install. If I decide to make it permenant I'll glue them on with the same stuff supplied in the airplane kit. BTW, we're talking below 100 mph airplanes here.

The 1.5 mile dirt road to get to my place will make a perfect test site to spot any changes in the airflow on the rear window. What I am hoping for is a more attached airflow over the rear, and that is what vg's do. On a wing they keep the airflow attached to the upper surface longer, as the angle of attack increases when landing or flying slow. This allows for slower landings and as important better control authority at the lower speeds as you have more and "better" (non disturbed) going over the control surfaces. How this will translate to the Yaris is anyones guess, I did it halfway for a laugh (and no doubt will tell people who ask that it adds 10 mpg) and just maybe it may be not a bad idea.

I thought of extending them down along the sides, and may, I'll wait until I drive the wind tunnel a few times. I'll report back on results, if any. The airplane, a Rans S-7S kitplane. 3.5 GPH car gas at 90 mph. BTW, I've noticed that the guys who fly the big Cessna's or Maules (8 to 14 GPH) also drive big pickups or SUV's, they wouldn't be caught dead in a Yaris! Some of us just like to do more with less I guess
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Old 05-22-2013, 09:27 PM   #2
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What a coincidence . I've installed them since one week ago.

However, My design was drawn from the Mitsubishi's type and is significantly larger than yours.




Need a bit more of testings. But my butt-o-meter says the car is now more stable at high speed (>80 MPH) .
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Old 05-22-2013, 09:35 PM   #3
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Also, I'm planning to apply a pair to the side mirror trims. I saw the new Camry Hybrids and Prius Cs have them .
The new Mercedes S-Class (W222) also has VG-ribs built onto the side of the side mirror housings.


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Old 05-23-2013, 10:03 AM   #4
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Very cool..... yeah mine are smaller, and just like the ones we use on the wings of the planes, in fact extra left over ones. So zero cost anyways.

I just noticed the streamers on the area downwind of your vg's, that looks like exactly the kind of airflow you'd want, nice and laminar. I haven't tufted my HB, I may do so if I get more serious about this, as that is the way to see what's really going on.

80 mph is high speed in my book!
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Old 05-26-2013, 11:06 PM   #5
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Since reading the post about "being more stable at high speeds", it occured to me that I had not had my HB up to highway speeds since the vg install, just secondary road/ 45 mph driving. So, I made a special effort to take the interstate into town, and I got up to the blistering speed of 65 mph and then almost 70, rather then my usual 60. The results were very interesting.

I should mention I took EVERYTHING out behind the drivers seat, 2 years ago, including that framework that supports the seat and maybe adds stiffness to the unibody. I have good tires and a aftermarket rear sway bar, and the front end is set to specs. So, the highway speed straightline handling to date, which, to be generous, could best be called "sporty", has just been something I have learned to live with. I just figured being so light, it was to be expected. That and maybe that steel tube structure for the seat was allowing some flex, or something. Or, maybe the heavy semi traffic and the resulting dished out slow lane (where I am all the time) had the Yaris needing pretty constant attention to not look like I was driving impaired. No big deal really, l like everything else so much this was a small price to pay and just part of the deal, I'm no whiner.

BUT, now with the vg's......it's like it's on rails! The thing tracks like a much heavier car now, and the work load is much reduced, the difference is amazing! Too soon yet to tell if there are any mpg changes, but just the handling difference makes this experiment a success. Furthermore, it was pointed out to me that I had them too far rearward, they need "room to work". That is, moving them forward a bit would allow the airflow a little more room to get re adjusted somewhat. This made perfect sense to me, as on the airplane we put them ahead of the area we want the airflow to stay attached to, by 6 or 8" or so. So, I pulled them all off (just double sided carpet tape) and then just to make sure I wasn't imagining things, drove it on the interstate again, and, the squirrley handling was back! So, no question the vg's are doing something, and that something is good. They are now semi permenantly glued down right behind the antenna, about 6 or 8" from the rear deck drop off, and while I have yet to drive it at freeway speeds since the move, I am real pleased so far. I will report back after a couple tanks mpg wise, if it's the same I'll be happy, I'm thinking whatever is going on to effect the handling so much (less ass end drag and turbulence?) must have favorable results on the mileage, that would be a real bonus if it did.
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Old 05-27-2013, 12:15 PM   #6
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Quote:
Originally Posted by Idahotom View Post
Since reading the post about "being more stable at high speeds", it occured to me that I had not had my HB up to highway speeds since the vg install, just secondary road/ 45 mph driving. So, I made a special effort to take the interstate into town, and I got up to the blistering speed of 65 mph and then almost 70, rather then my usual 60. The results were very interesting.

I should mention I took EVERYTHING out behind the drivers seat, 2 years ago, including that framework that supports the seat and maybe adds stiffness to the unibody. I have good tires and a aftermarket rear sway bar, and the front end is set to specs. So, the highway speed straightline handling to date, which, to be generous, could best be called "sporty", has just been something I have learned to live with. I just figured being so light, it was to be expected. That and maybe that steel tube structure for the seat was allowing some flex, or something. Or, maybe the heavy semi traffic and the resulting dished out slow lane (where I am all the time) had the Yaris needing pretty constant attention to not look like I was driving impaired. No big deal really, l like everything else so much this was a small price to pay and just part of the deal, I'm no whiner.

BUT, now with the vg's......it's like it's on rails! The thing tracks like a much heavier car now, and the work load is much reduced, the difference is amazing! Too soon yet to tell if there are any mpg changes, but just the handling difference makes this experiment a success. Furthermore, it was pointed out to me that I had them too far rearward, they need "room to work". That is, moving them forward a bit would allow the airflow a little more room to get re adjusted somewhat. This made perfect sense to me, as on the airplane we put them ahead of the area we want the airflow to stay attached to, by 6 or 8" or so. So, I pulled them all off (just double sided carpet tape) and then just to make sure I wasn't imagining things, drove it on the interstate again, and, the squirrley handling was back! So, no question the vg's are doing something, and that something is good. They are now semi permenantly glued down right behind the antenna, about 6 or 8" from the rear deck drop off, and while I have yet to drive it at freeway speeds since the move, I am real pleased so far. I will report back after a couple tanks mpg wise, if it's the same I'll be happy, I'm thinking whatever is going on to effect the handling so much (less ass end drag and turbulence?) must have favorable results on the mileage, that would be a real bonus if it did.

How did you come up with the angle pairs that you used?
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Old 05-29-2013, 08:27 AM   #7
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I used the same spacing and angles as the company I use (www.microaero.com) determined long ago to be the most benefical and lowest drag. All that ever changes is the fore and aft positioning. Note the small size....all that is needed to effect the boundry layer they claim. They provide an adhesive vinyl stencil that you simply layout and stick down, and it has cutouts so you put the vg's where the cutouts are, real quick and simple. I have high regards for this company, as do others in the aircraft world, so I trust they have this all figured out by now and just did it like they do.

I had a little time to kill yesterday, and stopped by a Toyota dealer and took a Prius C for a test drive. To my surprise the salesguy really knew his hypermiling and hybrids details. He was all excited to show me the side vgs the little Prius has, and some other little aero details that I hadn't noticed. Toyota really seems to have done their homework on that rig, pretty damn cool. But as the hybrid advantages are greatly reduced in open highway driving as compared to city driving, where it really shines, and with my rural location such as it is, the Yaris is much more cost effective. They worked me up a trade in price, 6K+ for my '08 HB with 70K+ miles, not too big of a rip off, and I was surprised at the (somewhat) low price of the C, 20K. Extremely high tech little rig, for better or worse, compared to the simple Yaris, I think I'll keep the Yaris!
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Old 05-29-2013, 02:54 PM   #8
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With my bro's Prius C, I get a minimum of 65 mpg (more usually in the 70's) in the city. I never drove it on the freeway yet, but when we took it out the other day, and with my bro driving (not as good at hypermiling as me), and with the AC on, he got 61 mpg over the course of around 60 miles. It's a pretty good car. Not as much space as my Yaris, definitely slower, and the HU is harder to work with, requiring you to be stationary to Bluetooth pair or enter a destination in the navi.

I had VG's on my sedan before set to the Vortekz default spacing and angles. When ever my rear window would fog up, a few minutes of driving on the freeway would create triangular clearings on the top of the window and eventually would clear the entire window. I took the VG's off (since too many people wanted to race my car and I was getting tired of that), and now I have to use the rear defroster to clear the window, so I know they definitely worked in regards to changing the air flow. I only saw .xx mpg improvement with them tho.
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Old 05-29-2013, 11:16 PM   #9
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With my bro's Prius C, I get a minimum of 65 mpg (more usually in the 70's) in the city. I never drove it on the freeway yet, but when we took it out the other day, and with my bro driving (not as good at hypermiling as me), and with the AC on, he got 61 mpg over the course of around 60 miles. It's a pretty good car. Not as much space as my Yaris, definitely slower, and the HU is harder to work with, requiring you to be stationary to Bluetooth pair or enter a destination in the navi.

I had VG's on my sedan before set to the Vortekz default spacing and angles. When ever my rear window would fog up, a few minutes of driving on the freeway would create triangular clearings on the top of the window and eventually would clear the entire window. I took the VG's off (since too many people wanted to race my car and I was getting tired of that), and now I have to use the rear defroster to clear the window, so I know they definitely worked in regards to changing the air flow. I only saw .xx mpg improvement with them tho.
Wow. If someone could consistently average 65 MPG.....and someone averaged 40 MPG in a base Yaris....the extra cost (given the figure for the C that Idahotom quoted) would be made up within 195,000 miles (or a bit less) with $3 a gallon gas --- 3000 gallons for the C and 4875 for the Yaris at the 65 and 40 MPG levels. With gas at $3.15-3.20 minimum here, and over $4.00 in parts of California, that gap would be closed in fewer than 195,000 miles. Prior to purchasing my Yaris, I tried to estimate at what point the gas savings on the standard Prius would justify the cost premium. I figured it would be at over 300,000 miles.
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Old 05-29-2013, 11:28 PM   #10
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Wow. If someone could consistently average 65 MPG.....and someone averaged 40 MPG in a base Yaris....the extra cost (given the figure for the C that Idahotom quoted) would be made up within 195,000 miles (or a bit less) with $3 a gallon gas --- 3000 gallons for the C and 4875 for the Yaris at the 65 and 40 MPG levels. With gas at $3.15-3.20 minimum here, and over $4.00 in parts of California, that gap would be closed in fewer than 195,000 miles. Prior to purchasing my Yaris, I tried to estimate at what point the gas savings on the standard Prius would justify the cost premium. I figured it would be at over 300,000 miles.
Yup, it's $4.03 for 87 here (bro and I only use Chevron). That car really does great on mpg. When ever I'm in it and my bro is driving, I try to teach him how to drive more efficiently. lol. It beats the Camry it replaced. Best I could get out of it was only 28 mpg, and it was a 4-cylinder model (on it's last toe about to die).
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Old 05-30-2013, 12:11 PM   #11
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Thanks; I'm gonna keep an eye on this thread; I've been thinking of doing the same thing. My goal is to keep the back window clean(er) during a rainstorm. I bought a rear air deflector for a Dodge Voyager van (the rear roofline has a similar curvature to the Yaris) but haven't done anything to install it because it requires a little customizing (cutting down), custom mounts, and drilling holes. Maybe a combination of both the deflector and VGs (on top of the deflector)?

You can get VGs on ebay but there is a company that makes \/ shaped VGs called Air Tabs. I was thinking of sticking those on...
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Old 05-30-2013, 12:39 PM   #12
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Thanks; I'm gonna keep an eye on this thread; I've been thinking of doing the same thing. My goal is to keep the back window clean(er) during a rainstorm. I bought a rear air deflector for a Dodge Voyager van (the rear roofline has a similar curvature to the Yaris) but haven't done anything to install it because it requires a little customizing (cutting down), custom mounts, and drilling holes. Maybe a combination of both the deflector and VGs (on top of the deflector)?

You can get VGs on ebay but there is a company that makes \/ shaped VGs called Air Tabs. I was thinking of sticking those on...
Do you have a spoiler on your LB?

Are you going to place yours where the OP placed his? If so, I would get the same ones he has since the size and shape may make a difference on where the placement should be. I would conduct tests like he did. I remember LT Noogie did. I'm not sure if he test videos (taped on yarn on his back window) were lost in the hack or not.
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Old 05-30-2013, 12:45 PM   #13
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This is interesting my yaris is so squirrly when driving it on the freeway its almost to the point where is dangerous and scary especially if its a really window day i feel if im not paying attention 100 percent on the road its going to wander to the next lane, all the suspension mods I have done have greatly improve that but if something as simple as this can make a great impact i think ill give it a try as well
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Old 05-30-2013, 12:49 PM   #14
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http://www.youtube.com/watch?v=We8LWkqjdX4

After watching this video i am ordering some on ebay right now lol http://www.ebay.com/itm/Universal-Fi...67a531&vxp=mtr
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Old 05-30-2013, 06:01 PM   #15
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Do you have a spoiler on your LB?
No, no spoiler. I was thinking of the factory spoiler that has a space between the spoiler and the roof. But I couldn't tell if, in that space, the air is directed downward to clean the rear window.

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Are you going to place yours where the OP placed his? If so, I would get the same ones he has since the size and shape may make a difference on where the placement should be.
I really am stumped about what to do. I suppose the best first step is to install VG and see if they are effective enough at cleaning the rear window. If not, then take the next step with the rear deflector. One last concern with the deflector is how much it will mess up my gas mileage; I want to do things that increase mileage, not decrease it...
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Old 05-30-2013, 06:34 PM   #16
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No, no spoiler. I was thinking of the factory spoiler that has a space between the spoiler and the roof. But I couldn't tell if, in that space, the air is directed downward to clean the rear window.



I really am stumped about what to do. I suppose the best first step is to install VG and see if they are effective enough at cleaning the rear window. If not, then take the next step with the rear deflector. One last concern with the deflector is how much it will mess up my gas mileage; I want to do things that increase mileage, not decrease it...
I'm not too sure about the spoiler part, but for the VG's, you'd have to really play around with them. Their distance from the edge of the hatch and each other, the angles of each one, etc.

What is a rear deflector, btw?
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Old 05-31-2013, 05:07 PM   #17
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What is a rear deflector, btw?
They kind look of like rear wings except, instead of generating downforce, they just take the air flowing over the roof and deflect it downward over the rear window. Back in the 70s and 80s, before rear window wipers were available or popular, this was the "technology" to keep the rear window relatively clean. I am guessing that with tightening fuel economy rules, the rear window wipers became the standard as automakers were looking for ways to reduce drag.

http://www.andysautosport.com/toyota...p00000132.html

But the Yaris rear wiper is so small, it is IMO really ineffective. Plus, all that crap on the rear after a rainstorm is really depressing to look at.

Huh! I just noticed (and read) IdahoTom's third post about the stability. I always thought my Yaris's squirrelly handling was due to the fact that it is FWD (I've had nothing but RWD cars until now) and just tought I would live with it. This alone is almost enough for me to scrap the deflector idea and buy and install VGs...

Last edited by Yaristeve; 05-31-2013 at 05:21 PM.
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Old 05-31-2013, 10:12 PM   #18
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They kind look of like rear wings except, instead of generating downforce, they just take the air flowing over the roof and deflect it downward over the rear window. Back in the 70s and 80s, before rear window wipers were available or popular, this was the "technology" to keep the rear window relatively clean. I am guessing that with tightening fuel economy rules, the rear window wipers became the standard as automakers were looking for ways to reduce drag.

http://www.andysautosport.com/toyota...p00000132.html

But the Yaris rear wiper is so small, it is IMO really ineffective. Plus, all that crap on the rear after a rainstorm is really depressing to look at.

Huh! I just noticed (and read) IdahoTom's third post about the stability. I always thought my Yaris's squirrelly handling was due to the fact that it is FWD (I've had nothing but RWD cars until now) and just tought I would live with it. This alone is almost enough for me to scrap the deflector idea and buy and install VGs...
Ah, looks like duckbill spoilers. lol.

Yeah, get some and just play around with the settings until you get the yarn strings all flowing straight and not erratically.
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