Is there any new experience to report, about the effectiveness of using Vortex Generators?
No track time since the April event. Going back to Buttonwillow 6/23-25.
Will be able to get some lap times to do a 'before & after' with the AirTabs.
In any case, for an investment of only $27.50, they sure look cool! (see #52 in the background)
I am ssssoooo waiting to see if there is any difference with Air tabs.
I am just about ready to get them just for the cool factor.
For the June event I'm going to get some times with the airtabs, then switch tops with #25 and compare the times.
Without airtabs I can't stay full throttle in 5th going clockwise through the riverside turn. Rear end gets way too light and starts 'dancing'. Got my fingers crossed that the vortex generators will help get some air down to the rear spoiler!
Man I wish I lived in Kalifornia. That is WAY bigger than NPR in Lousianna.
i saw an EVO with vortex genorators on its roof yesterday...
Well so much for that shit. If the ricers guys start putting them on then I will keep them off.
UNLESS someone has evidence of it really working. then I will just paint them flat black like the targa top.
A friend of mine is a retired engineering professor and we were talking about the vortex generators at one of our Porsche Saturday AM get togethers. He is very well known and respected in the engineering and PCA racing communities.
Here is what he said after I showed him a picture off the internet:
"What this picture shows are a type of vortex generator but these are WAY to
large! The next time you fly look out the window of the aircraft about where
the engines are mounted below the wings and you will see a row ( or two ) of
small one or two inch high hat appear to be tiny wings sticking out of the
wing and with a small angle to the flight direction. These produce vortices
which help keep the flow attached to the wing and increase lift
The add-on's in the picture you sent may make the owner happy but will only
increase the drag. I can't see that they will produce any help for any
thing."
wow, talk about a bummer.....
That last post kind of takes all the fun out of it...
...Except, our cars don't go 500mph.
I'd like to see some wind tunnel pics.
KT
I started this thread, because I had intended to install the Factory Mitsubishi VG. The ones you are referring to are designed for Semi's, with long straight, flat panels. As I understood, they were trying to get clean release at the rear, to lessen drag. The smaller version on Mitsu. were developed, not just eye candy. There design is to keep air attached, reducing lift, and or keeping air in the vicinity of wing/spoiler.
I still think there is potential for improved stability at speed.
I'm going to say they make an improvement.
KT
numbers will tell.
all else is conjecture.
They're cute!
They look cool, I hope they have some benefit.
So any word on the track testing?? Faster slower or just cute sorry cool.
There seems to be a couple of potential solutions, Subie rear window diverter, Mitsu vanes & these vortex generators. I wonder if any really work in our targa configuration?
Where can I find the Mitubishi vanes? at least a picture.
Subie window diverter?
I imagine something in the middle size wise.
Then test it old school tape a bunch of yarn on the deck lid and up the duck tail fin.
I am sure the caw catcher air dam make my car more like a brick through the air anyway.
Vortex Generator test this weekend!
Running Friday-Sunday @ Buttonwillow and will be running stock & the 'vortex' top to get lap times.
Should be fun if the 4 holds up in 100 degree plus heat!
Looking foward to the results
KT
I was searching around and found Vortex generators used on airplanes.
They however wer putting them on the leading edge of the wing in an effort to keep air flow against the control surfaces.
Little bitty things not more than an inch high and 2-3 inches long.
My point is I guess the results or affesct depends on where you place it.
Results are in!
914 http://www.914world.com/bbs2/uploads/post-5027-1148486336.jpg Test, 6/23-25 http://www.buttonwillowraceway.com/, http://www.buttonwillowraceway.com/images/race_01_config.gif, Clockwise
Subjective results:
Observation #1: Substantial difference in the rear end feel going clockwise around the http://www.buttonwillowraceway.com/images/race_01_config.gif. Previously the rear would get very 'light' and start twitching around through this turn, limiting throttle to about 50% in 5th. With the vortex generators I could actually feel the rear end 'squat' over 100 and could keep about 90-95% throttle through this turn! Appears that the vortex generators are helping reduce the air turbulence behind the back window and getting some air flow to the rear spoiler.
Observation #2: Previously would only have to 'lift' exiting Riverside to make the R to L transition going up to http://www.buttonwillowraceway.com/images/race_01_config.gif. With the increased exit speed from Riverside, this is now a 'brake' (a 'tap' is not enough! Almost went farming the first time through )
I was not expecting this much difference. As a matter of fact with all of the feedback on why this wouldn't work, I was wondering if I would notice any difference at all. I'm very happy with the results
Objective results:
Times showed a 1/2 second improvement, or about 6 car lengths through this section. I'm sure there is more out there as I work with this new setup.
Summary:
Even if the times did not improve I'd keep the vortex generators just for the increased stability and confidence in high speed handling. The rear end skating was too much 'excitement' for me...
Question now is, will the increased drag slow me down on other tracks?
More info on the AirTabs I used at: http://www.airtab.com/
Hope this test and results was of value to some of you!
Thanks for the update.
I would like to try them.
Are they adhesive applied?
Removable?
Thanks, again.
KT
Awesome. They *should* increase top speed too by reducing all that drag in the rear end....keep us posted as you get more experience! Who's going to build a targa top with the smaller vortex fins??? (like on the Evo and another, yellow 914 racer I've seen a photo of)
The AirTab site has a new photo showing http://www.airtab.com/Images/photogallery/gallery1.htm#RT . Good pic of how it helps get air down to the rear spoiler on a 914..
Greg - it's good to hear they were working for you. Not to be too much of a devil's advocate, but did you swap the roof with the stock one from the Orange car to see if you could directly correlate the advantage being the tabs? Just asking as you mentioned you planned to do this...
This rules out any advantages possibly gained by track conditions that day v. previous days you have been there (tires stuck better, less/more wind velocity at a different direction, etc).
I think they are bitchin' and intend to get some for my car, but just wondering if you did a direct comparison within the same day with/without.
Im going to buy some...
Anybody tossed them under the car, say in front of the engine on each side and notice a reduction in head temps? If it works well up top, it should work down under so to speak.
Possibly YES, looking for any advantage I can find, if it helps at 7.50 a side I would do it in a heart beat, I have the stock flaps installed, but will be switching to a bigger engine, and want the additional cooling help any place I can get it.
I know Joe Ricard mentioned it somewhere between the 27 914 boards we now live on, but I have not seen numbers. You know with out flaps my head temps where 345, with them I am now running 325, with vortex generators, I now run head temps at 0 degrees Kelvin
Absolute zero could be fun brings up a whole new set of problems thou. But I could stop paying to have parts cryroed!
Have a look here:
http://www.prfprod.com/
These are much smaller than the AirTabs and come in sheets 12" wide with two, three or four rows of VGs. Four sheets will do the roof. I've ordered some of the two-row type to mess with and will let you know what I find.
These look like the same ones that are on the yellow Wayne Baker car that you might have seen at the track...
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Hi Mike,
Those do look like what is on Wayne Baker's car
I've been happy with my setup. Anxious to hear your results.
Here is another vendor that I just came across recently. Closer to aircraft style
http://www.vortekz.com/
Greg
I took the photo, so I can answer the question. Yes this is the car he drives. He explained to me someone else owns it.
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