Another home made vortex generator
Hi all, I have been lurking here for the last year off and on. Somebody in the thread on airtabs had suggested using old CD's for making vortex generators. That is what I did today! I will upload some pics as soon as I figure out how to get them sized right.
Phil |
I'm most anxious to see.:)
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Sweet! Cheaper than airtabs & more colorful too.:thumbup: :cool:
Very well presented, as well. |
Thanks, SL8Brick, I will be happy if they just keep the rear window a bit cleaner! I will get a chance to test them out tomorrow when I drove over the mountain to work. I didn't put enough thought into things to do any A-B-A testing but I usually go thru a tank of gas a week. Should show in the fill-ups if there is a significant improvement in economy.
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...and that's a VW Passat wagon, is it not? What engine...TDI?
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I wish..... I insisted on all wheel drive since I drive over a mountain pass twice a week. Best engine combo I could get was the 1.8T gasser. At least it isn't the v6.
I was looking at removing the roof racks since I have never ever put anything on the roof of a car. I just don't know if I want to rip out the headliner to pull the bolts out. I guess I could just build a little bubble thingy to bolt on in place of the rails. |
I'm a VW/Audi parts consultant...Gotta luv the 4Motion. And I agree, as far as FE goes, the 1.8T is the lesser of the two evils.;)
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Quote:
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I hung a bunch of old CDs out on a tree and found that they started delaminating after a while.
You could use scrap plexiglass to make vgs (check hardware stores). Can be cut to shape using a jigsaw held upside down in a vise...easy on the pressure. Use WD40 or water to lube the metal cutting blade so it doesn't melt the plastic. Edges can be ground on a sander. If you put plexiglass in an oven...it is formable...need to regulate the heat. Don't need that much temp...forget what it was. No smell if you don't go too high. The heat gun and vise method might work too. Plexiglass will last a long time. |
If they prove worthwhile I may go buy a sheet of polycarbonate and cut some out of that. I have also been dreaming up a spoiler/boattail out of polycarbonate. I think it could be done to look fairly good.
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The CDs only work if they are Earth, WIND and Fire
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philp100 -
That is soooooooo righteous! What a great use for the R&D "CD-Coasters" we end up creating at work. CarloSW2 |
Well the initial drive with them has provided no feedback at all. I had to drive 35-45 mph for about 80 miles of my 150 mile trip due to the snow and idiots over the pass yesterday. The rear window did not stay any cleaner with them on. I ran a steady 65 when I got over to I-5 and my trip computer says i was running better mpg than I have the last few tanks but the weather has been completely different.
One negative I have found with them is the guy with the lifted 4x4 must have thought they looked cool in his high beams as he put them on several times while right behind me in the right lane of a passing zone..... I think I will leave them on for a few more tanks of fuel and try to do some A-B testing when I take them off. |
At this point I am going to call this attempt a failure. I did not go into doing this with a good enough plan and the weather has not cooperated this week so I have no idea if it made any differnce in FE. The rain and snow and wind finally detached 3 of the 6 VG's after 400 miles. It made no difference on how dirty my rear window got.
I think I will talk to the VW dealer and see if there is a kit for deleting the roof racks. Probably a much better chance of seeing an improvement. |
The guy in the 4x4 probably thought you were a Martian.
You might try testing some alum vgs in summer? |
Dang Zuq, The time stamp says you replied at 3:07AM!
I need to take the time to be more serious with my testing. I have been looking at adding a spoiler to extend the roof anther 6". It looks like it would be even easier to make than the VG's. I still may look into VG's for my 4x4 dodge and various tralers. |
I'm a truck driver and have been researching the vg's for my use. This is how I came acrossed this thread. From what I have read the Votex generated is 4 times the height of the vg. This leads me to think the reason for your failure of proof of concept is the cd in unaltered form is too big. A 1 inch vertical vg will create a 4 inch vortex. That's all you need. Spaced 3 inches apart. As large as those CDs were I might even hypothesize that they distorted under load and possibly lost functionality. Love the effort keep it up.
I drive a 2013 peterbuild and currently average 7.5 to 8 mpg weekly avg. many variables to account for but for every 50 gals a week I can save is between 175 to 200 dollars increased income per week. Needless to say I take this subject seriously. |
The CDs are an interesting material to use. My question is their durability. Especially with particles from the road constantly beating on the plastic.
I've been working with this design but recently decided to go with the delta wings. Aluminum flashing does very well and is pretty cheap. A little rustoleum does well for coating. I've been going off this page for reference Vortex Generators for Enhanced Aerodynamics :: Sigma Automotive There was also a paper on them I found that went extensively into the science and experimenting. The author concluded with ideal dimensions for a delta shaped VG. I gotta google it if anyone wants the link. But in my experiments using tuft testing I have found that these air tab shaped VGs have done very well. Admittedly, I grew tired of the aesthetics which is why I switched to delta VGs. Anyone have any results comparing the two types? |
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