cjsafski

iTrader: (2)

Sonny's wing in the pic is still not 100% complete. I still need to weld together the part the wing bolts to and the struts together. The flat plates with only a single bolt through them will disappear. Also the side to side play right now is a little much and should probably be braced.

The ones I made for my car are a little more sturdy. The NA trunk was a little different which allowed me to move the mount back and run shorter arms to the wing.

mr_hyde

iTrader: (4)

Chris, what's your plan for the trunk lid? Just cut slots from the back for each upright or do you have fancier ideas? It will be nice to not worry about getting punted and crippling the wing mounts.

cjsafski

iTrader: (2)

On both Sonny's and mine the plan is to do long cuts in the trunk. We talked about doing stubs coming out of the trunk that that struts bolt to and doing cuts barely big enough for the struts. Personally I don't like that since if the car becomes endurod and something happens with the battery or anything else that ends up in the trunk it would take extra time to fix. For the case of my car I dont have space/money for a truck and trailer so I have to drive to the track. I need to be able to access the trunk without unbolting things. I may build something the trunk closes onto to hide the cuts or just dgaf.

Depending on how the trunk is on crusher I have a few ideas to make it cleaner. Apparently the later years like Sonny's got some funky gussets above the tow hooks which is why I had to give his mounts so much of a rake. If those are not there, I may be able to have the mounts pass through barely above the tail light and maybe angle up after that. Should look much cleaner. Since the taillights on my NA were closer this was not doable.

emilio700

iTrader: (3)

What we'll do for Crusher is make the struts stop just above the trunk and add some sort of QR clevis mount or something.

Keith@FM

iTrader: (1)

Everything old is new again - looks a lot like the setup on our Track Dog from forever ago. I've gotta say, the slotted trunklid is a bit of a pain in the *** to live with. A QR would be pretty much required.



A guy wire X made a big difference in rigidity on my tall wing mount. Although it would make the slotted trunklid pretty much a no-go.

emilio700

iTrader: (3)

Wires are very high drag. We get the required stiffness with a single strut located under the trunklid.

Leafy

iTrader: (1)

Not only that, but they disrupt the airflow under the wing, and the airflow under the wing is the important part.

Keith@FM

iTrader: (1)

I'm comfortable with the position. They're behind the wing, so airflow disruption isn't an issue. I also kept them a bit lower to keep them away from the wing. Drag - well, I know wires are draggy, but it was the cleanest solution in my mind. Since my mounts are attached to the car at trunk height, a strut down low wouldn't help. I could have increased the thickness of the uprights, but that's not the clever solution and had some other effects I wasn't happy with. The wires not only stopped the side-side movement, but they also made the mounts stronger in the longitudinal direction as I attached them where the mounts want to bow under high load.

Leafy

iTrader: (1)

Well Keith, there's always the overly robust option. You can grab the wing endplate and rock the car back and forth with 500lb springs in the back.

Full_Tilt_Boogie

iTrader: (1)

^that looks more draggy than the wires, more frontal area anyway.

But anyway, couldnt you have the upright coming up right on the edge of the trunklid, then if the trunklid was held in place by dzuz fasteners you could lift up one side and pull it backwards through the space between the uprights and spoiler?

Supe

It should help with small rocks/debris. It's amazing how beat up the front end of my tegris splitter was after a single two day event on a public road.

Leafy

iTrader: (1)

Hm, I never had any splitter tip damage with my plywood ones, the last car had 1 auto-x and 15k street miles on it. Including winter in new england. Word from the wise, as cool as you think you are intentionally plowing snow with your splitter, DONT. You'll spend hours trying to get the snow out that has packed itself into spots you didnt know it could.

00MugenS2

Dollars spent: $45
Hours spent: 5hrs
How effective: Currently untested


First:

I didnt want to loose the rear window, but since its made of Lexan, it is very easy to make some vent holes. For the same reason I dont want to loose the rear window, I didnt want water to get into the holes in case of rain. So for $20 I ordered 4 - 3 1/2" Snapvents to fill the holes (same ones that are used in the lexan quarter glass windows)







Also, everyone knows that there is a vacuum created behind the car as your are driving. So this is to reduce the vacuum and pull air out of the cabin.






And last, is to remove the air that creates the lift in the rear fender wells, and use the vacuum behind the car to pull it out. This will both reduce drag AND lift. Cost was only $20 for the 2 1/2" industral vacuum hose from Home Depot



Break out the reverse lens and break away all the plastic on the inside.









Inside the fender

njn63

iTrader: (4)

Really would like to see some data on the wheel well/tail light idea. In theory it should work but it's something I haven't seen before.

sixshooter

iTrader: (12)

The license plate cutout will give you a surprise headache from the exhaust fumes being pulled into the cabin. The holes in the bottom of your rear window will allow airflow back into the cabin. Holes at the top of the rear window would draw air out of the cabin.

Opel:


Porsche:



Miata

00MugenS2

I will not argue that the high velocity air over the roof line would suck air out to the cabin better, but this if designed for the windows being up and vacuum would be the only way to get air out of the cab. I belive that when the windows are down there will be enough pressure inside the cabin to push the air out.

All of the wind tunnel info ive seen shows that the area at the bottem of the rear window is a high pressure area on the miata. That is caused by hardtop droping down to quickly and the airflow not able to stay attached. Thats why the best option would be to have the hardtop that extends to the rear of the trunk.

I think that the flow from the side windows to the rear vents wil remove the high pressure by speeding up the air. Project G said that the with the 2 large vents the had a large increase in air flow throught the cabin.

I plan on doing testing with vent open and closed.

mr_hyde

iTrader: (4)

I've thought a lot about improving overall aero by ducting and channeling air from places you don't want it to places you need more of it (or less lack of it?). It always seemed some large ducts from the trunk floor to the finish panel area would be very helpful and the same principle works for the wheel wells.

Let us know how it works. Tuft tests at the license plate and better yet, manometer results in the wheel well and license plate (before/after) would be great.

Effective or not, props for working outside the box!

sixshooter

iTrader: (12)

Yes, the base of the rear window is a higher relative pressure area than inside the cabin. That is why air flows from there into the cabin. The purpose of a rear spoiler is to increase the pressure (and reduce the air speed) in that trunk lid area to reduce the lift in the rear of the car.

In the case of the "project g" car, he is reducing the effectiveness of the rear spoiler in the picture you posted and pulling huge amounts of air into the cabin from the base of the rear window. That car owner is obviously very confused about anything to do with actual performance, just looking at it.

motormechanic

iTrader: (1)

you can't look at Project-G cars as your reference points for aerodynamic benefits (no offense to them). Sixshooter is right, the base of the rear window is very high pressure, as seen on Plucas' diagrams. Even with the windows down, you will pull in air from there. Put them at the top where the air hasn't separated as much yet, and you will have air pulled out.

Braineack

iTrader: (62)

He can put on hood risers to counteract the effect.