Downforce needed - battle of the craptastic eBay wings

[BlackbirdM3]

Simple solution... What e30 won a World Touring Car championship? Oh yeah that would be an M3... The rear spoiler of an M3 with a DTM gurney flap would work wonders. Now, you guys have a couple stikes against you, one you lack the step on the roof for the M3 rear window and C pillar. You might be able to fake it by using a piece of clear plastic wall edging mounted in aproxamatley the same place. This will cause the air to trip and fall down over the trunk lid. Your missing rear window is going to screw this up horribly. You can get an idea of what the air is doing back there by mounting a go pro camera looking back at the trunk and attaching some long pieces of yarn and mounting the fronts of them on the front wind shield and letting them fly back over the back of the car, and then off the back of the car. Take the car for a spin and see what the yarn does. You might want to mount the camera in a few different places as well as moving the yarn around. You will want to use several different sizes so you can see whats going on. If the strings are too long they won't work. We played around with this on our Lemons car (former TRON, now Flailing Lizards Ford ZX2 Escort.) We have played around with this, and we did get the car to handle better.

Back to making a fake M3 spoiler. You need the step in the roof to get the air to flow down onto the trunk and then over the spoiler mounted there. When I drive my M3 in the rain, I've gone 150 miles with rain water on my rear window, that air there doesn't move, its totally still. In some areas I've seen water droplets moving up the rear window toward the roof. That means the air is flowing well aft of the rear window and is going over the rear spoiler (I can see it in the rear view mirror.) Since you don't have a rear window, it might do odd things. (Back to using the yarn to see what the air is doing.)

If you guys are clever, I bet you could rig something up like the proven M3 spoiler. You can even add a big or bigger gurney flap off the spoiler for more downforce. Heck you get it right and you might be able to find a few more seconds per lap on top of having a good handling car.

If you are going to run a locker rear end, learn how to drive one. Its not like a LSD. On throttle it should keep things under control, off throttle it will rotate, and in the rain its just not a good idea what so ever. I run a Detroit Locker on my Datsun, in the rain its so much of a handful that I'd rather walk to work.

Will

[CorvallisBMW]

You're counting that wing in the budget, right? *cough*cheaters*cough* :)

My car hasn't had a huge need for downforce, but then again we haven't exactly been breaking any speed records with an eta motor. Will see if things change with an M50 under the hood. Maybe the fins are the key?

Wow, and I thought our motor swap was going to raise eyebrows ;)

[Jparkr]

You mentioned not having played with rear tire pressures. That's where I'd think to start. It may not solve your issue altogether but in the rain tire pressures are vastly different than in the dry. Take 5 pounds out see what happens.

We started with 30#
Five # were removed when I got out of the car and James got in, It helped a little. The weight helped the most. A little more down force and the car may be as good as we can get it to be in wet conditions.

[joshh]

You mentioned not having played with rear tire pressures. That's where I'd think to start. It may not solve your issue altogether but in the rain tire pressures are vastly different than in the dry. Take 5 pounds out see what happens.

[LTDScott]

You're counting that wing in the budget, right? *cough*cheaters*cough* :)

My car hasn't had a huge need for downforce, but then again we haven't exactly been breaking any speed records with an eta motor. Will see if things change with an M50 under the hood. Maybe the fins are the key?

[Van Westervelt]

I have a ricer twin foil wing, that came off an e30... lol.

If you want it or to take a peep, hit me up on my cell.

[Nsquared97]

Well in that case I would forget about a trunk spoiler and just mount one (or whatever else you come up with) directly to the roof. Plenty of clean air up there. But I still doubt you are going to find a low budget aero solution that will make a huge difference with the traction problems you guys are having. I could be wrong though, very curious to see what you guys come up with.

[CorvallisBMW]

We have no rear window, so a roof spoiler that directs air down over the back and on to a trunk-mounted wing won't work.

Yes I'm sure there are all kinds of fancy aero-experiments we can do, but remember this is a $500 SHITBOX. Our dedication is only as deep as our wallets. I'm really just looking to hear some experience/ideas on a spoiler vs wing.

[Nsquared97]

Try to get a wing above the roofline. You can test out your wing or spoiler setup on the street with like 5" pieces of yarn taped in locations to look at in the wind. You can use a stick with yarn attached at different points to see where the airflow is in a 3d sense, just have it stick up from the trunk or wherever you want to see it's effect. When you see fresh air, you know how far up you need to put a spoiler/wing to have it be most effective.

Another good way for testing airflow is to mock up something to hold a smoke bomb out in front of the car, and then drive. The smoke will show you how the air is flowing around the car, and what needs to be changed. This is what we did to test the aero on the A-mod car I posted.

[JeffRR]

Spend your energy working on the mechanical understeer, listen to Ben he's got the right idea.

How's the alignment? Add front RS and remove rear RS, springs / bars what ever it takes.

[Jaxx_]

most of the posts were tl;dr, but you need fresh air for a wing to be effective. I run a spoiler in autox and it only helps in high speed sections.



This is to the 10" max spoiler constraint in Street Prepared rules for SOLO II. Spoilers are going to be like this, and wings are going to have air flowing under them.

Try to get a wing above the roofline. You can test out your wing or spoiler setup on the street with like 5" pieces of yarn taped in locations to look at in the wind. You can use a stick with yarn attached at different points to see where the airflow is in a 3d sense, just have it stick up from the trunk or wherever you want to see it's effect. When you see fresh air, you know how far up you need to put a spoiler/wing to have it be most effective. VGs will help as well, but those will probably be a bit too expensive to just buy outright.

Hope this helps.

[tinkwithanr]

That Cessna wing could be considered ballast and downforce....

[CorvallisBMW]

We've thought about a fuel cell, but it only provides weight when it's full. We plan on adding ballast but a wing would also be helpful.

[mcr_driver]

not exactly cheap but incase you don't already have but what about a fuel cell for more rear weight bias?

[camshaftgsxr]

http://en.wikipedia.org/wiki/Chaparral_Cars