I'm working on a track car that will primarily be used for hillclimbs and track events (high speed stuff) with autocross being secondary.

I've been studying and researching aero modifications till I'm dizzy and wondered what options others are using besides the GT racing predator wing?

If you have real world experience I'd love to hear what you're using, mounting tips/ pics, and thoughts in general.

I'll be running in classes dictated by displacement only, so rules will not be a limiting factor to size, shape etc.

Thanks for your time,
Andrew

For the car in my sig, I have a GT Racing wing I bought from them years ago. I don't think they make that one any more, but it's about 11-12" cord. I got mine full width of my car, 76". I'm not sure it's the best wing out there, but it does work. I built custom uprights from 3/16" aluminum that attach to the tube frame in my car. For 914s, a more common place is the outer portion of the rear trunk area. I'm not familar with the Predator wing. Maybe someone else here has some experience with it. If you don't mind spending more money, look into Good Aero or Crawford Composites.

Scott

What's your budget?

We have a 70" fiberglass Predator wing on Papa Smurf. I like it, but it seemed to bend in the middle at speed (downforce) so we strengthened it up internally. Supposedly the CF one is stronger, though Joel at GT did not understand why ours did what it did. I do have the GT-Racing aluminum uprights for sale if you're interested, we ended up making our own...

It is relatively simple to make whatever you want using readily available foam cores.

There are a lot of outfits out there that cut foam cores (primarily for model planes) either from an airfoil catalog on their website or custom to your specs. Basically take the cores they send and wrap them in a couple of layers of fibreglass or carbon and you are good to go. It is nice in that you can build the mounts into the wing anywhere you want and have thousands of airfoils available. Polyester resins will eat the foam, but lay it up with epoxy and you'll be fine.

Try this:

http://www.flyingfoam.com/

Flying Foam is the place I use. As an example I just got a main wing and flap 48" wide (a touch wider than a 914 deck lid), and paid less than $50 including the shipping. Now, there is still all of the layup to do, but it will still come in cheaper than most of the available composite wings and is more appropriate to the application.

For whatever it may be worth...

Mugs

Sorry- just got back from Rennsport! Bob...I saw you were there and Im sorry I missed meeting you...you were one of the ones I was looking forward to speaking with!

Interesting about the predator..I have read some on the bird board and had not heard of any issues. Mugs...thanks for the link, that makes sense and I have access to a father that worked in the fiberglass industry for 30+ yrs and my buddy who is Boeing quality control Engineer so I should be in good hands with the laying of the fiberglass.

I appreciate the feedback and if you have any other experiences Id love to hear from you.

Regards,
Andrew

Hey Mugs
while I agree one can be made, if you mount the wing way on the ends where the trunk/fender gap is, you REALLY need to strengthen it up so it doesn't bend in the middle. that's what was happening to ours - people following me said it was bending down in the middle big time. We had to put a steel rod inside down the leading edge to keep it from bending. I guess it's generating a lot of downforce, pushing the middle down somehow. In fact, you could push down the middle and bend it without a lot of effort just standing there. If it's mounted closer to the middle maybe it wouldn't happen...

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Bob - The wing should NOT be bending at all...at least so much that even is visually noticeable. In theory, "real wings" that are efficient should be capable of producing at least 400 lbs of downforce (depending on pitch and speed). The equivalent of two of you (maybe 2.5) sitting in the middle of your wing. I see poor wing/strut set ups on the track failing (to some extent) all the time. It is one area for sure that a builder should not skimp on the part nor the application. But you know all of this already...

Tony

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Hey Mugs
while I agree one can be made, if you mount the wing way on the ends where the trunk/fender gap is, you REALLY need to strengthen it up so it doesn't bend in the middle. that's what was happening to ours - people following me said it was bending down in the middle big time. We had to put a steel rod inside down the leading edge to keep it from bending. I guess it's generating a lot of downforce, pushing the middle down somehow. In fact, you could push down the middle and bend it without a lot of effort just standing there. If it's mounted closer to the middle maybe it wouldn't happen...
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I know is shouldn't be bending, but it was. Like I said, you could just push on it and it would bend with little effort. GT-Racing was shocked - so they send another one...which did exactly the same thing. We have about as strong an upright set up as you can get - bolts into the chassis in multiple places with mutliple supports in the trunk. VERY strong. But...the wing still bent at speed.

Here is what I choose to do after much research...

Started with G-Stream wing - wind tunnel tested and proven wing profile - and costs a bit. I had my struts and uprights built from scratch for strength, adjustability and removal. The mounts are secured to the core and the aero-tube is simply to break the air. Lots of work (too much really) went into this set-up. The wing is capable of producing up to 600 lbs of downforce and is effective with speeds as low as 60 mph.

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Just a comment, I was able to purchase a real ALMS Flying Lizard Porsche 997 GT3 RSR Factory Wing from the Flying Lizard Team car #44. This wings mounting plate was cracked. It became garage art. What you will see in the photo's are that the wing is bent in the opposite direction to fight off the tendency to want to bend.
This is a Porsche numbered part starting with 997, in the photo it shows the interior strengthening chords which are placed about every 8", the wing weighs less than 3 pounds and is stiffer than a Pay Day ^*%#er. My point is that all the wings I see are straight across and this one is bent in the opposite way to fight the tendency to bend. It also has an unbelievable wicker bill on it (Gurney Flap).

It is a real cool piece and I love it and loved making the struts for it!

Vysoc
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Vysoc - Very nice piece you have there...very expensive new (and used) too!

One thing that hasn't been mentioned is matching the potential downforce to the cars ability to overcome it too. A serious wing/splitter combo will need some serious power as to not over-slow in the straights.

This is my race cars original wing - it was waaayyy too much for the cars power and eventually replaced with the smaller unit. The large HSBC wing is an actual F! Jaguar piece - my car didn't have the 850 hp to push it through the air!

F1 Jaguar Wing
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New "Stohr" Wing (only good pic I could find, I survived!)
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Stan really knows about wings. http://www.dauntlessracing.com/pages/about-us

He also understands what works at low speeds for all you autoxers out there.

While he primarily builds for Stohrs, he always has bits and pieces lying around. Worth a trip to Vacaville if you're in Northern California.

Glad you made it out of there safe (and the real Jag wing) Cracker!

Does anyone here have lap time data on your home track comparing lap times with and without your wing setup? Part of my fear about me going solo on this endeavor and which lead to me reaching out to you other track guys/gals is I didn't want to do "more harm than good" without talking with some of you with real world experiences (Drag vs downforce).

Vysoc, Cracker, Bob, Randal- thanks for your input..this is becoming a good source of info.

Andrew

Andrew - I don't. I'm transitioning from the D-Sportsracer to the 914 - my decisions to this point have been predicated on the weight of the teener, the power of the teener and efficiency of the wing and splitter. Here is the splitter I had built for it...it extends 30" deep back to the steering rack support brace and is fastened to a fabricated bracket. Most 914's don't run much a splitter IF at all but my wings effectiveness would most likely require one. This one is adjustable from 3" to 5" in depth. Cheers!

PS: The splitter has 4 layers of Kevlar and two of carbon fiber. It has four bonded-in steel plates the full thickness of the splitter to mount it. I too am not complying with any historic regulations - I'm building it simply as an exercise of what can be done with a 914 (short of Maltese Falcon's build, of course!).

Tony

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[quote name='naro914' date='Sep 30 2015, 04:50 AM' post='2245330']

[/quote]
Hey Mugs
while I agree one can be made, if you mount the wing way on the ends where the trunk/fender gap is, you REALLY need to strengthen it up so it doesn't bend in the middle. that's what was happening to ours - people following me said it was bending down in the middle big time. We had to put a steel rod inside down the leading edge to keep it from bending. I guess it's generating a lot of downforce, pushing the middle down somehow. In fact, you could push down the middle and bend it without a lot of effort just standing there. If it's mounted closer to the middle maybe it wouldn't happen...

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I've noticed that the GT wings do tend to be a bit flexy. You aren't the first one to have that problem, I've seen quite a few over the years and they all seem to bow a bit.

If you get the layup right you can make something that is every bit as stiff as you need to eliminate the flex. Adding a spar to the core will obviously help as well. Th guys at Flying Foam are happy to cut a full span hole for a tubular spar or slot for a blade-type spar. A carbon tube (or aluminum for about 1/10 the price) down the middle makes the thing as stiff as a surfboard.

For the particular application that I was mentioning above, the wing and flap will be supported at the tips with two hinged supports between the wing and flap. The main wing element is pretty thin (the car is a GT5 four cylinder), but I'm pretty sure we can make it stiff enough to not require a central support. If needed it will be very easy to add after the fact and won't need to be much more than a thin blade.

I haven't started on the layup yet, but the cores are here and I'll try to get a few pics posted here a bit later. I'm still paying the price for being away at Rennsport. Four days of work to catch up on!

Mugs

Tony- The wing convo came up because I was planning a splitter very similar to what you have there. I opted for an IMSA airdam for ease of mounting the oil cooler, brake ducting and mine had the integrated lip which will allow a splitter to be easily mounted.

I'm not sure the "GT" rear spoiler does much as far as downforce with the 914 roof line being what it is and thought with a splitter I may have too much front grip (although we do have our engine weight back there)

Beautiful work on the front rail!

Wow Cracker! You are allowed to put car parts on the Steinway?!!! To think I get castigated for having stuff on the coffee table...

It is a very good point about designing the aero bits to suit the car. That is kind of what I meant when I said something about being appropriate to the application, but I utterly failed to make the point. One of the things that is nice about rolling your own is that you can source cores in just about any size and section that you want.

Glad you made it, by the way! Scary pic...

Mugs

1) Andrew - I have a 4"-5" "GT Spoiler" on my car...for looks only. Without it the back end of a teener falls away to nowhere. Bob could probably speak to whether it provides any appreciable downforce but everything I've seen is simply for aesthetics. FWIW: While I am building a fairly radical 914 it is by no means a pure race car...it has full lights, glass (front/rear) windshield, steel bodywork (including the trunk that weights like 500 lbs!) - therefore, what I'm doing won't apply 1 to 1 - way heavier than what you're building. Also, my experience has shown the front end has quite a bit more grip than the rear. Bob and others can speak to this 100-times better than I can - chime in guys?

2) Mugs (and everyone else): Please take the "Steinway" pic the right way...that was for my "Buds" and the "bridge-there" was - Craftsmanship. Therefore, that picture is a bit tongue and cheek. I just don't have another picture of the strut cores...

PS: I KNOW my wife was away at the time That's an 1894 art-case baby grand. Those teener parts were in high-company!

Tony

With the VERY limited time I've actually been able to use the wing and splitter (that's a whole other story!!!) I can say that they CERTAINLY gives me more grip on a few of the corners I know at CMP - carousel, T8, and kink. But I really haven't had a chance to explore limits like I did in the past - haven't had enough laps.

For anyone who may still be looking, here are a couple of pics of the foam cores from Flying Foam.

For those unfamiliar with foam wing cores, the actual cores are shipped in the blocks they are cut from. The extra pieces are sort of "negatives" of the wing core (Some folks call the leftover bit wing beds). They not only protect the cores during shipping, but are awful handy when it come to skinning or glassing.

The pics show the main wing and flap cores. There are two of each and they will be joined end-to-end prior to skinning to create a full span wing and flap. I tried to hold the flap core in sort of the position it will take, you get the idea...

Mugs

I see this familiar beast sports one of his wings.

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Always wondered where he got his wing from, never asked.

Britain@Britainsmith.com
Ask him, he'll tell ya.
My old racecar has been reworked and is a lot quicker.

My car came with what looked like a 70s Dodge Daytona rear wing, and had a huge front splitter to compensate. I removed both of them since it wouldn't comply with vintage racing. Car was used in PCA racing, which allows ridiculous wings. Previous owner spend a ton of money getting the wing and splitter built. The rear attachment for the wing was very ingenious. The 1st picture below has the transport windows installed, again another engineering marvel. They bolt in place and are easily removed, supports were added so the lexan doesn't flex. Since these pictures were taken the front end was redone to accommodate a huge oil cooler. Car is on display in the museum section of the Porsche Experience Center in Atlanta, GA.

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This one worked very well for me

http://cirodesignracing.com/wing/

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That thing is gnarly looking. but it's fast.