Rear deck lid spoiler/wing thread.

[Kalstar]

What do you think will work and what won't? How wide, how tall, materials, ect.........

Will these work?

http://www.ebay.com/itm/UNIVERSAL-51-TOYOTA-BMW-X6-E71-Z3-E37-Z4-E89-SPORT-GT-REAR-WING-TRUNK-SPOILER-/370807492081?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3AZ4&hash=item5655d94df1&vxp=mtr

http://www.ebay.com/itm/CARBON-FIBER-E71-F10-E34-E82-E85-E89-E37-E65-E66-E38-GT-REAR-WING-TRUNK-SPOILER-/251273766676?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3AZ4&hash=item3a81156714&vxp=mtr

Updated link

http://www.ebay.com/itm/CARBON-FIBER-UNIVERSAL-51-993-996-997-986-987-970-GT-REAR-WING-TRUNK-SPOILER-/251342718315

[metalmaker12]

I like the carbon one jim, it would work with my theme in looks, but I like the apr wing that has the aluminum frame mounted directly to the 818 lower frame extension, which is fully functional. Something like the R but lower.

http://www.xplosiveperformance.com/assets/images/as-107035.jpg

[Xusia]

Oooh! I like that carbon fiber one! That would go well with my intended look (and for me, it would all be about the look). I might seriously consider that.

[THE ITALIAN]

You have to mount it to a serious part of the car (like the frame)
The mount to the wing would have to be universal (not pre-existing)
even if just for "looks" it will rip off your rear lid.
I would say that with just a cosmetic value, it will produce a couple hundreds pounds of "downward force"
and for race, it should produce 3 to 400 lbs.

There are diff designs that offer several speed values according to your needs
A good wing will add "Oprah" downforce.

[flytosail]

Aerodynamically, will the windshield of the S negated the wing?

[Xusia]

In the auction ad, it states specifically the intended mounting point is the trunk lid. It can't be producing much down force if that's the case. Either way, I'm pretty sure I can figure something out...

[narkosys]

Shane at vRaptor speedworks (http://vraptorspeedworks.com/custom-gtm-parts/) has a mounting system for the APR wing for the GTM. I am sure that it can me modified for the 818.

P

[Wayne Presley]

The CF one in the first post is just for looks, has no camber to the airfoil....

[Matty_STi]

Aerodynamically, will the windshield of the S negated the wing?

Negate need for wing? no
Negate effects of wing? no
Change the dynamics of a wing package? probably

Wings (well any aero equipment in general) are incredibly complicated pieces of technology. To just slap one on and hope for the best will give you mediocre results at best. There is a reason F1 guys spend so much money on CFD and related software packages and why they employee so many engineers who work with just aero bits. If it were easy everyone could get close to F1 lap times (spoiler alert, they don't). Stick to a proven design that has been run through simulations so you at least have an idea of how it will perform free air. From their you can extrapolate what you need to based on the current aero features of your car and see how the wing will perform. (taped string method works great if you really want to get back to basics.).

I will be posting lots of aero stuff when I am getting closer to my build, alas I have a couple dozen projects totally unrelated to cars and fun stuff that are keeping me down. :( (fml)


-Matt

[THE ITALIAN]

I thought FFR was doing either real time or simulated 'TUNNEL" TESTING.
I know that the windshield will push air (AT A CERTAIN SPEED) Like if you drive faster in the rain -as I have in my roadster, under 40mph I got wet, over 40 I stayed dry (CALIFORNIA RAIN) NOT REAL RAIN.
There is deflection and downforce, but a wing & a spoiler are designed to push the drive wheels into the pavement.
The Gumpert Apollo on youtube has some info and also the Veyron, these cars have incredible "ground affects"or what I call , vacuum.
I think even an amateur installing a wing will get downforce just by accident, but for best results, it would have to be in tunnel conditions
My past "Chev-Z" (240z-chevy) When we bolted a "spoiler" from a proven race team to the deck lid, we measured the level of the rear body before and after at 135 MPH
and if it were not for the stiff koni's & springs, I think it would have had tire rub.
The force actually pulled the bolts and the spoiler became loose.

the more you use the wind, the more HP you need to push forward.

[Matty_STi]

I thought FFR was doing either real time or simulated 'TUNNEL" TESTING.
I know that the windshield will push air (AT A CERTAIN SPEED) Like if you drive faster in the rain -as I have in my roadster, under 40mph I got wet, over 40 I stayed dry (CALIFORNIA RAIN) NOT REAL RAIN.
There is deflection and downforce, but a wing & a spoiler are designed to push the drive wheels into the pavement.
The Gumpert Apollo on youtube has some info and also the Veyron, these cars have incredible "ground affects"or what I call , vacuum.
I think even an amateur installing a wing will get downforce just by accident, but for best results, it would have to be in tunnel conditions
My past "Chev-Z" (240z-chevy) When we bolted a "spoiler" from a proven race team to the deck lid, we measured the level of the rear body before and after at 135 MPH
and if it were not for the stiff koni's & springs, I think it would have had tire rub.
The force actually pulled the bolts and the spoiler became loose.

the more you use the wind, the more HP you need to push forward.

Multiple points of contention here:

The windshield will act as a ramp. But what happens when that air attaches to surfaces behind it and pulls back down? Now you've got high speed accelerated air traveling over lots of surface area that equals low pressure which equals lift. Your rain analogy is missing a whole lot of points.

Ground effects are not a vacuum necessarily. Keeping a linear unchaotic flow pattern underneath the vehicle can create a uniform pressure distribution which will prevent air from packing up into certain spots (If the air is "packing up" i.e. compressing into a slow moving fluid, that will generate higher pressures (or at least a higher pressure differential and thus lift the car from underneath or at the very least unbalance the car). You won't always see negative pressures (i.e. a vacuum) with a ground effect system. in fact you could see higher than atmospheric pressures but as long as the system is performing as required that positive pressure differential over ambient/atmosphere may be a good thing.

A wing and a spoiler are not designed to just push the drive wheels into the pavement. There is much much much more to it than that. Smoothing air flow can increase over all aero efficiency from the front of the car increasing downforce all around and possibly lowering drag. I really don't feel like writing a tonne about this but wings are designed to take air flow and gain a benefit for the vehicle they are attached too. That benefit can be a multitude of things. Your simplification does not do them justice.

An amatuer installing a wing at random can create down force sure. But what does that mean to the overall aero setup of the car? It could cause extreme understeer, increase drag with little increase in tractive benefits so slowing the car without providing a downforce bump that is worthwhile enough to make up for the added drag. Tunnel Testing isn't the be all end all. That is just a best condition lab environment. Real world still needs to happen.

"The more you use the wind, the more HP you need to push forward" -> This is wrong. Flat out wrong. No if's ands or but's it is just wrong. If you use the wind right you lower drag increase downforce smooth airflow and gain efficiency. Which means quicker acceleration, quicker braking and shorter stopping distances, higher top speed, getting to stop speed faster, higher lateral G's and aero effects at lower speeds.



-Matt

[Matty_STi]

Matt, I am not an expert and I won't get in a spitting contest, but I take Expert words to heart because they know more than I.
You should watch this program, They even state how they need much more HP because of the ground effects, and they have built a hell of a car and proved it.
It wasn't my intent to tell anyone what will work, I only know what I have done and my experience in road racing starting when I was 17.
If what I said was wrong, then the Gumpert/Apollo team is wrong, they do have more experience than me, maybe not you.
<http://www.topspeed.com/cars/gumpert-apollo/ke1056.html>
Anyone that watches this can learn second hand what they have, even with moving pictures!

That Nat Geo vid (though a cool look into the company) is not even a basic primer on aerodynamic sciences. They very briefly glance over topics related to aerodynamics and classical newtonian physics. Could probably fill most of a Bachelors of Science degree in aeronautics with classes related to those topics.. That vid would be like using a grade 7 science video to teach mitochondrial genetics to post grad genetics majors. In other words really dumbed down.

Lets break this down here:

There are 4 things that allow a car to reach a top speed. Tire friction, Drag, engine power, and transmission gearing.
1: The transmission gearing should top out at redline with little power to push beyond that and the car having no extra power to spare. (realllly dumbed down because not the point at play here)
2: engine power. As long as it pushes the car through the air and tops out it's rpm with not much room to spare we are good.
3. Tire friction. This is where that vid goes waaaaayyyy awry. Downforce isn't actual weight you are pulling it is pressure downwards. In other words friction goes up but inertia and momentum do not they stay the same as the actual mass of the car. Tire friction aka rolling resistance is a FRACTION (and a small one at that) of the force that is keeping a car from reaching top speed.
4. Drag. This is what really makes or breaks a cars top speed. If the engine doesn't have the power to push faster than the drag created then that is the cars top speed. A well designed aero package will produce big downforce figures without causing huge bumps in drag. Ground effects kits are fantastic for this because they accelerate the air not slow it down thus meaning there is much less drag and thus the car can go much faster for a given topspeed. An F1 car from 15 years ago has more drag then an F1 car today but the F1 car today makes higher downforce numbers, so not only can it corner faster but also get to it's top speed faster and do so more efficiently.

There is a story I heard a while ago about a race team. They were concerned about their top speed as they couldn't keep up with other cars (this was before CFD and hiring of aero engineers was such a big deal). They could keep up around the corners and had a great chassis and great acceleration but died on the straights. So they pressured their engine guys for more power. They got more and more power out of each rebuild and would shoot past their competition under acceleration but a long straight would have everyone catching up. They were flying around corners but big fast tracks were still killing them. The reason, the crew chief would crank more and more wing angle with every bump in power. Paying no attention to the drag being created by the additional wing angle because he didn't know that was a problem.

So back to the point I am making. Yes indeed what you said is in fact wrong. You are taking grade 7 science and trying to apply it to a very advanced concept, it doesn't work. The Gumpert Guys know what they are doing, but they also are dumbing their explanations down so that laypersons viewing that video can have a basic understanding of what is going on. That is not meant to be a comprehensive view on car aerodynamics or to be used by someone trying to setup a go fast car or race car.


If you want to get into the real nitty gritty of car aero check out the F1technical.net aero forum at http://www.f1technical.net/forum/viewforum.php?f=6 those guys will have all the info you can handle and then some.

-Matt

[Kalstar]

Ok I am glad I am less smart then both of you, I couldn't argue my way out of a paper bag when it comes to these topics. So that said...... What will fit on the back of this car, look good, be functional "enough" and not give the 818 the shopping cart look. I was thinking a speed controlled wing off a Cayman or Boxter. Maybe run it off the VSS of the ABS. Let's see some pics of what you're all thinking. I have a wing on the GTM and it really "made" the look of the car. I think the 818 will be the same (same designer).

[Wayne Presley]

Ok I am glad I am less smart then both of you, I couldn't argue my way out of a paper bag when it comes to these topics. So that said...... What will fit on the back of this car, look good, be functional "enough" and not give the 818 the shopping cart look. I was thinking a speed controlled wing off a Cayman or Boxter. Maybe run it off the VSS of the ABS. Let's see some pics of what you're all thinking. I have a wing on the GTM and it really "made" the look of the car. I think the 818 will be the same (same designer).

I do believe the car looks more correct with the wing, it really changes the visual impact.

[bnr32jason]

I fully agree the just from an aesthetic standpoint, a wing is going to be a great thing even on the 818s. I just want something about half the height of the 818r's wing.

[Wayne Presley]

I fully agree the just from an aesthetic standpoint, a wing is going to be a great thing even on the 818s. I just want something about half the height of the 818r's wing.

Google some images of the Lotus 211, I think that is what you are looking for

[Xusia]

For me, even that's a bit much. On an actual race car, those wings look correct. But on a street car, they just scream "wannabe" to me - even if they are functional.

[flynntuna]

+1 I'm torn on the whole wing thing. A lip on the rear trunk maybe.

[wleehendrick]

For me, even that's a bit much. On an actual race car, those wings look correct. But on a street car, they just scream "wannabe" to me - even if they are functional.

My thoughts exactly... here in CA, practically every car with a big wing is an crappy civic with an unpainted body kit. Even if functional, on the street (where my car will be most of the time) a big wing is associated with the rice (race inspired cosmetic enhancements) crowd.

Although not nearly as functional, for a primarily cosmetic effect on a street car, I'd like a carbon fiber lip spoiler. This is what we put on my wife's 135i, and I think something similar would work well for the 818. However, it would obvioulsy need to be fabricated specific for the 818:

17965

[Matty_STi]

The lower the wing the less air it will grab and the less effective it will be.

APR designed their dual element wings so that they grab and efficiently use air on the side of the car but if they aren't mounted high aren't adding a tonne of drag due to the center element causing additional turbulence despite little additional down force again. In fact that flatter center section will help smooth airflow lowering drag.

When it comes to looks wings really do mess things up sometimes. Things can really become disjointed and weird, despite how effective they may be. **reference global time attack and unlimited pikes peak cars**

-Matt

[Xusia]

Hi Matty, I don't doubt that. Those APR wings (and similar ones) seem highly functional. On the other hand, I don't care about function because I don't plan on doing any competition with my 818. As I stated in a previous post, it's all about completing a certain look, and wings like the APR don't look right on a street car to me - they scream "wannabe". I realize not everyone thinks as I do, and I sincerely mean no insult - build your 818 how you want. If you like or simply want a big wing like the APR, go to town!

As long as a wing like the one in first post doesn't pose a safety concern, it would work for my purposes.

[Mechie3]

I'm going to see how an S202 (Subaru special edition WRX in Japan) wing looks when I get my kit. Already have the wing and can easily machine uprights for it. Not sure if it'll be too ricey or not.

[Matty_STi]

Hi Matty, I don't doubt that. Those APR wings (and similar ones) seem highly functional. On the other hand, I don't care about function because I don't plan on doing any competition with my 818. As I stated in a previous post, it's all about completing a certain look, and wings like the APR don't look right on a street car to me - they scream "wannabe". I realize not everyone thinks as I do, and I sincerely mean no insult - build your 818 how you want. If you like or simply want a big wing like the APR, go to town!

As long as a wing like the one in first post doesn't pose a safety concern, it would work for my purposes.

Yeah that's why I added the second part about wings messing up the look of things.

If you aren't doing much in regards to performance driving then find a wing/spoiler/thingy that fits your look. A decklid spoiler is probably a safer bet than anything else truth be told as it keeps the back end from looking too plain, adds that sports car look without being ostentatious. If you are going for the non-wannabe look (can't stand ricer as that term is just really racist) even a smaller wing low mounted is hard to pass off. More so because people who don't know will think why do you have a wing and those that do will laugh at the useless wing you have mounted and call you a wannabe. Course that being said if you don't care what others think do what works for your design eye and be proud of it - if you like it who gives a poop what others think! :)

From my vantage I would rather see someone use something that looks good and doesn't slow their car down/add drag/lower efficiency/etc. (thus my suggestion about a decklid spoiler).

-Matt

[Matty_STi]

What will fit on the back of this car, look good, be functional "enough" and not give the 818 the shopping cart look. I was thinking a speed controlled wing off a Cayman or Boxter. Maybe run it off the VSS of the ABS. Let's see some pics of what you're all thinking. I have a wing on the GTM and it really "made" the look of the car. I think the 818 will be the same (same designer).

Well the speed controlled wing idea, though cool, would be a ***** to implement. The wing is controlled by the ecu and some other black boxes shoved in different hidey holes. Course you could take a raspberry pi or arduino controller a couple DAC's and do you're own controller but I am not sure how much you know about programming and circuit design. **as an aside I plan on doing active aero with my 818 and using linear actuators with inputs from throttle, brakes, and vss/abs, will be playing around with a few different controller ideas see if a syvecs will work to control it too.**

Plus it will add weight over a simple aluminum stands/carbon airfoil wing. If you go for it (which I honestly believe would be hella cool) I will offer what support I can cause that would be awesome to see!



I do believe the car looks more correct with the wing, it really changes the visual impact.

+1

-Matt

[FFR-ADV]

Does anyone know what angle of attack the APR wing on the 818R was set at during the most recent track testing? Method of measuring angle is shown on APR website since the wing does have a variable angle off attack over its surface.

This could be linked to down force and drag versus angle versus speed from APR website:

http://www.aprperformance.com/index.php?option=com_content&task=view&id=181

Cheers!

[Xusia]

Course that being said if you don't care what others think do what works for your design eye and be proud of it - if you like it who gives a poop what others think! :)

That's pretty much my attitude. It's about what *I* like the look of. I'm sure there will be those who think as you outlined, but I don't really care. I think wings look good (loved them since the Countach), but most of the functional ones seem to work better than they look, and conversely those that look good are functionally deficient. If they can't understand that, oh well! :)

[Wayne Presley]

Does anyone know what angle of attack the APR wing on the 818R was set at during the most recent track testing? Method of measuring angle is shown on APR website since the wing does have a variable angle off attack over its surface.

This could be linked to down force and drag versus angle versus speed from APR website:

http://www.aprperformance.com/index.php?option=com_content&task=view&id=181

Cheers!


I know the angle :p

[07FIREBLADE]

Wayne want to spill the beans plz.....

[Wayne Presley]

Wayne want to spill the beans plz.....

but isn't the anticipation great?

[07FIREBLADE]

Lol, I'm dying for my kit but I have to wait until august of next year so its really not that big of a deal for me. Waiting for HB annual event next year where there will hopefully be a couple 818. Just trying to pry some info from you for the sake of you knowing and not telling.

[wleehendrick]

Waiting for HB annual event next year where there will hopefully be a couple 818.

If all goes to plan, I'll be showing mine at HB next year.

[Wayne Presley]

The wing was set at 0.2° measure per APR

[FFR-ADV]

Thanks Wayne,

For the APR GTC300 used on the GTM:

at 80 mph Downforce = 672 N (151 lbf) Drag = 76 N (17 lbf)
at 100 mph Downforce = 1058 N (238 lbf) Drag = 120 N (27 lbf)
at 120 mph Downforce = 1534 N (345 lbf) Drag = 174 N (39 lbf)

See: http://www.aprperformance.com/index.php?option=com_content&task=view&id=181

Perhaps downforce could be further increased with Gurney Flaps available for this wing as an option from APR Racing:

18124

Cheers!

Also attached image for another interesting APR wing sideplate:

[Xusia]

Admittedly, I know nothing about wings or downforce, but that seems like a lot!!

[Matty_STi]

I believe they measure free air (or its a sim based number done free air).. I may be wrong so don't quote me on that. Buuuuuut if it is free air then when placed on a car you will get potentially very different numbers.

350lb of down force though a big number I wouldn't necessarily call a lot. There are cars running upwards of a couple thousand lbs of downforce. For a single element wing that's pretty good though.

-Matt

[THE ITALIAN]

Thanks Wayne,

For the APR GTC300 used on the GTM:

at 80 mph Downforce = 672 N (151 lbf) Drag = 76 N (17 lbf)
at 100 mph Downforce = 1058 N (238 lbf) Drag = 120 N (27 lbf)
at 120 mph Downforce = 1534 N (345 lbf) Drag = 174 N (39 lbf)

See: http://www.aprperformance.com/index.php?option=com_content&task=view&id=181

Perhaps downforce could be further increased with Gurney Flaps available for this wing as an option from APR Racing:

18124

Cheers!

Also attached image for another interesting APR wing sideplate:
THANK YOU!
For the "average guy" and if you have a stiff suspension, this will work - you don't need to know "Quantum Physics" or the answer to "why we are here", after all, we just want traction.

[FFR-ADV]

Of course we will want to keep the aerodynamic downforce on rear tires in balance with the front so it doesn't become to little up front compared to rear traction and not contribute enough traction up front to maintain steering through the corners with higher G's. Aerodynamic downforce lets cars like those from Radical get 2.5 G lateral cornering G's (that will work the neck muscles). The new Radical RXC Lemans Style street/track car is a 900 kg coupe with 380bhp @ 6750rpm and 320lb ft @ 4250rpm. This seems within shooting range for the 818 with a removable hardtop, more aero downforce, full track tires when on the track, traction control and a reliable WRX 350 WHP build. WOW!!!!

Will we learn more from Factory Five 818 wind tunnel testing results and the removable hardtop at the open house on June 15?

1813518136

Interestingly the RXC wears the following tires:
Road Tires: Dunlop, front 235/620R17, rear 290/645R17 (making up for limited street tire traction???)
Race Tires: Dunlop SP Sport, front 215/45ZR17, rear 255/40ZR17

BTW the RXC Prices starting at $160K - $200K + frt / duty.

Can't wait to get my 818 this fall!!!!!!!!!

Cheers!

[Matty_STi]

Of course we will want to keep the aerodynamic downforce on rear tires in balance with the front so it doesn't become to little up front compared to rear traction and not contribute enough traction up front to maintain steering through the corners with higher G's. Aerodynamic downforce lets cars like those from Radical get 2.5 G lateral cornering G's (that will work the neck muscles).

^This.
If you don't have balanced aero and downforce you will loose grip and traction. If you have downforce on the back end that is causing understeer you've messed up. Stiff suspension doesn't solve that either (that's just a band-aid and doesn't fix the issue), and causes it's own problems. You want stiff but compliant as well. It's not about "quantum physics", but there is a right and wrong way to this and just throwing parts at something can become an expensive waste of time and lead you down a rabbit hole of time and money with no results. If you want looks and don't care really about performance so much then go with what looks good. But if you are wanting to do a performance build then there are rules to follow - it's called physics and it's the law.

I would rather see people here spending their money and time and effort on solutions that work then fumbling around in the dark. Especially when others have done all the heavy mental lifting and the body of knowledge is vast.

And the radical has probably a 1k lbs+ downforce total to get those numbers.

Hopefully everyone is having a good weekend.

-Matt

[metalmaker12]

To get true results that work, a variety of chassis mounted wings need to be tested in a wind tunnel for proper downforce levels that work in balance with the suspension. Than once you have a good baseline from that, you run the car at a track measuring downforce levels, oh wait, factory five is doing this except backwards, but it is still much more effective than any of us just talking about it. It is physics and it is being applied for this project, they know a thing or two about wings and they are doing a fine job testing what really works. Good job FFR

[THE ITALIAN]

To get true results that work, a variety of chassis mounted wings need to be tested in a wind tunnel for proper downforce levels that work in balance with the suspension. Than once you have a good baseline from that, you run the car at a track measuring downforce levels, oh wait, factory five is doing this except backwards, but it is still much more effective than any of us just talking about it. It is physics and it is being applied for this project, they know a thing or two about wings and they are doing a fine job testing what really works. Good job FFR

RIGHT , Done & thank you. That thread is over. Now I made some wings out of balsa wood and some old Playboy's I found in my garage. I strapped them to my back and I'm about to jump off of my 2 story roof - I'll let you know how it goes and how far I travel.

[metalmaker12]

Lol, I just did that, I would rethink the balsa, the playboys worked out better

Btw, saw the 818 in person today

[wallace18]

I remember a Red Green episode in which he duct taped a ironing board to the trunk of a car for a rear wing. LOL.

[FFR-ADV]

For those considering a Lambo style doors the Men From Maine (Red Green) have some internet help videos to aid you in your conversion project:


https://www.youtube.com/watch?feature=player_detailpage&v=3bZIcMcSXZk

More customization help available on Youtube:

[flynntuna]

I don't care who you are thats funny right there.