Aero resistance

I can only speak for my own road experience and say that I don't need a wing weighing me down or effecting the aero in a negative way by lifting the front end, drag slowing me down and worse of all adding weight especially  high to the ground swing weight being furthest to the rear. 

 Im certainly not slow as I do take some turns at 70mph with the car hugging the road and I could probably take them faster but Im afraid of messing up and killing others and myself in the process. 

 My car is more than capable primarily because my car is lighter than stock, has great suspension, good alignment that is neutral but bending to oversteer at the limit and most of all is running extreme summer tires.  Never encountered a problem with lifting.  

 Newer tire technology is so good It makes it very hard to shake the car loose. 

 I think if you race on a track and then encounter issues, I feel at that time a wing is warranted as a necessary evil to win a race but for all other situations its best to work on other areas before using a wing if it can be avoided.  

@dev

The point is that increasing downforce does not hinder you to get to 70 mph but it does give you an extra margin of  traction meaning more safety margin at the same speed meaning safer pedestrians. Oh and it applies to braking too.

It is even within the realms of reality to reduce drag and increase downforce at the same time by improving the aerodynamics. Ok, within reason ofcourse. Point is that the drag coefficient of the Spyder is 10% worse than that of the current Ford Transit van; there is room for improvement and ány improvement counts for more with a lighter car and even more more with a lightened lighter car like yours 😉  

Posted by: @petrus

@dev

The point is that increasing downforce does not hinder you to get to 70 mph but it does give you an extra margin of  traction meaning more safety margin at the same speed meaning safer pedestrians. Oh and it applies to braking too.

It is even within the realms of reality to reduce drag and increase downforce at the same time by improving the aerodynamics. Ok, within reason ofcourse. Point is that the drag coefficient of the Spyder is 10% worse than that of the current Ford Transit van; there is room for improvement and ány improvement counts for more with a lighter car and even more more with a lightened lighter car like yours 😉  

 

The problem with driving at very high speeds on public roads is not so much about traction issues as I don’t have any that I would benefit from a wing. The problem is blind corners where I finish the corner at such speed that the car in front or cyclist suddenly appears because they have slowed down to make a turn, just made a turn onto the street or suddenly stopped. No amount of downforce or braking would save me from rear ending the object in front of me.   Also driving at those speeds is not just about grip as you need to have quick reaction times and if you make a mistake and unsettle the car abruptly no amount of aero or brakes can save it including a parachute. 
If the wing was very effective at delivering downforce then it would hinder my ability to accelerate in a straight line by creating  lots drag.  It would be trying to solve a none issue with one that will create an issue.  It is in essence a double edged sword. 

If you look up some of the old archives on Spyderchat it was found out that unless the wing is way up high to grab clean air it is of little benefit in regards to downforce.  I would say a wing is more or less a big bandaid to fix a specific problem that is only seen when you are competitive.  
There  are several tracked Spyders that do very well without them. 

@dev

Why concentrate on only the wing? That is only óne aero add on. So you don´t like them. Fair enough. I don´t like wide body kits and/or massive front things. There is no doubt about the well designed ones working like a treat though.

Why again that high speed on open road ´argument´?  As I point out  it works at cyclists speeds!!

Again; at very much legal speeds, aero can both reduce drag and add downforce. I cannot see ány downside to extra downforce; just more safety margin at the same speed.

Btw. even below the high speed airflow a rear spoiler/wing can add significant downforce by deflecting the separated turbulence upwards and/or creating a higher pressure area either or both of which will deflect the high speed airflow resulting in negative lift.  The rear wing on the R34 GTR sat well under the air flow yet it still added significant downforce by this deflection. A Gurney flap on a very modest spoiler will have a notable effect in less instability though turbulence and downforce though deflecting. All at véry low cost.

Lastly a modest rear edge/lip/spoiler is likely to impróve the drag coefficient as is a modest air ´dam´under the font bumper. See the air deflectors in front of the front wheels. Toyota even offered a rubber lip/´dam´ to fit under the front bumper per the FL. Fits on the PFL too. Cheap, invisible unless you look for it and it wórks.

Here´s an example of a rubber strip for unde the front ?size=154895&height=800&width=800&hash=7ee43c0ab5dbe1f4832dd510aabe2546

I have something akin not so far up front nor going all round and it works:

The problem I have with aero  is you never know what you are getting by just throwing something on with no means of measuring its effectiveness. There is no doubt that arrow can be effective but without a wind tunnel  you don't know how its going to impact the car and its not something you can guess at as it requires precision placement.  There are all kinds of fools on the internet that believe adding canards is somehow improving the aero when it actuality they don't really care and just want it to appear that they know what they are doing to make their car look serious when it's not.   

 From the actual street cars that were turned into race cars  using the proper way to implement aero made the cars look weird, mostly ugly with huge front spoilers and some other additions  that ends up looking goofy but fictional.   Granted our cars don't have the best coefficient of friction but you would have to add weight and radically  change the design to make it work for any kind of marginal advantage on the street. In the case of lotus they needed to add two oil coolers because there just wasn't enough ventilation from underneath the car because they made it smooth from underneath with plastic shielding.  

Everything has consequences. Its not as cut and dry but a necessary evil if you want to win races. The people that I would be more inclined to trust with  radical set ups are those that win trophies consistently because they have proved what they have done has an edge. In reality however the ones I see win have simple set ups when it comes to aero and everything comes down to the suspension and most of all talented driving skill and experience.   

On another subject, some of the fastest guys out there have reached similar conclusions   that bracing is just unnecessary weight that slows them down from being competitive. When I found this out it changed my view on bracing that more is not better.  

 I added a front lip to my car. It did next to nothing in terms of aero which is a good thing because it didn't screw up what was already working well.   It looks great though and thats the reason why I have it. 

I agree with the bracing. That is first hand best practice experience and works (on the street) for my MR Spyder too.

Mind that I do not disagree with the extremes concerning aero either. Again though my first hand best practice experience with bad aero cars is that some minor mods are effective without much if any downside.

Remember the first gen. Ford Sierra? Ford very quickly came out with an aero upgrade behind the rear quarter window: Just a 5 cm. wide strip the length of the C-pillar and it did wónders for the stabilty at legal highway speeds.

The optional facrtory abs rear spoiler on the 3 and 5 doors  Volvo 300 series is another example of an aero add on being véry effective with no downside; impróving the drag coefficient even!  That thing is 140 x 20cm and sitting 10 cm. above the deck 

No doubting that massive splitters or wings come with both massive advantages and ditto, mostly inherent,  downsides. Get it wrong and the advantage is dwarfed by the disadvantage.

Been looking at a lot of SuperGT MR-S cars and they all have a wide 3D wing but with Gurney flap and at a strinkingly shallow angle of attack. Obviously they try max. downforce with minimum drag for max corner speed without the lack op power costing them too much top end. 

For a lighthearted touch; 

Is autocorrect turning "aero" into "arrow" for you dev?

Anyways, i think aero and mechanical grip from suspension and tire setup are both important.

the thing that is possible in combination is to have a car that can rotate easily at low speed and have neutral stability at higher speeds.  tuning an mr-2 spyder's handling characteristics sans aero to be ever so slightly oversteer-weighted and then adding a wing to pull the grip balance rearwards for more neutral handling at higher speeds is something that can be done when you put the two together.  there's interaction between mechanical and aero grip that have to be taken into consideration when you seriously are considering either for performance reasons.

then of course, there's gas mileage. gas is pretty expensive in some locales.

In formula one they can do innovative things by redirecting little  ducts and trap doors  so they can have an edge over their competitors which is great but it requires high degree of engineering.  

The aero I have seen on some street cars are generally exaggerated because they need to be to have any noticeable effect.  
I use to sell a  lip spoiler that goes on the back bumper and was once asked a question if it actually helped. I basically said it probably spoils the air and not in a good way but you will not notice it and that is the same with a lot of these aero mods.  
When it comes to a street car it’s generally pointless unless the car is so bad aerodynamically that it has to reengineered.  A lot of times aero changes on passenger car are done to cut down on wind noise or gross mistakes that are obvious. 
As for our cars they generally don't have a problem in this area that needs to be addressed and if it appears to be the car should be inspected for mechanical faults first.   

I have often found at meets that they guys that placed the most emphasis aero mods can’t really drive and are usually the slowest so they timidity migrate to the back.  I doubt it’s the drag but who knows.  Some of the quickest were those with stock everything and a good alignment. 

if a product already exists, it's easier to slap onto a car is what it comes down to.

not trying to be in  favor of aero over suspension mods here. at USA speeds, aero is relatively un-helpful unless it's very aggressive and extreme. as for germany/autobahn speeds, you'll need to at least cancel out enough lift for the car not to be squirrelly at 100mph (it's what killed an audi TT test driver and resulted in the recall that added a little lip spoiler to all of the original TT's)

i for one would love to drop a few K on some proper adjustable suspension links front and rear with adjustable coilovers and tune for mechanical grip. just saving up right now.

Im also not in favor or against but only what can be proven to work and what is actually practical for the street, after all we are not trying to win a race.  We do know a wing on our cars can actually help but at what lengths you need to go to get it high enough with a good support structure to make it work, and with that change you need balance out the front. All of these things have consequences that can increase the complexity if you want to do it right otherwise it becomes a stylistic choice.   

I would say the suspension and tires has the greatest effect, actually I take that back,  good driving skills with experience is the number one thing you can do. If the guy in the stock Spyder is putting you to shame which I have witnessed then the other stuff is nice to have hobby wise and they can help give you the feel of stability but it doesn't mean the car is less capable without those upgrades just harder to drive. 

Eventually you do reach a limit and tires and struts can transform the car to give a confidence inspiring ride for a street driven car.  What is most important is this aspect of confidence because it achieves the end result which is not just speed but fun to drive so you can get a thrill.  I never   felt the car lift but initially I thought I did but that was because I was driving with shot suspension causing the car to float around turns. Coilovers fixed that and now it glued to the pavement. 

Quite a few Spyder enthusiasts mention that they feel the difference of having the spare wheel/tool kit in the frunk or it stripped.

Aero mods can very easily have more effect in negative lift at either end from surprisingly low speeds.

The Spyder has a pretty bad shape with airfoil lift.  Aero mods that reduce this, restore the weight of the car on its tyres. 

Aero, suspension, skills are not either or. Why would a good driver not set up his/her car suspension up properly? The answer is that he/she will be quicker with it well sorted. Same aero and wheras the Spyder is off factory quite well set up suspensionwise, aero-wise it is not so much.

The Audi TT is a good example Refirendum and the bum of the Spyder is very much alike. 

As Dev observed the air flow behind the cabin of the Spyder is detached. It is very turbulent. There is nothing to spoil and a lot to gain in reorganising it. Even redirecting the turbulence a bit and/or providing a tear off strip improves stability and reduces lift.

A rear wind Dev, does not née´d to be in the high speed airflow above the separation area behind the cain to create negative lift. It only needs to redirect the direction. The flow goes downwards over the bubble and any upwards redirection = downforce. Because of this downward vector, the wings on the SuperGT cras appear so ´oddly´ angled: they áre angled in the airflow. This downward flow over the bubble is the reason behind the ´3D´ shape too. The flow is not angled the same way all across the rear of the car and with the 3D shape the wing can sit in the lowest layer and still be angled more correctly over the entire width.

Yes, better driving skills are the most crucial factor. That however does not preclude a good driver from using whichever factor helping him/her. There is no reason why he/she should not buy better tyres than the ones it came with from the shop floor despite there being way more bad tyre choices than good ones! Same thing suspension set up. It is very easy to set the car up wórse than stock yet you agree it is an area where gains can be made. Same thing aero. I simply do not get why aero seems to be the black sheep of mods. Sure you can get it wrong; just like tyre choice and suspension mods. Aero is nó different so my question is why the aero resistance???

I think we have a little misunderstanding.  The little lip spoiler that I sold does nothing positive or negative that can be observed from the person driving the car. This is the same with just about  every aero modification sold for the Spyder including side skirts, lip kits and so on.  This has been observed by hardcore competitors that were trying to win races. It was determined that what was available was stylistic  rather than functional. I can understand that If the car was designed poorly that aero can cause issues but that was never been observed with the Spyder except in one case which was the first year of production where they added a little lip like flap  under the front that you couldn’t see. It looked like some kind of flap that helped with high speed stability.  In a case like this it works because there was engineering science behind it.  

I have removed my side mirrors and exchanged them with small carbon fiber ones that claimed better aero but that didn’t do anything you would notice.   With aero unlike suspension mods you need to go big and build your own because there is nothing in the market that makes a difference that can be felt. I’m sure it does something but not enough to be appreciated.  I would say it’s more or less icing if you can get it to work after all other things you try are exhausted. 

Unlike the TT no one had any safety issues with the aero design of the car.