Great dual wing solution!

 

Very 380 cuppy ! Nice!

 

Whatever floats your boat, but I'm not a fan of the ironing board on the back for street use.

 

I understand your doubts. Personally I can't help myself, I'm an aero addict. When you drive a car with proper aero and experience the 4C finally being planted at 180kmh sweepers you can't go back.

I also got so used to it that I feel like something is missing without a wing.

It's just that there is such a thin line between a useless fake bling bling wing and a proper motorsport effective wing and getting it wrong makes then the entire car look wrong quickly. Trust me that's not the case here.

 

Some basic technical insight...

 

@Philster thanks for standing for us. However, no offense was taken. I appreciate every opinion. Positive and negative. I listen to every opinion, but don't bother with it too much if it doesn't help me. I just do what my intuition tells me too, I don't care whether it gets public approval or not.

We are different people, have different tastes and ideas and as long as there is a respect in between, all is good. I used to think I'm always right and my way is the only way. Now with years I used to get better accepting the diversity. There are many things I don't like neither understand. Some are doing air suspension on 4C, other are PPF coating, waxing, polishing cars, keeping them in garages not to put miles on them. Things like this I'd never do, yet I cannot say they are wrong. They are just different. Different thing floats their boat, and that's probably what the @AROC 4C wanted to say. He probably hates our idea, feels bad for our 4C not being pristine, yet it will make me and probably a few other weirdos happy when we'll be setting new PR's on the track with help of this carbon fiber ironing board. For me improving performance is what floats my boat. BTW, some front aero is coming this / next year too.

Just do more of what makes you happy, let it be PFF, more carbon fiber or simply blasting another trackday. Love and peace to everyone. 🥰

 

For those interested in more technical aspect of this project here is some data from CFD analyze.

 

What speed generated these results, and do you have similar tables for other speeds?

 

Funny how one very clean simple addition, that doesn’t detract, interfere or change a single factory line changes the personality so much.

The big wing turns our cute little rascal into a scary mofo. Unlike eBay tat that’s stuck on a Mazda with tape, this says motorsport prepared carbon asskicker.

 

What's mechanical grip?

It's the amount of grip G-forces, the car can generate through the corners, braking or acceleration. Car's weight and tire grip dictates it. When you are in the corner, the car's tendency is to go straight (centrifugal force), and you prevent doing it so by turning the wheel. The tires friction allows you to maintain the direction unless your speed is too high. After this point the car will either understeer or oversteer out of the corner. Making the car heavier will generate bigger friction between the tires and the surface, but it will at the same time also generate bigger centrifugal force, so we didn't achieve anything. The lighter the car, the faster it will go through the corner, but at some point if the car would be too light the friction between the tires and the surface would be too low to provide any more grip. In very simplified words, a 1000kg car and 2000kg car can eventually achieve same cornering speed but will require different tires to do so, but both will be limited with grip at some point. The heavier the car, the wider the tires are needed.

What tire width is optimal?

Wider tires create more mechanical grip, to a point where they don't anymore. Putting ultra wide tires on lightweight car like 4C would cause the tires not to heat up, reduced friction to the ground and eventually reduced grip. The wider you go, the softer the compound needs to be to make it work. You can try putting square setup on a 4C and have some fun. Soon you'll notice it handles bad. Now take the measurements of the tire temps and you'll notice a significant difference between the fronts and the rears. The reason for that is that the rear tires have to carry about 600kg of weight, while the fronts only 400kg. That means the rears will have 50% more work to do than the fronts. Because of that we have staggered setup right from the beginning. Whatever tire width and compound you run, make sure you get the temps to operating level to perform at it's best. For me 215 / 265 works the best, but this also depends of the spring rates, aero, and actual weight. Definitely, a square setup is not something you would want on your 4C.

How to go faster through the corners then?

We are limited by mechanical grip, but what we can do is increase aero grip. By creating downforce on the car, we increase the downward pushing force on the car, increasing the friction between the tires and the surface, meaning we increase grip of the tires, yet not affecting the centrifugal force in any negative way as we haven't increased the actual car's weight.

So how does aero actually work?

The same principle (Bernoulli) that allows an airplane to rise off the ground by creating lift from its wings is used in reverse to apply force that presses the race car against the surface of the track. On the cars we are using actually a reversed airplane wings design. This creates high pressure area above the wing and low pressure area under the wing. Both forces combined create downforce, a suction effect pulling the car to the ground, increasing aero grip.

How does aero work on 4C particularly?

It works very well because the car is very light so even smallest added aero greatly benefits the performance of the car. Generating 100kg of downforce on a car that weighs 1000kg is 100% more effective than generating 100kg of downforce on 2000kg car. In simple words, the 4C with same amount of aero than a 1000kg heavy car will benefit twice as much from it. If we could increase our cornering speed for 10%, the heavier 2000kg will be able to increase it only for 5%. Once again, lightness is the key and by adding aero we can embrace it so much more.

What about the drag?

This is one and the only negative effect of the aero. At this point, it is very important to work smart and analytic. Having a small wing with aggressive AOA (angle of attack) will cause much more drag than a big wing with low AOA So the general rule of thumb is, to install as big wing as possible at the least aggressive angle as possible. This will yield the best drag / downforce ratio. With approach like this, the increased grip and speed through the corners and braking will be far more significant than the top speed loss due to the drag. Coming 5km/h faster out of the corner and braking 10m later will make up for the lost power due to the drag. The tighter the track the more obvious this will be.

Did you know?

The higher the speed, the more prone is car to oversteer due to the aerodynamic effects. Doing an instant maneuvering of aggressively turning left at let's say 40 km/h will result in understeer. Doing the same thing at 140 km/h will result in oversteer. Imagine doing this at 200 km/h. Car would easily spin out. First generation of Audi TT, was notorious for being dangerous to drive at high speed due to the amount of lift it was generating. It generated 67kg of lift at 200 km/h which resulted in numerous crashes on highways leading to lawsuits and later recall of all the cars, where all the TT's were fitted with a small rear spoiler. On the other hand too much of rear downforce over the crest could be an issue too.

 

Is this for the coupe only?

 

Yes, coupe only.

 

Do you also have one for a spider?

 

I did say "for street use" guys. I actually like GMS products and are thinking of getting the catch cans. The duck tail is interesting too. Yes, I should have worded it differently. No harm meant.

 

Nothing more thrilling then driving with a big ass wing on a street. It's kind of penis extension. Some use big SUVs, me I prefer small car and big wing on it. A true mandingo race car. 😂

Anyway. GMS carbon rear louver and GMS carbon rear hood off to a customer in USA on Monday morning.

Did I mention that it takes less than 5 min to remove entire wing assembly? ⌚

 

Nothing more thrilling then driving with a big ass wing on a street. It's kind of penis extension........

mmm, think i need one.....🙃🙃🙃

 

Hey Rudi,

Would you upload a picture of the view from the rear view mirror with the louver installed? I am curious to see how much it affects the visibility.

Thanks.

 

Sorry, I missed your post.

I can upload a pic, but it's not much to see and I rarely look back.

 

You can also pre-order here:

ALFA ROMEO 4C SLR carbon rear wing (adjustable)- GMS

ALFA ROMEO 4C SLR carbon rear wing (adjustable)- GMS

alfissimo.com

 

@GMS , I like that there's a carbon trunklid designed to support the wing instead of trying to strengthen the OEM one hoping it doesn't warp or crack.

Are there end plates in the works for this wing or a reason why this design wouldn't benefit from any?

 

We've been testing the wing and the hood quite a lot lately, even at speeds above 240km/h and so far so good. I still haven't decided on the end plates design yet as this is the part that is hard for me to make it effective and at the same time look right. Of course, the end plates are nothing but benefit on the wing as they reduce drag and increase downforce. They will be incorporated therefore, but are not key process at this stage of testing and development. Also, for some reason, the entire car, with wing on, but without end plates, looks less aggressive, than with them, so perhaps for the street, some, might even care to run without, as the ultimate drag and downforce is not what you are probably looking for on a street.

 

Maybe the Germans can help you out. Were just released/spotted last week:

 

The idea of "Swan neck" wings (mounted on the upper side) is to reduce the air disturbance as the bottom of the wing is generating more downforce than the upper side of the wing, therefore also the end plates are always longer on the bottom side than upper side. Personally I'm not much of a fan of "Swan neck" mounting style as it requires bigger mounts which at the same time means more air disturbance (but on top), so the effect are somewhat diminished and for my taste makes the car look too "racey".

The mounts on that Cayman above are weird and too much angled, like toe out (following rear hood line). Probably it's just a render as I doubt the final design will be like that.

The reason the 911 series run such big wings, now even dual element, is that they can't equip an efficient rear diffuser as the engine right at the back. Probably next series will be MR (engine first and then gearbox) platform and not RR anymore (gearbox first and then engine) which will allow for proper diffuser among other benefits of MR vs. RR. They are just making slow transition, not to loose the die hard 911 fans and to send out new 911 version every 2-3 years, but they will eventually move to MR platform with 911 series, I'm confident in that.

BTW, here is a photo I've just received from a fellow Alfista in USA.

 

Don't like swan necks either. Was more for the end plates I showed the pictures. I'm more a diffuser guy than a wing man btw.

The 911 in competition version (GT2 RSX2T5-i-don-t-know) has its gearbox and engine switched already.

Alfista for the States was on Facebook, and not many seemed to know where the parts came from (I pasted the links), but were very approving!

 

Looks like Mikey Turbo upgraded his car on his latest video.

 

Duck tail / wing fan here. 3 for 3 in the garage right now, but one will soon be gone and replaced by a 4C spider............. NO 4C ducky 4 spidey ?

It's not going to ever be in the works for them ?

 

Six people died in those crashes in Europe

 

I would like to fit a wing if it makes my car more stable at high speeds, up to 100mph it feels fine but over this speed I really lose confidence as it starts to feel light and I'm worried what might happens next, very small feeling of left to right sway. I always end up easing off and coasting back down to 80 or 90 where she feels safe. Heavy powerful front engine cars probably don't experience this, I know it's to do with lightweight and mid engine but if a tail could anchor the car down a bit and keep it stable that would be great. I have Jamie's blocks fast road fitted to help.

 

In that respect I feel Cipsonys’ side diffusers seem to make a difference. No need to ask how I know. At speed you can feel the rear plant itself more securely. No measurements apart from those that Cipsony made but my arse felt more confident at speed with them.

 

I agree. We chose the most effective (large but low drag drag profile) single element wing that we could fit within 4C's dimensions. The CFD analyze for the wing is done in free flow, so yes the numbers are probably a bit off, but it's out of our budget range to afford wind tunnel and 4C has other critical aero issues to sort out priority (front radiator air stream flowing under the car).

It's step by step improvement, even though small. First we reduced the rear end weight by GMS carbon rear hood to decrease oversteer tendency, lower the CG and provide supprot for the wing. Then we added the louver, to decrease the aero lift (with closed rear glass, the airstream going down the roof towards the end of the car is trying to lift the hood, but with open slots in the louver, it can't so, the lift is decreased and the hot air is sucked out of the engine bay instead). Third step was the rear wing which is the major element to the rear downforce. And we need to remember, that it's the fast corners that big improvements in lap times can be made, not the slow, especially if you're low on power, like the 4C is compared to other big guns. Accelerating out of a tight corner from 45km/h, instead of 50km/h is not much of a game changer in terms of lap times. Bringing 175km/h out of the corner to the main straight, instead of 170km/h it is. And if we take a look at the CFD downforce/drag charts, the drag bhp consumption is not nearly as bad as the downforce is increased. Roughly we sacrifice only about 3% of bhp, while downforce is generated in amount of about 17% of the rear end car's weight (600kg rear axle weight vs. 100kg of downforce). That's decent. For me, it's a fair deal, I'll take it. So far, we've shaved 2.5s off our lap times from 1.38.8xx to 1.36.3xx with increased aero, and no change in power, yet I believe we can take another 0.5s off, with fine tuning the rear wing's AOT in combination with suspension fine tuning. So the rear wing helps us a lot, as the car finally feels more stable at high speed sweepers, but surely, entire car could be even further optimized by the use of wind tunnel etc., but that just ain't happening. We must stick with methods that are economically viable for us. For me, if the lap time will drop next time after next mod, the job is done. And that will be the front hood with reversed airflow (above the car, instead under the car).

 

seeing if this link works w/ a tire size comparison 235/35/19 vs. 275/35/18 are as close as you can get w/o much impact on the speedo..........

Tire Size Comparison

Tire size comparison the easy way. Use our tire size comparison calculator to compare diameter, width, sidewall, circumference and revolutions per mile.

tiresize.com