Do any of these aftermarket diffusers actually create downforce?

[The-Traveler]

I keep seeing a bunch of them online, seems like anyone with a modified exhaust has one. The only one that looks like it might do something is the very expensive one that comes in two carbon pieces, to cover the exhaust entirely.

The others don't look functional to me at all.

Does anyone have proof that they do anything?

Thanks.

[Altazima]

Originally Posted by The-Traveler

I keep seeing a bunch of them online, seems like anyone with a modified exhaust has one. The only one that looks like it might do something is the very expensive one that comes in two carbon pieces, to cover the exhaust entirely.

The others don't look functional to me at all.

Does anyone have proof that they do anything?

Thanks.

http://www.m3post.com/forums/showthread.php?t=728578

http://www.m3post.com/forums/showthread.php?t=658300

[dparm]

I tend to put my faith in the factory "diffuser" or whatever you want to call the unusual shaping at the bottom of the bumpers. We know that BMW is doing extensive wind tunnel testing and trying to make the car stable at high speeds. As soon as an aftermarket piece is added, you've disrupted their design and the net effect may be worse.

The only route I would realistically take would be the M3 GTS lip and matching rear spoiler (since they were designed to work together), though for street use those are probably pointless.

[1MOREMOD]

I would guess only the varis does much and still that is minor smoothing out the turbulence of airflow as it exits under the car.

[Tracyis300]

I believe it's just for looks.
But they can work? If you can get a underbody that can channel the air from front to back like most super cars?
Examples: GTR, LFA, 458 speciale

[Rat3d ///M]

GTR and supercar dont belong in the same post. Supercar performance? Maybe. But not a supercar. The only people that push the issue of the GTR fighting for the right to be called a supercar are GTR fanbois who play way too much Gran Turismo and owners who need to justify the fact they spent so much money on a Datsun.

[1MOREMOD]

Just a short time ago gtr put smack down on everyone and everyone else stepped up big time.

[Law]

Originally Posted by ||||||||||

GTR and supercar dont belong in the same post. Supercar performance? Maybe. But not a supercar. The only people that push the issue of the GTR fighting for the right to be called a supercar are GTR fanbois who play way too much Gran Turismo and owners who need to justify the fact they spent so much money on a Datsun.

This.
I'll put my flamesuit on because I feel the term "supercar" is used to liberally by magazines and car enthusiasts alike.
The problem with the term "supercar" is that there is no official definition as in FIA official, not webster dictionary official, so it is always open to interpretation.
With that said, I don't consider cars like the GTR or R8 to be supercars. High-performance sports cars? Yes. Supercar? Definitely not.
I cringe a little bit every time they get referred to as supercars.
A supercar should first and foremost be bespoke as well as all of the following: very exceptional performance, unique/exclusive/inspiring styling and have very limited production & not based on a mass production platform (or any other platform for that matter).
Additionally, the cost of ownership and even the obtainability to a supercar should be quite difficult (such as on the basis of previous ownership or by invitation).

The GTR and R8 are simply too mass produced. While expensive by average standards, they are still easily obtainable compared to true supercars & ownership is as simple as walking into a dealership and walking out with the keys after some paperwork.
These are cars that are very much civilian cars that have the bonus of high-performance & often used as everyday daily drivers.
It's not uncommon to see these cars getting groceries or parked at an office building from the hours of 9-5. One can make the argument that this renders these cars "everyday supercars" but I beg to differ.
These are not "everyday supercars". These are everyday cars with "supercar" performance.

[DSilk]

Originally Posted by Law

This.
I'll put my flamesuit on because I feel the term "supercar" is used to liberally by magazines and car enthusiasts alike.
The problem with the term "supercar" is that there is no official definition as in FIA official, not webster dictionary official, so it is always open to interpretation.
With that said, I don't consider cars like the GTR or R8 to be supercars. High-performance sports cars? Yes. Supercar? Definitely not.
I cringe a little bit every time they get referred to as supercars.
A supercar should first and foremost be bespoke as well as all of the following: very exceptional performance, unique/exclusive/inspiring styling and have very limited production & not based on a mass production platform (or any other platform for that matter).
Additionally, the cost of ownership and even the obtainability to a supercar should be quite difficult (such as on the basis of previous ownership or by invitation).

The GTR and R8 are simply too mass produced. While expensive by average standards, they are still easily obtainable compared to true supercars & ownership is as simple as walking into a dealership and walking out with the keys after some paperwork.
These are cars that are very much civilian cars that have the bonus of high-performance & often used as everyday daily drivers.
It's not uncommon to see these cars getting groceries or parked at an office building from the hours of 9-5. One can make the argument that this renders these cars "everyday supercars" but I beg to differ.
These are not "everyday supercars". These are everyday cars with "supercar" performance.

I agree.

[BNBM3]

Originally Posted by Law

This.
I'll put my flamesuit on because I feel the term "supercar" is used to liberally by magazines and car enthusiasts alike.
The problem with the term "supercar" is that there is no official definition as in FIA official, not webster dictionary official, so it is always open to interpretation.
With that said, I don't consider cars like the GTR or R8 to be supercars. High-performance sports cars? Yes. Supercar? Definitely not.
I cringe a little bit every time they get referred to as supercars.
A supercar should first and foremost be bespoke as well as all of the following: very exceptional performance, unique/exclusive/inspiring styling and have very limited production & not based on a mass production platform (or any other platform for that matter).
Additionally, the cost of ownership and even the obtainability to a supercar should be quite difficult (such as on the basis of previous ownership or by invitation).

The GTR and R8 are simply too mass produced. While expensive by average standards, they are still easily obtainable compared to true supercars & ownership is as simple as walking into a dealership and walking out with the keys after some paperwork.
These are cars that are very much civilian cars that have the bonus of high-performance & often used as everyday daily drivers.
It's not uncommon to see these cars getting groceries or parked at an office building from the hours of 9-5. One can make the argument that this renders these cars "everyday supercars" but I beg to differ.
These are not "everyday supercars". These are everyday cars with "supercar" performance.

So your definition of a supercar is basically "expensive" and "exclusive because it's expensive". I might disagree with that. A car with supercar performance and unique styling from the factory sure sounds a lot like a supercar to me. The GTR is nothing like any other Nissan. It's not a Sentra with a bigger engine. It fits every category you mentioned other than it's affordable.

By the way, based on a quick search of sales numbers, Nissan makes about as many GTR's as Lamborghini does the Aventador..... What is not exclusive about that?

[dparm]

I dunno about you guys, but it's pretty easy to buy a Ferrari, Lambo, etc. here in Chicago. By the above poster's definition, that means the 458s on the showroom floor down the street from me aren't supercars.

I will agree that the term is nebulous and can be attributed to a very wide gamut of vehicles.

[Rat3d ///M]

Originally Posted by BNBM3

So your definition of a supercar is basically "expensive" and "exclusive because it's expensive". I might disagree with that. A car with supercar performance and unique styling from the factory sure sounds a lot like a supercar to me. The GTR is nothing like any other Nissan. It's not a Sentra with a bigger engine. It fits every category you mentioned other than it's affordable.

By the way, based on a quick search of sales numbers, Nissan makes about as many GTR's as Lamborghini does the Aventador..... What is not exclusive about that?

The difference between the Aventador and the GTR is the Aventador's MSRP is near $400,000. The GTR is around $100,000. Furthermore, Lamborghini is a company that produces nothing but high performance, exotic vehicles. By definition Lamborghini is an exotic car manufacturer. Nissan is a company that specializes in economy cars, family sedans, SUV's and pick-up trucks. They just happened to make one high performance vehicle that everyone for some reason is about, and said car is suddenly labeled a supercar? What about an R34? Is the R34 a supercar? The R33? R32??

Despite the fact that the definition of a supercar has been so watered down and diluted within recent years, please tell me, what makes it a supercar? It's performance? I've seen Toyota Supra's with 1200whp, does that make them a supercar? It's not all about performance and numbers. The GTR is nothing more than a [very] fast sports car. It is not nearly exclusive enough, and by design is very dissimilar to any other high performance car made by Mclaren, Lamborghini, Ferrari, Pagani, Bugatti, etc. that has earned the right to be labeled a manufacturer of supercars or exotics.

IMHO, for what it is worth, a "supercar" is typically (though not always):

1. Mid engine, rear wheel drive platform
2. V10 or V12, naturally aspirated motor
3. 2 seater (i.e. no backseat)
4. Exclusive, and high in price/demand
5. Unique in design, and "exotic" looking
6. Sleek, flowing body lines, low stance, wide wheelbase

The GTR is none of those. Thats not to say every supercar has to have all of those characteristics, but the GTR has none.

So Ill stand by my previous statement. A "super car"? Maybe, but that is certainly a matter of opinion. I respect them, I am sure they are amazing, but I have never driven one, so I can't comment on it's performance. Does that make it a supercar? (see what I did with the spacing there?) Not in this lifetime. Sorry to anyone else who thinks so.



This has earned the right to be called a supercar. This:



..not so much.

[BNBM3]

Originally Posted by ||||||||||

The difference between the Aventador and the GTR is the Aventador's MSRP is near $400,000. The GTR is around $100,000. Furthermore, Lamborghini is a company that produces nothing but high performance, exotic vehicles. By definition Lamborghini is an exotic car manufacturer. Nissan is a company that specializes in economy cars, family sedans, SUV's and pick-up trucks. They just happened to make one high performance vehicle that everyone for some reason is about, and said car is suddenly labeled a supercar? What about an R34? Is the R34 a supercar? The R33? R32??

Despite the fact that the definition of a supercar has been so watered down and diluted within recent years, please tell me, what makes it a supercar? It's performance? I've seen Toyota Supra's with 1200whp, does that make them a supercar? It's not all about performance and numbers. The GTR is nothing more than a [very] fast sports car. It is not nearly exclusive enough, and by design is very dissimilar to any other high performance car made by Mclaren, Lamborghini, Ferrari, Pagani, Bugatti, etc. that has earned the right to be labeled a manufacturer of supercars or exotics.

IMHO, for what it is worth, a "supercar" is typically (though not always):

1. Mid engine, rear wheel drive platform
2. V10 or V12, naturally aspirated motor
3. 2 seater (i.e. no backseat)
4. Exclusive, and high in price/demand
5. Unique in design, and "exotic" looking
6. Sleek, flowing body lines, low stance, wide wheelbase

The GTR is none of those. Thats not to say every supercar has to have all of those characteristics, but the GTR has none.

So Ill stand by my previous statement. A "super car"? Maybe, but that is certainly a matter of opinion. I respect them, I am sure they are amazing, but I have never driven one, so I can't comment on it's performance. Does that make it a supercar? (see what I did with the spacing there?) Not in this lifetime. Sorry to anyone else who thinks so.



This has earned the right to be called a supercar. This:



..not so much.

You just keep redefining it with rather vague requirements, and continue to suggest price/exclusivity makes it a supercar. I simply don't agree.

I think you just hate the GTR because of all the fan boys, for the sake of being argumentative. Everything about the GTR says supercar other than the Nissan branding. It's outrageously fast around a track, exotic, unique, well engineered, etc.... from the factory. What about this suggests it's anything but a supercar? Only European styling and naturally aspirated engines can be used in a supercar, I guess? Is a Gallardo a supercar?

[CognitiveDistortion]

Yeah...not sure about that backseat bit.

Astons's Rapide and Ferrari FF both have back seats...

[Rat3d ///M]

Originally Posted by BNBM3

You just keep redefining it with rather vague requirements, and continue to suggest price/exclusivity makes it a supercar. I simply don't agree.

There are no truly defining characteristics that make any car a supercar, at least not anymore. My "requirements" weren't really requirements at all, just me stating in my honest opinion (IMHO) what a supercar or "exotic" car typically consists of. You may choose to disagree, and you are well within your right to do so. Opinions are like assholes, everyone has one, and they are usually full of shit

I think you just hate the GTR because of all the fan boys, for the sake of being argumentative.

You are at least half right. I never said I hated the GTR. In fact, I stated a couple times in varying ways that I respect it. I said it may very well be a "super car", and that it is probably amazing to drive. Never once did I say I hated the GTR. I will go so far as to say I don't care for the styling, and they are not my cup of tea, but I don't hate them. I do however cringe when people call it a supercar, because it just isn't. We can argue about it all day, but it would be like the special Olympics.

Everything about the GTR says supercar other than the Nissan branding. It's outrageously fast around a track, exotic, unique, well engineered, etc.... from the factory.

Not everything about the GTR says supercar except the Nissan branding. In fact, I have bolded the only two of those characteristics that I agree with, and the latter has nothing to do with it being a supercar, or not being a supercar

What about this suggests it's anything but a supercar? Only European styling and naturally aspirated engines can be used in a supercar, I guess?

Nope, never said that either of those factors have to be present for it to be considered a supercar.

Is a Gallardo a supercar?

I don't know if I would call a Gallardo a supercar, though they have more of the typical supercar characteristics than a GTR does, there is no arguing that. The only reason I would say a Gallardo wouldn't qualify as a supercar by definition based on characteristics a typical supercar possesses, is that they are becoming very affordable. There is no exclusivity to owning them anymore.

There are countless individuals who have YouTube channels dedicated to their purchase and ownership of a Gallardo, and their massive popularity comes from the fact that they are rather ordinary individuals in terms of their jobs and income. Their stories give people like you and I hope of owning an exotic one day. Point being, the Gallardo can be had for under $90,000 nowadays, making it more and more achievable for people like you and I. They were also produced in fairly high numbers.

But the Gallardo is definitely an exotic, there is no question about that. A budget exotic? Yes, but an exotic nonetheless. I would put it in the same category as the Ferrari 360 Modena. And for the record, I would take a stock 2004 Gallardo before a 1000+ whp GTR, in a heartbeat.

Originally Posted by CognitiveDistortion

Yeah...not sure about that backseat bit.

Astons's Rapide and Ferrari FF both have back seats...

Aston Martin and Ferrari also build nothing but high performance sports cars and exotics. Lamborghini had an atrocity of an SUV (or whatever that thing was) at one point too, that doesn't mean they stopped being any less of an exotic car manufacturer. With Lamborghini and Ferrari, their claim to fame is exotics. The companies have prestige. Nissan's claim to fame is the Sentra, Altima and Maxima. They made one mass produced production car that can compete in performance with Ferrari and Lamborghini's slowest vehicles since the mid 90's, and that makes it a supercar?

[BNBM3]

Originally Posted by ||||||||||

There are no truly defining characteristics that make any car a supercar, at least not anymore. My "requirements" weren't really requirements at all, just me stating in my honest opinion (IMHO) what a supercar or "exotic" car typically consists of. You may choose to disagree, and you are well within your right to do so. Opinions are like assholes, everyone has one, and they are usually full of shit




You are at least half right. I never said I hated the GTR. In fact, I stated a couple times in varying ways that I respect it. I said it may very well be a "super car", and that it is probably amazing to drive. Never once did I say I hated the GTR. I will go so far as to say I don't care for the styling, and they are not my cup of tea, but I don't hate them. I do however cringe when people call it a supercar, because it just isn't. We can argue about it all day, but it would be like the special Olympics.




Not everything about the GTR says supercar except the Nissan branding. In fact, I have bolded the only two of those characteristics that I agree with, and the latter has nothing to do with it being a supercar, or not being a supercar




Nope, never said that either of those factors have to be present for it to be considered a supercar.




I don't know if I would call a Gallardo a supercar, though they have more of the typical supercar characteristics than a GTR does, there is no arguing that. The only reason I would say a Gallardo wouldn't qualify as a supercar by definition based on characteristics a typical supercar possesses, is that they are becoming very affordable. There is no exclusivity to owning them anymore.

There are countless individuals who have YouTube channels dedicated to their purchase and ownership of a Gallardo, and their massive popularity comes from the fact that they are rather ordinary individuals in terms of their jobs and income. Their stories give people like you and I hope of owning an exotic one day. Point being, the Gallardo can be had for under $90,000 nowadays, making it more and more achievable for people like you and I. They were also produced in fairly high numbers.

But the Gallardo is definitely an exotic, there is no question about that. A budget exotic? Yes, but an exotic nonetheless. I would put it in the same category as the Ferrari 360 Modena. And for the record, I would take a stock 2004 Gallardo before a 1000+ whp GTR, in a heartbeat.



Aston Martin and Ferrari also build nothing but high performance sports cars and exotics. Lamborghini had an atrocity of an SUV (or whatever that thing was) at one point too, that doesn't mean they stopped being any less of an exotic car manufacturer. With Lamborghini and Ferrari, their claim to fame is exotics. The companies have prestige. Nissan's claim to fame is the Sentra, Altima and Maxima. They made one mass produced production car that can compete in performance with Ferrari and Lamborghini's slowest vehicles since the mid 90's, and that makes it a supercar?

The Gallardo and R8 are practically the same car. Yet one is closer to a supercar and the other definitely not.....

I don't know man, it seems your definitely of a supercar is merely super-expensive and from Europe - and even then who knows. You are entitled to your opinion, I guess.

I don't think a supercar is all about prestige, cost, and exclusivity. We'll just have to disagree.

[Tracyis300]

Oh lord! What did i start?

These arguments about manufacturers are a bit selfish and laughable

Enthusiasts have been trying to define on "what makes a car super" For years. And it can be a number of things? like what some posters have mentioned, that can help give a better definition?
But it is up to "YOU" to say if a car is "super or not"?

Is "Batman" a "super hero" or just a "vigilante"?.... Yes, No, or both.

I put the GTR in there? Because I believe it's a supercar. And how i define a supercar (even though the other two that I mentioned may or may not do the same thing?) is not by manufacturers, engine size?? or price point!
But as a car that can do it all?
It's nice looking (to my standards), record breaking performance (and each of it's model year has proven to break records), and can be used on a daily basis.
So If that's not "super" enough? Then we are all lost souls?

Anyway! This thread is about "rear diffusers" for our E9x's. So lets get back to the main topic?

[DSilk]

Originally Posted by CognitiveDistortion

Yeah...not sure about that backseat bit.

Astons's Rapide and Ferrari FF both have back seats...

And neither qualifies as a supercar. Defining a "supercar" is like defining beauty. You can't necessarily put it into words, but you know it when you see it. While superlative performance is a part of what makes a supercar, and what distinguishes it from merely an exotic, it isn't the sum total of it.

The first car to earn the supercar designation was the Lamborghini Miura. It was set apart from the competing Ferraris, Maseratis, and Aston Martin, not by it's cost and not by its performance, but by its then exotic for a road car layout and spectacular design. While the competing Ferraris, Maseratis, and Aston Martins were front-engined, the Miura mounted its V12 engine transversely amidships. Moreover, although the Ferraris, Maseratis, and Aston Martins were generally handsome (beautiful in the case of the Maserati Ghibli), they were attractive in a conventional sort of way. The Miura looked almost shockingly alien by contrast, a feature taken to a new extreme by its successor the Countach.

For what it worth, both the Miura and Countach can now be outperformed by a wide variety of lesser modern cars, yet they are still supercars. The Miura was not as fast as the Ferrari 365GTB4 "Daytona", which was its contemprary, but the latter was never considered to be a supercar. The Maserati Bora was a phenomenally beautiful mid-engined car that was very fast and very expensive, but it also was never considered to be a supercar. Exotic, yes. But not a supercar.

[SunnyD]

Man how did we go from non-functional diffusers to the definition of the word "supercar"? Since we're on this topic, how do you guys differentiate the term "super car" vs. "hyper car"?

[Edward]

If I had to put my money on it, I would guess that any add on diffuser that doesn't extend further to cover more than the painted portion of your rear bumper center underneath the car is aesthetic only.

Just because it has little vertical strakes doesn't make it a functional diffuser.

[Law]

Originally Posted by BNBM3

So your definition of a supercar is basically "expensive" and "exclusive because it's expensive". I might disagree with that. A car with supercar performance and unique styling from the factory sure sounds a lot like a supercar to me. The GTR is nothing like any other Nissan. It's not a Sentra with a bigger engine. It fits every category you mentioned other than it's affordable.

By the way, based on a quick search of sales numbers, Nissan makes about as many GTR's as Lamborghini does the Aventador..... What is not exclusive about that?

You're missing the point. "Expensive for the sake of being expensive" is not the only determinant of a supercar otherwise a Rolls-Royce Phantom would be a supercar.

Obviously the GTR is not just a Sentra with a bigger motor.
The GTR is built off what Nissan calls the "Premium Midship" platform, which itself was an evolution of the "Front Midship" platform (Fairlady Z (350Z/370Z), Skyline (G35/G37), Fuga (M35/M45), etc.)
Its VR38DETT engine architecture evolved from the mass produced VQ family of engines that powered a whole generation of Nissan/Infiniti vehicles are still in use today.
The R35 GTR is the first GTR not to be based off the Skyline chassis, hence the omission of the "Skyline" designation from its model name but its development still spawned from the existing Front Midship Platform and VQ engine architecture.
Even if its production and manufacturing are segregated and specialized from the rest of the Nissan/Infiniti, the GTR was not truly engineered from scratch even though Nissan markets it as otherwise.

Moving forward, since you want to talk about numbers, let's talk about numbers.
I doubt your Googling abilities, because the numbers you claim are completely off.
MY------Aventador (Global)----GTR (US only)
2011------447---------------------1294
2012------976---------------------1188
2013------1113--------------------1237
2014------1110--------------------1436
------------3646--------------------5155
Since the Aventador began production in 2011, the GTR's US sales alone has consistently surpassed the Aventador's worldwide sales every single model year.
Add up the total and you'll see that the GTR's US sales exceeds the Aventador's global production numbers by 41% thus far.

At the time of writing, there have already been 10,122 GTRs sold in the US alone.

Based on your quoted statement, I bet you're also not aware that the Aventador is nearing the end of its production run.
The reason? Because production is capped at 4000 units and as we've seen above, as of the 2014 MY, they have already reached 3646 units. Its predecessor, the Murciélago, had its production capped at 4099 units. Before that, the Diablo sold 2884 units. The Countach? 2049 units. Again, these numbers are global figures.

Take a look at the GTR figures again: there are more GTRs in the US than there are Aventadors and Murciélagos in the entire world combined.

GTR exclusive? It is nowhere near the level of true supercars when it comes to exclusivity.

[ilikebmxbikes]

so how about those diffusers...?