FDNewbie

iTrader: (10)

How much does it run? I heard Mazda's in Irvine is like $50K an hour

iluvmy3rdgen

What size windtunnels are they? For cars?

jeremyb

Cannards?

FDNewbie

iTrader: (10)

These CF peices on the front bumper:









The first two are the C-west ones, the second two are the FEED ones.

Rhode_Dog

Well you would think the feed stuff is wind tunnel tested by how much it costs.

Rhode_Dog

double post

FDNewbie

iTrader: (10)

You would, wouldn'tcha?? Following that logic, RE's stuff would hafta have been born, prototyped, designed, tested, and shipped, all from within the windtunnel!

Rhode_Dog

lol

scotty305

iTrader: (2)

re: aerodynamics.
A wing will make downforce on the rear. The basic design of wings has been tested in wind tunnels, so it is very possible to find a wing package that will be efficient (good amount of downforce vs drag) and put it on your car and see pretty good results.

Underbody channels, splitters, and canards are very body-dependent, so it will be more difficult to find something that has been tested and proven that is available for our car. It might be possible to get some qualitative results by imitating the circuit-racers' bodywork, but if you want something that is scientifically proven by engineers, you're going to have to design it yourself, and the R&D on this sort of thing is pretty pricey, it's both difficult theory and extensive testing.

re: prices,
On a somewhat unrelated note, I asked a friend stationed in Okinawa to buy me a copy of that Gran Turismo 4 videogame, and he said it was $68 USD. It's possible that stuff in Japan is just overpriced sometimes, and expensive other times.

-s-

Rhode_Dog

Here is an article about how Prodrive used mostly cad drawings to design functional stuff for that race Ferrari they built, and after everything was built and put onto the car and wind tunnel tested it, all their drawings/R&D proved effective.

Still though.

That would be expensive.

http://www.geomagic.com/advantage/au...ive-index.php3

Howard Coleman

iTrader: (6)

Aerodynamics is a legitimate and very significant factor as to fd performance. And here again we see the high relative value in the fd design.

Mazda spent huge amounts of resources sculpting the fd’s aerodynamics in recognition of aerodynamic’s importance as to determining vehicle performance. Mazda pushed to the edges the envelope by, for instance, shrinking the cockpit to the point of almost being claustrophobic… all to lower the frontal area and drag coefficient.

Mazda placed significant emphasis on the nose of the fd, making it as small as possible with as little cooling openings as possible.

All because of the great cost of aerodrag. Everything in the formula is constant for a given vehicle ( drag coefficient, frontal area and the divisor) except for MPH.

MPH is cubed!

That means that it takes EIGHT times as much power to go 200 mph as it does 100 mph.

It takes 3.3 times as much power to run 150 mph vs 100 mph.

Above 85 mph aero is king.

It is the excess power above what is needed to drive the fd at, say, 100 mph, that is available for acceleration.

So even if you are not a Bonneville participant, if you drag race for example, aerodynamics is important as the slicker your car the more power is available to accelerate.

Which brings me to ask….

Do you want to look fast or go fast?

The “tuner” front ends for the fd are for looking fast, they have all the aerodynamics of a Hummer. Slap one of those on your car and you can just kiss all of mazda’s aero investment goodby.

If mazda’s well designed R1 aero package swaps away some aero slickness for a bit of downforce w just a splitter and a smallish rear wing in a low pressure area what do you think the huge tuner front end does to the car. The R1 package increases aero drag by 6.9% requiring 6.9% more hp to accelerate even w the non R1.

My bet is that the front ends pictured in post #29 add 15% more drag due to increased frontal area and god-awful drag coefficient.

So here’s my take:

Aero factors are more important than most realize. The stock front end is a thing of beauty engineering-wise…. compact with just enough power robbing ducts to provide cooling. I run it w the R1 splitter and no wing at 25 inches ( low is fast aerowise) of ride height front and rear measured at the wheelwells.

I routinely track my car at Brainerd Int’l which has a 6000 foot straight leading to a banked wide radiused turn which I run 165 mph thru and my car is very well composed. I could run through it a bit faster but I track on Toyo Proxes street tires so elect to leave something on the table.

BTW, 7Langit, I like your mods… front splitter, relocated battery ( I run 52% rear-weight), the Pettit/ASP large IC (super efficient and better aero and weight distribution than fmic), getting rid of the bose weight….

Also above, there were numerous posts about low…. Low is fast both for straight-line speed and cornering as the only 2 factors primarily effecting fd lateral weight transfer is center of gravity and track width.

howard coleman

Mr. Stock

Well written, informative post.
But you fail to mention the shortcomings of the FD aerodynamic design.
Although the stock front end may possibly be a thing of beauty, there is certainly room for huge improvement.
The coefficient of lift for the front of the FD(R1/R2) is 0.10 and for the rear is 0.08.
In contrast, the estimated coefficient of lift for the 1995 Ferrari F355 is -0.24.
Now, Ferrari achieves that number without large visible aeodynmic aids. Truly, this represents an aerodynamic thing of beauty.

FDNewbie

iTrader: (10)

Howard, I understand what you're saying, but is it fair to say they're THAT bad aerodynamically? I thought it was fact that Mazdaspeed wind tunnel tests all its products, and their front bumpers, esp. the GTC, are considerably larger than the stock one. All their spoilers are considerably larger as well.

I'm not trying to say/argue that they'd have less frontal area and hence less drag coefficient. But I'd think that it's definitely an acceptable amount, considering the added cooling effects from larger front air dams and the bumper itself sitting lower (the bottom edge), reducing lift on the front end. Ditto w/ the spoilers (larger drag, but prob. not too much to make the added downforce they make a negligible benefit). Yes? No?

Kento

He's referring to the front ends in that one post, but just because a product has been "wind tunnel tested" doesn't automatically qualify it for "aerodynamically efficient component of the year award." Mazdaspeed most likely intended the GTC bumper to be run with heavily modified racing-- as in "on a racing circuit"-- cars that have fully developed aero packages and big hp engines. By "fully developed", that means if the openings for cooling airflow aren't properly engineered beyond just the opening (as in properly ducting the airflow after the radiator), a ton of aero drag results.

Downforce, especially that created with spoilers, is a tradeoff with aero drag. You can't have one without the other, and that drag increases in a major way with speed.

dgeesaman

iTrader: (7)

As I understand it, the undercarriage covers make a tremendous difference in getting negative lift. Ferrari can afford a few thousand dollars to cover the undercarriage with special pieces no problem, but on the 35k budget of the FD I imagine Mazda engineers did what they could with a lot less.

Plus, what Kento said is all-important - racing performance is a tradeoff of aerodynamic drag, appearance, downforce, engineering/wind tunnel cost, and cooling. A race team might be happy more downforce at the cost of drag if they need it by next month and giving up some top end speed is not an issue if this moves them faster in the corners (keeping in mind that faster corner speed can create higher straightaway speeds). Or, a race team may happily give up a few mph top end if their engines have been overheating before the end of the race, and they don't have the time or budget to ensure the drag coefficient is the same or better.

Mazda engineers aren't dumb - I'm sure they would like a negative lift coefficient, but that's getting nitpicky for a car that will in most cases never exceed 130mph in its lifetime. Although an excellent track car, it wasn't designed strictly for 130mph+ driving.

For any of us to stand about and assume that any aftermarket (or stock) part is optimized for maximum downforce, with minimal additional drag, and with extensive wind tunnel or CFD testing to ensure the change improves all aspects of the aerodynamics, is silly. No matter what we do, a bolt-on is still a bolt-on, and is difficult to fully integrate into the original design without the original design data. To engineer an aero product to that level is way more money that can be justified by aftermarket sales volume.

That said, sometime I'd like to tinker with a CFD tool and use an FD body as the model. Just like that Ferrari team did, but not playing for keeps. It would take a very accurate CAD model of the car first, which is why it's just an idea.

Dave

Howard Coleman

iTrader: (6)

"Although the stock front end may possibly be a thing of beauty, there is certainly room for huge improvement. The coefficient of lift for the front of the FD(R1/R2) is 0.10 and for the rear is 0.08. In contrast, the estimated coefficient of lift for the 1995 Ferrari F355 is -0.24. Now, Ferrari achieves that number without large visible aeodynmic aids. Truly, this represents an aerodynamic thing of beauty...."


I like ferraris too and I respect some of their engineering but You are quoting lift/downforce numbers and seem to be trying to equate them with aero efficiency.

As Kento correctly states…. The downforce/drag equation is a tradeoff. If, for example Ferrari wanted downforce they would have to accept a lower drag coefficient.

If you want to properly compare the fd w any other car multiply the frontal area times the drag coefficient. I await your Ferrari frontal area and drag coefficients.

Only then will we be able to evaluate if the fd has “room for huge improvement.”

FYI the 2005 C6 Corvette’s aero numbers are 21.9 sq ft frontal area and .28 drag. That factors to 6.132.

The fd is 19.26 w a .29 drag (non R1) or 5.585

Advantage fd by over 9%.


“is it fair to say they're THAT bad aerodynamically?”

Yes.

If the R1 splitter and small wing located in a low pressure area increase drag 6.9% what do you think the Hummer tuner nose does to the drag?

“considering the added cooling effects from larger front air dams”

the way to cool the car is with the right engine support systems not by garfing up the aerodynamics. My car currently makes 480 flywheel hp and runs 84 C water all day. It would not run any cooler with a bigger hole in the nose. There is more than enough duct area for oil coolers, brakes etc on the stock setup.

I am frustrated by a lack of appreciation for the fd engineering. Is it a perfect car? Of course not. There were a number of mistakes made engineering the car… primarily with the turbosystem.

There were almost no compromises with the chassis and aerodynamics that set it apart from being a true racecar.

Mazda spent far more on the design than where it priced the car… for instance they had 2 teams that could not talk to each other for a year whose one job was to take weight out of the car. (just look at the swiss cheese front sway bar mounts).

As I said in an earlier post, do you want to look fast or go fast? I bring this up because I have absolutely no problem with anyone doing whatever to their fd. If you want it to look fast… fine. Just don’t rationalize it into being something it isn’t.

The bottom line for me is performance. Since Ferrari has come up twice in this thread with great reverence I thought you all might be interested to know that the Ferrari Club of America has an annual track day at Brainerd Int’l Raceway and I have tracked my car with them at 4 of their annual affairs….. all kinds of ferraris including a bunch of Ferrari Cup cars.

I have never been beaten in my fd.

howard coleman

ExpensiveHobby22

Just wanted to point out. "You have never been beaten in your non-stock fd".

Sorry, couldn't resist.

ExpensiveHobby22

We have a full size aero acoustic wind tunnel and a 3/8ths scale model tunnel. Yes, they are for automobiles.

Trexthe3rd

One word BERNOULLI.

You want to play with aerodynamics, first understand the Bernoulli concept. Check this link http://home.earthlink.net/~mmc1919/venturi.html

F1 race cars have invested literally billions since it's inception in this area and is the pinnacle of aerodynamics as applied to the automotive technology. It's common knowledge that a F1 car can create enough downforce to run completely upsidedown at speed while having the lowest drag coefficient on four wheels.
The reason why people always bring up Ferrari is because of their use of the F1 technology in their production cars. When a car can create over 800 lbs of down force without a shopping cart wing, it has done something right. And yes we are talking about even down force across the entire car not just the 25 lb down force on the back created by the alluminum bench.

The FD's under body panel design did incorporate the Bernoulli effect but not nearly to the extent of cars like Enzo. If you really want to, study the under body panel of Enzo and F1 cars and duplicate the design fabricate and apply it to a panel that will cover the entire under side. Get rid of any wing and body kits, and stick with the stock front end.

rynberg

Common misconception. Modern F1 cars actually have horribly high drag coefficients, due to the FIA regulations. The 2002 Ferrari car experienced a full 1G of deceleration simply by letting off the throttle at 200 mph.....

Mr. Stock

Re-read your post and found this mistake.

Drag inreases with the square of speed, not cubed,

Mr. Stock

Ferrari F355 has a coefficient of drag of 0.33 and a frotal area of 1.9 sq. m(20.45 sq ft).

Mada RX7 R1 has a coefficient of drag of 0.31 and a frontal area of 19.26 sq ft.

I admit that the R1 drag numbers are better, and that would translate into better fuel economy and straight-line top speed given that other variables such as egine power, gearing, etc are constant.

However, for a race car or a sports car, fuel economy and straight-line speed is not top priority. Cornering speed, I would say is much more important, if not most important.

To achieve high cornering speed, the tires have to be planted. Actually, even for top speed runs, it is important for the car to stay on the ground. Although the coefficients of lift for the R1 of 0.10/0.08 are respectable numbers for a "passenger car", the tendency of the RX7 at speed is to get lighter as the speed increases. The F355, on the other hand, achieves downforce with its coefficient of lift which would make the car more stable as the speed increase.

This is what one wants to achieve as one modifies a "passenger car" into a race car. To come from a factory, with downforce already designed into its stock body and achieving the above mentioned low drag numbers, I am much more impressed by the design of the F355 than the R1.

Mr. Stock

All open wheeled cars have poor coefficient of drag.
Formula 1 cars have coefficient of drag 2 to 3 times that of most passenger cars.

FDNewbie

iTrader: (10)

I think this point was right on the money. The FD was designed as an ultimate track car, not an all out straightaway racer. It's not a Ferrari F-50, where it's actually designed to push 200mph+.

I don't think any of them are optimized in that sense, and maybe this is wishful thinking, but I'd like to think aero parts from companies like Mazdaspeed, C-West, FEED, and RE definitely have some aerodynamic testing behind them. From my understanding, these are usually parts they've actually run on their GT cars and what not, that have eventually reached the market. Do any of those companies have the budget or will to go through the kind of testing Mazda did when they were designing the FD? Prob not. But I think that their products probably do what they're supposed to do, and only that. Ie, create downforce, w/o much consideration to drag effect. That isn't too bad...you can take the old school American approach - just add power

I'd love to see something like that really happen.

Point well taken.

I personally agree w/ you 100%. There's a lot of reasons why the FD is #1 in my book, end of story. It really is simply an amazing machine. But then again Howard, please understand that that for people to appreciate, they have to understand. Someone like myself who well...sux at physics lol and hasn't taken any mechanics/engineering courses in his life isn't going to be able to appreciate the engineering that went into the design of the FD as much as someone like yourself. On the same token, I bet you that most of you don't appreciate the intricacies of the human body, simply because that isn't your specialization. But that's where I can go on for hours So it really comes down to what you know, and only then can you really fully appreciate it.

I personally want both. I like the body kit look...it's just my taste, and I honestly believe that I feel a difference in stability of the car at high speeds from stock (R2) to now (front & rear bumpers, sideskirts, RE diffuser, undertray, and GT spoiler). Maybe that's what I WANT to believe lol...but who knows. I can tell you that the drag I was experiencing from 160 - 165mph was HUGE. I ran right on up to 160, and it took quite a few seconds ot hit 165, at which point I decided to shut her down. Was she rock solid/stable? YES. But she simply was facing too much drag & wind resistance.

That's what I'm aiming for w/ the body kits etc. Form + function. At least in my mind, downforce/stability is paramount, esp. since to counteract drag, you can always "just add more power"

My hat's off to you, Howard

scotty305

iTrader: (2)

To expand on this a bit, F1 cars have a much higher HP-to-weight ratio than passenger cars, and high-speed cornering is important enough to them that trading acceleration for cornering grip is acceptable. Most teams have multiple aero packages; they will run a wing combo that produces less downforce (and drag) on circuits with long straightaways and fewer corners.

It might be useful for the original poster to consider the goals of your car: if you're doing top speed runs, you want as little drag as possible, with just enough downforce to keep the car stable (look at the Racing Beat top-speed Bonnevile car). If you're in need of more grip at track days where average cornering speeds will be between 50-100mph, you might want to trade some drag for the additional downforce. In any form of racing with corners, I'd advise you to look into tires and suspension first. Adding aeros to mask a poor suspension setup can create a car with ugly split-personality handling characteristics.

I'm no aerodynamicist, but I think that the aero guys should agree that even a plain flat undertray will definitely be a helpful thing, assuming it doesn't weigh too much.

-s-