Is the RX-8 Spoiler Functional?
05-12-2007, 07:29 PM
#27
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BMW has the second most powerful super computer in europe to do just that. Even then its very much guess work. Aerodynamics is still as much art as it is science. Pringles used the services of another one of the worlds most powerful super computers to engineer the packaging conveyance system for their chips. They used it to calculate the speed at which pringles chips will take flight! It seems kind of silly, but I guess getting all those chips in cans quickly can save them alot of $$. So I think we are still quite a ways off from having desktop simulations of aero packages.
05-12-2007, 08:42 PM
#30
Audi was prompted by customer complaints and accidents to add the little lip on the tt. So not much testing going on there! Apparently a 1:1 scale wind tunnel is stupid expensive. One of the reasons BMW bought Sauber was to get a freebie wind tunnel thrown in for their race team and their road cars. I guess areo just loses out in the cost benefit world of production cars. How often do we go fast enough to justify it anyways?
05-13-2007, 12:57 AM
#32
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i hear that the downforce cause by the 8's spoiler isn't wasted, its used for regenerative braking, like in a hybrid. That's how it has such stupid-awesome stopping power. 
no but really, it's not functional. I hear the MS spoiler is adjustable to be, but not the stock one.
no but really, it's not functional. I hear the MS spoiler is adjustable to be, but not the stock one.
05-13-2007, 01:16 AM
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BMW has the second most powerful super computer in europe to do just that. Even then its very much guess work. Aerodynamics is still as much art as it is science. Pringles used the services of another one of the worlds most powerful super computers to engineer the packaging conveyance system for their chips. They used it to calculate the speed at which pringles chips will take flight! It seems kind of silly, but I guess getting all those chips in cans quickly can save them alot of $$. So I think we are still quite a ways off from having desktop simulations of aero packages.
05-13-2007, 09:42 PM
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it has been said that the euro lip spoiler for the rx8 does actually lower the cd. i have not seen good pictures of it, but i hear it is very similar to the r-magic lip spoiler. would it be safe to assume that the r-magic would provide a similar benefit? or could even a small change in design actually increase cd?
05-13-2007, 10:42 PM
#37
I was under the impression that a true "spoiler" (not a wing) is supposed to be curved on the bottom, and flat on top. Much like an upside-down airplane wing. As an airplane wing passes through air, lift is created. As the spoiler passes through air, downforce is created since the curved side is on the bottom instead of the top. Look at the OEM spoiler - curved on the bottom, flat on top.
I would assume that this would only have any noticeable effect at extremely high speeds, though. I may be wrong, but it always seemed to make sense to me.
I would assume that this would only have any noticeable effect at extremely high speeds, though. I may be wrong, but it always seemed to make sense to me.
A rear wing is like a tail aka as a stabilizer or elevator on an airplane. It has a larger curve on the bottom than the top. It is an upside down wing and produces lift in the downward direction. It also produces "induced drag " which will increase the cd.
John
05-13-2007, 11:25 PM
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Doesn't anyone care what Mazda says?
Many people say that stock spoilers do not decrease drag (cd), a few say they might. Most write on their own authority, a few give technical reasons, sometimes pointing out that finding the answer to this question requires expensive engineering resources.
Mazda developed the RX-8 shape with airflow -- a complicated design problem involving lift, sidewinds, drag, etc., etc. -- and then designed a stock spoiler.
The Mazda RX8, a 191-page bound book published by Mazda and given to early US RX8 buyers, states at page 55:
"The RX-8 attains a respectable drag coefficient of 0.31, the same number as the RX-7. [Note it does not say which generation. Other discussions in the book usually use Gen 3 for comparison with the 8.] An optional rear spoiler lowers it further to 0.30.
"The car's lift coefficients are 0.08 at the front and 0.07 at the rear with the rear spoiler."
Mitch
Mazda developed the RX-8 shape with airflow -- a complicated design problem involving lift, sidewinds, drag, etc., etc. -- and then designed a stock spoiler.
The Mazda RX8, a 191-page bound book published by Mazda and given to early US RX8 buyers, states at page 55:
"The RX-8 attains a respectable drag coefficient of 0.31, the same number as the RX-7. [Note it does not say which generation. Other discussions in the book usually use Gen 3 for comparison with the 8.] An optional rear spoiler lowers it further to 0.30.
"The car's lift coefficients are 0.08 at the front and 0.07 at the rear with the rear spoiler."
Mitch
05-13-2007, 11:51 PM
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awesome. its good to have numbers.
is it certain that they are talking about the US spec spoiler? the euro lip spoiler is also an OEM part. would anyone happen to know how effective the euro lip spoiler actually is?
is it certain that they are talking about the US spec spoiler? the euro lip spoiler is also an OEM part. would anyone happen to know how effective the euro lip spoiler actually is?
05-14-2007, 12:02 AM
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Mitch
05-14-2007, 12:24 AM
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Many people say that stock spoilers do not decrease drag (cd), a few say they might. Most write on their own authority, a few give technical reasons, sometimes pointing out that finding the answer to this question requires expensive engineering resources.
Mazda developed the RX-8 shape with airflow -- a complicated design problem involving lift, sidewinds, drag, etc., etc. -- and then designed a stock spoiler.
The Mazda RX8, a 191-page bound book published by Mazda and given to early US RX8 buyers, states at page 55:
"The RX-8 attains a respectable drag coefficient of 0.31, the same number as the RX-7. [Note it does not say which generation. Other discussions in the book usually use Gen 3 for comparison with the 8.] An optional rear spoiler lowers it further to 0.30.
"The car's lift coefficients are 0.08 at the front and 0.07 at the rear with the rear spoiler."
Mitch
Mazda developed the RX-8 shape with airflow -- a complicated design problem involving lift, sidewinds, drag, etc., etc. -- and then designed a stock spoiler.
The Mazda RX8, a 191-page bound book published by Mazda and given to early US RX8 buyers, states at page 55:
"The RX-8 attains a respectable drag coefficient of 0.31, the same number as the RX-7. [Note it does not say which generation. Other discussions in the book usually use Gen 3 for comparison with the 8.] An optional rear spoiler lowers it further to 0.30.
"The car's lift coefficients are 0.08 at the front and 0.07 at the rear with the rear spoiler."
Mitch
05-14-2007, 01:43 AM
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Interesting point. An earlier Specifications section of the book breaks out European and US figures where different -- mostly in power and transmissions (they have a 5-speed manual as well as the 6), but a slight difference in length as well. That section does not list cd or lift. The language of the book that I quoted doesn't answer your question, but my hunch is that the number is the same or, if different, the US number would be given. No proof of that, thought.
Mitch
Mitch
05-25-2007, 10:26 AM
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Aerodynamics are for people who can't build engines.
-- Enzo Ferrari
(source: http://en.wikipedia.org/wiki/Portal:Cars/Quotes/4)
Personally I liked the look of the spoiler on the car, that's why I opted for it. Weight wasn't a concern ... car is pretty light as it is .... and it was a daily driver (not a track car).
-- Enzo Ferrari
(source: http://en.wikipedia.org/wiki/Portal:Cars/Quotes/4)
Personally I liked the look of the spoiler on the car, that's why I opted for it. Weight wasn't a concern ... car is pretty light as it is .... and it was a daily driver (not a track car).