Re: ALL MX3 AERO PARTS!!!!
Posted: December 6th, 2010, 5:16 pm
Moon, Evo and Ryan are right.
Mazda has a history of putting function over form. In '80, they had 2 versions of the RX-7: RS and GS, IIRC. One of them (I think the GS) had a little spoiler in the back. That spoiler alone gave the car a CX of 0.32, against 0.34 of the model without it.
The plates Evo is talking about were called (at least colloquially, in Spanish) "polleritas" (little skirts). They were used in the '70s, in the times of the extra wide slicks, when Niki Lauda and many of the all time big dogs used to race. They were responsible, together with all the other stuff, of the crazy lap speeds achieved in those times, but also of the violent accidents that were part of almost any race. The thing is, when they worked, they worked great, but when for any reason one of them malfunctioned, and let air under the car, being that the car was going much faster than it would without them, it lost control instantly, with the driver being unable to react. Because of that, the FIA decided (in the late '70s or early '80s, I'm not sure) to ban them, and start limiting other factors, like the width of the tires.
Finally, coming back to the topic, EVERYTHING put outside of a car will affect aerodynamics, for better or worse. There's no such thing as a purely cosmetic add on. Another myth is that you need to go a certain speed for those spoilers to "start acting". That's not true. The moment the car starts moving, all surfaces start having an effect. True, there IS a speed at which those spoilers will be most efficient, but that doesn't mean they won't work outside that range.
But that doesn't mean they will affect handling, or grip. Many times, those spoilers are there to improve gas mileage, by delaying the formation of a turbulent boundary layer in the back of the car.
In a nutshell, a "boundary layer" is defined as the portion of the air surrounding a moving object in which the airspeed is between 1% and 99% that of the object.
There are 2 kinds of boundary layers: laminar and turbulent. Laminar boundary layers are those in which the air moves "in line", all molecules in the same direction. They are low pressure, high speed layers, and produce little drag. Turbulent layers are the contrary: the air starts creating little vortexes, "bumping with itself". So they are low speed, high pressure, high drag layers.
If you look at the MX-3 user manual, it specifically says not to drive the car with the hatch open. That's because the turbulent boundary layer produced in the back of the car can literally "suck" the exhaust gases into the cabin, intoxicating the occupants.
Some spoilers will work by delaying the formation of that turbulent layer in the back of the car. Then, since the car doesn't have to "drag" behind it a big chunk of air that isn't moving, its drag coefficient (CX) goes down, and its fuel mileage goes up.
Being that most companies, over the last 20+ years, have been doing everything they can to improve fuel mileage, it's a safe bet that those Mazda spoilers will make a difference.
Mazda has a history of putting function over form. In '80, they had 2 versions of the RX-7: RS and GS, IIRC. One of them (I think the GS) had a little spoiler in the back. That spoiler alone gave the car a CX of 0.32, against 0.34 of the model without it.
The plates Evo is talking about were called (at least colloquially, in Spanish) "polleritas" (little skirts). They were used in the '70s, in the times of the extra wide slicks, when Niki Lauda and many of the all time big dogs used to race. They were responsible, together with all the other stuff, of the crazy lap speeds achieved in those times, but also of the violent accidents that were part of almost any race. The thing is, when they worked, they worked great, but when for any reason one of them malfunctioned, and let air under the car, being that the car was going much faster than it would without them, it lost control instantly, with the driver being unable to react. Because of that, the FIA decided (in the late '70s or early '80s, I'm not sure) to ban them, and start limiting other factors, like the width of the tires.
Finally, coming back to the topic, EVERYTHING put outside of a car will affect aerodynamics, for better or worse. There's no such thing as a purely cosmetic add on. Another myth is that you need to go a certain speed for those spoilers to "start acting". That's not true. The moment the car starts moving, all surfaces start having an effect. True, there IS a speed at which those spoilers will be most efficient, but that doesn't mean they won't work outside that range.
But that doesn't mean they will affect handling, or grip. Many times, those spoilers are there to improve gas mileage, by delaying the formation of a turbulent boundary layer in the back of the car.
In a nutshell, a "boundary layer" is defined as the portion of the air surrounding a moving object in which the airspeed is between 1% and 99% that of the object.
There are 2 kinds of boundary layers: laminar and turbulent. Laminar boundary layers are those in which the air moves "in line", all molecules in the same direction. They are low pressure, high speed layers, and produce little drag. Turbulent layers are the contrary: the air starts creating little vortexes, "bumping with itself". So they are low speed, high pressure, high drag layers.
If you look at the MX-3 user manual, it specifically says not to drive the car with the hatch open. That's because the turbulent boundary layer produced in the back of the car can literally "suck" the exhaust gases into the cabin, intoxicating the occupants.
Some spoilers will work by delaying the formation of that turbulent layer in the back of the car. Then, since the car doesn't have to "drag" behind it a big chunk of air that isn't moving, its drag coefficient (CX) goes down, and its fuel mileage goes up.
Being that most companies, over the last 20+ years, have been doing everything they can to improve fuel mileage, it's a safe bet that those Mazda spoilers will make a difference.
I haven't seen this first hand, but fowljesse and others have made offhand comments about it. I can't verify it, but Jesse is very knowledgeable and I give credence to anything he says. MoonEggs is probably the most knowledgeable on the subject of OEM/MazdaSpeed body kits, so anything he says would be good to keep in mind as well.