CRX wing spoiler aero question
09-30-2009, 05:14 PM
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Re: CRX wing spoiler aero question
EDM and mugen would give you the same effect. they really aren't large enough, except the nascar one, to do a lot that would be easy to notice. the edm and mugen would help turbulance behind the car, the nascar would give you rear down force, and the SiR, depending on the airfoil could do nothing or more than anything else.
10-01-2009, 08:00 AM
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Re: CRX wing spoiler aero question
The EDM and Mugen wings won't increase downforce in the traditional sense (which is downforce gained from aero drag), but they will actually increase downforce (minimally) by removing turbulence or "lift" at the rear of the car. Think of it as "freeing up" downforce by reducing rear drag/turbulence/lift.
Edit: Since I'm not a Aerodynamics Engineer, take my opinion at face value.
Edit: Since I'm not a Aerodynamics Engineer, take my opinion at face value.
10-01-2009, 11:06 AM
#5
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Re: CRX wing spoiler aero question
The Mugen style will add some stability,but will have less drag,thats about all.The "old" nascar would be the better one IMO(Manny uses one),it will create higher pressure on the rear deck as well as lower the pressure around the rear bumper,with very little drag depending on angle of attack.I would like to wait till J mac chimes in.
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10-01-2009, 11:25 AM
#9
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Re: CRX wing spoiler aero question
EDM and Mugen would do the best in the area of low drag, with little downforce. The SIR actually should increase stability becasue of the mounts are verticle causing wind to rush past it on both sides causing the rear to stablize, like a fin on a shark or rear fin on an airplane. The nascar is just killing aero smoothness, but forces the air to hit it pushing real hard backard, causing the wing to descend, which is attached to the car.
Down force is hardly ever realized at 60mph but you will notice a difference from wingless at 80-90 and above. I think at 120 with the Nascar type you may not be able to accelerate as you would with the other wings.
Still the Nascar would be best, not considering a GT wing, at the track.
Down force is hardly ever realized at 60mph but you will notice a difference from wingless at 80-90 and above. I think at 120 with the Nascar type you may not be able to accelerate as you would with the other wings.
Still the Nascar would be best, not considering a GT wing, at the track.
10-01-2009, 10:01 PM
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Re: CRX wing spoiler aero question
I used a "NASCAR " one I personally made for a H4 car. It was extremely effective . It was roughly 4 inches tall and had end plates. I might have some pics of it.. The guy that bought my car still uses it today . I did back to back testing and actually PICKED UP mph when using it. I was really suprised but it proved extremely effective at high speed and did almost nothing at low speed keeping the car free and reducing overall drag on the car.
This was on a CRX also
This was on a CRX also
10-02-2009, 05:02 AM
#11
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Re: CRX wing spoiler aero question
Thanks for the input everyone. THe only NASCAR one I've seen so far is on Benoit Pecqueur's H4 CRX, featured in GRMotorsports Feb 09. It sounds like the way to go, and some good pics would be great. I'd also love to hear JohnnyMac chime in on this.
10-02-2009, 05:47 AM
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Re: CRX wing spoiler aero question
That is in fact one that I had made. There were 3 of them, the final one had some endplates that increased efficency and reduced some drag. Its on Manny's CRX now. Ill see what I can find
10-02-2009, 03:08 PM
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Re: CRX wing spoiler aero question
Of the OEM styles, I would think the EDM would be the most efficient profile wise, but I think most of the OEM spoilers are fairly heavy. Not sure if the small amount of aero is worth the large weight penalty though.
Last edited by solorexer; 05-23-2011 at 09:48 AM.
10-10-2009, 11:55 AM
#17
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Re: CRX wing spoiler aero question
10-25-2009, 01:43 PM
#18
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Re: CRX wing spoiler aero question
I've ordered the $199 fiberglass EDM spoiler mentioned above. I figure it will do for my modest needs, and a gurney lip could be added at a later date if desired.
10-27-2009, 01:01 PM
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Re: CRX wing spoiler aero question
THere is a considerable boundry layer at the rear of the car , a 2 inch does not see much air. depending on how loose your car is, I would start with a 6 inch and work down. Use endplates if at all possible. I angled mine back around 25 degrees from verticle.
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10-27-2009, 10:52 PM
#20
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Re: CRX wing spoiler aero question
theres an EDM 16v spoiler for sale.. brand new in box.
http://www.crxcommunity.com/viewtopic.php?f=8&t=33306
im no johnny mac, im not shilling my own part, im not vouching for the seller.
btw, i would hardly say its got any sort of gurney flap.
also, again, im not johnny mac, but what the "nascar" style effectively does heavily depends on its height. that ridiculous CF one showed above is just horrible.
what i understand how it works, when it works properly, is it helps actually streamline the tail by making the hatch less of a slope as it dams up the air in front of it and the air just goes above it at a slimmer taper. it also helps reduce lift, which for all intents is like adding downforce. at least this was all illustrated in some BRE literature i glanced at for the 240Z. i figure its the same concept as keeping the tailgate up in a pickup for better mileage.
http://www.crxcommunity.com/viewtopic.php?f=8&t=33306
im no johnny mac, im not shilling my own part, im not vouching for the seller.
btw, i would hardly say its got any sort of gurney flap.
also, again, im not johnny mac, but what the "nascar" style effectively does heavily depends on its height. that ridiculous CF one showed above is just horrible.
what i understand how it works, when it works properly, is it helps actually streamline the tail by making the hatch less of a slope as it dams up the air in front of it and the air just goes above it at a slimmer taper. it also helps reduce lift, which for all intents is like adding downforce. at least this was all illustrated in some BRE literature i glanced at for the 240Z. i figure its the same concept as keeping the tailgate up in a pickup for better mileage.
05-22-2011, 07:49 PM
#22
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Re: CRX wing spoiler aero question
Some of the research I did before construction of my spoiler:
I think mine may be more efficient with a gurney strip, but I didnt think they were legal in prepared, but most everyone running a spoiler at nationals this year was using one. I will be in that group next year.
Of the OEM styles, I would think the EDM would be the most efficient profile wise, but I think most of the OEM spoilers are fairly heavy. Not sure if the small amount of aero is worth the large weight penalty though.
My design makes a noticable difference to the "feel" of the car in high speed steady state. I do not notice it as much in transients however. It is kind of hard to determine any quantifiable benefit at a auto-x because there are so many variables from course to course. I did end up with more rear roll stiffness after installing it.
I am by no means an aero engineer, so I am interested to see what JMac says if he sees this thread.
I think mine may be more efficient with a gurney strip, but I didnt think they were legal in prepared, but most everyone running a spoiler at nationals this year was using one. I will be in that group next year.
Of the OEM styles, I would think the EDM would be the most efficient profile wise, but I think most of the OEM spoilers are fairly heavy. Not sure if the small amount of aero is worth the large weight penalty though.
My design makes a noticable difference to the "feel" of the car in high speed steady state. I do not notice it as much in transients however. It is kind of hard to determine any quantifiable benefit at a auto-x because there are so many variables from course to course. I did end up with more rear roll stiffness after installing it.
I am by no means an aero engineer, so I am interested to see what JMac says if he sees this thread.
05-23-2011, 03:38 AM
#23
Re: CRX wing spoiler aero question
Because at higher speeds the back of the car can get light from high pressure trying to "lift" the car off the pavement which can get very scary. Sort of like an airplane wing. If you have never experienced it at the track you will never know.
08-29-2015, 11:19 AM
#24
Re: CRX wing spoiler aero question
I think unless you need a lot of added downforce, you need a large airfoil. But from what I have learned, they will do nothing.
Th crx has a cutoff section that creates a circle of air behind it and makes the wind think there is a larger airfoil behind it.
Th same principle behind these designs
The whirlpool of air that is created can also have the affect of pushing against the flat cutoff section. creating a negative drag.
If you need downforce, add a front splitter and you can add a diffuser. A rear diffuser also aids in exhaust scavenging. And side skirts help to guide air faster and with less turbulence under the underbody, to create suction as well.
Th crx has a cutoff section that creates a circle of air behind it and makes the wind think there is a larger airfoil behind it.
Th same principle behind these designs
The whirlpool of air that is created can also have the affect of pushing against the flat cutoff section. creating a negative drag.
If you need downforce, add a front splitter and you can add a diffuser. A rear diffuser also aids in exhaust scavenging. And side skirts help to guide air faster and with less turbulence under the underbody, to create suction as well.
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