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Rear diffusers...let's see them!!!
- Thread starter MetalSpikeRacing
- Start date
Which diffuser is that again?
lol.
It's not finalized yet, but I wanted a clean look and got the idea from the Dodge Viper.
Haha!
Home made.
Well Dave......tell that to Dodge.
LOL.......my first thought when Turbo2go wrote that was , "how does he know that?" Maybe the answer is...."he doesn't" :tongue: Although I welcome an explanation as to why it isn't effective.
Any turbulence created just beyond the diffuser makes it essentially ineffective. When his diffuser ends under the car, turbulence is created behind it and makes it nothing but extra weight.
There is a lot of info on automotive aerodynamics on the web, as this is a common racing question. Everything I've ever read recommends they extend beyond the car unless engineered from the beginning as an entire system including what is in front and past it, and things like the wing used with it. Just because the Viper has a diffuser that is like that, doesn't mean you can do the same on an NSX and it will work.
Not trying to be.a jerk to REDNSXT, just trying to be helpful. I just don't see how that thing will work. But it doesn't matter, none of us race in F1, and I am not an aerodynamicist. I'm stating what I have read.
There is a lot of info on automotive aerodynamics on the web, as this is a common racing question. Everything I've ever read recommends they extend beyond the car unless engineered from the beginning as an entire system including what is in front and past it, and things like the wing used with it. Just because the Viper has a diffuser that is like that, doesn't mean you can do the same on an NSX and it will work.
Not trying to be.a jerk to REDNSXT, just trying to be helpful. I just don't see how that thing will work. But it doesn't matter, none of us race in F1, and I am not an aerodynamicist. I'm stating what I have read.
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Is your exhaust pushing down on the diffuser? I saw your car at the Blox Racing OH today and was wondering. Also, is yours Downforce or Taitec? I want to get one of the two and am deciding whether Taitec is worth the extra money.
- Joined
- 19 February 2008
- Messages
- 1,532
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Just to chime in here, anyone who went to NSXPO'11 might have heard a presentation made by a gent (can't remember his name) who was very thorough in his explanation of aerodynamics and how downforce is created. He was, in short, brilliant and VERY thorough in his explanation of diffusers. And while Ross could work on his delivery, every thing his says is true and proven. The tack on diffusers offered do nothing for downforce at speed and likely add weight and drag. The whole undercarriage must be designed as one piece to direct air from the front of the car rearward. I know DF offered this package, and some racers on here have done this very thing, but there are other cooling risks that must be addressed.
I'm just surprised that no one else that attended NSXPO'11 has mentioned this. Still, they do look rather sporting!
I'm just surprised that no one else that attended NSXPO'11 has mentioned this. Still, they do look rather sporting!
Suprisingly, the photo I found of the NSX GT2 Lemans car's full body under tray only had a small ramp opening to the tranny area and that was it for cooling to the engine bay.
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juice is correct about both the diffusers (functionalities) as well as DF having the complete underbody diffuser package. as a matter of fact the DF track nsx will be at south coast acura this thursday 8-2-12 at apox. 7pm. that's the one that has the complete underbody diffuser, side vent oil cooler, and a window garnish that pulls air out of the engine bay instead of pushing air in. yes i have driven that track nsx and boy is it easy to drive at higher speed. if you guys have some time this thursday go check it out at south coast acura you won't be disappointed.
Did df modify your taitec diffuser out did they make a completely new one?
just like what peter said the two outside taitec/DF pieces are left as is and the center piece is replaced with the new TRUE CENTER exit diffuser.
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I guess my question was lost in translation. Sorry.. I'm wondering if DF made the outer pieces or if you had a Taitec one that they modified.
The reason I ask.. is for the folks interested in this.. do they need to buy a Taitec > cut it up > install the DF center.
Your "taitec/DF" comment is all sorts of confusing for my really small brain :smile:
sorry for the misunderstanding i thought you knew that the taitec and DF diffusers are the same. so if u have either one of them, and u wanted go go this route, all u got to do is buy the center piece and install it. there is no modification needed.
i figured that would be common sense but i guess not. not a shot at anyone just a random thought.
- Joined
- 15 May 2007
- Messages
- 26
Here is a reality check. My field is vehicle aerodynamics and have worked in the field for 43 years. I managed all of the National Research Council of Canada's low speed wind tunnels, including the 30' x 30' full-scale tunnel that has a full-scale rolling road and is large enough to test a full-sized tractor-trailer (look at my Prime photo). Check out http://www.nrc-cnrc.gc.ca/eng/facilities/iar/9x9-wind-tunnel.html
I have conducted wind tunnel tests on virtually every kind of surface vehicle from Olympic bicycles, motorcycles, ships, trains, trucks and many types of racing cars. I have also conducted fundamental research on diffuser aerodynamics. If you are so inclined, have a look at the Society of Automotive Engineers papers:
SAE980030 "The Aerodynamic Performance of Automotive Underbody Diffusers".
SAE2000-01-0354 "Selecting Automotive Diffusers to Maximize Underbody Downforce".
Diffusers generate down force by reducing the flow losses under a vehicle. This allows more air to flow under it, increasing the under-body flow speed. The increased flow speed produces a pressure reduction that results in the down force (negative lift). For the diffuser to work, as smooth an under-body as possible is required with no major flow leaks. Most of the down force is generated on the under body, not the diffuser. So, if the front bay and the engine bay are not covered with a belly pan, then little gain will occur since the pressure drop will be lost. What you have with many of the diffusers that I see in the photos are style and no substance. Some tine ago I saw an article by someone who done a nice belly pan with reasonable provision for engine-bay ventilation. This is the way to go.
Hope that this helps.
Kevin.
I have conducted wind tunnel tests on virtually every kind of surface vehicle from Olympic bicycles, motorcycles, ships, trains, trucks and many types of racing cars. I have also conducted fundamental research on diffuser aerodynamics. If you are so inclined, have a look at the Society of Automotive Engineers papers:
SAE980030 "The Aerodynamic Performance of Automotive Underbody Diffusers".
SAE2000-01-0354 "Selecting Automotive Diffusers to Maximize Underbody Downforce".
Diffusers generate down force by reducing the flow losses under a vehicle. This allows more air to flow under it, increasing the under-body flow speed. The increased flow speed produces a pressure reduction that results in the down force (negative lift). For the diffuser to work, as smooth an under-body as possible is required with no major flow leaks. Most of the down force is generated on the under body, not the diffuser. So, if the front bay and the engine bay are not covered with a belly pan, then little gain will occur since the pressure drop will be lost. What you have with many of the diffusers that I see in the photos are style and no substance. Some tine ago I saw an article by someone who done a nice belly pan with reasonable provision for engine-bay ventilation. This is the way to go.
Hope that this helps.
Kevin.
Thanks for posting in this thread Kevin.
I invited Kevin to post here to offer his expertise in all things aero. He is an invaluable member of the local NSX community and has delivered a great technical presentation to the NSXCC on NSX aerodynamics.
I invited Kevin to post here to offer his expertise in all things aero. He is an invaluable member of the local NSX community and has delivered a great technical presentation to the NSXCC on NSX aerodynamics.
Thanks for posting Kevin and Oyagi for inviting you.
It appears, once again, there is no free lunch. For a car driven on the street the additional labor due to a full underbody come maintenance time combined with the need to engineer custom cooling vents/side mounts puts diffusers squarely in the "looks cool only" column.
Too bad we don't Kevin's wind tunnel at our disposable for testing though. hint hint.
I have this but not in carbon. I want this terribly but will at some point rub the outer fin on something and it would KILL me. Someone buy this so I'll not be so tempted.:frown:
http://www.nsxprime.com/forum/showthread.php?t=164713
It is pure sex.
http://www.nsxprime.com/forum/showthread.php?t=164713
It is pure sex.
Some recent pics
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I personally don't care if it's effective or not. I think it's the best looking diffuser I have seen on prime so far. It's present, but subtle. Very, very nice :biggrin:
Wow, I was gonna watch some porn later but this'll do fine.:wink:Some recent pics
