The Great FD3S Under-body Aerodynamics Thread: Photos, Products, Ideas, Results
05-01-10, 01:23 AM
#102
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Heat Issues : Just another challenge.
I read through, and love, love this post. I feel that functional aerodynamics are the ultimate modification to cars. It really takes elegance, thought, patience and science to pull performance out of car via it's aero qualities. I look forward to experimenting with underbody aero myself on my FD track project.
One thing that was brought up repeatedly was the issue of heat retention and potential melting/overheating or fires. While this is an issue, I don't think it's necessarily going to make belly pans an impossible project for our cars.
If you look at the underside of the audi R8 they've used NACA ducts to vent cooling air up to the differential / drive train as well as utilize aluminum panels over higher heat areas vs FRP (Fibre reinforeced ABS I believe) on cooler points. Heat could be routed through an aluminum center channel, out rear wheel wells, etc. Just remember for every in, you have to design an out and you can make it happen.
http://image.motortrend.com/f/roadte...ercarriage.jpg
Dream big, make it happen, and keep me posted so I can steal your good ideas ;-)
Danny~
One thing that was brought up repeatedly was the issue of heat retention and potential melting/overheating or fires. While this is an issue, I don't think it's necessarily going to make belly pans an impossible project for our cars.
If you look at the underside of the audi R8 they've used NACA ducts to vent cooling air up to the differential / drive train as well as utilize aluminum panels over higher heat areas vs FRP (Fibre reinforeced ABS I believe) on cooler points. Heat could be routed through an aluminum center channel, out rear wheel wells, etc. Just remember for every in, you have to design an out and you can make it happen.
http://image.motortrend.com/f/roadte...ercarriage.jpg
Dream big, make it happen, and keep me posted so I can steal your good ideas ;-)
Danny~
05-01-10, 01:45 AM
#103
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Oh, also just for consideration. There are myriad reasons why Mazda would forgo underbody work on a car such as the FD even though it would provide the car with added performance.
Just some examples ....
1: Crash Testing/wear and tear - Adds additional material that must be controlled in the event of an accident/incident ( retardly over sized speed bumps?)
2: Warranties/Reliability/liability - Underbody aero panels experience high amounts of load and may detach if not carefully maintained and inspected ( not necessarily a common occurrence for a RX7 owner)
3: General Car Use - Highest Speed Limit in the USA is 75 mph. Aero equipment is generally aimed at higher speeds. For those of us taking our cars to road courses we're dramatically deviating from the intended use of these cars meaning that in all Mazda's design work they may not have focused on the effects of 120+ MPH speeds.
4: Cost/Benefit - All cars are build on a budget. Even though underpans make a difference, it may not have passed the finance committee.
I think that using the combined effort of people on this thread we could really gather some useful data and testing numbers to design a quality aero solution for the FD :-)
Some tests I'd love to see done:
1: air speed under car F/R at a control speed/location
2: Shock travel measurements at a control speed/location
3: Fluid Dynamics Simulation with 3d models (F1 uses it!)
4: Wind tunnels! (basically, this combines the top 3 into one expensive awesome test)
Cheers guys, I'm glad I'm not the only one who's excited about this stuff!
Danny~
Just some examples ....
1: Crash Testing/wear and tear - Adds additional material that must be controlled in the event of an accident/incident ( retardly over sized speed bumps?)
2: Warranties/Reliability/liability - Underbody aero panels experience high amounts of load and may detach if not carefully maintained and inspected ( not necessarily a common occurrence for a RX7 owner)
3: General Car Use - Highest Speed Limit in the USA is 75 mph. Aero equipment is generally aimed at higher speeds. For those of us taking our cars to road courses we're dramatically deviating from the intended use of these cars meaning that in all Mazda's design work they may not have focused on the effects of 120+ MPH speeds.
4: Cost/Benefit - All cars are build on a budget. Even though underpans make a difference, it may not have passed the finance committee.
I think that using the combined effort of people on this thread we could really gather some useful data and testing numbers to design a quality aero solution for the FD :-)
Some tests I'd love to see done:
1: air speed under car F/R at a control speed/location
2: Shock travel measurements at a control speed/location
3: Fluid Dynamics Simulation with 3d models (F1 uses it!)
4: Wind tunnels! (basically, this combines the top 3 into one expensive awesome test)
Cheers guys, I'm glad I'm not the only one who's excited about this stuff!
Danny~
05-19-10, 01:30 PM
#104
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I frequent f1technical and they have been having extensive talks about underbody aero with the advent of the double diffuser in f1 and found some CFD tools this thread might be interested in. If anyone was interested in running CFD simulations there is one available at http://caelinux.com/CMS/ . There is also tons of info at http://www.cfd-online.com/
05-19-10, 06:12 PM
#105
Banned. I got OWNED!!!
Our diffuser in the works. Sides additions have not been added, nor has it been trimmed to its final dimensions. With the complete undertray in place, the underside will gain 16" in length.
Seems it would have been much better to just get different wheels.
12-11-10, 04:12 PM
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Mazda has been doing high performance computer simulations (computation fluid dynamics) since before 1989... I remember that the FD was tuned and tweaked on a Cray... No doubt some of that was a "computational wind tunnel" 
It will be interesting to see how well a new product could enhance performance
BTW does anyone remember the Chaparral 2J
---
AP
Published: December 01, 1990
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TOKYO, Nov. 30 — The Mazda Motor Corporation, the Japanese auto maker, purchased a high-performance supercomputer from Cray Research Inc. in an effort to improve its automotive research and development ability. It said the new computer, the Y-MP2E-216, offered about three times higher performance than the Cray X-MP-216 model that Mazda bought from the Minneapolis-based manufacturer in April 1989.
Mazda officials said they expect the new model will increase the company's computer simulation capacity in such areas as crash analysis for improving vehicle safety and vehicle structural analysis for weight reduction. Business sources said the new supercomputer would cost about $10 million.
It will be interesting to see how well a new product could enhance performance
BTW does anyone remember the Chaparral 2J
---
AP
Published: December 01, 1990
Sign In to E-Mail
TOKYO, Nov. 30 — The Mazda Motor Corporation, the Japanese auto maker, purchased a high-performance supercomputer from Cray Research Inc. in an effort to improve its automotive research and development ability. It said the new computer, the Y-MP2E-216, offered about three times higher performance than the Cray X-MP-216 model that Mazda bought from the Minneapolis-based manufacturer in April 1989.
Mazda officials said they expect the new model will increase the company's computer simulation capacity in such areas as crash analysis for improving vehicle safety and vehicle structural analysis for weight reduction. Business sources said the new supercomputer would cost about $10 million.
Last edited by Digital Dude; 12-11-10 at 04:40 PM.
12-13-10, 02:37 PM
#114
To confirm what Jared said, the splitter is not attached to the front bumper and can be installed and removed with the bumper in place. The splitter also does not need the usual front lip reinforcement tabs that are usually attached to the front bumper. There are two bolts at the engine subframe and six bolts at the frame mount plates. They can be accessed by the bumper inlets or at the fender wells.
12-13-10, 05:12 PM
#115
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Hey guys, I know my post count says im new here, but actually since i dont yet own an FD, most of my time on this forum is spent reading. Occasionally however i find some really interesting threads and i can't resist chiming in.
Well, after reading all 5 pages, here goes.
While theres been some real thinking out of the box in the first few pages, the latter half has been dominated by some pretty awe inspiring race designs. Kudos to all the people involved! I just thought i'd try to steer the thread into the road car side of things to address a few aero problems that i dont think have been tackled yet.
I dont remember who or on which page, but i saw someone quoting a series of autospeed articles on front splitters and underbody aero. There is some truly amazing literature in there (and i really suggest that people who are interested in aerodynamics take time to go to a library and check out some of the books mentioned in there!) However what struck me the most in all those articles was this graph:
The title of the graph is pretty self explanatory, the result however is often overlooked. Not by OEM's however, which is why many cars are fitted with tire deflectors as standard. You don't often see them but they're those small black tabs infront of the wheels of your daily grinder designed to patch the problem.
If this is true for a road car, imagine the effects of our beloved 255, 265 section front tires on the fd. Not pretty. So my mind kept dwelling on what could be done to channel the air away or around the front tires and under the car, so to reduce drag and increase downforce. And then i came across this:
This was fitted to a Subie (a subie part in an fd forum, oh the heresy) but notice the cleverness of the design of the brake ducts (forget the poor attempt at creating a venturi channel), a portion of the air that would normally hit the front wheels is being channeled up and around the wheels into the wheel well, considerably reducing drag, while cooling the brakes in the process! The downside is the splitter area is decreased thereby reducing its efficiency BUT if the above tecnique was applied together with inward facing wheel deflectors, placed just before the wheels, the remaining air would be channeled into the underbody, gaining back some of that lost efficiency. On top of that, the high pressure area created by the vertical deflectors would force more air into the ducts, cooling the brakes even more!
Like i said i dont have a car to test this theory on, but if anyone wants to give it a shot, the glory is theirs if it works!
I understand this might be less appealing than the tried and tested flat splitter for track only drivers, but it should appeal more to people who road their cars, as reducing drag is more important than increasing downforce in that circumstance.
Well, after reading all 5 pages, here goes.
While theres been some real thinking out of the box in the first few pages, the latter half has been dominated by some pretty awe inspiring race designs. Kudos to all the people involved! I just thought i'd try to steer the thread into the road car side of things to address a few aero problems that i dont think have been tackled yet.
I dont remember who or on which page, but i saw someone quoting a series of autospeed articles on front splitters and underbody aero. There is some truly amazing literature in there (and i really suggest that people who are interested in aerodynamics take time to go to a library and check out some of the books mentioned in there!) However what struck me the most in all those articles was this graph:
The title of the graph is pretty self explanatory, the result however is often overlooked. Not by OEM's however, which is why many cars are fitted with tire deflectors as standard. You don't often see them but they're those small black tabs infront of the wheels of your daily grinder designed to patch the problem.
If this is true for a road car, imagine the effects of our beloved 255, 265 section front tires on the fd. Not pretty. So my mind kept dwelling on what could be done to channel the air away or around the front tires and under the car, so to reduce drag and increase downforce. And then i came across this:
This was fitted to a Subie (a subie part in an fd forum, oh the heresy) but notice the cleverness of the design of the brake ducts (forget the poor attempt at creating a venturi channel), a portion of the air that would normally hit the front wheels is being channeled up and around the wheels into the wheel well, considerably reducing drag, while cooling the brakes in the process! The downside is the splitter area is decreased thereby reducing its efficiency BUT if the above tecnique was applied together with inward facing wheel deflectors, placed just before the wheels, the remaining air would be channeled into the underbody, gaining back some of that lost efficiency. On top of that, the high pressure area created by the vertical deflectors would force more air into the ducts, cooling the brakes even more!
Like i said i dont have a car to test this theory on, but if anyone wants to give it a shot, the glory is theirs if it works!
I understand this might be less appealing than the tried and tested flat splitter for track only drivers, but it should appeal more to people who road their cars, as reducing drag is more important than increasing downforce in that circumstance.
Last edited by Gladius; 12-13-10 at 05:23 PM.
12-16-10, 02:26 AM
#120
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Can you make one for '99 spec bumper/lip? I need something to balance out the extreme rear downforce bias with the stock rear wing on max rake (even though then it looks like a big air brake!) and resulting understeer.
12-19-10, 06:50 AM
#122
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