how to generate more down force up front?
 

well, rear downforce is easy... just buy a big ass ricer wing and you can have all the downforce you want in the back. add to that a diffuser under the gastank (some say its worth it some say not) to smooth out flow under the rear of the car and thats about all you can do... short of engineering some sort of venturie tunnels to SUCK the car down.

anyway, downforce in the back is easier to obtain... but the problem is when you add a huge stupid ricer wing to the back, you make the front end lighter, making the situation up front even worse than with no spoiler at all. so considering we can easily add basically however much D.F. to the rear.... how can we plant the front better at high speeds?

ill throw out 2 things to start:
1) smoothing out flow under the front of the car (which damian has been exploring recently with some coustom underbody pannels)
2) the addition of the '99 front lip (or equivalant sort of splitter)... it does have a good pitch to it, but im not sure how much downforce it actually generates... i believe the main benefit of the lip is to evacuate some air to the sides of the car where the little "side flares" are.

basically the purpose of this thread is to talk about and explore new/old methods for generating downforce in the front of the car(with an emphasis on minimized additional resistance, although that IS one of the big tradeoffs to downforce).... so... lets talk. -heath

Lowering the car will help from negative pressure building up under the car.... we can imagine the car being like an airplane wing... Downforce for the front end... I guess building a wider body will help dramatically.... more surface area...more pressure builds on top of the car. my 2 cents.

That's why they make those front diffusers, the one's that attach to the sides of the front bumper, I'm not sure what they are called but you see them a lot on cars with body kits

One word: cannards.

https://www.rx7club.com/attachment.p...chmentid=80227

go to an F1 tech site ( should be sumthing) you may as well learn and understand from the best, maybe after that you can apply it to FD's

Thank you Jim, I knew I could count on you....:bigthumb:

unfortunatly i believe no company produces cannards for the FD....

there's a lot of universal one's that will fit....

^ yup

i know... but its kind of a shot in the dark without propper testing. im not opposed, BUT (especially when it comes to stability at insanely high speeds) im a bit worried to add un-tested stuff that could upset the front and possibly lead to a high speed disaster. not saying that i wouldnt try out things, just that id like a way to measure WHAT effect its having on the car before i take it even faster. i have an old beat up bumper assembaly that i wouldnt mind swapping onto my running FD if i could have a way to measure effects of different alterations to it... well i guess there is always seat of the pants measuring as well.

another question: as far as air vents such as on the elise, gt-40, and various other cars... are they just used for cooling, or does the internal angle of the outlet add any downforce??

http://www.supphoto.net/galerie/phot...phie/lotus.jpg

http://www.cobracountry.com/cav/CAV-GT40-19-frontal.jpg

know any links? know anyone that has used these before on an FD?

I was waiting for "V8". ;)

Just search google and you'll find some universal ones.

( http://shop.store.yahoo.com/sgpracin.../caficaun.html )

I might just be tempted to try and fab some on my own, I need a new project anyway.

I would think ducted hoods (like the scoot hood) and also, channeled mirrors like ones on re-amemiya vehicles would also contribute to downforce. Since the air that flows through the ducts would help stabalize the vehicle.

http://rxecret7.com/cwesbumcar.html
http://rxecret7.com/frbuca1.html
http://rxecret7.com/panspgt20frb.html
http://www.jt-imports.com/FEED_FD_Parts_List.htm

The closet aerodynamicists around here should stay in the closet.

I saw this on JT imports.

FEED Original bumper fin set

http://www.jt-imports.com/FEED_front..._bumper_FD.jpg

so for those of you with the 99 spec front end, you can get cannards to aid in front end downforce.

Now if only someone fabricated some for the 93-95 front end. Any takers? Damian? :D

Yes to both. The air that enters the inlet is ducted through the cooler(s) and when sent down a properly designed exit duct can be used to generate downforce on the front as well. This is at the expense of sending heated air over the car which tends to effect things in the rear. This is why nearly every clean sheet of paper racecar uses hip radiators and carefully controls where the warmed air is routed.

Ride height in and of itself doesn't contribute downforce. Rake contributes downforce.

but nothing beats some high speed dynamic testing. remember the benz race cars flying off the track? you would think those guys would have a handle on things but shit happens

Take a look at the Nov. issue of Racecar Engineering (it's a Brittish mag.). There is an article on just this subject (front end downforce). Oct issue delt with air dams, this one is on splitters.

That is by far one of the best magazines I have ever read. Problem is, price reflects this fact IMO.

Why not go world of outlaw's style and put one of those tuner wings in the front of the car to? :)

What about the ducts on the front of the Porsche GT2 bumper? Those would be pretty easy to replicate with a duct coming off the back of a FMIC/SMIC and just pull the duct upwards. Might have to duct it into a vented hood like the KS or MazdaSpeed....just a thought

http://hk.geocities.com/forte_lsm/im...orsche/GT2.jpg

How does the Mazdaspeed GT-C front bumper measure up for downforce? I know it's good for increased airflow into the engine bay, but is the (rather aggressive) lip on the bottom effective?

can you explain a bit about the effects of the heated air over the top of the car? basically there are a few things preventing this sort of design on the FD... (well first off there are not enough owners to make this practical)... but besides that you would have to move the radiator and the intercooler to make room for that type of air channel in the front. a radiator could sit at the top of the channel, however that may impede some airflow and reduce downforce (but it seems you would get WAY more than currently exists).... second would be to deal with the placement of the intercooler. it would be very interesting to relocate the intercooler UNDER the car (with a scoop on the botton of the car to pick up cool air and direct it towards a coustom intercooler.... a brick type (deep, and wide... but not tall) would work well under the car.... the scoop which could extend slightly below the underbelly cover would also create downforce which would be a plus. add to that a very simple flow path from the turbos (under the car, right bend to IC, and back to the top on the drivers side to the throttle body) ... would also increase turbo efficiancy. so added benifits of said modifications (if it could be pulled off) would be -> downforce generated from sealed outlet channels from bumper through hood, better cooling for radiatior (not impeded by IC, and not blowing hot air back into engine compartment), downforce generated from air scoop under car to feed couston intercooler setup, colder intercooler via dedicated IC scoop, simplified turbo piping w/ less bends and less length = more efficiant turbos and better turbo response. soooo... combine all that with a nice smooth under belly pannel like damon's, add a splitter, and some cannards on the sides.... and you will have a really great track/street car which will STICK to the road the faster you go. then balance that with a RICER wing on the back (but hopefully something more tasteful), cause you will actually need it to counter the extra downforce in the front. it would be fun.... someone get to work :biggrin:

^ a little less complicated version of that idea

What about the people that have a V mount setup....They could take damian's new underbelly tray, cut a duct in on the bottom with a very small lip to catch air from underneath the car, and force it upwards through the radiator. Then build a short splitter from the bumper inlet to seal off the top of the radiator and the bottom of the IC, then build a duct from the top of the IC up through the vented hood. That way you'll have two sealed, ducted inlets (bottom of car through the rad/ic, and one from the front going over the face of the rad and up through the ic)

http://www.jt-imports.com/My_FD_1.JPG just another one

I saw the post and was thinking the same thing.

Just a guess here, but it probably causes a lot of turbulance due to the hot (low density) air meeting the cold (higher density) air, and rapidly cooling. The rapid cooling would cause the cold air to try to fill the pressure gap left by the previously hot air. It would probably throw off laminar flow a bit.

Somebody will have a better answer shortly.......

http://www.pac-gate.co.jp/feed/fd3s/fd-fcr1.jpg

I read that most of the higher end Japanese tuners do wind tunnel test their products (something that attributes to their price for this stuff), mazdaspeed, mugen, all the big dollar ones do. I also "heard" (no flames please) that feed does too.

Minimizing lift is probably the first place to start. Look at nearly every production-based race car and they have very low front bodywork, even if it's something as crude as a lip extension. This prevents air from flowing under the car and creating upward pressure as it slows down due to the irregular-shaped underbody. A flat underbody panel is helpful, adding rake will aid in minimizing lift (look at Nascar, they are very limited in the aero department, they use suspension settings to induce rake in the underbody).

I'm not sure how effective it would be on our cars, but many LeMans prototypes use vented /louvred front wheelwells to create downforce. Take the Audi R8 for example: http://www.mulsannescorner.com/audir8-01-5.html

I think the most effective thing in terms of actual downforce would be a front channel, similar to the ones pictured above. One thing could be improved is the relative flatness of the front edge of the car below the headlights; angle it further downward like Ferrarri's.

What type of racing is this for?
-s-

If that was the case, then supersonic aircraft (the friction of the airflow over the skin of the aircraft heats both to high temps) would have some serious problems with aerodynamic drag...
The heated air is less dense, reducing the effects of any aerodynamic downforce designs.

OK, that makes sense. So, along the same lines: Will my car be less stable at high speeds on a hot day, on a hot surface. I plan on competing in the Texas Mile, a one mile standing start land speed race, and I'm now concerned with the high speed aerodynamics of my car. The race is about 75 miles SW of Houston, and if I attend a summer race you can figure on at least low 90's for local temperature, and the runway will be much, much hotter.......

Or, is it such a small difference that I shouldn't be concerned with it.

I doubt the difference would be noticeable, for a couple reasons:

1. The effect mentioned by Kento is caused by only some of the air being heated, the air that has passed through the radiator. An increase in ambient temperature would make all the air less dense, for a somewhat uniform decrease in both lift and downforce.

2. A 60 degree day vs. a 90 degree day is only 30 degrees difference, while the surface of the radiator should be nearly 200 degrees, that's a good 100 degrees difference at the least. I'm guessing you wouldn't notice the difference in stability between summer and winter. When is the last time you heard of people avoiding racing in the summer due for fear that their cars aren't as stable at high speeds? Sounds a bit silly to me.

-s-

No, it won't make a difference, because the general atmospheric conditions are "hot", not just the airflow traveling over the top of the car.

I'd just like to cover all my bases. Thanks, Kento.

I should probably take that advice. Aerodynamics is a non-obvious science. Instead of testing and measuring and trying to understand what is happening, people just slap stuff on hoping it works.

Example: What do you think happens to all that air that goes though the radiator? It does just disappear. (It vanishes into thin air!) No, it gets dumped underneath the car and generates alot of lift. This is why most race cars have massive hood venting. (look at a C5R.) It's not just to help cool, it's to prevent all that enters the nose from going underneath the car. Now look at all the aftermarket body kits with the huge radiator opening. More air though the radiator means more air pushed underneath the car which means more lift. Take a hint from nascar and use the smallest radiator opening you can get away without overheating.

Another example: You've heard stories of headlght covers flying off FDs at speed. That right there should tell you that there is a low pressure area over the head light cover (or a high pressure area underneath it). But for some reason, some people think that the headlight cover is a good place for air intake.

Actually that happens because the plastic tabs at the front of the cover through which the mounting screws pass crack. The cover flutters a little at the front until it catches enough air to rip it off the car. About the same as driving around with your hood popped and no auxilary latch to ensure it can't open further; it would eventually fly open when you went fast enough.

As for high speed aero on the FD it is already very good for a street car. I don't think there's any use in sweating these things unless you really are driving it 150 mph on a track all the time.

Downforce on a car is especially tricky. You'll hear teams talk about the center of pressure on a car (the center of pressure is to aero what the center of gravity is to mass of the car). If your center of pressure moves around at different speeds the chassis is not consistent as speeds vary. It's very difficult to make the front and rear of the car equally efficient so that the chassis doesn't exhibit different handling characteristics at different speeds. Sometimes you hear teams talk about pitch or yaw sensitivity. This normally is a result of the center of pressure moving around as speed, pitch and yaw varies. This is why you'll see an F1 car for instance make a front wing change and then the redesign the barge boards and the rear wing as well. It all has to work together.

nix that