what are sum body kits that actually add down force, ive heard feed and re amemiya but what else, because ive heard alot of horrable storys about body kits flying of while driving and stock rx7s lifting into the air of course its not till 140+ but i was just intrested on any body kits that possitivley affect aerodynamics ?



just throw out their pple https://www.nopistons.com/forums/pub...O_DIR#>/ar.gif https://www.nopistons.com/forums/pub...O_DIR#>/ar.gif

A stock FD will do 160+ without any body enhancements.

front bumpers with a larger front spoiler and adjustable wings will create more downforce.... but side skirts dont do anything

sideskirts do the same things as rear air deflectors. they give the air a path to follow preventing turbulent air from getting under, and flipping or at least instabilitizing, the car.



kevin.

best way to improve aerodynamics is to create a panel that covers the whole bottom of your car.... no turbulance at the bottom= downforce yo



as per sinful7

this is absolutely correct...



by giving a correct path and non-disturbance corrected directed airway for the air that is coming through the front, you will be able to (theorectically) negate any lift force which is normally associated with interrogated fronts..



think of it more like...



if you ever put your hand out of a window at regular speed (ie 60mph+)

put your hand out, and turn it various angles.

then, try making your hand a V-ish structure (i.e. bending your hand, and moving your fingers..) you'll see how how the air moves... it moves the same way across surfaces on your car!

i thought about contracting someone to create an underbody cover (like the srt-10) out of cf. But i doubt its worth the trouble.. i guess we'll find out this summer at the track. :-D

right, but i was more specifically wondering about aftermarket kits, like i kno that Mazda Speed has been wind tunnel tested to perform at high speeds but i was wondering abotu any others that can maintain speeds of 140+ like cwest, feed, ings etc etc



thank you

where are you going to drive faster than 140 ?

I think that that's one of the shallowest arguments ever. Answer this question then, where are you going to drive 160, 190, 210, 230? Well? WHO CARES, cars do those speeds, it's not a question of doing it, it's a question of being able to do it. Who drives their FD's to top speeds on occasion, the answer is, very few people. But, the car can do 160 stock.



Veilside tests their kits in wind tunnels, and so does MazdaSpeed.



BTW Martin, your statement was incorrect. Putting an underbody panel to cover the whole underbody is not a good way to go. At higher speeds, it will act like a wing and can fly the car off the ground with the slightest change in elevation. Just look at LeMans cars, I'm sure they have some holes to prevent air from collecting under the pannel.

it wasn't an argument.. it was a question.. read a little more carefully.



so i am going to repeat my question.. not trying to be shallow...



where are you going to drive faster than 140 ?



and i will add the following...



do you plan on racing this on a track, or do you just want to know that your car aerodynamically is stable at these speeds ?



oh and srce, i understand that people want to max their car out. but it is very foolish to drive at high rates of speed (160 +) if the proper percautions are not taken..



doing stuff like that just for kicks sounds pretty shallow...

i took my t2 to a little over 160 on my speedo for kicks. Am i shallow?



As for having an underbody cover. Think of a defusser, and make it the length of the car. It directs the air under the car to cause less turbulence and more stablization. Sure it will act like a big wing is too much air gets under there. Thats why race cars are so low to the ground. I personally want a road race car that i can drive to the track. So anything that makes it stick to the ground better, is a good idea to me.

aerodynamics matters at less then 140.... true it may not flip the car over at lower speeds but it still matters

t2's can do that speed? ive been up to 155+ with room to spare but i didnt think a 2nd gen had the gearing for that.



fd tops out at something like 168 i think

what do fc/fb top out at?

i was quoting sinful7



also if you read all the road and track magazines, they sometimes show the underbody of supercars such as enzo's..... and they are as flat as a board, sometimes with diffusers towards the rear...... there must be a reason why they do that

ive heard of pitted underbody where there are small holes cut so as to allow a small amount of air through but i think the lift danger is more evident on lemans cars because of their weight. no matter how super light a production car like the enzo is, i dont think its light enough to actually lift because of an underbody pannel



my vote.. martins idea.. well sinful7's idea is a decent one... but i might cut holes just in case https://www.nopistons.com/forums/pub...IR#>/smile.png

mike i have some cf to play with.... maybe we can make some and cut lil holes for the radiator or something https://www.nopistons.com/forums/pub...IR#>/smile.png

i thought fc and fd's had the same gearing for manual transmission

https://www.nopistons.com/forums/pub...1047683621.gif from original question, but:



[fact]a flat bottom is good if the car is really low, like F1 low. This causes the air going under the car to do so at in increased speed.[/fact] Faster moving fluids have lower pressure, therefore it creates more downforce. [my conclusion] A flat bottom on a stock height street car, at high speeds with no other means of downforce (spoiler/wing), would be bad (at high speeds). [/my conclusion]



though I could be wrong, I'm no physicist.

remember people.. lift is a very powerful tool. It only takes 120mph for a 747 to get enough lift to take off. Thats a multi million pound aircraft.



granted the wings are huge, but that just goes to show you what air causing lift can do.



As for my t2 doing over 160, well my tires a taller than stock and i took the car to 160 on the speedo with about 2k rpm before redline. The car was still pulling and i got scared and shut down. :(

umm no offense guys but can we get back on topic, yes my car will be equipped with all the neccesary precatuions so i dont kill myself at these speeds, i just want to kno what body kits are stable enough to handl these speeds



MARTINN u ever get those rims of buddy

what rims?

i'd say any of the actual race team kits. If they use it on their car, its gotta be decent and functional.

remember u couldnt get ur rims off because sum1 had used a gun to get them on



race team kits? what are race team kits, the only race team kits ive seen are cwest and re amemiya but what about ings, feed, drft, ms, gp, vertex etc etc etc

Now if this is flat as a board, then I'm jumping off a bridge.

ahahahahahahahahaha

im pretty sure drft is a subdivision of cwest so i think they would test as for the rest i dont know. i think it would be safe to say with a diffuser, wing, and a front spoiler/bumper u should be safe



no offense but if ur someone who has either the job hobbie or nightlife to be doing these speeds on a regular basis. you should have some better sources then a bunch of knucklehead rx7 owners with a lot of time on their (our) hands.



none of us really talk to any of the big companys side from JT and some of the other japan/store owners. but even then i think we mostly get our info on bodykits and such through word of mouth magazines and the net

lol ya i think i already found otu the answer, but i was just asking to see wat u guys could tell me

ooh yeah..... well at i've had my rims on since august..... so the answer is nope https://www.nopistons.com/forums/pub...IR#>/smile.png

the fd has the gearing to do like 200, the engine explodes at about 180 though

The bottom of the Ferrari Enzo is a totally SMOOTH surface, not necessarily flat. A smooth surface will reduce turbulence because the air has a uniform surface to flow against. Now the enzo has shaped venturi tunnels that actually suck the air up and away from the rear of the car, causing a low pressure area under the car and creating downforce. At the front it also has the F1 style nose to direct airflow as well as motorized flaps to control the amount of downforce at the front of the car. So flat underbodies help *to some extent*, but its the venturi tunnels that REALLY make the biggest differences.



EDIT: This is why the diffusers you can buy for the rear of our cars are actually quite pointless. Those diffusers only smooth out the last 12" or so of the air flowing underneath the car. Now if someone would integrate that RE diffuser into a totally flat underbody with ribs to direct the airflow, im sure wind tunnel testing would show a lot of improvement in downforce and Cd.



-Zach

hes right on the money with this. F1 cars do have ducts to evacuate some of the air UPWARD, which also adds to the downforce, but also eliminates the problem of having too much air underneath the car. I was also watching this show on SPEED about the death of an F1 driver (i forget his name), but he entered a corner at normal speeds, but went STRAIGHT and into the wall. They found out that the car actually was TOO low to the ground, stopping the airflow underneath the car and it caused an aerodynamic stall and a loss of almost all his downforce, which made the F1 car act like a civic at 160mph going into a turn. So if someone is going to make an underbody tray/diffuser/venturi tunnels for the FD...dont drop it too low!!! *phew*.....back to the topic folks! https://www.nopistons.com/forums/pub...DIR#>/wink.png

You're talking about the great Ayarton Senna, I have the vid of that crash, totaly ghostly.

ha ha.. we already know your shallow

As I was telling Martin, a flat underbody panel would help. The air under the stock chassis is turbulent as it spills over the various protrusions. If you smooth out that surface, then the turbulent air will be reduced, and thus encourage laminar flow and an increase in flow velocity.

A wing lifts because the air travelling above the wing is moving faster than the air below the wing. The result is a lower pressure on top, and the air below pushing the wing up.

So what happens if you decrease the flow ratio by simply increasing the flow rate below the wing? You get less lift.

I would concede that given certain vehicle shapes, it might be possible to increase lift because the underbody tray would create more of a wing effect. However! If you couple the underbody tray with a rear diffuser and a good sized wing on the rear, I would be inclined to think that your downforce would be largely increased over that of a stock-body car, and I think it is due in large part to the lowered cd and the increased airflow of a flat-bottom car. Also, (akin to F1 cars)any lift effects could be largely negated by the allowance of air to move from the bottom to the top of the car.. Maybe in the form of an aerodynamic inlet in the underbelly, and a corresponding vented hood.. But I most definetly digress..



Wind tunnel testing is very a expensive and time consuming venture. Most reputable aftermarket companies will simply track test their car. It's pretty easy for a trained driver to feel the subtle differences in handling that are changed by aerodynamic effects. I would most definetly trust someone who has successfully maintained a high rate of speed in real world conditions, rather than that of a wind tunnel tested model..



Oh, and on another note, sideskirts are funtional. They serve two main purposes. The first, is to create a more aerodynamic design by disallowing air coming from around the side of the nose to re-enter the underbody portion. Secondly, it is designed to reduce turbulent airflow leading from the nose and front tire over the back of the vehicle to cfeed the wing. when coupled with a wing that hangs over the side of the vehicle, the sideskirts can do more than you'd think!



Same goes for the popular rear diffusers. The accomplishment there is two fold; acceleration of the air to decrease pressure (And increase downforce), and to smooth the air as it joins the post-wing flow.

Turbulence at the rear of the car is a significant cause of drag and could potentially contribute to the ineffectiveness of a wing.

....he just used bigger words than me https://www.nopistons.com/forums/pub...IR#>/smile.png

Right! And on another interesting note, did you know that the shape of a bodykit can have different reactions with a vehicles performance? If the nose of your car is more aerodynamically efficient, your coefficient of drag is lower and will allow a higher topspeed and faster high-level acceleration. Conversely, a blunt, squared front end will cause better handling, manifested in a faster turn-in response. The effect is distinctly pronounced on F1 cars - on the canard, a lower angle of attack (read: more aerodynamic) will result in a slower turn-in (understeer). Increase the angle of attack (read: more blunt), the better the turn in response. Of course, there's always a balance, and if the angle of attack is too compromised, turbulent air will destroy the effects of the canard.. It is, however safe to assume for a street application, high speed turn in response will be increased (paralleled by drag) with a blunt front end.

i got sum pics of the front bumper ill post em in a sec

its been more than a sec.

its been like a day now