Koo...I will, by the way it does make more of a difference (you might not notice it, but it does) at speeds of much lower than 150. It's just that the higher the speed the faster the air...the more then downforce. If you have a fully down (or even a diffuser and front undertray) you'll easily notice it at 80mph (depending on how good it is...even lower speeds). It does make a big difference when it's done "right", not just half the package. Although just a diffuser by itself will still give a nice amount of help.

BTW...still looking for a freaking picture of the NSX. If only you guys were here you could see the damn magazine (EVO...in case you were wondering issue 043, pages 82/86/87/89/91) with a GREAT picture of exactly what I want to show you...that's always the case!

Oh DEAR GOD there's so much more I could post right now, but I just got out of the lab (shop...samething but this is big enough to be called a lab...especially since we pay a lab fee to use the thing besides classes) for the day and I wanna go chill and EAT, and probably stop by the library (exciting...I know, but how do you think I know so damn much).

 

Hey, I think I have a paper that I wrote a while ago (not for a class...just for myself to study) of collected information on aerodynamics (nothing too "overhead"). Maybe after the holiday I'll post it (and heck probably revise it), many pics including Ferrari's Enzo underbody (which I've disected a million ways already), the Mazda RX-792, and other cars. Either way have a good holiday!

 

one thing to mention is that it can be dangerous to mess with aerodynamics without knowlege. for example adding a rear spoiler and a funtional rear diffuser w/o any additional downforce adders to the front can cause highspeed instability with the rear getting massive grip and the front becoming very floaty. same applies opposite.

 

No, the RE Amemiya Diffuser fits well with my Knightsports Dual exhuast.

 

great point jeremy
on 911's they HIGHLY advise that you add the same style front lip and same style wing. or else you will ruin the balance of the car.

 

and most diffusers ive seen appear to be symetrical so there shouldnt be any problems with dual exhaust, and also if its made for the FC it should work just fine with dual exhaust as thats what the FC comes with factory and what most people upgrade to is another dual exhaust.

 

KiyoKix, While I agree with the technical aspects of the lecture for today, I think its foolish to assume that this bolt on product can do very much other than replicate the appearance of a full belly pan's rear contours.

With the upward sloping facets that protrude into the underbody air stream this device is a wing! It would require the rest of the flat belly pan to make it anything more than just a wing.

The diffuser is used to transition the rear of the car from vacuum to atmospheric pressure without causing paracitic drag inducing turbulence. I'm sure we agree on this.

The bottom of an FC is no where near smooth enough to create downforce from bernouli's <sp?> theorum! The subframes and exhaust plumbing, differential, control arms... all cause so much turbulence below the car that suction is not an option. Not to mention the ground clearance of most of our cars is well beyond the proximity required to gain this effect.

For these to properly work the venturi would need to extend for a good portion of the underbody of the car. If you look at a picture of the belly pan for a formula one car you'll notice that the rear of the venturi's looks remarkably similar to the verticle channels in the RE-A "diffuser."

It's like saying you have a ferrari because you own one wheel. You're missing 98 percent of the parts.

If you were to throw a car with one of these into a wind tunnel you would notice that this piece is scooping air from underneath the car. A diffuser wouldn't have any air coming between the body and itself. This is a wing...

 

I understand the basic principles of aerodynamics. What I was getting at was more allong the lines of what jeremy was saying. Here you have this aftermarket piece that was bolted onto a car that already has an aero scheme in place. What will it do to the car in real life? Unless somebody's been working real hard with the CAD team or had the car in the tunnel, nobody really knows.

Cory Waters
Theroy shmeory

 

you aren't going to see any major benefits w/o a front diffuser, i'll agree. but a full belly pan is pushing it a little. the r34 skyline makes full use of this with a front and rear diffuser.

 

A belly pan would be an awsome idea for this setup.
If im understanding what you guys are saying then your saying that a difuser will not be very functional without the other components (ie; front spoiler, smooth underbelly) So why not manufacture an underbelly for our cars like the 911's have and ****. It would not only more than likeley make our cars faster (By giving us a almost perfect aerodynamic shape) But it would also inhibit rust and damage from debris off the road.
Only questions is what it would cost to create such a thing??
Just a thought

 

a lot. not to mention you have to watch hot spots and yet allow enough air through not to overheat components like exhaust and differential.

 

I've been mulling over that exact same question for a long long long time....

the problem with creating a smooth underside of the car is that it will have to be capable of holding a significant portion of the weight of the vehicle. (if its actually functioning) the belly pan of the car when making a vacuum will have a significant load placed apon it and therefore must be capable of such stress.

I've been talking this one over with a professor of mine for a couple months and he seems to thing that more benefit could be made with very low lying body skirting than trying to flatten and smooth the entire belly of the car. I'm still not convinced though. I think the car is flat enough that relatively light materials could be added to smooth it out without altering the appearance of the car. (stealth is very important to me as I don't need cops or robbers attention)

For less than 50lbs I would think you could put aluminum plating under the chasis and add some nice ducting to help move air through the engine bay.

 

rotary extreme sells them and has pics...id have it on my avatar but i was banned from this forum for no reason so i had to make a new name on here

 

Also, don't get me wrong here... A lower wing would be trick as hell and very functional. It's just that this is not a diffuser.

 

might be wrong but i always thought that the aero dynamics of a car are always conflecting with each other... if you have studied about aero dynamics then im shure the airfoil has come into play, it seems to me that a car's shape is close to the shape of a air foil and that the curve across the top just mimics the most crutial part of the airfoil, wouldn't the curve across the top of the car just creat a low pressure zone and suck the car up just like the top portion of a air plane wing does? although creating a loss in presure under the car could ultamatly "zero out" the effect of the low pressure sheet across the top of the car it still will be there at some point in time, adding such things as wings just for downforce seems to me like adding a smaller wing to guard ageans't the realty big one from creating lift, im shure that for the shape of a cars body to realy creat lift it would have to be going realy fast but still.... well thats my 2$

 

the shape of a car in most cases does not promote the adhesion of the airflow over it throughout the entire trip around the body. the new VW beetle is one such exception. they're so smooth that they actually produce a dangerous amount of lift above 130mph. most car bodies cause what an aerodynamics person reffers to as a stall. the car body doesn't keep the air molecules flowing properly and therefore doesn't cause lift.

 

i found another pic of a rear diffuser, not a CF one but a diffuser never the less

im not sure of the differences between 2nd and 3rd gen ones but they sell both here, might beable to get a better pic if you email em



i got the pic here

http://www.i-m-racing.com/reamreardif.html

-Jacob

 

Damn we're gonna have some fun with this one. I'll post more later (I'm seeing a sticky now...).

 

wow great info man.....but you should space out the paragraph...im getting dizzy

 

Sry

 

so is he going to make some or what.

 

I have pics of the rear diffuser from the Viper GTSR....That thing is monsterous.....I'll post it this weekend when I get back home.

 

Koo, I have pics of many diffusers and underbody designs, when I get a chance I'll put them all together and post them. Sorry I didn't post today...busy day!