http://www.lotustalk.com/forums/f152...-anyone-86195/

Interesting how a stock EVO 7 has downforce on both ends of the car, while cars costing several times more still generate lifts.

 

Does anyone have wind tunnel test results for a 8, 9, or 10?

 

Who did the testing? I didnt really read through the thread but Im not sure how accurate it is...I was told that evos do not generate real downforce. Soooooo, Im not sure I trust those figures. Call me a skeptic but I was always under the impression that evos lift at speed?

 

I'm with this. Stock Evos are the furthest thing from being aerodynamic.

 

I think its interesting a lot of the exotic cars generate lift, i always assumed they would generate good downforce

 

I remember reading that the Cyber Evo just barely makes downforce instead of lift. Going to have to join the other skeptics here.

 

I would say it accurate, or at least the testing is. If you look at the images you can see the cars are sitting on big circles on the test platform. All they do is place them on there, the circles being weigh scales, and run a 200km/h breeze over them. Simple, accurate and quick to set up. Interesting to see the Evo is one of the few cars with downforce at both ends.

If you look at the two Porsches, the gt3 and the 997 Carrera S, you see the two elements that make the difference (with two body shapes pretty much the same), a lip and the wing. I would suggest that adding a lip that sticks out further than the bumper (all of them?) would increase high speed downforce on the front of an Evo.

Would be interesting to see the McClaren P1 in the test. It's meant to be one of the few "road" cars with true downforce. The rear wing has to be lowered at high speed to stop the increase in this downforce from breaking the rear suspension. I guess that's what you get for a million + dollars.

 

would be nice to see if a vortex generator actually helps in this scenario. thanks.

 

Vortex generators do a different job, the reduction of drag. My understanding is that they breakup the boundary layer of air traveling over the car. If this layer is allowed to pass unhindered over the roof and down through the rear spoiler it creates a low pressure eddy behind the car. Being low pressure the car is sucked back into this section of air, kinda dragged back. The test linked by the OP does not have the mechanism to test for this, from what I can see.

There is a good article on vortex generators and their implementation here -

http://geetaebook.com/pdf/aeronautic...Generators.pdf

Just as a matter of interest I've always thought that the best thing we could do for the aerodynamic efficiency of the Evo platform is to close in the area between the rear suspension arms and the lip of the rear bumper. This area basically works has a parachute on our cars, a great big scoop grabbing the air moving under the cars floor-pan. I'm surprised that no company has made some sort of panel to close off this area. An item such as this would do more for aerodynamics on an Evo than all the lips, canards and vortex generators made.

 

Very interesting! Thanks!

 

Im sorry sir evos are not designed to have lift at speed from the evo II to X. Its really not hard to see that there is a more balanced and constant downforce to the CT9A shell and the 8/9 were slightly better for front cooling not necessarily downforce.

The wing on the 8/9 had less air turbulance from keeping closer to the cabin lines than the 7 breaking the lines. Notice the wing on those illustrations was much larger compared to the other cars tested.

if someone can mange to find the back to back testing of the CT9A vs the GDB subaru then you can see the difference in front lift versus almost identical rear downforce numbers.

 

@VWJETTY. While I have no scientific proof, when my clearcoat starting pealing from my wing I was a bit baffled that it wasn't pealing evenly. Then I noticed the vortex generator fins are angled slightly outward & that the wing was pealing from the outside in. Take it for pure scientific speculation.

@Fireescape. APR makes a rear diffuser that doesn't completely seal up that area but looks like it would be some what functional, although I think I'd try to close it up a bit more. It's also only for the USDM version bumper.

 

I do agree with this. Also I was told stock muffler is partly doing this job covering that large area. That's one of the reasons I choose against aftermarket exhaust which keep that area empty and I've got ETS Quiet which covers at least something there.

Oops. A little note, I was talking about Evo X which has a comparable bigger muffler standing 90 degree to the car and occupying that space.

 

Or just make full flat undertray

 

Like I said in my original post I'm not too sure how legitimate those finding truly are. I'm not trying to stir up any internet drama here and can tell from some of the comments that a couple folks appear to be much more well versed on the matter than myself.

I only said what I said based on memory of past discussions on the topic.

If the test really is as simple as Fireescape makes it out to be then I guess its hard to argue the results as the concept is quite straightforward.

It is certainly interesting and I hope that more knowledgeable members step up and add their .02 so we can get to the bottom of this.