So I'm working on some aero parts, and have my car setup with sensors to measure downforce etc. Evo's and pretty much every street car actually create LIFT, not down force at speed. Even wings and splitters on EVO's just help minimize lift, not create true downforce. Here's a thread talking about what I'm working on https://www.evolutionm.net/forums/sh...d.php?t=346323

I realized that the only way to really get past lift and into down force would be to clean up the underside of the car and make it as flat as possible, so here's what I've got so far ...

- Extended the APR splitter back to the chassis braces. Used aluminum sheet. I welded supports and captive nuts unto the chassis braces so it just bolts up.

- Full length plastic side skirts that stick out roughly 2 inches and come in under the car to the boxed frame.

- Center section, aluminum sheet slightly bent to create clearance for exhaust.

The car is now TOTALLY smooth to the rear axle/gas tank area. I just need to build a rear diffuser now.

Here are some pics.

 

Wow!That is pretty cool!When do you expect to have a rear diffuser for the USDM rear?Will the rear diffuser be a seperate option?Also will it fit any type of exhaust?

 

very interesting, Keep up the great work

 

How do you counter the extra heat that is going to build from the metal and the exhaust? I am just curious. It looks awesome. Keep us posted.

 

I would be VERY interested in purchasing this if you decided to produce. Can't wait to see how the testing turns out. Subscribed.

 

nice work im sure there is some more R&D left but keep us posted!

 

looks great. it would be interesting to see this set up in a wind tunnel in comparison to the stock undertray

 

Looks really good! But yes like the others I'm concerned about buildup of heat.

Nonetheless, very promising project. I like it a lot.

 

Interested as well.

 

Looks awesome... as others have stated heat soak would be a concern of mine as well.

Doing a hell of a job though, keep up the good work.

 

Looks bad *** man! I'd really be interested to see the wind tunnel results from this!

 

That is sweet. Nice work.

 

Heat is on my mind as well, that's why the center section is aluminum. It's impossible to totally seal off the area between the undertray and the chassis, so there will still be airflow past the exhaust. If it is a problem I'll create scope to let more air in.

I don't have the money to go knock on Boeing's door and get some wind tunnel time, although it would be sweet. I have some test setups which can rough out lift/downforce and drag. I have some data from before the undertray, I just need to go out and get some more now. I just need a little time, probably in a few weeks.

The rear diffuser I'm planning will be for the USDM 8 bumper. It will require cutting the rear bumper, the lower lip of the bumper needs to cut away to create the proper shape for a real diffuser.

 

This is exactly what I've been looking for the evo to be made. Putting on after market exhaust manifold on my friends 2006 330i I noticed that BMW's are pretty covered up underneath. No wonder why they hand pretty good on high speeds.

What about the factory jack points, are you going to leave any open areas for those? Its hard to tell from the pictures if you completely covered those up.

Also besides aluminum have you considered using high impact/temp plastic?

Excellent work for your efforts!

 

I thin you need some openings so the exhaust heat gets out... kind of like the beat rush front undertray has