1988 Audi 80 quattro mod thread.

[fjasper]

Thought I'd stake out some ground for this project.

Cd 0.29 factory, we'll see how far I can take it.

The suspension has been modified for autocross, but it's currently sprung at approximately stock height and rate. It can be raised or lowered a couple inches from the current setting.

Here's the car before any aerodynamic mods:



Here are some pictures of what I did on Saturday:

Looking back from the front, showing aluminum with gills letting air in to cool the exhaust:


This one may be a little confusing, because the dual exhausts on the back end of my other car also show in the picture. Looking forward from the rear wheel well showing the gills to let air flow out of the engine compartment:


Control arm fairings:


Spats. The license plates will be used as a framework for larger convex coroplast fairings.


Mirrors delete (replaced with internal mirrors):


Partial wheel covers. These wheels are high-offset, so the wheel actually sticks out further than the tire, so a full cover would require a domed shape. I have another set of wheels that are nearly discs that'll be going on once I get appropriate tires on them.

[fjasper]

I've played with VGs on the roof, and I know I can make the airflow stick to the back window with two VGs near the centerline, 8" ahead of the back window (normally airflow separates on the center 1/4 of the back window, top to bottom). They change the airflow to an inward direction on the bottom outside corners of the rear window and trunk lid.

Anyone care to guess whether this would be good or bad for drag reduction? I think it might be evidence of outward-turning vortices forming at the rear corners of the roof, like the 30-degree fastback example in Hucho but opposite direction spin. Might just be converging flow, though.

Also, a VG about a foot inward and forward of the back corner of the hood kept airflow attached to the side windows (eliminating the whorl at the upper front corner of the front window), but that was with mirrors in place, so I'll have to try that one again.

Hopefully I can get time to do some tuft or grease-blob testing and some A-B-A to sort it out.

[FastPlastic]

Looks like someone been busy. Looking good

[fjasper]

Yay! 60% over EPA. I added side skirts and cleaned up the diffuser as well:





Also a pair of VGs (bent from a single piece of license plate) on the roof to keep the back window clear.