Writer seeking examples of tested DIY aero mods for book

[JulianEdgar]

Porsche Cayenne - development of the front aero. It's pretty trick.

https://www.youtube.com/watch?v=qzGQdVXGCHM

[freebeard]

I just watched it. The Concept/Implementation cross-sections were informative. There appear to be louvers in the wheelwell that flow outward in the outer well, and inward toward the centerline.

And the air curtain duct is more or less continuous width with some bellmouthing at the inlet.

[JulianEdgar]

Originally Posted by freebeard

I just watched it. The Concept/Implementation cross-sections were informative. There appear to be louvers in the wheelwell that flow outward in the outer well, and inward toward the centerline.

I see the outward louvres in the wheel well, but the other louvres are the shutters and intercooler core, no?

Originally Posted by freebeard

And the air curtain duct is more or less continuous width with some bellmouthing at the inlet.

Assuming the air curtain duct remains the same height along its length (no idea if it does) the intake area is about double the exit area on the 'implementation' drawing.

[JulianEdgar]

Latest videos.

Edgarwit external air curtains (about a 5 percent reduction in drag):

https://www.youtube.com/watch?v=MaGg_8M8Us8

Be wary of aerodynamic testing that uses small models (they often don't work):

https://www.youtube.com/watch?v=qjIKe4vUI3s

Applying and understanding wool tufts (basics, but people asked for it):

https://www.youtube.com/watch?v=m8_Z_vskvrs

[JulianEdgar]

And, a repeat of another thread, but also here so we have continuity:

Throttle-stop speed testing of aerodynamic drag - a new way of testing changes in drag:

https://www.youtube.com/watch?v=tVAokIdaXm0

Measuring changes in car drag (ie quantifying changes in Cd):

https://www.youtube.com/watch?v=Wi-TemRJ7CM

[teoman]

Julian, you should also have a look at Vekke’s approach ( a fellow forum member).

In principle it is a similar approach but he fixes the injection amount above a certain rpm and measures the max speed rpm of the vehicle. He used this technique to make engine modifications.

[JulianEdgar]

Originally Posted by teoman

Julian, you should also have a look at Vekke’s approach ( a fellow forum member).

In principle it is a similar approach but he fixes the injection amount above a certain rpm and measures the max speed rpm of the vehicle. He used this technique to make engine modifications.

I don't understand what is being described. Do you have a link?

[teoman]

Vekke used a similar approach by checking maximum speed achievable by the vehicle. His approach was not to limit the throttle input, rather, he tuned the (VW TDI diesel) engine so that it would inject a fixed amount of fuel every time achieving fixed power from the engine.

[JulianEdgar]

Originally Posted by teoman

Vekke used a similar approach by checking maximum speed achievable by the vehicle. His approach was not to limit the throttle input, rather, he tuned the (VW TDI diesel) engine so that it would inject a fixed amount of fuel every time achieving fixed power from the engine.

But a fixed amount of fuel does not equal a fixed power! It closer approximates a fixed torque. But given the influence of that on the drag calculation (^2 rather than ^3), the basic approach should still be valid (on diesels anyway).

(But I am still struggling to understand how that helps on engine modifications, as you suggested.)

[JulianEdgar]

Latest videos.

Aero flow disturbance of driving lights:

https://www.youtube.com/watch?v=zjttwGPWh-s

Designing rubber mounts for vibration reduction:

https://www.youtube.com/watch?v=rrUUs7uC8ag

Lessons from Porsche in designing ducted cooling systems:

https://www.youtube.com/watch?v=tfw17CVb4M0