Porsche 928 more aerodynamic going backward?? Mythbusters to test with body reversed

[QuickLTD]

I did a quick search and didn't see this posted anywhere. Basically they cut off the body and swapped it around end for end to test the "myth" that the car would be more aerodynamic and thus faster in reverse.

Mythbusters Tests The Porsche 928's Aerodynamics... In Reverse

[PaleMelanesian]

It looks to me like the original design was better. In reverse, the windshield drops too quickly, likely giving flow separation. Whether it reattaches on the hood later will make or break it.

[Piwoslaw]

The comments are the best thing on that page

BTW: It looks like Jalopnik used the title of an old thread of mine for inspiration:
Teardrop aerodynamics... in reverse!

[QuickLTD]

I understand it makes for good TV to cut a car up and show it re-built but with today's technology wouldn't it have been easier if not more accurate if they just ran the car through a wind tunnel backwards or run the shape through an aerodynamics program? They seem to be chummy with NASA among others that have access to such equipment. In fact just for giggles someone should run it through the Flow Illustrator (both ways) that we use here.

[d0sitmatr]

I never believe a thing those guys do.

did you know they did a test on trucks a while ago and found no difference between an open bed and a bed with a tonneu cover on it ?
they also stated the truck got the best mpg with the tailgate removed and a cargo net in its place, 2nd best was tail gate lowered, then the open bed and tonneu was equal.

I can say, beyond a shadow of a doubt, that my truck gets just about 1/3 better mpg with the tonneu on than off.

I paid close attention to the sponsors for that particular episode, and the car manufacturer was at the top of the list. (2 I think)

[MetroMPG]

Awesome find, LTD!

I added a poll to the thread - go vote, everyone!

Mike: these guys often sacrifice the scientific method on the altar of infotainment.

It'll still be fun to watch. I'm planning to catch this one.

[MetroMPG]

Originally Posted by PaleMelanesian

It looks to me like the original design was better. In reverse, the windshield drops too quickly, likely giving flow separation.

Not just flow separation, but the potential for a pair of massive counter-rotating, energy sucking vortices.

However, there's no massive cooling system hit going backward...

The greenhouse is also significantly wider at the A pillars than the C pillars, which is bad for wake size.

Tough to call, but I'm voting for "better going forward."

[Weather Spotter]

I would say that it is better going in reverse but there pour testing will not show it. Give an EM that car for a week and it would work much better in reverse

[QuickLTD]

Obviously not 100% to scale but these line drawing clearly shows what Metro is describing about the greenhouse

[d0sitmatr]

added my vote to the poll
while I think it honestly has the potential to get better CD in reverse, I only think it would do so if originally manufactured that way.
just flipping the body around on the frame just isnt going ot cut it