Roof spoiler effectiveness

[Eatoniashoprat]

Originally Posted by gonebuggy

Driving a bug that regularly sees over 100mph, a rear spoiler is not what you need to worry about. The rear of my car stays nicely planted. but the front end starts to feel light. you can start to feel the steering loose it's responsiveness (very slightly, but still a loss) Not having run a front, or rear spoiler i cant say how effective they would be. I think a small "lip" over the rear window would help, but personally i'd concentrate on keeping the front planted.

Alex

Thanks Alex, that's interesting to hear. So if no front air dam is used then the best one can do is have the car as low as possible to the ground and possibly the front a little lower than the back? Is your car fairly low?

[judgie]

i have done some testing on track with a few bits and i can tell you the biggest differance in time was a deep front spoiler and splitter, just under 8 seconds at prescott which is under a mile long
didn't feel a lot different. the rear wing i run makes approx 80kg of downforce at 90mph and makes a huge difference to how the car feels at speed but not a lot in time, just feels a lot more stable.
if you want to make a big differance but not have it on show then try and make the under side as flat and smooth as poss with a slight front rear rake. front lower. vented backs to all wings makes a differance.
what ever you do make it strong, made the mistake of making the front splitter mounts out of 1.5mm alloy plate, at 100mph it bent now you can stand on the splitter.
cheers rob

[Eatoniashoprat]

Good info Rob, thanks.

[Turbo Haraune2]

I have a porsche "whale tail" on my car. it works from about 60mph.
Drove it once without the tail and declid, and it felt unstable over 65mph.

Get a big spoiler.

[Eatoniashoprat]

Originally Posted by Turbo Haraune2

Drove it once without the tail and declid, and it felt unstable over 65mph.

Get a big spoiler.

Holy , is your car really light or something? That speeds seems pretty slow compared to many others experiences with hi-perf suspension

[jrinlv]

Rob good info what size holes do you run on the rear of your fenders and how far up do you go? thanks JR

[Turbo Haraune2]

Originally Posted by Eatoniashoprat

Holy , is your car really light or something? That speeds seems pretty slow compared to many others experiences with hi-perf suspension

My car isnt specially light. about 900kg ready to go.
But the whale tail is a big wing and make a big difference to aerodynamics.

and as we all know the beetle isn't very good aerodynamic from original design.