how far should a diffuser stick out the back of the car?

Far enough but not too far

Im on the beer already

far enough to impeed the car behind

how long is a piece of string?

There's that word again

Ideally it needs to be as long as possible, useually determined by regualtions. Other than that, not too far so as to make it look funny or to move the centre of pressure ntoo far back.

might be a plan to email brawn racing as they seem to know quite well

i was thinking more like 2-3"

quote:

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Originally posted by westf27
There's that word again

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2-3" will be fine

i think anything up to 6" should look alright, above 6" and it'll just look silly

[Edited on 17/4/09 by blakep82]

Wouldnt an effective front splitter be a better use of time?

Aerodynamics is not something we should even attempt to dabble with, because, let's face it, who's got a clue ?

Here's the one that convinces me not to dabble.

F1 rear wings, dictated entirely by the regs regarding chord size, height, width, distance from the back of the car. Designed to give some downforce, but not too much. Designed to let the car behind follow and have a chance of overtaking.



Top level hillclimb car. Fit as big a wing as you want, fit it where you want and use as much power as you can afford to pull that big ol' wing along.



Do I think I know why the hillclimb car's wing is bigger ?

Absolutely.

Do I actually know why they're different ?

Not really.

Diffusers ?

On sevens and stuff like that ?

Aye, right.

Now don't get me wrong, I have friends with diffusers fitted to their cars, but without a sound knowledge of why you're doing it, all you're doing is giving money to the man that sells the carbon, or God forbid, the sheet ally...

If I came across as negative, I apologise.
If it's something you want to do, don't ever let me or anyone else tell you not to.

I won't be doing it myself, but hey, we're all different

that one on the turbo blade is rather tasty.

Im going to make front and rear and whiskers for mine, i like um

i want one to fill in this big space in the back panel on mine



but its not going to work unless the whole underside is panelled in really...

I'm pretty sure the one on that turbo blade is one of the ones that does cock all.

They aren't too hard to design, even the current F1 diffusers are pretty much flat or gently curving for the most part. It just needs a smooth trasition into it, to have around 7-12 degrees of divergence with the ground, be sealed at the sides, have as smooth a flow into as possible, and that's about it.