If I put a sheet of aluminium on the underside of car mounting it to 3-4 beams/struts across the width of the car so it is tightly secured.

Would the wind/air rip it off considering there is gaps where the exhuast runs all the way along the underside of the car?

what are you looking for here?

Streamlining?

Downforce?

Not that any of it will matter at the speed of a 1.4 16v

Are we talking the whole length of the car or just a section?, Unless you know what your doing or have proper help i wouldnt even bother. Think of how badly it could go wrong at 70mph

Middle section only for streamlining. If anyone knows abit about the physics please help. Thanks. :)

I really wouldn't bother..... do it right and I very much doubt you would notice any difference do it wrong and and it would produce drag and even worse could fly and hurt someone at speed.

I'm sorry but this guy is living in "cloud cookoo land" if he thinks bolting a sheet of ally under the car will miraculasly turn the car into a supercar beating machine with incredible fuel savings, at the end of the day the basic body shape is as aerodynamic as a brick and any "underfloor" tricks will not transform it into a world beating machine

with a bit of design knowhow you can achieve good things and those stating that the speed of a 16v 6n won't be useful obviously know nothing about aerodynamics. a flat sheet wont be much use but a whole underfloor would be awesome, the idea is to create a half venturi under the car to increase the velocity of the air (thus reducing pressure) which will create downforce over the underside of the vehicle, introduction of vortex generators to the splitter will further reduce the pressure under the car too.

buy a couple of books and you can find all you will need and gain a good understanding of aero.

start with http://www.amazon.co.uk/Competition-Car-Ae...1190&sr=8-1 this one is a real user friendly book using simple terms and good diagrams as well as actual results to back up what is being said.

move onto this http://www.amazon.co.uk/Race-Car-Aerodynam...1313&sr=1-1 this book provides a much more in depth look into aero but is a more complex book to read.

I am studying aerodynamics as part of my motorsport degree.

with a bit of design knowhow you can achieve good things and those stating that the speed of a 16v 6n won't be useful obviously know nothing about aerodynamics. a flat sheet wont be much use but a whole underfloor would be awesome, the idea is to create a half venturi under the car to increase the velocity of the air (thus reducing pressure) which will create downforce over the underside of the vehicle, introduction of vortex generators to the splitter will further reduce the pressure under the car too.

buy a couple of books and you can find all you will need and gain a good understanding of aero.

start with http://www.amazon.co.uk/Competition-Car-Ae...1190&sr=8-1 this one is a real user friendly book using simple terms and good diagrams as well as actual results to back up what is being said.

move onto this http://www.amazon.co.uk/Race-Car-Aerodynam...1313&sr=1-1 this book provides a much more in depth look into aero but is a more complex book to read.

I am studying aerodynamics as part of my motorsport degree.

But the aerodynamics of the basic bodyshell are that of a brick, so no underbody work will make this into a slipsteaming, petrol saving machine, the guy's living on cloud cookoo land

You'll be surprised!

it will nige! a bluemotion polo is still a brick yet uses subtle aero tweaks to save fuel. the grille, skirts, undertray and rear spoiler do a surprising amount of work. if you wanna know about how even really small changes can make huge differences research the aerodynamic device known as a gurney flap. I was doing an aerodynamics based product this year and on a front wing for a formula renault a small strip of metal (no more than 10 mm) attached to the end of the wing at a right angle increased downforce for that wing by 20%

You'll be surprised!

Nick, you work on current/future cars and they have been designed with fluid dynamics, the basic Polo shell is an aerodynamic "brick" and cleaning up the underfloor will not make it give supermodel performance

It really won't make a difference. You don't go fast enough for the underside to matter. You could spent thousands improving its drag coefficient, but all you'd get is 1-2 mpg better off. Be spent thousands designing that car, your never going to improve it in any worthwhile manor with aluminium, body filler and a calculator.

It will make a difference, probably just not worth the hassle.

Honestly like a small vertical plate on the underside around 10x300mm can make a big difference to certain things.

Think about that when you go sticking splitters on or slamming the shit out of it

But the weight of the ally will probably have more of an effect

It really won't make a difference. You don't go fast enough for the underside to matter. You could spent thousands improving its drag coefficient, but all you'd get is 1-2 mpg better off. Be spent thousands designing that car, your never going to improve it in any worthwhile manor with aluminium, body filler and a calculator.

you can design things to work at low speeds F1 aero doesn't work at low speed but doesn't mean nothing will. VW also used CFD to design the car at great expense (proof is how the rear tapers inward and down to reduce the wake (thus reducing drag). however vw have to make compromises in aero to please all markets if you want to make efficiency savings you would lower the car, have a smooth undertray, low drag wheel covers wake reduction devices, smaller intakes, tighter shutlines.

Sorry. I ask for advice. Please don't say I live in cloud coo coo land. Reducing CD by 0.1 is equilvant of 100kg.

People probably thought the same when I bought some light weight alloys and it brought my 0-60 from 8.3 to 7.8.

Reducing CD bt 0.1 will increase my MPG by 6-7 but I will need a full undertray with bluemotion delfectors but it has to be done right.

Thanks nige for the other helps.

Edited 24 June, 201214 yr by damunk

All I can say is try it man! :)

Yeah sure. I have a guy who will make sure I do it so it is safe. :) I will come back to you with results :) and the blue print if it is a success.

Just consider other elements such as air escaping the engine bay an such

Yeah this site is very good. http://ecomodder.com/

Explains alot showing examples of other peoples designs. On the "forum"

It is very interesting.

p.s Any of you guys watch the footy? :(

Edited 24 June, 201214 yr by damunk

Yeap, Italy were definitely the better team, but keep this thread on topic :)

i fold my rear seats down, thus lowering the CG i.e. laying down on a frozne pond - reducing the weight. Also polish the paint to reduce wind resistance

Surely with the alloys reducing the weight alone wouldn't knock half a second off the 0-60, not by a long shot. How where you measuring it and no doubt you changed the tyres along with the alloys?

Edited 25 June, 201214 yr by Mclovin

Got to admit, I'm not expert on aerodynamics. What's the score with the rear diffusers on the cup cars? Or is that more about stability at speed than streamlining?

which cup cars yeti? 9n3 cup cars? some diffusers are purely aesthetic like the Focus RS some others like the clio rs200 provide a small amount of negative lift on the rear axle to reduce the chance of the back end out on cornering. same with splitters at the front.

I like aerodynamics, its like black magic that you can't see but it makes a right difference. I once maxed my MR2, but had to turn the lights off as it wouldn't go any quicker with them up!

Anyway, I can't imagine a flat floor being worth the hastle, however it would still make a difference and if you want to do it, find out and go for it!