How can i make one of these rear diffuser thingys for my indy?

Dont have much money so its going to have be very locost style

Not worried about it being carbon.


Description

That guy made his own, was the first thing i asked him when i saw it too...

Does not look like rocket science...

Get some 2-3mm ali plate and produce two shallow trays and one deep one to go in the middle..

Rivot the trays together, drill some holes and mount to the car using some ali tube to space it to the right height...

I made my own in Carbon Fibre with 1.9mm Ali Fins...

I never got round to finishing it before I sold the car as I was going to put vertical fins on the end pieces and extend the ali to run down the car...

Does your car have a full floor, because if not then a diffuser will be for looks alone...

Steve

I thought I had some better photos of it than these, but I can't find them right now!!!

yes steve, my indy has a full floor in it.

sorry im not very good at the design side of things.

It's not rocket science - but it is fiddly to do it. A photo of mine about half way down here :- http://www.locostbuilders.co.uk/viewthread.php?tid=82829 .

Simply made with 2mm verticals and 1.6mm horizontals and lots of rivets. Mine was made in three sections - a low middle bit to clear the deDion and the outers which are higher.

Looks good IMHO. After the gearbox rear seal leaked, it was "pleasing" to see that the oil tracked all the way to the back in nice smooth lines!!.

Mines Purely cosmetic, I had some of the abs carbon effect sheet left over from the interior so came up with this, nice and simple and easy to make.
Would of liked the fins a bit bigger but the sheet wasn’t long enough!

I do like the look of that one though Matt who’s is it?



Rear diffuser

They look good but perhaps WorX would like to enlighten us if they make a real difference and at what speed they have any effect. Also are they worth fitting on a road only car?

I fitted one I got of Scotlad, last year.

I can confirm at Bruntingthorpe the front end got a lot lighter at high speed with the diffuser fitted than without it, which I took as it pulling the back of the car down a little.

Mike

Here's mine. It's got more fins now but it's just folded and rivited ally'.

http://i189.photobucket.com/albums/z282/adrianthorp/Pre-SVA002.jpg

Do a bit of reading first. The angles are pretty important if you want it to be effective. 9' springs to mind as being best but not more than 15'. Don't quote me on that though; I'm no aero' expert!

adrian

Made mine from ali. Made a cardbord template and transfered to the ali. Just took time to work it out.
Now have a flat floor from the gearbox back

Youcan make a simple mould for an undertray from melamine faced hardbord and chipboard, then lay-up fibreglass after waxing. If you want it to be effective then keep the smooth side underneath to flow the air more effectively.
Keep the angle to about 7 degrees if having only a short upturn, but this can be incease to about 9 degrees if taken over a longer length.
Do be aware that downforce induced behind the rear wheels will unload the fronts, so you may need to increase downforce at that end too, which isn't so easy on a road car.

I work with wind tunnels. We recently had a student do some tests with a basic model car with a adjustable diffuser and the ideal angle was considerably different to that expected. We've also done some recent work on a proposed production car and the diffuser didn't produce any downforce at all, it just increased the drag. You might be reducing your performance.

I played around with the idea of one for the Nova, it never got past the prelim stages as i never got round to paneling the whole underside of the car. But i found an Elise S2 111s diffuser not only looked good but was easy to fit and relatively easy to get hold of .







[Edited on 7/8/08 by loggyboy]

LINK TO CARBON DIFFUSER




But how much!!!

[Edited on 7/8/08 by matt.c]

At £629.95 thats not very locost but very nice

But you could get it for £370 in black epoxy?

Steve

I think It looks shocking on the Nova!! Sorry bud!
Personally, i feel that it needs to be one of two things.
Installed correctly and looking good if for aesthetics, or installed corectly and functional. Either way, having a wind trap under the car is just going to cause problems.

quote:

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Originally posted by loggyboy
I played around with the idea of one for the Nova, it never got past the prelim stages as i never got round to paneling the whole underside of the car. But i found an Elise S2 111s diffuser not only looked good but was easy to fit and relatively easy to get hold of .







[Edited on 7/8/08 by loggyboy]

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quote:

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Originally posted by MakeEverything
I think It looks shocking on the Nova!! Sorry bud!
Personally, i feel that it needs to be one of two things.
Installed correctly and looking good if for aesthetics, or installed corectly and functional. Either way, having a wind trap under the car is just going to cause problems.

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