Sorry for the pun!

Just been looking over fleabay and found this

VORTEX GENERATOR Skoda Octavia Fabia Felicia RS 5 Turbo on eBay Body Modifications, Exterior Styling, Car Tuning Styling, Cars, Parts Vehicles (item 110157974899 end time 19-Aug-07 23:22:16 BST)

I know they run this on the FQ400 and I believe the one of the special Scoobies now uses this but I was wondering if changing the airflow with these bits would make any difference to the amount of soot that gets layered on the back end?

I am guessing its the vortex effect that creates the problem in the first place but I'm sure there must be some aerodynamic boffins out there who can add a comment or two?

All the best

No they wouldnt help... the fundamental problem with the furby is its hatchback shape is as aerodynamic as a brick. at high speeds the air-pressure drops behind the tailgate meaning the flow of air above and below the car get pulled into this low-pressure area, which creates alot of turbulance and increases drag.. it also circulates dust and soot which some will stick to the bodywork..

the only way to cure it would be by it growing a boot... or some f**koff huge spoiler

THIS PDF explains better how the aerodynamics work

No they wouldnt help... the fundamental problem with the furby is its hatchback shape is as aerodynamic as a brick. at high speeds the air-pressure drops behind the tailgate meaning the flow of air above and below the car get pulled into this low-pressure area, which creates alot of turbulance and increases drag.. it also circulates dust and soot which some will stick to the bodywork..

the only way to cure it would be by it growing a boot... or some f**koff huge spoiler

Bring on the WRC!

Even a massive spoiler wouldn't help much - just watch a WRC car with a similar shape on a dusty section... Infact - you'd need an 'anti-spoiler', a wing which forced air down over the back which might give you a clean rear end with the slight drawback of becoming air-borne past 90...

Put the WRC spoiler on backwards?

saw Ch@v'd up Puma the other day with a row of those little fins across the roof , to go with the large spoiler on the boot

re the way to avoid a sooty rear end , give it a "Sweep" perhaps

Yep, not much you can do about it - a re-design might do it though

Even at low speeds it's an issue. While the car's still warming up in cold weather, you can see the exhaust vapour going near vertically up the back of the car as you accelerate

Steve

No one has pointed out the least destructive way to the body work to reduce soot.

The cupra intake and a panel filter, it definately worked for me.

If it was done properly and wind-tunnel tested, then - yes, it might well reduce sootiness of the RS.

When done properly, they cause airflow to continue down the rear screen rather than detaching further up nearer the roofline. They actually promote rear end lift. On the EVO they counter this by having a rear spoiler. The spoiler works more effectively with the vortices than without, so the overall effect is about neutral.

With a Fabia.... I dunno, it's a bit of a reach. And you'd have to lose the roof lip spoiler.

J.