RS airbox on ST ?

[Priceyy12]

Anyone recommend putting the rs airbox or just the lid on the st and changing the airfilter ?

 

Failing that what else can I do to improve the sound a bit without spending to much ?

[Stoney871]

Look at this on eBay http://www.ebay.co.uk/itm/142522207761

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[Bannko]

RS airbox is the same as ST. Just the lid is different. 

And please note that the RS lid is much higher and the rubber part touches the bonnet - some kind of heat shield so that the hot air from the engine will not be sucked inside.

So i do not recommend making a hole into your existing one. But i am also not sure if it is possible to buy the RS lid, i think you have to buy the whole box as a set.

I have this RS air box in mine 1.5Ecoboost and there is a sound improvement so at least i can confirm you that :) 

 

[alexp999]

I have the RS lid on my ST.

Had to buy the whole airbox from Ford, but just used the lid.

As Tomas said, don't just drill holes as the RS lid is designed to seal against the bonnet and only allow flow from the front of the car, to stop it sucking hot engine air in.

It does sound a bit better from outside, but the Focus is so well insulated it makes no difference inside unless you have the windows down.