St to RS airbox conversion

[Stoney871]

I've been looking into this for a while and just can't decide whether the top cover off an RS airbox will fit onto an ST airbox.

Any ideas folks?

The reason I ask is I found this on eBay and would rather not get a whole Rs airbox if just the top cover is needed.

https://www.ebay.co.uk/itm/Focus-ST-RS-Airbox-Conversion-Kit/142586246924?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

[JW1982]

The complete Focus MK3.5 RS air filter housing is a direct fit to the Focus MK3/MK3.5 ST. 

The top part of the MK3.5 RS air filter housing is also a direct fit to any Focus MK3/MK3.5. 

I installed the top part of the RS air filter housing on my 1.0 ECOboost air filter housing without any problems. The bottom part can also be installed into any Focus MK3/MK3.5 but this requires some extra parts like the additional ST/RS air intake hose and snorkel.

The Focus MK3.5 RS air filter housing is only available as a complete assembly which consists of the bottom part, top part and the original paper air filter insert. Some sellers only offer the top part (and simply throw the bottom part away to reduce shipping costs).

Until last Year the complete RS air filter housing could be bought a lot cheaper from the USA than in Europe. Some official USA Ford dealers offered the complete RS air filter housing for under 50 Dollars while the European retail prices are just above €100,-. Currently the USA retail price is about 80 Dollar.

 

The UK eBay seller is offering only a 3D printed custom mesh part. To install this custom part you need to cut the original RS mesh part from your own RS air filter housing.

[alexp999]

I have the RS lid on my ST. Had to buy the whole box from Ford though.

[Stoney871]

Thought that was the case but wanted to be sure.

The RS lid is higher than the ST one but I suppose that is to facilitate the contact between the top rim and the bonnet liner.

[alexp999]

Yeah otherwise the seal won't make contact and it'll suck in hot engine air.

[Stoney871]

Definitely a project I'll put some serious consideration into doing then.

If anyone sees an RS airbox lid for sale anywhere I'd appreciate the heads up.

[JW1982]

A few weeks ago I ordered some genuine Ford parts from a German parts supplier to service 2 vehicles.Because I had to pay the shipping costs anyway I decided to order the complete RS air filter housing also. I paid €80,- for the complete RS air filter housing  I sold the original paper air filter that came with the housing for €11,- to my parents so the RS air filter housing only costed me €69,-.

I order most original parts from:

http://www.original-teile.de/lang/uk/index.html

The only downside is that the part prices can be different each day. 

[Bol]

On 11/26/2017 at 10:01 AM, JW1982 said:

The complete Focus MK3.5 RS air filter housing is a direct fit to the Focus MK3/MK3.5 ST. 

The top part of the MK3.5 RS air filter housing is also a direct fit to any Focus MK3/MK3.5. 

I installed the top part of the RS air filter housing on my 1.0 ECOboost air filter housing without any problems. The bottom part can also be installed into any Focus MK3/MK3.5 but this requires some extra parts like the additional ST/RS air intake hose and snorkel.

The Focus MK3.5 RS air filter housing is only available as a complete assembly which consists of the bottom part, top part and the original paper air filter insert. Some sellers only offer the top part (and simply throw the bottom part away to reduce shipping costs).

Until last Year the complete RS air filter housing could be bought a lot cheaper from the USA than in Europe. Some official USA Ford dealers offered the complete RS air filter housing for under 50 Dollars while the European retail prices are just above €100,-. Currently the USA retail price is about 80 Dollar.

 

The UK Ebay seller is offering only a 3D printed custom mesh part. To install this custom part you need to cut the original RS mesh part from your own RS air filter housing.

So can it be installed on 1.0? Could the extra st/rs fit on 1.0?

[JW1982]

To install the complete RS air filter housing onto a 1.0 or 1.6 ECOboost (and probably also other engine types) you need the following parts:

RS air filter housing. Finis 1937555. Part number G1FY-9600-RB  €142,60
Tube. Finis 5167301. Part number CV61-9A675-AD  €22,32
Tube. Finis 5176123. Part number CV61-9C679-BC  €33,09
Tube. Finis 1745845. Part number BV61-9C679-CA  €11,53
Bracket. Finis 5160503. Part number CV61-9E635-AA  €8,85

From a performance point of view installing only the top part of the RS air filter housing is more than enough on a 1.0 or 1.6 ECOboost. The additional intake tubes do not improve performance or sound. Just installing the top part is enough to make the induction sound a bit louder. However do not expect miracles because most of the induction noise is dampened by the turbocharger anyway. 

These days the top part of the RS air filter housing can be bought from AliExpress for about €20,- to €30,- (versions without RS logo are also available). I have seen one of these in real life and to be honest it looks and feels the same as the original one.

[Bol]

Did you change the airbox lid on your car?  So just by installing the rs aibox lid (the top part) can be good for performance? because some claim that it will take heat from the engine. Also you say that the other parts like the twin tube will not increase sound or peroformance, right?

[Bol]

If the second pipe (the one whoch goes downside) from rs airbox is added together the whole rs airbox will it increase performance or make better sound, or should just the lid be changed? Do you have the rs lid on your car?

[Bol]

Did any error codes showed after you did this change?