I have a Mazda 121 basically the same as a fiesta mk 4 I have a standard air filter in box the air inlet sensor is housed in the air filter box when I want to put a cone filter on but will have nowhere for the sensor to go with put causing turbelance any ideas ( tube from the engine inlet has a metal casing with a chip connected with the sensor to the air filter box) will try and get pics thanks in advance

On some cars K&N etc make kits with pipes/ hoses to refit the MAF sensor

In general the cone filter is a waste of time - it loses power because it draws warm air from under the bonnet (cooler air = more oxegen per cc = more power) and the most it achieves is more noise

Heat sheilds and cool air intakes do not work if the cone filter can draw any warm, underbonnet air

A lot of manufacturers now make encapsulated cone filters now (BMC, pipercross(viper)) to combat this problem

Fully encapsulated pipercross viper cone filter/ induction kit -

More info -

http://www.europerformance.co.uk/blog/pipercross-viper-induction-kits/

BMC cda (carbon dynamic airbox) -

http://www.bmcairfilters.com/carbon-dynamic-airbox/parts_prd_pr3_4_1.aspx

Even so often the stock airbox outperforms these - this is because the stock airbox is often "tuned" or "matched" to the engine to boost torque a little (the aftermarket "performance" filters are not)

You may be better fitting a panel filter from K&N or pipercross -

http://www.ebay.co.uk/itm/Ford-Fiesta-Mk4-5-1-25-16v-PP88-Performance-Replacement-Air-Filter-Kit-/350493215640?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item519b060b98#ht_2927wt_1141

http://www.ebay.co.uk/itm/Pipercross-PP1368-Fiesta-Mk4-95-99-1-25-16v-petrol-performance-panel-air-filter-/280891878995?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Model%3AFiesta%7CPlat_Gen%3AMK+IV&hash=item416675ee53#ht_976wt_932