My 2002 WRX 2.0litre - Air filter kit - issue?
 

Hey guys

I have finally got round to working out what mpg my car gives me and during this run over 24 hrs.

I did a run of 99.2miles according to google maps I ended using £30 worth of fuel, at £1.3499 This means I got 22.222litres (4.6 gallons) of fuel used for the trip, thuis making a 20mpg run. Now 90% of the 99 miles was on the M6 !!!!!!!

I think that my air filter could be the cause of the poor fuel economy? What do you guys think? Any easy method to test my theory and would anyone know if/how/where to get the stock parts nice and cheaply? The filter was fitted to my car when I bought it.


Look at my filter at the moment.

https://img853.imageshack.us/img853/8008/imag0280e.jpg

https://img190.imageshack.us/img190/8624/imag0281r.jpg

https://img856.imageshack.us/img856/6338/imag0282.jpg

As the car has not been remapped for that filter I suspect it could be causing all kind off issues with your AFR and general running of the car.

Hopefully someone here can help you out with getting the stock assembly for you car so you can return it to stock. :)

If most of the mileage was on the M6, the map and filter shouldn't make too much difference as in theory, you'd have been cruising(?) and in closed loop fueling mode.

Therefore the AFR / O2 sensor would have been the primary control mechanism not the MAF.... assuming no untoward signs of an engine issue (excessive oil consumption etc), I'd be looking at the O2 sensor first.

Not sure what other mods you're running but assuming you're reasonably stock, I'd bin the induction kit anyway - the stock assembly is good up to and beyond 300bhp.

Everything else is totally stock.

^ I'd definitely put a stock airbox with a free flow (Green or K&N style) filter on instead of the induction kit in that case.

Any idea, where I can get one cheap.

ebay or the for sale section here.

Just keep an eye out on eBay or send a message to the breakers on there.

I'd get your car up on a rolling road as well BTW and get them to compare their wideband AFR to the values the ECU is reporting - should give an indication as to whether your O2 sensor is on the way out.