52 plate WRX bugeye sportwagon. 64000miles, FSSH, unmodified and not driven by a loon.

Got a question I would like some advice on please...
If I were to fit a free flow air filter like K&N or one of the Green types (not a replacement panel filter, an air box replacement type), would I reasonably expect to have to carry out some other tuning work to allow the increased air flow to be managed safely by the engine, or will it 'learn' how to run ok without any other mods.

Very interested in a response to my (probably very stupid) question.
Better that I ask than pretend to know like a lot of people out there!
Please be gentle LOL.

 

I asked a similar question on this too, the general feeling was thet it will allow the engine to breath easier. One comment that made sense was "try cycling up a hill with a face mask on, then take it off and do it" you dont get there any faster but it didnt require as much effort. I would assume the MAF and ECU would control the change in airflow for you but I really am no expert on this.

Bigandy

 

Again, no expert but i have fitted cai's to many cars and i believe the maf and ecu will adjust the fueling to match the denser air flow.
What are you wanting to achieve by fitting the air cone??

Steve.

 

When I had my remap done after fitting an induction kit, the MAF had to be rescaled some 20% (from memory). I.e. my MAF was reading 20% out due to the kit, so I would definitely not bother without a remap!

Also, the standard air box on a new age is really good, so most likely, you wont see any performance benefits anyway. The reason I went for an induction kit was because of the FMIC piping which got in the way of the standard air box.

 

I still wouldn't get up the hill, facemask or not! lol

 

Not sure what you mean, replacing the stock element in the standard airbox IS a replacement panel filter, I assume you mean not an induction kit?

If what you do replaces the MAF tube, you will need remapping, a replacement panel filter in the airbox does not, a CAI shouldn't, some shorties (filetr in the engine bay on the MAF tube) do as they upset the airflow into the MAF giving a change in reading.

Simon

 

I think for starters it would depend on the induction kit. If the pipe diameter where the MAF is located is larger than the stock diameter, then you are going to need a remap to rescale your MAF, otherwise it will read incorrect airflow and risks running lean.
If the diameter of the MAF housing is the same as stock, then you may be alright without a remap (but I would say this is very much dependent on how well designed the induction kit is ... the more straight pipe before the MAF, the more consistent the airflow through the MAF and the better the chance that the ECU can deal with any fueling changes correctly).
Saying that though, you will never maximise the gains for any modification unless you map for it.

 

Like someone has already said the standard airbox is a pretty good design, i would just put a k&n panel filter in. Induction kits are only really any good if you have a big power engine or FMIC.

 

Thanks for the info everyone.
A stock motor = keep the perfectly adequate air box arrangement

I'll spend the money on some new gearbox & diff oil, which is due a change this weekend! Castrol Syntrax/Driveline here I come.

ON THAT NOTE - does anyone know if there are washers to replace on the diff oil drain/filler bolts that come out?

 

i had a 1994 wrx turbo a while back. i found after putting a hks mushroom air filter on, the dump valve sounded much louder and i could hear wastegate chatter through my air filter.

sounded awesome. then i had a fmic fitted and it sounded double awesome.

not everything is done to enhance performance, some things are done to enhance the driving experience

 

For sure i agree with several of the opinions above, i have a HKS hi flo on my wagon but im going back to box and panel filter asap. It does sound good, although i think definitely burns more fuel due to the standard map & MAF sensor and unless u are running at least 350bhp+ and FMIC is really not necessary.