Ok, so the first thing I do is remove that factory scoop thing. If I leave the hole that removing that creates open, will it hurt anything? im not gonna like blow anything up am I? Or water wont get into places its not supposed to when it rains or any crazy things like that. Also the plug cover for that hole. pn46059FA000 That will work on the 04 wrx's too right? Thanks

 

The hole is fine; the only thing is that the engine bay will probably get dirty fast. The fender plug should fit an 04 fine if you're concerned about the filth.

 

definitely concerned about the filth, so I will have to pick up that fender plug.

 

so if I put the scoop back when im done, I wont have to plug that hole will i?

 

Correct. As well as the added bonus of supplying fresh, cool air to the fender well at speed. Not that there isn't enough under normal conditions...just saying...

 

That fender well ges REALLY dirty, plug or not plug, it'll greatly shorten the life of your filter (or filter oil). You are better off taking ot the silencer, cutting off the tear-drop-ish portion and sealing the hole so that you are just left with a bend, then installing as usual, including the ram. If you do not want to hack it up I've seen some places around the 'net or Ebay that sell just the bend/elbow, but they are pricier than the item is worth.

jason

 

Honestly, in over a year and 25,000 miles, I haven't really noticed a huge increase in dirt on the filter, though I will agree that it is a dirtier place to collect intake air. My setup now has the large box hacked off, connected at the scoop, but not actually inserted into the airbox. I cut off the portion that connects to the airbox so it sits about 1/4" away from the hole in the box, both for "increased" airflow and the sound .

Hold the "it's a sound only mod" rants for just a second: I ran for a long while with no elbow at all, and loved what seemed to me to be quicker spool-up (at least according to the factory boost gauge). I re-installed the hacked elbow portion in an attempt to help pull outside air rather than engine compartment air, and the car felt a little less snappy with the boost. I noticed that the elbow fits inside the hole in the airbox, and has a wall thickness of about 3/16", which translates to a 3/8" decrease in intake diameter at that point. Now I know that Vishnu and others have proven "by the numbers" that this mod doesn't make any extra HP, and I'll agree with that. However my own anecdotal evidence seems to show some performance benefit, albeit small.

 

The MAF sensor is VERRY picky about it's position and the amount of airflow. A larger intake tract will cause the sensor to detect too much airflow (because there is) or a slight misalignment of the MAF can cause similar problems. The stock airbox has been proven effective on 300+ HP cars, so it's not generally thought of as a restriction.

 

Spot on w/ the MAF comment.

As for the dirt, my basic FRAM looked like crap after not too long, but then I drive hard in the CIty all the time. *shrug*

Removing the silencer won't make you spool up quicker. The turbo is run by the turbine, not the compressor. What makes you spool faster is openning up the exhaust, i.e. a catless uppipe and dp will do this for you. The way to get more air into the turbo by modifying the intake is increasing the size of your compressor inlet (read, "smaller A/R" ). A CAI probably becomes helpful for applications over 300whp... so basically the infinitessimal effect of removing a silencer never makes a difference.

Its more like this: there is NO GOOD REASON for silencers. Its just another bump in the intake path. Common sense says, "Remove it".

jason