Was bored today so decided to pull the airbox out and look at how it could be modified.
My main aim was to improve the sound/ airflow by drilling the airbox whilst minimising the amount of hot air coming into the box.

I ended up drilling a few holes at the front of the air box and lots below and on the wheel arch side. This gives it a sound far more akin to a cone filter whilst preventing heat soak. 

Below are a few pic's of what I did.

Inside box


Front of box


Arch side of box


Box with duct fitted


Plan to rig up a second air feed into the box also as the standard feed is pretty naff by the looks of things.
First impressions are good. You can now hear the dumpvalve going off alot louder and you get a bit more of sucking/ fluttering sounds also.

Turned my TMC up to 8 and it all feels mighty rapid

This kinda mod has been around for ages and is a great DIY way of improving airflow into the factory airbox, good thinkin about running a secondary airfeed into the box.

DIY Hero lol

Yup that's the same intake on the evo. Can't see it getting much air there. Want to run a second one up from lower down and cut the current piping so my new feed will feed into the factory one

As FWD says it's an age old trick. Did it to my TT a few years back and got good results. Definately the povo way into IK territory

any one know if the bmc ota induction kit with pop off valve fits the evo?

external needed.

Quote from: Missing in Action on May 01, 2011, 12:05:03 PM

surely though thats just sucking hot air in from the engine bay therefore its pointless?

Yup, I did this on my Ibiza Cupra before I got a proper kit. Sounds nuts, but not doing to be giving any increases at all I wouldn't of thought...

As Ben says, it's more for the sound than anything else although if you look where the holes are placed it's going to be getting more cold air as there will be more air zipping though the grill than what the og airfeed is sucking in. I didn't drill any holes engine side so it's going to be more effective than your regular cone filter setup, espeshily when I have the secondry feed in place. Heat soak will be minimal as the box still surrounds a good 95% + of the filter.

id rather have hot air than the no air that gets in a standard. the forge kit tbh gets a he;; of alot of hot air in and still felt better than standard box. will agree a external vent is the best way but so bloody ugly.

Plan to rig up some ducting behind the lower left airvent, not sure if it's a dummy vent as standard though. Will get under the car tomorrow and see what can be squeezed in.