Here’s a silly little modification to the intake system you may enjoy. A total freebie that actually impressed me with the difference it made.
This great hunk of plastic is affectionately known as the ‘snorkus’ among the WRX community. It’s the intake resonator chamber located within the inner-wing area of the GD chassis Impreza’s (and possibly others).
I believe its technical nomenclature is a Helmhotz Resonator, and it’s primarily used to control (or quieten) the intake noise. It’s also supposed to limit turbulence in air flow for better engine intake…smoothness… – or something.
Some argue that this intake chamber (henceforth referred to as the ‘snorkus’) aids the performance of the intake system, and in turn gives a performance boost to the engine. Even so far as increasing BHP and MPG. Hell, the Subaru engineers wouldn’t have created it for no good reason would they?
Search the web and you’ll find countless forum posts explaining the technicalities and arguments for and against keeping the resonator in place in terms of performance.
I’m not smart enough to argue either way but one thing I know for a tried-and-tested fact is removing it gives one hell of an improvement of intake noise. You can hear the intake whine and the turbo spool very nicely! Just the kind of sounds I like.
But just removing the snorkus seemed a little boring, I wanted a bit of a project to make the intake louder in an “OEM-plus” kind of way. I also wanted to make sure there was zero chance of any easy water or dirt ingress pre-filter with the removal of the snorkus.
So I set about transforming the snorkus into a simple elbow bend connecting the front ram air intake and the airbox itself. To do this I needed a saw, a heat gun and a Saturday afternoon.
First things first, removing the snorkus. Actually a fairly easy, if fiddly, job. The snorkus itself lives in the offside inner-wing area, is pushed onto the ends of the ram air intake and airbox, and is held on to the chassis with a couple of bolts.
I’d read a number of forum posts saying it’s best to attempt removing the snorkus by taking off the front wheel but I managed to do the whole removal process with the wheel on full opposite lock. It was a bit of tough squeeze after peeling back the plastic wheel liner, but we made it out eventually.
Now we chop off the entire lower section of the snorkus so we’re left with a 3-holed bit of pipe. Our aim then is to seal off the lower hole so we’re left with a simple elbow through pipe.
I tackled this job with my heatgun, and plenty of fresh air. You don’t wanna be breathing these fumes for long. A number of passes with the heat makes the plastic malleable enough to bend inwards, eventually closing the hole (after a few attempts).
It’s certainly not pretty, but it works!
However I knew that having a sealed elbow pipe wouldn’t have much benefit in terms of intake loudness over just having the entire resonator in place as it was before. I quickly refitted the pipe at this stage and although the noise was slightly louder, we can improve it more. So out comes the power drill.
I suddenly had flashbacks to being a 17-year-old kid again, drilling the airbox of my 1.0 Vauxhall Corsa! I’m sure a few of you can relate to such antics…
And we’re eventually left with this. I’ll say it again – it’s certainly not pretty! But remember, it’s going to live in the inner-wing area where nobody is ever going to see it again. And I’m quite happy with that.
*There are more drilled holes on the other side too, but I can’t find the picture I took of those…
Fitment is obviously the opposite of removal, albeit much easier now due to the reduced mass of plastic we’re dealing with. Modifying an original part like this also has the benefit of allowing you to fit it back exactly how it was before.
Looking under the bonnet you’re none the wiser that the modification has ever taken place.
Now for the final test drive. With the modified elbow in place it’s not quite as loud as it was with the snorkus entirely removed, however with the new holes drilled it’s certainly 100% better than it was. I can also rest assured that the airbox intake itself isn’t exposed to the elements via the inner-wing.
There we have it. A “technically” free way to instantly improve the sound of your WRX & STi!