Is there any milage removing the air flow restrictor im told is in the inner wing part of the air intake ? ive been told theres a block in there on std, and this inturn reduces the air flow into the engine acting as a restrictor? can i simply remove it, or will this have other affects on my engine and its set up,.
thanks

 

i removed mine ages ago but some say that there is a danger of maf failing due to more water spray from wheels but not had a problem and use standard filters as i only had problems with oil ones..anyway i think its better and sounds better too can just hear a small amount from ome dump valve and more turbo whistle which is just right for me...just block square hole up inside engine bay for more cooler air

 

No. Tried it once, datalogged the changes very carefully, quickly decided it's better on than off, with one caveat.

No, whoever told you that is talking from where the sun don't shine. It was slightly true on the early Imprezas as the induction path took a number of right angle turns and the resonator itself was a different shape. However, the one on your car is not restrictive at all. You can see for yourself if you take it out. It's an open U-shaped pipe with two different resonator chambers underneath, a low frequency and a high frequency one.

The logic of saying it's a restriction is undermined somewhat by the fact that the internal diameter of the resonator is considerably larger than the turbo inlet pipe that runs under the manifold and the turbo itself. So, by definition, if there's a "restriction" in the system, it's somewhere else.

As has already been said, removing it will make induction noise a little louder, and you can expose the air filter and airflow sensor to moisture. However, that doesn't consider the main purpose of the resonator, which is to take turbulence out of the inlet air and therefore make the mass airflow readings more accurate.

If you datalog your mass airflow sensor readings before and after removing the resonator you will see that the response is much smoother and consistent under boost with it than without it. Without it you can get a surprisingly spiky curve which will at one moment make the ECU overfuel, and the next make it underfuel. Even on a standard, fundamentally rich-running map that trait is undesirable. On a mapped car it's even moreso as it requires the mapper to build in more safety margin than might otherwise be the case.

Where there can be a little bit of an advantage on a late classic is in modifying the resonator, rather than removing it completely, so that it takes its inlet air from the wing rather than the engine bay, or even fitting something like the newage air intake venturi under the bonnet so a cold air feed is assured. Even that is marginal though. Where you're at at the moment, you'd be better off just leaving as is.

 

Splitpin - can removing this resonator cause turbo surge? And is it only effective with the airbox or does it also help an induction filter?

 

It shouldn't cause surge, no, and given that an induction kit doesn't draw air through the resonator, is unused and pretty much unusable in that application anyway.

 

Wow ! that told me I will leave it on, cheers for the advice mate