wrx sti ppp

I want to get rid of the resonator baffle in the inner wing on my 05 STi...simply for a little more induction noise/weight saving.

all i plan to do is saw off the baffle and seal the opening with duct tape...something i have heard other folk doing without spending a £200 on a Prova item!

so the question is this...by removing this part of the resonator will it cause any damage to the MAF/engine due to increased airflow or cause it to overboost or anything like that due to unpredictable air speed/volume?

i want to do this tomorrow but dont want to screw the car up...obviously. any advice from those that have done this or those that know about such consequences gratefully received.

Splitpin

At rough estimate you're going to get rid of about four ounces of plastic. You'll save more by having a good pee before going for a drive.

The answer to that specific question is no, because there won't be any increased airflow. However that doesn't mean there isn't the potential for problems.

Both Harvey and I have tested this. It doesn't materially affect boost control but we both independently found that it causes a small power loss (Harvey quantified it as 6bhp, I didn't actually put a number on it but would suspect mine was similar).

From the data I got, the output of the MAF sensor becomes noticeably "spiky", presumably because the resonator plays a role in removing turbulence from the inlet air, and without it, the air travelling through the measurement tube is significantly "rougher" and hence difficult to measure consistently. Think of the difference between a smooth flowing river and white water.

The ECU contains an error correction mechanism designed to smooth out/correct "normal" measurement fluctuations, but the spikes I was seeing were getting through that and causing noticeable variation in load calculation (and hence mixture/ignition timing), and as a result, the ECUs ability to control the engine becomes less precise.

The bottom line is that I found the airflow measurement tracks more consistently and accurately (and I can map the car more exactingly) with the resonator fitted than without it.

It's your car but the best advice I can give you would be to leave as-is. Your mileage may vary, but, for the reasons above, I would suggest that your engine will probably perform more consistently, and ultimately better, with the resonator in situ.

Butty

iTrader: (2)

Splitpin,
Did the trial work look at any pressure drop across the resonator(+ bonnet edge intake)?

wrx sti ppp

Thanks Splitpin...i am quite happy to take your advice as definitive. i was always led to believe that the baffle/resonator was simply to allow Subaru to pass drive by noise regulations...but reading your response it would appear that it has a role to play in smoothing the airflow pass the maf. kinda makes sense i guess. removing it would take out that consistency. i think i will leave well alone...thanks for your advice, much appreciated.