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Removing Hemlholtz resonator - capping of the hole in airbox
I am running the IPD Competition plenum and 82mm throttle body.
The IPD-kit comes with a silicon hose to fit the bigger TB. This hose by-passes the Helmholtz resonator. There is a flexible silicone cap to close the open hole of resonator box. Just to prevent dirt to enter, as the box itself is closed off from the airbox itself.
The nicest solution would be to remove the resonator chamber complety from the inside of the air-filter box. as it will free up some space above the filter for air to flow. However then I will need something else to close the hole in the airbox as in the current situation the neck of the resonator sticks through the hole, the IPD cap is fitted on this neck. When removing the box there will be no support to mount something on.
I have seen the so called 'orange cap' suggested. But this cap is unavailable. Any other DIY alternatives that will work?
Fabspeed has a cap that comes with their intake hose kit. http://www.fabspeed.com/996-carrera-...r-upgrade-kit/
It will fit from inside into the hole and screws into the existing holes where the renoator is fixed.
I removed the complete resonator, then Dremel-tooled the top of the old resonator to mimic the Fabspeed neck and bonded the neck to top of airbox cover. Hasn't budged after thousands of miles.
The resonator cancels certain frequencies in the lower rpm ranges. Capping the top cancels the effect and allows a more distinct engine "voice" and a little more growl. I removed the resonator, entirely, since I didn't see a need for the obstruction to airflow after the filter and before the butterfly valve. Isn't more airflow the primary purpose for the mod kit in the first place?
The resonator cancels certain frequencies in the lower rpm ranges. Capping the top cancels the effect and allows a more distinct engine "voice" and a little more growl. I removed the resonator, entirely, since I didn't see a need for the obstruction to airflow after the filter and before the butterfly valve. Isn't more airflow the primary purpose for the mod kit in the first place?
Question which might be solved by this... I did the muffler delete, it was a bit too droney, so I installed the CC inserts. It eliminated the drone, but when the car is decelerating in gear it gets this raspy sound(almost ricer like). Would this resonator removal get rid of this sound ?
Question which might be solved by this... I did the muffler delete, it was a bit too droney, so I installed the CC inserts. It eliminated the drone, but when the car is decelerating in gear it gets this raspy sound(almost ricer like). Would this resonator removal get rid of this sound ?
No. Induction noise and exhaust noise are to different animals.
Astro,
Are you referring to exhaust overrun burble noise? So you gutted the muffler or removed it? CC inserts? Any of these exhaust flow variables change flow rates, hence engine frequencies and noises. Exhaust noises are what you’re talking here. Resonator is intake side.
Question which might be solved by this... I did the muffler delete, it was a bit too droney, so I installed the CC inserts. It eliminated the drone, but when the car is decelerating in gear it gets this raspy sound(almost ricer like). Would this resonator removal get rid of this sound ?
My car has a WRX-like rasp when decelerating as well, and it’s quite loud. It got loud after I did the Fister hack. It’s loudest when the ECU cuts fuel during decel, and when cold. I don’t really care for that sound, but it’s not a big deal. I figure I could always replace the mufflers at some point.
"Are you referring to exhaust overrun burble noise? So you gutted the muffler or removed it? CC inserts? Any of these exhaust flow variables change flow rates, hence engine frequencies and noises. Exhaust noises are what you’re talking here. Resonator is intake side."
Yes, I removed the mufflers and just have the bypass pipes. Due to drone I installed Car Chemistry inserts which got rid of the drone, but must have changed the exhaust flow rates a little and I'm getting some of the sounds as described in the this other response.
"My car has a WRX-like rasp when decelerating as well, and it’s quite loud. It got loud after I did the Fister hack. It’s loudest when the ECU cuts fuel during decel, and when cold. I don’t really care for that sound, but it’s not a big deal. I figure I could always replace the mufflers at some point."
So when I started looking for threads which might address this issue I came upon the resonator one...
If your car is running rich, or if you're running sport cats or catless, the backfiring will be much more pronounced. My C4 with sport cats and Tubi mufflers made fantastic noises between gears.
"Are you referring to exhaust overrun burble noise? So you gutted the muffler or removed it? CC inserts? Any of these exhaust flow variables change flow rates, hence engine frequencies and noises. Exhaust noises are what you’re talking here. Resonator is intake side."
Yes, I removed the mufflers and just have the bypass pipes. Due to drone I installed Car Chemistry inserts which got rid of the drone, but must have changed the exhaust flow rates a little and I'm getting some of the sounds as described in the this other response.
"My car has a WRX-like rasp when decelerating as well, and it’s quite loud. It got loud after I did the Fister hack. It’s loudest when the ECU cuts fuel during decel, and when cold. I don’t really care for that sound, but it’s not a big deal. I figure I could always replace the mufflers at some point."
So when I started looking for threads which might address this issue I came upon the resonator one...
If you still have the old mufflers, see if putting them back solves the issue.
11-13-2017, 08:03 AM
Removing Hemlholtz resonator - capping of the hole in airbox
