Resonators instead of secondary cats? Noise cancelling?

fatjoez · 05-07-2010, 07:45 AM

Heya

I've got a 135i, all standard except,
the wide resonator/muffler & secondary cats have both been replaced with straight pipe

Considering noise cancellation options at the moment,
a muffler shop suggested adding in 2 Resonators in place of the secondary cats for $180USD,
much cheaper than a new midpipe..

But how much noise cancelling would this provide?

My135 · 05-07-2010, 03:22 PM

Adding the secondary cat back to the mid-pipes makes no sense since it will reduce your power gain although it will quiet the sound more than adding the resonator. Adding the resonator will tone down the sound a bit (not a whole lot) but it won't reduce any power gain. Just my 2 cents.

fatjoez · 05-07-2010, 04:30 PM

I see, and not sure if you're familiar, but towards the rear end of the midpipe, after the 2 pipes have joined & just before the next part bolts on, there's a large resonator (also removed)

What would you reckon about

- adding resonators back in place of the secondary cats
- adding back another large resonator in place of the old one if the smaller resonators dont provide enough cancelling

btw: powers not realllyyy my concern its a daily driver and has plenty power, I actually was under the impression that secondary cats wouldn't provide as much noise cancelling?

My other question regarding secondary cats, the muffler shop I went to said they could put cats back in but they'd be aftermarket ones not like originals.

What are your thoughts on this? I'm not too knowledgable about how they work, so would there be any compatibility issues??

vitig · 05-08-2010, 12:30 PM

I have only replaced secondary cats and the noise is a few more than standard.Whit ressonator replaced(i have it before replace cats) the noise is more in middle rpm.Now the car have more sound but similar than original.

fatjoez · 05-08-2010, 07:19 PM

I see, so most likely if I can get the resonator back in the midpipe, the missing secondary cat won't be as noticeable...

View Poll Results: Recommended option?
leave as is	1	9.09%
add resonators	10	90.91%
add secondary cats	0	0%
Voters: 11. You may not vote on this poll

05-07-2010, 07:45 AM	#1
fatjoez student 226 Rep 911 Posts Drives: e90 Join Date: Sep 2009 Location: Bermuda Triangle iTrader: (0)	Resonators instead of secondary cats? Noise cancelling? Heya I've got a 135i, all standard except, the wide resonator/muffler & secondary cats have both been replaced with straight pipe Considering noise cancellation options at the moment, a muffler shop suggested adding in 2 Resonators in place of the secondary cats for $180USD, much cheaper than a new midpipe.. But how much noise cancelling would this provide?
	Appreciate 0 Tweet Quote

05-07-2010, 03:22 PM	#2
My135 Lieutenant Colonel 85 Rep 1,609 Posts Drives: Join Date: Mar 2008 iTrader: (0)	Adding the secondary cat back to the mid-pipes makes no sense since it will reduce your power gain although it will quiet the sound more than adding the resonator. Adding the resonator will tone down the sound a bit (not a whole lot) but it won't reduce any power gain. Just my 2 cents. __________________ 7/08 135 Coupe, Crimson Red, 6 SP, Sport, Taupe Lette/Aluminum. Performance Mods: JB4 on Map 5, BMS DP Fix V3, Injen polished intake, AR Catless DP, Maddad resonated mid-pipes, aFe exhaust polished tips, ST Suspension Coil Over and Hotchkis front sway bar. Others: BMS OCC, BT Scanner, Mud Flap. Next Mods: AA Front Strut Brace.
	Appreciate 0 Quote

05-07-2010, 04:30 PM	#3
fatjoez student 226 Rep 911 Posts Drives: e90 Join Date: Sep 2009 Location: Bermuda Triangle iTrader: (0)	I see, and not sure if you're familiar, but towards the rear end of the midpipe, after the 2 pipes have joined & just before the next part bolts on, there's a large resonator (also removed) What would you reckon about - adding resonators back in place of the secondary cats - adding back another large resonator in place of the old one if the smaller resonators dont provide enough cancelling btw: powers not realllyyy my concern its a daily driver and has plenty power, I actually was under the impression that secondary cats wouldn't provide as much noise cancelling? My other question regarding secondary cats, the muffler shop I went to said they could put cats back in but they'd be aftermarket ones not like originals. What are your thoughts on this? I'm not too knowledgable about how they work, so would there be any compatibility issues??
	Appreciate 0 Quote

05-08-2010, 12:30 PM	#4
vitig Private First Class 4 Rep 189 Posts Drives: 135i Join Date: Jun 2009 Location: España iTrader: (0)	I have only replaced secondary cats and the noise is a few more than standard.Whit ressonator replaced(i have it before replace cats) the noise is more in middle rpm.Now the car have more sound but similar than original. __________________ 135ijb3, h & r filter, SSK, CDV,clutch stop, klracing fmic,seccond catted ,225-255 michelin ps3, E93F-E92R swaybars.M3 parts front.M3 tension rear.Plates mod(F-2,0º R-1,5º).Bilstein + stock springs.Ps rotors.Subframe bushings.Weichers fstruut.Finally mods sdiff and raceland dp.
	Appreciate 0 Quote

05-08-2010, 07:19 PM	#5
fatjoez student 226 Rep 911 Posts Drives: e90 Join Date: Sep 2009 Location: Bermuda Triangle iTrader: (0)	I see, so most likely if I can get the resonator back in the midpipe, the missing secondary cat won't be as noticeable...
	Appreciate 0 Quote