Magnaflow exhaust drone, considering welding stock resonators back on...

[01northernS4]

I know my magnaflow is a 2.5" system straight through and the resonators are stock diameter but since my piggies are also stock diameter been thinking the stock resonators will not affect performance that much... the drone is actually getting worse and I hope the stock resonators are tuned to perhaps kill the dreaded 1500 to 2000rpm drone... I have a tip so staying out of that range is not easy unless I start playing with the paddles all the time.

Has anyone done this?

Again, I can't see it really affecting the performance since the piggies are still stock diameter and the bottle neck exists already.

Fingers crossed...

[01northernS4]

Also, would it matter if I welded them on before or after the x-pipe?

Thanks again

[dparm]

The stock resonators are tuned to work with the stock mufflers and stock tubing. You have neither of those things. They're also not 2.5".

Best bet is to go to an exhaust shop and have them install the largest resonators possible. Magnaflow sells resonators in a variety of lengths from 8" all the way to 22".

[01northernS4]

The stock resonators are tuned to work with the stock mufflers and stock tubing. You have neither of those things. They're also not 2.5".

Best bet is to go to an exhaust shop and have them install the largest resonators possible. Magnaflow sells resonators in a variety of lengths from 8" all the way to 22".

agreed with what you say and is what I was going to do.

but in speaking with some locals that have welded in resonators and had no reduction in drone I felt that my only options were to go back to stock or try something different.

I was hoping the stock resonators might be tuned, ala corsa or apr style center resonators, to eliminate drone. And since the piggies are already stock diameter, welding the stock resonators in would be matching that bottleneck so I shouldn't see a hit on performance.

I know my tubing diameter and mufflers are different but I think it may be worth a shot... and much cheaper than buying resonators that I'm told/heard won't affect this particular setup drone wise... think it might work dparm?

also, if anyone has changed out ONLY their mufflers to magnaflow (stock resonators intact), are you experiencing drone? This would be the closest setup to what I am proposing otherwise.

Thanks

[dparm]

Resonators ARE tuned, that's what they are. The resonators are tuned to the resonances generated by your stock system. Aftermarket exhaust is a different pipe diameter, different bends, different wall thickness, etc. It's an exhaust system -- everything has to work together.

Your piggies are making the car very loud too.

Don't take this personally, but why do people buy aftermarket exhausts and then complain when it's louder than stock? Isn't that the point...that it's louder? I guess you need to ask yourself why you bought the exhaust in the first place.

[01northernS4]

Resonators ARE tuned, that's what they are. The resonators are tuned to the resonances generated by your stock system. Aftermarket exhaust is a different pipe diameter, different bends, different wall thickness, etc. It's an exhaust system -- everything has to work together.

Your piggies are making the car very loud too.

Don't take this personally, but why do people buy aftermarket exhausts and then complain when it's louder than stock? Isn't that the point...that it's louder? I guess you need to ask yourself why you bought the exhaust in the first place.

I have no problem with how loud it is... I just don't like the drone. Sounds very cheap... and incredibly the drone keeps increasing! Otherwise the exhaust is doing exactly what I wanted. More performance, better look, great price and sound...except for that dreaded 1500 to 2000rpm range... and I know exhausts exist that do not have this (corsa, apr, supersprint). Without drone the magnaflow would be perfect.

Anyways, I thought there might be a chance the stock resonators were tuned to a certain frequency irrespective of pipe tubing and mufflers but I guess I might be wrong in this respect... saw supersprint offers a mid muffler/x-pipe/resonator (PART NUMBER 766903) that promises to eliminate drone that they sell separately so figured welding in the stock resonators might be an option.

So again, if anyone has only swapped out their stock mufflers for magnaflow cans and left everything else intact (stock resonators), please chime in on if you have any drone I describe above.

[dparm]

I'm not saying the stock resonators will do nothing, but you can get some very weird and unwanted sounds by piecemealing an exhaust together. A properly-tuned exhaust should not drone. Does Magnaflow sell a resonated version of that exhaust?

If you go on Youtube, there are folks who swapped the Magnaflow 14851s onto the stock exhaust tubing.

[01northernS4]

True, never thought of that... maybe I'll try out the stocker resonators and if not good/doesn't help move onto magnaflow resonators and finally just throw on the stock exhaust if I cannot kill the drone... to bad, otherwise system is great.

Thanks dparm!

[hungryhippo]

I thought the magnaflow catback replaced everything after the cats and included resonators. Mine did. My car droned with mycatless downpipes, but it sounded great. It's much quieter with piggies now.

[01northernS4]

I thought the magnaflow catback replaced everything after the cats and included resonators. Mine did. My car droned with mycatless downpipes, but it sounded great. It's much quieter with piggies now.

It does but for the b7 s4 the b7 rs4 magnaflow must be used and it doesn't include resonators... the b6s4 magnaflow exhaust did include resonators

[dparm]

Interesting design decision. Not sure why they left those off. Sounds like a mistake on their part.

I would look at the B6 version and see what they did for resonators -- you could probably get them welded in, but the bigger the better.

[Denker]

Interesting design decision. Not sure why they left those off. Sounds like a mistake on their part.

I would look at the B6 version and see what they did for resonators -- you could probably get them welded in, but the bigger the better.

I'm guessing the RS4's headers come into play in the decision vs the S4?

[dparm]

I'm guessing the RS4's headers come into play in the decision vs the S4?

Yes, but it's also a different motor that makes different noises.

[Denker]

Yes, but it's also a different motor that makes different noises.

If the OP would just upgrade to the JHM longtube headers all should be good right? $$

I dunno, I've read so much misinformation and opinion that it all starts to blend so I was thinking the RS4's equal length headers and therefore "tuned" exhaust pulses might negate the need for the resonators found on Magnaflows B6 S4 system.

[01northernS4]

Interesting design decision. Not sure why they left those off. Sounds like a mistake on their part.

I would look at the B6 version and see what they did for resonators -- you could probably get them welded in, but the bigger the better.

Good point, I'll look into this

[01northernS4]

If the OP would just upgrade to the JHM longtube headers all should be good right? $$

I dunno, I've read so much misinformation and opinion that it all starts to blend so I was thinking the RS4's equal length headers and therefore "tuned" exhaust pulses might negate the need for the resonators found on Magnaflows B6 S4 system.

Also good point... sounds plausible for sure...

[Das Audi]

I was wondering how you made out after installing the RS4 Magnaflow system on your Avant like Bruno's. Speaking of Bruno's car did he resolve his droning issue? Maybe you can do the same thing he did if that is the case. I was thinking of getting the RS4 Magnaflow system through Bruno but wanted to hear how the droning went with you guys first. Please keep us posted on the resolution.......Thanks

[event]

J-pipe / helmholtz resonator.

[mistral cytz]

I'm running the B6 S4 magnaflow on my B7 S4 and it's pretty ideal sounding with piggie pipes which I recently had done. The sound is deep but too quiet with stock downpipes and cats, but as soon as I removed the pre cats it sounded much nicer and just loud enough inside the vehicle and probably much louder sounding to those outside as I drive by.

My only complaint with the B6 S4 magnaflow is the dual single tips rather than the dual split tips on the RS4 which obviously looks more stock and better IMO.

[mistral cytz]

I'm not running an Avant either. I've heard you guys with Avants get noticeably more volume out of the exhausts with less insulation and more windows or something ??

[Denker]

I'm not running an Avant either. I've heard you guys with Avants get noticeably more volume out of the exhausts with less insulation and more windows or something ??

I've always thought it was because Avant owners are typically more sensitive people in general.



Joking of course as I want one; just saw the opportunity for a ribbing.

[Das Audi]

I've always thought it was because Avant owners are typically more sensitive people in general.



Joking of course as I want one; just saw the opportunity for a ribbing.

And here I always thought it was the Cab owners that were a little sensitive......

Also kidding of course.......

[Denker]

And here I always thought it was the Cab owners that were a little sensitive......

Also kidding of course.......

Best one I've heard is that I drive a "lady-bathtub." Hilarious.

[01northernS4]

I'm running the B6 S4 magnaflow on my B7 S4 and it's pretty ideal sounding with piggie pipes which I recently had done. The sound is deep but too quiet with stock downpipes and cats, but as soon as I removed the pre cats it sounded much nicer and just loud enough inside the vehicle and probably much louder sounding to those outside as I drive by.

My only complaint with the B6 S4 magnaflow is the dual single tips rather than the dual split tips on the RS4 which obviously looks more stock and better IMO.

Is it noticeably louder/boomier/dronier in the 1500rpm to 2100rpm range to the point where it rattles your interior trim? lol

Avants are more prone to drone but that aside, resonators at dparm said, should resolve much of this.

[01northernS4]

I was wondering how you made out after installing the RS4 Magnaflow system on your Avant like Bruno's. Speaking of Bruno's car did he resolve his droning issue? Maybe you can do the same thing he did if that is the case. I was thinking of getting the RS4 Magnaflow system through Bruno but wanted to hear how the droning went with you guys first. Please keep us posted on the resolution.......Thanks

Bruno is happy but is also tone deaf, lol... kidding of course.

Mine is worse being tip for sure... otherwise almost the same. We also have different downpipes... he is running miltechs and I piggies

[hungryhippo]

resonators or bullet mufflers will help. you want the biggest diameter that will fit. i added 4" resonators on my corvette and it reduced drone and I no longer get black flagged for noise at the track. summit racing has a great selection.

[01northernS4]

resonators or bullet mufflers will help. you want the biggest diameter that will fit. i added 4" resonators on my corvette and it reduced drone and I no longer get black flagged for noise at the track. summit racing has a great selection.

Agreed... but I think the stock resonators might go a step further in that they may tune for the engine and downpipes as Denker alluded to above... resonators that you are talking about will muffle or suppress where as the stockers may eliminate? Not sure as they look like they have more going on than simple tubes and are triangular in shape...

[mistral cytz]

Is it noticeably louder/boomier/dronier in the 1500rpm to 2100rpm range to the point where it rattles your interior trim? lol

Avants are more prone to drone but that aside, resonators at dparm said, should resolve much of this.

No trim rattle that I notice at all but my last car was a Mitsubishi Lancer Evolution which rattled and buzzed running at idle so it could just be my perception owning my first German car.

At first I was annoyed that I bought the S4 B6 magnaflow over the RS4, but now I'm liking it a lot since I did piggy pipes.
I've driven Bruno's avant and it was amazing! I noticed a big different in sound frequency and volume since he has downpipes with HFCs, the RS4 magnaflow and the fact that its an Avant etc..

[Quadfreak]

Best one I've heard is that I drive a "lady-bathtub." Hilarious.

This....this is great. I got a buddy who drives a convertable M3 and refuses to put the top down with another dude in the car. Im gonna tell him this ha.

Anyways...I wouldnt put the stock resonators back on..going small to big to small and back to big again is not good for exhaust flow. I mean think of how bad traffic gets when they eliminate a lane on the freeway for a couple miles..That will be your exhaust.

On my B5 I had a custom exhaust and I threw a cheap glass pack where the resonator was..kept good flow and eliminated all drone...maybe something to look into..or call up Magnaflow and ask what resonators they reccomend for the system. You could also put it back to stock, sell this exhaust and then buy a tuned system with resonators or build a custom exhaust...lots of options here you just need to get creative

[01northernS4]

This....this is great. I got a buddy who drives a convertable M3 and refuses to put the top down with another dude in the car. Im gonna tell him this ha.

Anyways...I wouldnt put the stock resonators back on..going small to big to small and back to big again is not good for exhaust flow. I mean think of how bad traffic gets when they eliminate a lane on the freeway for a couple miles..That will be your exhaust.

On my B5 I had a custom exhaust and I threw a cheap glass pack where the resonator was..kept good flow and eliminated all drone...maybe something to look into..or call up Magnaflow and ask what resonators they reccomend for the system. You could also put it back to stock, sell this exhaust and then buy a tuned system with resonators or build a custom exhaust...lots of options here you just need to get creative

Great points... but I would weld the stock resonators to the stock (piggied) downpipes therefore from the manifold to the resonators would all be stock tubing diameter and then 2.5" straight back to mufflers so no small, big, small, big... maybe that would be okay?

Otherwise your other options all sound good and worth a shot.

Thanks Quadfreak.

[Quadfreak]

Great points... but I would weld the stock resonators to the stock (piggied) downpipes therefore from the manifold to the resonators would all be stock tubing diameter and then 2.5" straight back to mufflers so no small, big, small, big... maybe that would be okay?

Otherwise your other options all sound good and worth a shot.

Thanks Quadfreak.

Oh I see..hmm..ive never heard of or seen it done that way and it may or may not work.

Now this is just from my understanding (so dont flame me too bad if im wrong). but the resonators are designed to be mid way through the exhaust, because if you think about it this way: it gets quieted down from the cats...bounces around and starts getting loud through straight tubing, hits the resonator and disrupts the sound (drone), gets loud through tubing again then gets disrupted again as it comes out of the muffler. By putting the resonator after the cats, it might quiet it down some but idk how much of the drone it would eliminate.

Again, this is just my thought process on it. Someone correct me if im wrong (im trying to learn just like everyone else).

[dparm]

Resonator placement is controlled by two things: space under the car, and the correct location to tune out those frequencies (there's math involved). You probably won't have much choice on where they go.

[mistral cytz]

Just wondering if the OP ended up putting the stock resonators back in? I have the B6 magnaflow on my B7 and feel like the sound is right but the volume isn't enough. I have piggie pipes combined with the magnaflow. My magnaflow has 14" resonators I believe so would going to smaller resonators make a difference in volume? I'm not sure I want to remove the resonators completely in case of drone.

Anyone know if smaller, say 8" resonators would make a difference?

Thanks

[dparm]

Smaller resonators will make it louder, yes.

[mistral cytz]

Smaller resonators will make it louder, yes.

Thanks! And are most resonators the same? I'm just wondering if I get my 14"s replaced with 8"s whether the size difference will only change the volume and not so much effect how raspy and deep the exhaust sounds. I'm hoping the mufflers staying the same will keep the tone and sound while replacing smaller resonators will only bring up the volume since I currently like the sound, just need more of it.

Thanks

[QIKRNU]

I recently installed JHM headers, and my drone was considerably diminished, due, I believe, to the elimination of that empty can when they were made into piggies. You might try pulling your piggies and have a straight piece of pipe welded in to replace that empty can.

[01northernS4]

I recently installed JHM headers, and my drone was considerably diminished, due, I believe, to the elimination of that empty can when they were made into piggies. You might try pulling your piggies and have a straight piece of pipe welded in to replace that empty can.

Interesting, might have to try this

but your drone is not gone completely?

what exhaust setup do you have?

thanks!

[dparm]

Thanks! And are most resonators the same? I'm just wondering if I get my 14"s replaced with 8"s whether the size difference will only change the volume and not so much effect how raspy and deep the exhaust sounds. I'm hoping the mufflers staying the same will keep the tone and sound while replacing smaller resonators will only bring up the volume since I currently like the sound, just need more of it.

Thanks

There are a few different designs. Spiral-core is the newest and supposedly the quietest with less restriction, but I have no clue who makes them. The more traditional design is just a tube with perforated holes. Some vehicles have enough room to just put a second full-size muffler underneath.

[mistral cytz]

I had my pggies done with the cat totally cut out and replaced with just a straight pipe. It does help reduce drone and may actually be more efficient for exhaust flow as well. I think I'll be removing my 14" resonators and replacing them with 8"s

[01northernS4]

I'm not saying the stock resonators will do nothing, but you can get some very weird and unwanted sounds by piecemealing an exhaust together. A properly-tuned exhaust should not drone. Does Magnaflow sell a resonated version of that exhaust?

If you go on Youtube, there are folks who swapped the Magnaflow 14851s onto the stock exhaust tubing.

dparm, did what you suggested and I'm happy to say it's a definite improvement... while the drone is not completely gone, I feel like it's been improved by approx. 50%, and it sounds much smoother and more refined overall.

I bought the same resonators found on the B6 S4 system and had them welded in the same location... voila, drone improved and my ears don't bleed anymore, lol

Thanks again