RS4 B9 now quieter after front resonator delete

[Brompton]

Hi,

Can anyone help me please?

I took my car in for the front two resonators to be removed and replaced with straight pipes, but rather than making the car louder, it has made it quieter.

I can barely hear it in the cabin on comfort mode and in dynamic S mode, it has lost the on down shift and the pops and crackles. I'd even say the car feels less responsive in dynamic mode (but that could be just from the lack of sound)

Obviously I wanted it loaded so this is hugely frustrating. Has anyone else experienced this?

By the way the battery was disconnected when the work was done, so I'm wondering if that has done anything.

Thanks

[simundo777]

Sounds very odd.

Are the valves working correctly? Almost sounds like maybe they are stuck closed?

[Brompton]

I don't think so. I think the valves are working fine. When parked and turned off, up they are fully open, as they should be. There is also a note change between comfort and dynamic. Its just sound much quieter in the cabin all round.

The resonators I had removed were directly under the front seats and seemed to add a base tone. Perhaps that was their purpose! So far I can't recommend just removing the front two.

I'm tempted to have either the last (middle one removed) but that's quite small on the RS4, so I cant see how that will make much difference, or have the front ones put back on.

Its a shame to not hear the pops and bangs as much as before.

All the videos I watch before hand always showed the cars revving (ie not normal driving), they were popping and banging a lot, but mine used to have a nice muted pop and bang on regular driving and blips when changing down. These are now gone. Its like driving a standard A4!

Do you think disconnecting the battery caused an error? Or is it due to removing the resonators?

[partymonkey]

I thought (perhaps wrongly!) that all resonators did was modify the exhaust tone, so removing them wouldn't make the exhaust any louder, it would just sound 'different'. You've mentioned the lack of the bass tone, which could stack up with this view. Do you remember hi-fi stereos years ago used to have a 'loudness' button, that was to increase the bass frequencies at low volumes... Wondering if by removing those resonators you've eliminated much of the bass tone which perhaps we hear as volume???

Some of the exhaust noise we hear in the cabin is synthetically generated but I can't see that a battery disconnect would affect this or indeed have any impact on the valves.

I'm sure somebody with a far greater knowledge of exhaust systems (and indeed hi-fi gear) will be along to give you a better answer. I'd be tempted to stick them back on and enjoy the noise you had.

Good luck

[Brompton]

I thought (perhaps wrongly!) that all resonators did was modify the exhaust tone, so removing them wouldn't make the exhaust any louder, it would just sound 'different'. You've mentioned the lack of the bass tone, which could stack up with this view. Do you remember hi-fi stereos years ago used to have a 'loudness' button, that was to increase the bass frequencies at low volumes... Wondering if by removing those resonators you've eliminated much of the bass tone which perhaps we hear as volume???

Some of the exhaust noise we hear in the cabin is synthetically generated but I can't see that a battery disconnect would affect this or indeed have any impact on the valves.

I'm sure somebody with a far greater knowledge of exhaust systems (and indeed hi-fi gear) will be along to give you a better answer. I'd be tempted to stick them back on and enjoy the noise you had.

Good luck

Thanks Part Monkey, I suspect your theory is correct. I think I'm going to have them put back on!

I went down this route as I personally don't like the raspy noise of the after market exhausts for this car, and didn't want to spend £000s to end up being disappointed. This route seemed like a sensible alternative for a fraction of the cost. It seems like it hasn't delivered the results for me, but at least I can easily put them back on!

[MikeFish]

I thought (perhaps wrongly!) that all resonators did was modify the exhaust tone, so removing them wouldn't make the exhaust any louder, it would just sound 'different'. You've mentioned the lack of the bass tone, which could stack up with this view. Do you remember hi-fi stereos years ago used to have a 'loudness' button, that was to increase the bass frequencies at low volumes... Wondering if by removing those resonators you've eliminated much of the bass tone which perhaps we hear as volume???

Some of the exhaust noise we hear in the cabin is synthetically generated but I can't see that a battery disconnect would affect this or indeed have any impact on the valves.

I'm sure somebody with a far greater knowledge of exhaust systems (and indeed hi-fi gear) will be along to give you a better answer. I'd be tempted to stick them back on and enjoy the noise you had.

Good luck

Resonators don't normally change the tone, they just quieten it down and try to lessen any drone. I've removed the resonators on a few cars including 2 RSs and they always make it louder but with a similar tone.
Have you done a comparison outside the car? Maybe you think it's quieter because the artificial noise defaulted to the off position when you disconnected the battery? I've never had a car with the artificial exhaust noise so I'm not even sure if it can be turned off. Failing that, stick your face into the exhaust and make sure the valves open when they should, not just when the car is turned off.

[Brompton]

Thanks Mike Fish.

Good to hear it’s made the RS you’ve done loader. I’m going to check the valves as suggested and see if the sound actuator has turned off some how. But not sure how to do that.. so if anyone can help on that. It would be much appreciated.

Having done all that I’m going to get the last resonator removed and see if that makes much difference.

But why on earth Audi has made this car so quite escapes me!