jmphegle

Want to add some growl to the exhaust of my 2013 S4 but thinking instead of paying $1500 for a new exhaust why not just do an axle back replacement of the last two mufflers and tips.

Anyone done this or any thoughts?

UKS4APR1

I did this, however the mufflers are not just mufflers, they contain Helmholtz chambers.
In other words they are another pair of resonators.
In my case I refitted the OE mufflers as the drone at 1800 - 2400 rpm low speed/ high gear was not acceptable.
Not before I added some 1/4 wave resonators (J-Tubes) which helped a lot. Quiet when cold, but after a blast the drone returned at 1800 rpm.
Decided to quit messing about and refitted OE.
I did modify the tips though - so looks same only quieter.

planekiller1

Just add a bypass E-Cutout, eliminates all Resonators/mufflers then one flip of a switch and it's back to stock, make sure to buy an expensive one @ around $300 and not from eBay or it won't close and seal properly. I've been eyeing this one Link
Kurt

UKS4APR1

This is what the inside of the rear mufflers look like
Helmholtz chamber highlighted in red.

planekiller1

Basically making the air travel a longer distance before exiting is how you "silence" an exhaust system, eventually you get to the stock level where the pulsing of the engine firing can no longer be heard because it all flows at the same rate towards the end, resonators allow the gas to expand then back into the pipe slowing and softening the pulsing bit by bit before it exits, basic fluid dynamics of water and pressure flowing through different sized pipes is how the exhaust gasses act at high temp and pressure. The "drone" is because the engine is in harmony with the volume inside the exhaust at that RPM.
Kurt

jmphegle

won't the E-Cutouts be insanely loud?

planekiller1

It will, but isn't that the way your going? I find that unless you spend the money for a full cat back or even turbo back, you will never get the same results, so that's why at some point I'll go with the e-cutout as I either want to be a sleeper or i want to wake everyone up hahaha.
Kurt

jmphegle

thanks man. Ya I get it. Want your car to reflect your current attitude!

SR7D1

There is a great thread on this over at AZ. 47 pages including sound clips. Exhaust Mod - Resonator replaced w/ X-Pipe (video)I have modified my stock exhaust by removing the front resonators that are right after the downpipes, then remove the center resonator, leave the rear mufflers. No drone at highway speed and great noise when you mash the throttle.

DrGP

Yes, and Now ECS sells a stainless steel replacement with both exhaust pipes and an X pipe all in one piece. It makes the mod easier to do and everything is stainless https://www.ecstuning.com/b-ecs-part...003029ecs01kt/