Sound deadening for exhaust noise

[someone466]

Hello everyone,
I have an 07 Liberty Spec B. I recently got the chip torque ECU flash with the TCP turbo back quad tip exhaust. My aim was to get an exhaust which gave increased power without a droning noise.
The TCP exhaust is definetly quieter than my flatmates Forester with the MRT XC kit. However it does tend to resonate into the cabin if you go over 2000rpm. I wish I could just get it a little bit quieter as I will be doing some long interstate driving.

I have been told that I can either have a larger resonator fitted or I can get some dynamat sound deadening put in the boot and under the rear seats.

Does anyone have any suggestions? Any experience with sound deadening? I only need it to be a bit quieter ( I am not expecting it to sound like stock ). I am just after a nice noise without it resonating through the boot.

Cheers

[morbo1980]

Hello everyone,
I have an 07 Liberty Spec B. I recently got the chip torque ECU flash with the TCP turbo back quad tip exhaust. My aim was to get an exhaust which gave increased power without a droning noise.
The TCP exhaust is definetly quieter than my flatmates Forester with the MRT XC kit. However it does tend to resonate into the cabin if you go over 2000rpm. I wish I could just get it a little bit quieter as I will be doing some long interstate driving.

I have been told that I can either have a larger resonator fitted or I can get some dynamat sound deadening put in the boot and under the rear seats.

Does anyone have any suggestions? Any experience with sound deadening? I only need it to be a bit quieter ( I am not expecting it to sound like stock ). I am just after a nice noise without it resonating through the boot.

Cheers

I'm finding the same thing with my TCP exhaust so will be following with interest.
When cruising I find it almost sounds like air buffeting, similar to when your at highway speed with one window down with the wind buffeting through the window.
Enjoying the extra responsiveness though, and I haven't even had a tune yet.

[brainy]

I'm yet to hear these systems in the flesh, but what size is the center res? 12"?

You could go a 16" res in the center, or failing that, chuck in a straight through muffler. Will quieten it down without a decrease in airflow.

Unfortunately, i found that the drone in the car was caused by the rear mufflers i had before i put the Glasspak ones on.

But definitely start with replacing the center and go from there.

The TCP system already has a woven flex right?

[Bosco]

I know exactly what you mean about the noise. I have the same exhaust and had the same idea about sound deadening the boot etc. I don't really want to go changing a brand new exhaust just yet. I think I'll give it a go and see how it turns out. I've heard ebay is the cheapest place to buy dynamat. There are also alternative products on there that look good.

[mihai]

I know exactly what you mean about the noise. I have the same exhaust and had the same idea about sound deadening the boot etc. I don't really want to go changing a brand new exhaust just yet. I think I'll give it a go and see how it turns out. I've heard ebay is the cheapest place to buy dynamat. There are also alternative products on there that look good.

Look into Stinger Roadkill. 1 Sheet of roadkill is equivalent to about 2 sheets of Dynamatt

[tbear]

this is great feedback guys, I will get longer resonators put into my systems and see if this helps.

Unfortunately I dont get to ride in the cars for prolonged period of time, so these comments are great for my product development.

Let me know how the dynamat works out as well.

cheers
Tony
TCP

[someone466]

Hi Tony,

Can you let us know how the testing goes with the longer resonator. I love the sound of the exhaust, I just wish it did not resonate into the cabin at highway speeds. Otherwise it is excellent.
In the brisbane area, where would you recommend getting the resonator replaced?
Thanks

[ZeroPants]

this is great feedback guys, I will get longer resonators put into my systems and see if this helps.

Unfortunately I dont get to ride in the cars for prolonged period of time, so these comments are great for my product development.

Let me know how the dynamat works out as well.

cheers
Tony
TCP

Hey,
Im also interested with how this testing went as id be looking to by a full TBE system from yourself in the upcoming months, also was just concerned about the drone.
Any response would be great Tony.

Cheers

[Gambit]

3inch muffler where the resonator is, will definately shut it up.

[jeffas4966]

Hi Guys,
I have just had a TCP TBE fitted and the drone is terrible (borderline undriveable) to be honest. Going back to the exhaust shop tomorrow.

Rgds

Jeff

[tangcla]

I think the biggest bang for buck you can do to quieten down exhaust drone is to change out the rear mufflers. They all look the same from the outside, but the amount of glass packing in the muffler makes a big difference to the acoustics (without affecting flow). It would be more beneficial than adding in resonators IMO.

[Robbks]

you need to fit a good extra resonator in the style of the factory resonator unit.
i.e. straight through muffler with fibreglass packing.

Tony, this may need to be an added "Street" option for your systems.

it's been done on a couple of old RS libs that i know of
full 3" straight-through system, but an added 3" truck muffler just before the rear diff to keep the note but lower the volume

[jeffas4966]

I have had my TBE to both Maximum Motorsport and a Perth WRX recommended exhaust fitter. Both have mentioned that the piping is too big at the back, currently 2.5inches (I think) and should be reduced.

The exhaust fitter also confirmed that it is the rear mufflers that are causing the issue, he walked the car with a sound meter.

What I have experimented with is to block one of the twin pipes on each side with rags. This has certainly reduced the noise and has hardly reduced the performance (seat of pants guess). My next step is to block one of the outlets with a washer.

There is no space for an extra anything

Any thoughts

[yipming]

Put the old mufflers back on. Yes the 1.8" pipes will be a theoretical restriction, but when tuned there is practically no difference.

This is my experience with stock turbo though, ymmv with bigger turbos.

Also one reason why sti muffler for wagon sell so well. Sedan don't suffer from the same problem.

[someone466]

I have been down to the exhaust shop and they say there is room for another resonator on the TCPexhaust. I think that is what I will end up doing in a month or so.