• Hi Guest why not show off your SEAT! (now fixed)
    You can now share your favourite car photos in the new media gallery including embedding pictures from your Instagram account.

Cat back exhaust too loud in the car

Sep 3, 2020
19
4
Hi guys,

Had a custom cat-back done on my Leon on Monday (see images below).
From the outside the car sounds great and not too loud, but from the inside it's horrendously noisy to the point where l change gears at 2,000rpm just to keep it down.

I'm taking it back for the garage to remedy (they have been awesome I would just like to say), but l was wondering if it has anything to do with the box being in the middle rather than at the back?

Would a bigger box at the back (with no box in the middle) make it quieter inside?

Also, cruising at 80mph on the motorway it settles down to just sounding like a continuous loud wet fart inside the car (hopefully it doesn't sound like it from the outside).

Any help would be much appreciated.
Screenshot_20200907-145710_WhatsApp.jpg
Screenshot_20200907-145646_WhatsApp.jpg
 

Charliessmith

Active Member
Jun 16, 2017
453
46
Hi guys,

Had a custom cat-back done on my Leon on Monday (see images below).
From the outside the car sounds great and not too loud, but from the inside it's horrendously noisy to the point where l change gears at 2,000rpm just to keep it down.

I'm taking it back for the garage to remedy (they have been awesome I would just like to say), but l was wondering if it has anything to do with the box being in the middle rather than at the back?

Would a bigger box at the back (with no box in the middle) make it quieter inside?

Also, cruising at 80mph on the motorway it settles down to just sounding like a continuous loud wet fart inside the car (hopefully it doesn't sound like it from the outside).

Any help would be much appreciated. View attachment 18180 View attachment 18181
You don't have a box (muffler) on the new exhaust system you have a resonator, the resonator will not make it quieter it just takes away the horrible droning at tick over and motorway speeds. You need to add a box (muffler) at the back and that will help with the noise level. Keep the resonator as well.

Sent from my SM-N770F using Tapatalk
 
Sep 3, 2020
19
4
You don't have a box (muffler) on the new exhaust system you have a resonator, the resonator will not make it quieter it just takes away the horrible droning at tick over and motorway speeds. You need to add a box (muffler) at the back and that will help with the noise level. Keep the resonator as well.

Sent from my SM-N770F using Tapatalk
Forgive my ignorance, but l've had exhausts done on my last 7/8 cars and they've all only ever had 1 box on them (albeit at the back).
Would it really need the resonator in the middle as well? Surely that would just make it more restrictive?
 

Charliessmith

Active Member
Jun 16, 2017
453
46
Forgive my ignorance, but l've had exhausts done on my last 7/8 cars and they've all only ever had 1 box on them (albeit at the back).
Would it really need the resonator in the middle as well? Surely that would just make it more restrictive?
It dont need the resonator it just is supposed to help with the droning. Ignorance forgiven lol
If you look inside a resonator they aren't really restrictive.
You could have just 1 muffler at the back.
What made you go for that exhaust system.

Sent from my SM-N770F using Tapatalk
 

adam davies

Active Member
Dec 30, 2019
58
23
Forgive my ignorance, but l've had exhausts done on my last 7/8 cars and they've all only ever had 1 box on them (albeit at the back).
Would it really need the resonator in the middle as well? Surely that would just make it more restrictive?
This is what youve got. You have a cat back straight through exhaust with a resonator in the middle. You need a backbox to make the car sound nice and not to loud. The resonator is in the middle this is what help with drone at motorway speeds and idle.
 

Tonezz

Active Member
Jan 12, 2011
977
53
Preston
Normal pre-fab cat back exhausts you buy are resonated or non-resonated.

Resonated generally don't sound much louder than stock at normal rpm but just gives a different tone, but when you go WOT it will sound loud.

Non-res will stay louder all the time.

But like said above they both have backbox/mufflers right behind the tips, its strange they didn't put one in unless you requested not to have it.
 
  • Like
Reactions: Charliessmith
Sep 3, 2020
19
4
So what I'm thinking now is that I'm going to get the mid box removed and fit a small back box to reduce the noise as the fitter said that a box at the back would make it incredibly quiet with the res in... what are people's thoughts?
 

BigJase88

Jase
Apr 20, 2008
2,572
467
Dumfries & Galloway
So what I'm thinking now is that I'm going to get the mid box removed and fit a small back box to reduce the noise as the fitter said that a box at the back would make it incredibly quiet with the res in... what are people's thoughts?
Yes. Why didn't you go that way to begin with? You have no silencer (back box) at the moment, no wonder it's loud, might as well of just taken the exhaust off at the manifold and ran without one :ROFLMAO:
 

Charliessmith

Active Member
Jun 16, 2017
453
46
So what I'm thinking now is that I'm going to get the mid box removed and fit a small back box to reduce the noise as the fitter said that a box at the back would make it incredibly quiet with the res in... what are people's thoughts?
I dont know what fitter your using but a muffler at the back will not make it incredibly quiet, it will make it quieter but not incredibly quiet, unless you use a giant muffler lol.
Also the resonator in the middle doesn't make it quiet it is there to stop the drone not the noise of the exhaust.
You should keep the resonator when you take it off just incase you want to put it back.

Sent from my SM-N770F using Tapatalk
 
Sep 3, 2020
19
4
I've gone back to Powerflow and they have said that it's going to cost me another £110 to have the rear box installed.
He said that he can't do it cheaper than that as that's how much the box costs him... that sounds like a lot of money for a small silencer!

Ended up having a 30 min argument with him as it doesn't give the sound l asked for in the first place (sporty but not loud).

So l don't end up going back, I'm thinking a small box on the back but leave the res in.
Question is, how small has the box at the back got to be to be the same sort of volume as a golf r (obviously it's going to sound different, but that's the sort of volume l want)
 
Sep 3, 2020
19
4
I would of took him up on the £110 rear box, i paid £170 many moons ago for a powerflow rear box so that's cheap
I have taken him up on it at the moment, but he admitted that it would have been less than that if he installed it with the initial system, which is what's annoying me as it's not what l asked for in the first place 😡
 

Tonezz

Active Member
Jan 12, 2011
977
53
Preston
So what I'm thinking now is that I'm going to get the mid box removed and fit a small back box to reduce the noise as the fitter said that a box at the back would make it incredibly quiet with the res in... what are people's thoughts?
How reputable is this guy? He seems to be able to make exhausts but what he is telling you is strange. Exhausts come with a muffler whether it is resonated or not.

If you don't mind motorway or constant speed drone and you want a louder noise all the time, take the resonator out. Otherwise leave it in.

Look at Scorpion/Remus/Cobra they all have mufflers.
 

Rich.T

Active Member
Feb 15, 2020
209
72
Think its one of those cases of get it how you want it and move on. Just pay your money and get it fixed.
 
Sep 3, 2020
19
4
How reputable is this guy? He seems to be able to make exhausts but what he is telling you is strange. Exhausts come with a muffler whether it is resonated or not.

If you don't mind motorway or constant speed drone and you want a louder noise all the time, take the resonator out. Otherwise leave it in.

Look at Scorpion/Remus/Cobra they all have mufflers.
He's been doing it for years and has nothing but 5 star reviews, so l thought I'd use him.

To be fair, he definitely knows what he's doing, which is the main thing
 
Listers, parts supplier