Its just too bloody noisy!!!

[fubar andy]

Got a problem at the mo with noise…

After my trackday the other week I had to blag my way on to the track as my car was over 105db’s (105 being the max limit) at a wonderful 107db’s. :roll:

Now I’m in a pickle as I need to quieten the exhaust system down, but try to keep its effective flow rate.
Speaking to a custom exhaust welder (not powerblow :roll: ) I might have burn/blown out my baffle which seems to a logical explanation to why its gone from 98db’s to 99 to 103 to 107db’s. :shock:

The system is a part custom 3” elbow and down pipe front section and cat back Blueflame/Mongoose 2.5” system.

Now my initial thought would be to cut the middle silencer open and re-pack it with fresh baffle and see how that works out?
I’m just wondering if anyone else has any ideas of how to quieten it down without putting a bung in or adding more silencer boxes

Perhaps some "tricks of the trade" that I could try or perhaps you’ve re-packed your exhaust and seen an improvement.

Any ideas or comment would be appreciated :-D

 

[stumo]

go see pipewerx

 

[campbellju]

I've got my old custom 2.5" system and backbox in the garage, that was quite quiet and good enough for 380hp previously. Its restrictive for me but would be fine for 350hp.

I need to clear the garage out as you know so give me a shout

 

[pulsarboby]

have you got a hks silenced decat fitted, that will knock around 3db off it

 

[Russ'R]

I have now swapped my 5" Mongoose tip over to a 3.5", I had problems at Nurburg last year so something had to go.

It seems a lot quieter on tick over, I haven't driven the car yet..in a few weeks I can tell you.

 

[fubar andy]

go see pipewerx

That might be an option; they created my custom 3” section. ;-)

I've got my old custom 2.5" system and backbox in the garage, that was quite quiet and good enough for 380hp previously. Its restrictive for me but would be fine for 350hp.

I need to clear the garage out as you know so give me a shout

Jim, if your free this weekend I might pop along to see that system and see if I can lower it a few db’s :-D

have you got a hks silenced decat fitted, that will knock around 3db off it

Bob, it’s not a HKS section, but the de-cat section has a silencer in it, not sure how much more an HKS section would make a difference :noidea:

I haven't driven the car yet..in a few weeks I can tell you

I have 7 days Russ :?

 

[pulsarboby]

i wouldnt worry too much andy! ive never known them to noise test cars or bikes at cadwell, but theres always a first time i suppose lol

 

[youngsyp]

Unfortunately, the only way to quieten down an exhaust system, is to add boxes, reduce it's diameter or change the material used to make it.

When the Police told me mine was too loud and I had to get it sorted, I had a silenced decat pipe made and that dropped the noise output by around 3dB or, halved the volume. That was after the removed my rear box and the sound output didn't change at all.
Needless to say, the volume of the exhaust went down noticably, and the tone also changed. Flow doesn't seem to have been affected though. To get one of these made would be very inexpensive.

You said about the baffles in your middle section going ?! If you have a Mongoose, that only has 1 silencer, being the decat pipe, doesn't it ?!
If you mean the 'bulge' in the pipe, towards the rear end, that's a resonator and will only just effect sound level output. It's main purpose, is to alter the tone of the exhaust note.
Ultimately, the only way to effectively reduce the sound output, is to have a rear box like Jim's left exit job, due to the layout of the GTiR's under side.

Paul

 

[Odin]

is to have a rear box like Jim's left exit job, due to the layout of the GTiR's under side.

Paul

You mean like this > ;-)

I had this full 3" system made by AAS in Newcastle, I had it designed with two proper boxes, One like the goose cat replacement box and this big back box exiting out the passenger side, It's defo a lot less boomy and quieter over all.




Rob

 

[youngsyp]

You mean like this > ;-)

I had this full 3" system made by AAS in Newcastle, I had it designed with two proper boxes, One like the goose cat replacement box and this big back box exiting out the passenger side, It's defo a lot less boomy and quieter over all.




Rob

That's him Rob, and very nice too. I'd forgotten you had something similar !

Of course the tail pipe size plays a massive part in sound level and quality too. If you have a 3" system, stay with a 3" tail pipe. Any bigger and it'll have a 'megaphone' effect on the exhaust sound.

Paul

 

[Fusion Ed]

I've got my old custom 2.5" system and backbox in the garage, that was quite quiet and good enough for 380hp previously. Its restrictive for me but would be fine for 350hp.

I need to clear the garage out as you know so give me a shout

Made 450+ on a 2.5 inch system (with custom turbo elbow) it was a major factor in restriction at that power, but the power was made Even removing my wideband lambda sensor from the tail pipe it gained around 7-8bhp on the dyno!!

 

[fubar andy]

You said about the baffles in your middle section going ?! If you have a Mongoose, that only has 1 silencer, being the decat pipe, doesn't it ?!
If you mean the 'bulge' in the pipe, towards the rear end, that's a resonator and will only just effect sound level output. It's main purpose, is to alter the tone of the exhaust note.

I think its going to be a case or chopping out the “cherry bomb” style resonator and installing a silencer in its place. :roll:

As long as I can quieten it down to around 105db’s then I’ll be happy.

I went out in Jims yesterday and its much quieter than mine, it’s pretty fast too! ;-)
I think that its time to sacrifice some sound so that I have some ear drums left

 

[antgtir]

I found that changing the tail pipe from the 5 inch to a 3.5 inch has made a difference to the sound from the exhaust, may or may not have reduced the sound but certainly changed the tone etc.

If you look at the mongoose rear tail pipe of the 3.5 inch size it has a little baffle inside, maybe its this that is having more of a significant impact on sound.

Have you a tester to see whether or not the changes you make are within limits?

Ant.

 

[Kev@Apex]

Go and see DCMS, tell them I sent you they are in Burnely.
www.DickinsonCMS.co.uk

They can add you additional silencers to get you on track, they are well used to doing it.
Donnington with its driveby limits is quite tough on Turbo cars.

 

[MORF114]

point tailpipe towards the floor, it will reduce the db reading a little.