Disco 2 Centre Exhaust Silencer

sierrafery said:

Unfortunately i have no ideea about that but IMO there must be some solution.... i'm asking again, is the noise the same if you rev it up stationary?

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I did respond to your question earlier when I said its sounded louder than my old V8 when idling.

When I rev the engine it is quite loud. It only resonates when driving and starts at quite a low speed, 20kph to 30kph.

Irish4x4 said:

I did respond to your question earlier when I said its sounded louder than my old V8 when idling.

When I rev the engine it is quite loud. It only resonates when driving and starts at quite a low speed, 20kph to 30kph.

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Diesels are louder than petrols in general IMO... i asked about the sound if you rev up the engine stationary cos exhaust droning should be the same at a specific rpm with stationary or moving vehicle so if it's loud only while driving it might be something else but if the exhaust is loud a better tail silencer should be enough... as i said mine is tuned up as well with straight through exhaust and it's not much louder than it was before and not annoying in the cabin

Irish4x4 said:

I did respond to your question earlier when I said its sounded louder than my old V8 when idling.

When I rev the engine it is quite loud. It only resonates when driving and starts at quite a low speed, 20kph to 30kph.

Click to expand...

Just remembered disco td5s have a turbo, turbos are natural mufflers. They rob energy from the high speed exhaust stream and that energy is noise, plus a resonator and muffler together, thats good ? but did the td5 have a resonator fitted in the exhaust when it left the factory ?

If you were doing a full performance exhaust, or a full cat-back, losing the resonator rarely causes issues of additional noise.

The bottom line is, reinstall every thing the check the sound level again.

sierrafery said:

Diesels are louder than petrols in general IMO... i asked about the sound if you rev up the engine stationary cos exhaust droning should be the same at a specific rpm with stationary or moving vehicle so if it's loud only while driving it might be something else but if the exhaust is loud a better tail silencer should be enough... as i said mine is tuned up as well with straight through exhaust and it's not much louder than it was before and not annoying in the cabin

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I have not tried reving the car up and holding it at a certain RPM level to detect stationary resonance. I will try this over the weekend and give you feedback.

Thanks for your insight. I appreciate it

discool said:

Just remembered disco td5s have a turbo, turbos are natural mufflers. They rob energy from the high speed exhaust stream and that energy is noise, plus a resonator and muffler together, thats good ? but did the td5 have a resonator fitted in the exhaust when it left the factory ?

If you were doing a full performance exhaust, or a full cat-back, losing the resonator rarely causes issues of additional noise.

The bottom line is, reinstall every thing the check the sound level again.

Click to expand...

I dont have everything. This is how I bought it

I fitted a "middle box delete" exhaust section in my TD5 a few years ago to get rid of the very heavy centre silencer.
As you have found the noise inside the car was unacceptable on long journeys.
After 1 week I decided it must be changed.
I had a straight through stainless steel silencer welded into the centre pipe by a local custom exhaust specialist. It's probably approx 350mm long.
Noise level inside car now reduced to acceptable levels and performance not noticeably reduced. Cost including fitting £80.

I agree totally that a sports exhaust one properly made for the vehicle should not be too loud. I have one on my Disco 1, in stainless and with just one box, at the rear.
It has made a great difference to the performance and the MPG has been maintained.
BUT it is not a straight through box like yours.
So, to me, you have two choices, either another central straight through box, or replace the end box with a more conventional one. Still wide bore though.
The previous owner was more concerned with out and out performance than comfort.
Everything is a compromise.
But if you put a conventional box with baffles in the middle you might as well throw the rest away.

Pawl said:

I fitted a "middle box delete" exhaust section in my TD5 a few years ago to get rid of the very heavy centre silencer.
As you have found the noise inside the car was unacceptable on long journeys.
After 1 week I decided it must be changed.
I had a straight through stainless steel silencer welded into the centre pipe by a local custom exhaust specialist. It's probably approx 350mm long.
Noise level inside car now reduced to acceptable levels and performance not noticeably reduced. Cost including fitting £80.

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+1^

sierrafery said:

Diesels are louder than petrols in general IMO... i asked about the sound if you rev up the engine stationary cos exhaust droning should be the same at a specific rpm with stationary or moving vehicle so if it's loud only while driving it might be something else but if the exhaust is loud a better tail silencer should be enough... as i said mine is tuned up as well with straight through exhaust and it's not much louder than it was before and not annoying in the cabin

Click to expand...

+1^ yet again!!!!

Pawl said:

I fitted a "middle box delete" exhaust section in my TD5 a few years ago to get rid of the very heavy centre silencer.
As you have found the noise inside the car was unacceptable on long journeys.
After 1 week I decided it must be changed.
I had a straight through stainless steel silencer welded into the centre pipe by a local custom exhaust specialist. It's probably approx 350mm long.
Noise level inside car now reduced to acceptable levels and performance not noticeably reduced. Cost including fitting £80.

Click to expand...

Thank you for your reply. It was really good to hear from somebody mentioning ne who had the same issue.

Here in Sweden there are large stores selling tons of DIY car parts. I checked today and they have a wide array of straight through and oval silencers.

Can I ask did the silencer you installed have any specific technical specification? Was it just to reduce noise or also to reduce/cancel reverberation? I saw online there are devices called Cherry Bombs for reverberation cancelling.

If you have any specification information you could share I would appreciate it.

Regards

Stanleysteamer said:

+1^

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?

Stanleysteamer said:

+1^ yet again!!!!

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??

Irish4x4 said:

Thank you for your reply. It was really good to hear from somebody mentioning ne who had the same issue.

Here in Sweden there are large stores selling tons of DIY car parts. I checked today and they have a wide array of straight through and oval silencers.

Can I ask did the silencer you installed have any specific technical specification? Was it just to reduce noise or also to reduce/cancel reverberation? I saw online there are devices called Cherry Bombs for reverberation cancelling.

If you have any specification information you could share I would appreciate it.

Regards

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The silencer I added didn't have any specification - other than matching the exhaust pipe internal diameter. It was just part of their range for building custom exhausts. The length was chosen to easily fit into the space available under the car - but be long enough to have some effect on noise.

Pawl said:

The silencer I added didn't have any specification - other than matching the exhaust pipe internal diameter. It was just part of their range for building custom exhausts. The length was chosen to easily fit into the space available under the car - but be long enough to have some effect on noise.

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Many thanks.

I will look at available silencers locally and create a solution myself.

Kind regards

Irish4x4 said:

?

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This just means I agree with what the previous poster said,
and again.
You've got the picture anyway.
I too tried to replace the central exhaust box with a straight pipe.
It made absolutely no difference, the sound didn't increase and nor did the performance.
BUT this was on a standard exhaust.
So the message seems to be:
Either replace the back box with a quieter one,
OR replace the centre pipe with a straight through one.

Irish4x4 said:

I saw online there are devices called Cherry Bombs for reverberation cancelling.

Click to expand...

Yes, Cherry bombs are well known straight-through exhausts, I have two in a system I built for a kit car.
But "reverberation cancelling" never heard that, in either sense!
Dosen't say this on the front page of their website, just says "designed to enhance the sound...."

sierrafery said:

Diesels are louder than petrols in general IMO... i asked about the sound if you rev up the engine stationary cos exhaust droning should be the same at a specific rpm with stationary or moving vehicle so if it's loud only while driving it might be something else but if the exhaust is loud a better tail silencer should be enough... as i said mine is tuned up as well with straight through exhaust and it's not much louder than it was before and not annoying in the cabin

Click to expand...

I tested the reverberation today. Took the RPMs up to 2k and held it there. Sitting inside with the doors and windows shut. The reverberation was very present. I could hear and feel it in my body.

I will try a straight through silencer and see if it at least reduces this.

Regards

Irish4x4 said:

I tested the reverberation today. Took the RPMs up to 2k and held it there. Sitting inside with the doors and windows shut. The reverberation was very present. I could hear and feel it in my body.

I will try a straight through silencer and see if it at least reduces this.

Regards

Click to expand...

I take it you have checked to see that no part of the exhaust is touching anything that it shouldn't?
The straight thru should sort it.
Best of luck.