Exhaust options

[edhorne]

Ok, Ok please don't judge me but in an effort to keep the Cerbera with 2 small kids I need to make it quieter

I currently have linked de-cats and a standard rear silencer.

I know I can go back to cats to make it quieter but I have two questions to put to you guys:

1. What combination of parts will make it quieter without seriously stunting the power output?

2. How could I make it sound OK but at a lower volume?

This doesn't need to be off the shelf parts, I could mix and match but it needs to fit in the normal place of course.

Although modern sports cars don't sound anywhere near as good as a TVR they seem to manage decent power outputs without setting off car alarms. Maybe some kind of valve?

The missus says it needs to be quieter or it's got to go so any help would be greatly appreciated.

Cheers

Ed

[Gazzab]

I would talk to ACT or Silverstone.
Linked de-cats and standard is quietest behind the standard with cats in. Maybe ACT can provide an ultra quiet system for you. Maybe talk to raceproved. Joolz made up a system for one of their cars. I am sure they can build you a quiet one.

[Gazzab]

http://web.me.com/philjames66/SilverstonePerforman...

[Gazzab]

http://www.actproducts.co.uk/shop/silencing-exhaus...

[edhorne]

Gazzab

Thanks very much. I'll make some calls!

Ed

[JensenA]

Ed - Go up and see Bell Silencers up in Old Town. They do Powerflow Exhausts - ie custom made - worth a shout, space is limited on the Cerb but they may be able to fit in some in-line silencers.

[edhorne]

Thanks Alan, I'll give them a try.

[Byker28i]

Seriously I wouldn't go near Bell. Their quality isn't what it was a few years ago.

Strangely enough, I ended up testing noise on various systems and I went with ACT's quiet system, which was 3db quieter that SP's and 5db quieter than the standard, with the added advantage of being smaller and a lot lighter. The cats make a huge difference, between 8-10db, but for me I'll take the added noise over cooking the cabin/gearbox.

Quietest I found was the ACT quiet system, with Cats and standard manifolds. I could get my car down to 96db at 4.5K revs. I've just replaced my manifolds with ACT's tuned system, which I think has made it slightly noisier, but I've not had time to test it yet.

[Steve_T]

I've recently fitted ACTs inline silencers in place of the regular decats. They've reduced the cabin noise quite significantly on steady throttle, which is excellent for the longer trips I'm doing this year. They're also a pleasure to fit as they're adjustable length, so there's no tension on the exhaust system anymore. Tim's also got a excellent idea how to space the pipes so they fit the cut outs perfectly, more of this anon.

[Byker28i]

Steve_T said:

I've recently fitted ACTs inline silencers in place of the regular decats. They've reduced the cabin noise quite significantly on steady throttle, which is excellent for the longer trips I'm doing this year. They're also a pleasure to fit as they're adjustable length, so there's no tension on the exhaust system anymore. Tim's also got a excellent idea how to space the pipes so they fit the cut outs perfectly, more of this anon.

That'll be interesting. Any idea how much noise they drop?



Got any pics?

Edit: Ah found them. http://www.actproducts.co.uk/shop/sjd02a-p-432.htm...

Edited by Byker28i on Tuesday 27th April 14:03

Edited by Byker28i on Tuesday 27th April 14:05

[Gazzab]

ISnt there a set of ACT decat pipes etc on classifieds?

[TT Tim]

Byker28i said:

Steve_T said:

I've recently fitted ACTs inline silencers in place of the regular decats. They've reduced the cabin noise quite significantly on steady throttle, which is excellent for the longer trips I'm doing this year. They're also a pleasure to fit as they're adjustable length, so there's no tension on the exhaust system anymore. Tim's also got a excellent idea how to space the pipes so they fit the cut outs perfectly, more of this anon.

That'll be interesting. Any idea how much noise they drop?



Got any pics?

Edit: Ah found them. http://www.actproducts.co.uk/shop/sjd02a-p-432.htm...

Have these on mine, not sure they drop the noise at all, with my custom 2.25" exhaust they do help to make it sound a lot throatier than a lot of Cerb's I've heard. Still 105dB + at 4K though.

Tim

[Steve_T]

Gazzab said:

ISnt there a set of ACT decat pipes etc on classifieds?

Yep, only noticed this afterward though.

[itiejim]

I've just bought one of these to weld behind the decat pipes:

http://exhaustpartsuk.com/index.php?main_page=prod...

It's nicely made in stainless and is unbaffled so should have minimal effect of power. Looks like it'll fit in the space perfectly, the pipes seem to line up close enough and there's even space to put a second 12" one in after if I need it! I'll report back once it's in and running.

[Rufus Roughcut]

When I bought my 4.5 the exhaust system had been decatted and a single straight through silencer per bank fitted at the back.



Inside the car it was noisy but not too bad, it was bearable! outside was a different matter

I've since fitted the ACT six silencer system, sounds superb outside but tends to 'drone' on the inside... that's my personal experience.



None too technical... we were doing about 70 ish cruising up the motorway on our way to Chatsworth last Sunday when my wife commented that it sounds like we're in an aeroplane.

[itiejim]

Nicely made system, but I can't see that the first and last pipes are going to have a dramatic effect simply due to their (lack of) volume.

I must say that I totally agree with the aircraft thing though, Cerbs definitely have an aeronautical drone to them.

[CER927]

Have you got the silencer installed in place of the decats now? I just was curious to see what difference it made.

[mikeinsheffield]

Depending on how sensitive your little ones ear's are (and how much greif SWMBO is giving you) - you could just try putting the CATS in? I run a 4.2 with new CATS and a sports back box, it's 106 dB and my two little one's don't mind it too much - I tend not to go stoopid with the loud peddal when they're in anyway....

[Ireland]

itiejim said:

I've just bought one of these to weld behind the decat pipes:

http://exhaustpartsuk.com/index.php?main_page=prod...

It's nicely made in stainless and is unbaffled so should have minimal effect of power. Looks like it'll fit in the space perfectly, the pipes seem to line up close enough and there's even space to put a second 12" one in after if I need it! I'll report back once it's in and running.

That's interesting.

I look forward to hearing how it works out.

[Byker28i]

mikeinsheffield said:

Depending on how sensitive your little ones ear's are (and how much greif SWMBO is giving you) - you could just try putting the CATS in? I run a 4.2 with new CATS and a sports back box, it's 106 dB and my two little one's don't mind it too much - I tend not to go stoopid with the loud peddal when they're in anyway....

I run the ACT quiet system as above, decatted with straight through pipes and it was 106db at 4.5k revs. I need to test it again as I've now got the ACT manifolds as well. With the cats in it was 98db at 4.5k revs, with the ACT trackday silencers it's 96-98db at 4.5k revs depending on who's measuring (my local trackday people/circuits seemto insist on 4.5k revs now).

I'd be interested if the cat replacement silencers made more of a difference