Quietening down Belanger system a tad

[f80m3driver]

Have just installed a full Belanger system in my 1998 GTS, a great product bought from JonB. Headers, metal HF cats, plus cat back.

It sounds great, but it's just slightly too loud. Need to quieter it down just a little both so it's 100% legal, and because I'd prefer slightly more sedate as well. I never track it, it's just a street car.

I was thinking of either changing the cats to the Belanger ceramic HF ones (which are supposedly a bit quieter than the metal ones?), or adding the cone mufflers.

Anyone had similar experiences and knows the best way to lose 2-3db? Will the change to ceramic cats do that?

[dave6666]

I've used both kinds of cats and although the tone is different from ceramic to metallic substrate cats I never noticed the noise being less. Being Belanger are you using his bullet mufflers (Walker / Dynomax glass packs) in the sills and no rear muffler? Or are you side exhaust?

[plumcrazy]

who says its not legal ?

[Fatboy 18]

Is this your rear set up?
https://c1.staticflickr.com/9/8569/15705147148_77fffbe80c_b.jpg (https://flic.kr/p/pVNZ67)IMG_1099 (https://flic.kr/p/pVNZ67) by Fatboy 18 (https://www.flickr.com/photos/90582394@N02/), on Flickr

[LifeIsGood]

Full Belanger = loud
Belanger headers with Corsa cat back = loud minus a little

[dave6666]

Full Belanger = loud

Bunch of wimps lol. My original side exhaust was full Belanger. And it was kind of tame, with side exhaust seeming to always be louder than rear exit.

[f80m3driver]

DB limit here is 90 for cars made after 1985, and this is currently sitting around 92-93.

[Martyb]

I have headers, no cats, and the Bellanger system pictured above with only the 2 rear mufflers, it's loud. I have also thought about a way to quiet it down a bit, until I walk behind it when it's idling, then I come to my senses :)

[ACR_VP]

I've gone down this rabbit hole completely already. I had a ported top end, highflow cats, full belanger catback and belanger headers, 3" the whole way from the header collectors... I have since switched to a corsa, and it's a touch quieter, but not really when you get on it...

My thing is I want my kids to be able to ride in the car without needing ear protection, and inside with my db meter I was around 95db's with the belangers, definitely not good for the little ones. The corsa is like 91-92... I am currently fashioning a pillow out of roxul safe n sound insulation, it's about 6" thick and will sit in the rear on top the spare tire (stuffed edge to edge in the back and up the rear of the wall, basically trying to cover as much tailpipe as possible) hopefully that will take off at least a few more db to where I don't need to worry about the little one's needing ear protection. And I can just take the pillow out when at the track or anything. The corsa is night and day difference as far as removing those headache inducing drone frequencies though.

[f80m3driver]

Hmmm ok... so nobody has tried inserting the vortex cone mufflers by the sound of it...

[dave6666]

Okay. I'll bite. What is a vortex cone muffler?

[plumcrazy]

how about another muffler in the sills ? cheap and easy to do.

[ViperTony]

Okay. I'll bite. What is a vortex cone muffler?

I think it's the vortex cones from Dynatech, you stick them in your tailpipe and they help, allegedly, quiet down the exhaust noise. I tried those several years ago but didn't seem to make a difference. Extra bullet or spiral flow mufflers would be a better and more effective option IMO.

[ViperTony]

Hmmm ok... so nobody has tried inserting the vortex cone mufflers by the sound of it...

I did and they did nothing. You can try to insert them at the header collector turnout area but you'd be better off adding additional mufflers in the side sills, either bullets or spiral flows.

[dave6666]

they did nothing

Based on a little exhaust pipe theory I read a few months ago that makes perfectly good sense that an inserted devise would do nothing. Not the way exhaust noise works.

Having played around with several types of mufflers recently I do endorse the spirals over the bullets. But that's based on tone rather than sound reduction. The spirals sound better but the glass packs will attenuate more.