Exhaust sound dilema

[martym00se72]

Hi All,
So I suspect I am in the same boat as a number of you in that I am the only driver of my GTV6. Therefore I only know what it sounds like inside the car.

To fix that I borrowed a mates GoPro, mounted it on a pole on the side of a quiet country road and drove past it a bit and then listened to the results. I am a little disappointed with the sound – I have heard better, and I seek your advice on how to improve it.

My current set up is – Greg Gordon silicone induction pipes, K&N cone filter, 3.0 12v with standard internals running L-Jet, stainless CSC headers into custom mild steel mid-section with 2.25in (or 2.5in – can't recall) parallel pipes with hotdog resonator about half way up on each side before they join together a bit before the rear section with an un branded muffler box.

I intend to keep the CSC headers. Non negotiable. But I am wondering if I should have a new centre section built up and either delete the hotdogs altogether for a straight through to the muffler or if I should have one built up with the join from each cylinder bank before going through a single resonator to the rear.

And / or do I replace the rear muffler with some 'known' brand. Feel free to suggest...

I am after something a bit crisper sounding and a bit barkier/sportier – I feel the character of the engine is not shining through

Also, anyone able to point us to YouTube (or other) links of known exhaust systems on our cars? So often I hear something I like but have no idea what configuration is used. And then you can listen to a tricked up 3.2 GTA engine and dream – and come thudding back to reality when the clip is done.
Cheers
Marty

[rowan_bris]

I have custom headers and CSC sport centre and rear on my car and it sounds great.  It is 24 valve though and they do sound a bit different

[Ian Morris]

I had a GTV6 in storage for a while during which time the rear muffler rusted out totally and the bottom fell out of it!
Started it and took it for a drive. It sounded great!
Best GTV6 sound I have ever heard. The bark was exhilarating.
Standard system except ditch the rear muffler and replace with pipe. And very cheap to do.
Try it before you embark on expensive solutions.

[jazig.k]

I wish I had means of recording my 3lt for you. My engine is prett much the same set up, cams and light port work. Megasquirt too, which I have tuned to give me lots of off throttle crackle.
I'm running CSC's, no cat, no centre muffler into a Magnaflow straight through 14" oval muffler. It's loud [ridiculously so] and it sounds amazing from outside and inside the car with full bias I'm sure.

My tip - Get rid of the hot dogs. To effectively run hot dogs you need to trial and error different lengths as short vs long tune out different exhaust frequencies.

[martym00se72]

Thanks - come to the conclusion that the hot dogs have to go - will get a straight through centre section built and see how that sounds with my current rear section and tweak that if needed.

[steveprytz]

I have a 2.5 and had the cat converter removed as was stuffed, sound improved significantly

[VeeSix]

I am with Ian, if you want a great sound at virtual minimum cost, just cut the rear muffler section out, straight pipe thru and put a nice large chrome tip on it.

[jazig.k]

This setup passes a rego check and the police leave me alone it is a lot louder than a standard system

Might be a great time to bring up the unannounced changes by the EPA to exhaust noise...

NO longer are the old 90/96dB measurements the legal standard!

The new change, without any notice release, is 5dB above the factory ADR compliance measurement [stock standard factory release measurment]. The RPM to test at is the factory peak power point for that given engine, regardless of modifications.

We JUST had a 3 week EPA blitz in Bendigo finish up targeting all exhaust systems specifically but they also had Highway patrol tag along to slap you with defect notices while you were reeling over the $600 fine you just got for the exhaust which WAS LEGAL just a couple years ago.
The ONLY way to avoid the fine was to prove you had it tested prior to law changes AND supplied the receipt for the exhaust test and fitting. In which case, you were given time to have the exhaust fixed and show up for a re-test.

If it interests anyone, I'm happy to go digging up the EPA documents again.

[poohbah]

Good headsup  - but that would be specific to Victorian EPA regs. Worth checking out what applies in your own state.

Certainly hope its not the case in WA - last time I checked my exhaust volume was in the +80db range.

NB - I just went and checked current WA legislation, and for cars post-1982 the max is 92 dB, and for cars pre-1982 (mine - just !) is 96 dB.

For those sandgropers wanting to read the current 2014 legislation, here it is: https://www.slp.wa.gov.au/legislation/statutes.nsf/main_mrtitle_13558_homepage.html

[V AR 164]

Might be a great time to bring up the unannounced changes by the EPA to exhaust noise...

NO longer are the old 90/96dB measurements the legal standard!

The new change, without any notice release, is 5dB above the factory ADR compliance measurement [stock standard factory release measurment]. The RPM to test at is the factory peak power point for that given engine, regardless of modifications.

Well then, looks like I'm going to have to keep far far away from the police....

But yes, I'm with VeeSix. I have only ever changed the rear mufflers on my cars and I get a nice sound. Unbolt the rear muffler and go for a quick drive up and down the street. If you like it, install a straight pipe and it should sound similar to no muffler (my experience).

[jazig.k]

Good headsup  - but that would be specific to Victorian EPA regs. Worth checking out what applies in your own state.

Certainly hope its not the case in WA - last time I checked my exhaust volume was in the +80db range.

Good point on the state thing. I figured you guys were all Victorian since you all seem like such reasonable guys! Guess you just don't know who you're really dealing with on the interwebs

I checked the BMW out. 73dB. Booked in for next Monday for 2x 200cpi cats and 2 rear muffler delete. Safe to presume I'll be pushing the 78dB I'm legally limited to. I'm keeping all the original and getting everything v-band flanged! Will make changes back and forth super simple if ever required.

[poohbah]

To clarify, I should add that while the current WA legislation sets the noise limit at 92db and 96db for post and pre 1982 cars respectively, all cars built since 1 Jan 2005 have had to comply with national ADR 83/00  to get licensed in the first place, which means they have to be 74db or less (though I gather older vehicles should still be fine).

However, it is possible that the approach in Victoria, as reported by jazig, could be adopted in other states. I cannot find any reference or announcement suggesting that is so in WA, but who knows.

[GG105]

I feel sorry for you poor bastards in Vic.

I'm with Sportiva on the muffler issue. I removed the rear muffler on my first GTV6, even then in my early 30s it was simply too loud. I then put an Ansa rear muffler on it which I thought was really cool, except it rusted out in 18 months.

I found you need to keep the rear muffler, as it does most of the work, fiddling with the two resonators and middle muffler is the go.

My current GTV6, which admittedly is stock, runs the standard system without the first two small resonators and from inside the car sounds great. I couldn't care less what it sounds like outside....

The little 2.5s have a sweeter sound than the bigger engines.

Good luck with it!

John

[GeeTV]

Can anyone recommend an exhaust shop in Melbourne? 
I'm pretty happy with the sound of my stock 2.5ltr but will your regular 'Midas' type outlet be able to source & replace a 'standard' Alfa exhaust system for my gtv6?... and do a good job!?

Of course, I'm all ears if there is a better solution than the standard one???... From a performance benefit point of view?!?