Exhaust drone....please help!

[StuRo]

Hi all,

It's been about 4 months now since purchasing my beloved CV8. Since then I have always felt, like many of you before me, that it feels like it's trying to disguise the fact that it is a V8.

So, on a budget, I've been looking at the various different options when it comes to the soundtrack...

The Wortec, i have to admit, sounds perfect...but that price tag puts me off somewhat. I know a lot of you say that it is well worth the money, but i just can't justify spending that much right now. On the other hand, however; I don't want to drown out the existing noise with a load of droneyness which according to some, is what would happen if I were to simply remove the cats/silencers/backbox...

So I went for somewhere in the middle... and had a custom stainless cat-back system made up and fitted yesterday.

Now revving it makes a nice noise and some burbly popping and banging usually follows.....BUT... there is quite a lot of drone... even when idling it's a little droney but mainly when under casual acceleration in a higher gear it gets very droney...

I went to this particular exhaust place on the back of both my neighbor's and a random bloke's recommendation (he said he took his C63 AMG there and came away very happy....why he would want to alter that AMG noise i have no idea...but anyway, I digress!) but now I'm beginning to doubt their workmanship.

The set up i now have is, from the stock Cats, into a Y-pipe and then a single large (not sure what diameter yet) pipe to a new back box/muffler (one of these straight through, perforated inner tube jobbys.

So yeah, long story short (bit late for that, i know): it's too droney! please help!

I know this topic must come up quite a lot and I've read through a lot of the previous threads, but I was hoping to get some fresh thoughts on what could be done/similar experiences people may have had etc..

sorry for rambling...thanks for reading (if you made it this far!) and thanks in advance for any suggestions/advice (i'm pretty new to both V8s and modding in general!)

cheers,

StuRo

[ARAF]

The rear box is your problem, and I'm sure their workmanship is fine, but these cars can drone.

You need something like this, just before the silencer to stop the drone.

[007 VXR]

At what speed and gear are you getting this
.

bet its high gear low revs ?

[StuRo]

Araf,

Yeah, i read about that approach earlier today, essentially altering the resonant frequency of the pipes to cancal out the drone as I understand it. My plan is to head back to the workshop (when I get back from my Jollies), and talk to them about it some more. I haven't touched any kind of welding kit in my life unfortunately, other wise i'd have a stab at changing bits around until I was happy! Maybe they'll be able to tweak it a bit...

Cheers mate

007 VXR,

it's in most gears really, around 2000rpm... especially bad in sixth

[007 VXR]

Most will do it in 6th at 2000rpm

try using a gear lower , should stop the drone.

[stigmundfreud]

an issue I had with the miltek on my old cv8 was that the exhaust would. over time, move back on the mounts (did it stock too) so it would end up vibrating against he bodywork

Araf whats that setup you have?

[bigwheel]

I see you've a '04 Monaro that will have a single, near-side exit exhaust.

Droning will not have been helped one bit by the single pipe after the Y-piece behind the cats. Certainly cheaper than twin pipes but it's a V8 that needs twin pipes by virtue of the V engine configuration.
Persevere with the single pipe and you're not going to get a solution.

[ARAF]

stigmundfreud said:

Araf whats that setup you have?

Standard boxes, with cutouts just before. The boxes seem to act as resonators when the cutouts are open, as we don't get any drone - which is usually worse on a Ute. This was all accidental, but I'm more than happy that it happened.

[rich24v]

bigwheel said:

I see you've a '04 Monaro that will have a single, near-side exit exhaust.

Droning will not have been helped one bit by the single pipe after the Y-piece behind the cats. Certainly cheaper than twin pipes but it's a V8 that needs twin pipes by virtue of the V engine configuration.
Persevere with the single pipe and you're not going to get a solution.

I would agree, single pipe system from cat back "Y" piece not good at all, I really think you will
struggle to get this anywhere near better. The "J" pipe (aka quarter wave pipe) mod does work quite
well with a straight through twin system with just rear boxes, but I doubt this fix will help
you much now...
What size tube did they use ?
I did a little work on my system a while ago, the qtr wave pipe did work,
still needs a bit more imo. http://www.lotuscarlton.co.uk/vxr8ex.htm

[ARAF]

StuRo said:

it's in most gears really, around 2000rpm... especially bad in sixth

1500-2000 revs seems to be bad for drone - which means you have to be exceeding the limit in top to stop it happening, or drop back to 5th.

[MyM8V8]

StuRo said:

Hi all,

It's been about 4 months now since purchasing my beloved CV8. Since then I have always felt, like many of you before me, that it feels like it's trying to disguise the fact that it is a V8.

So, on a budget, I've been looking at the various different options when it comes to the soundtrack...

The Wortec, i have to admit, sounds perfect...but that price tag puts me off somewhat. I know a lot of you say that it is well worth the money, but i just can't justify spending that much right now. On the other hand, however; I don't want to drown out the existing noise with a load of droneyness which according to some, is what would happen if I were to simply remove the cats/silencers/backbox...

So I went for somewhere in the middle... and had a custom stainless cat-back system made up and fitted yesterday.

Now revving it makes a nice noise and some burbly popping and banging usually follows.....BUT... there is quite a lot of drone... even when idling it's a little droney but mainly when under casual acceleration in a higher gear it gets very droney...

I went to this particular exhaust place on the back of both my neighbor's and a random bloke's recommendation (he said he took his C63 AMG there and came away very happy....why he would want to alter that AMG noise i have no idea...but anyway, I digress!) but now I'm beginning to doubt their workmanship.

The set up i now have is, from the stock Cats, into a Y-pipe and then a single large (not sure what diameter yet) pipe to a new back box/muffler (one of these straight through, perforated inner tube jobbys.

So yeah, long story short (bit late for that, i know): it's too droney! please help!

I know this topic must come up quite a lot and I've read through a lot of the previous threads, but I was hoping to get some fresh thoughts on what could be done/similar experiences people may have had etc..

sorry for rambling...thanks for reading (if you made it this far!) and thanks in advance for any suggestions/advice (i'm pretty new to both V8s and modding in general!)

cheers,

StuRo

Shame you didn't get some advice from forum members prior to making a decision based on a couple of people who, whilst well intentioned, know nothing about these cars and their idiosyncrasies, there is no need to re-invent the wheel (accepted that V8 exhaust tone is pretty subjective).

Hope you get sorted. I did a lot of messing about in the early days, welding up bits and pieces myself. Learnt a lot about how not to do it. There is another guy on here who is on his 4th or 5th iteration in building his own.

I know the Wortec is prohibitively expensive, but the sound is pretty hard to beat IMHO, although I'm looking forward to getting my 3" Kooks "street screamer" cat back from the states.

[StuRo]

Hmmmm... yeah, after having a proper look today at what they'd actually done, I did wonder why they would ditch the duel system!? I did specify a single tip but that was on the premise that the two pipes would merge at the back box anyway? (Like I mentioned earlier. .. I'm new to all this!) I think I'm right at the bottom of a decent sized learning curve!
Thanks for all the input thus far though guys

[MyM8V8]

StuRo said:

Hmmmm... yeah, after having a proper look today at what they'd actually done, I did wonder why they would ditch the duel system!?

That's easy. Profit.

At least you are having a go at it

[Drew SS]

Hi there well I've just done a new exhaust changed it around a bit i used to get drone nothing now I used a pacemaker H pipe this time and went from 2 into one with a magna flow box in the back end there's a minor adjust ment I have to make but all in all happy enough with it

[MyM8V8]

Drew SS said:

Hi there well I've just done a new exhaust changed it around a bit i used to get drone nothing now I used a pacemaker H pipe this time and went from 2 into one with a magna flow box in the back end there's a minor adjust ment I have to make but all in all happy enough with it

You can tell he's an Australian (now living in Ireland) can't you?

[Drew SS]

MyM8V8 said:

You can tell he's an Australian (now living in Ireland) can't you?

Ha ha not sure why they post upside down

[007 VXR]

Drew SS said:

MyM8V8 said:

You can tell he's an Australian (now living in Ireland) can't you?

Ha ha not sure why they post upside down

[Behold81]

Drew SS said:

MyM8V8 said:

You can tell he's an Australian (now living in Ireland) can't you?

Ha ha not sure why they post upside down

HA HA

[StuRo]

MyM8V8 said:

You can tell he's an Australian (now living in Ireland) can't you?

Hahaha!

Sorry for the delay guys, been on hols for 2 weeks. Thanks for the feedback too, much appreciated. I desperately need to get to one of these meets and meet some of you guys, trade experiences and check out other examples etc. Still haven't manages to get to one yet

Anyway going back to the issue at hand. ...I'm thinking of putting this down as a learning experience and starting from scratch! With that in mind, I've heard of people removing the middle silencers on the vxr models and being pretty pleased with the result... has anyone tried the same on an 04 CV8? Either that or removing the back box? Or will these both leave me with a load of unwanted drone again?

As always; any and all thoughts massively appreciated.

StuRo

[Behold81]

I have a VTII so the same exhaust config. I do have the winter in it and found removing my CATs caused a lot of drone without the centre boxes. So I have left them in. If there not hugely packed the difference in sound is more a rounding of the sound than a noise killer.

I have centres and rear in and it's still very loud!!!

This is with the centres in cats removed.

https://m.facebook.com/story.php?story_fbid=443874...