SV6 Exhaust - Big Issue

[BLAKVZ]

Hey guys,

New to the site. I'm aware there'd be tonnes of exhaust queries/issues on here bit I think mines rather different? I've owned the commodore for a couple of years now (Alloy190). I had a twin 2 1/2" exhaust system on the car, advance headers, twin high flows which I quickly realised was to big for the engine and I found when the rpm climbed through from 3000rpm to approx 4500-5000rpm the exhaust noise took on a whole different sound. It was making a braspy wet fart noise so to speak. So I downgraded the system to a single from headers back and I still have this ridiculously annoying noise mid rpm range, not quite as loud as the twin system. Its rather embarrassing.

I'd like to know whether other members have encountered this problem and what they did to achieve a far better exhaust noise. I've checked out plenty of youtube vids with the same system sizings but from different manufacturers which sound amazing and left me wondering where I went wrong with mine & what I can do to fix. Money is not an issue if more changes need to happen.

Any help would be greatly appreciated.
Cheers, Mick.

[impulsive]

Hey guys,

New to the site. I'm aware there'd be tonnes of exhaust queries/issues on here bit I think mines rather different? I've owned the commodore for a couple of years now (Alloy190). I had a twin 2 1/2" exhaust system on the car, advance headers, twin high flows which I quickly realised was to big for the engine and I found when the rpm climbed through from 3000rpm to approx 4500-5000rpm the exhaust noise took on a whole different sound. It was making a braspy wet fart noise so to speak. So I downgraded the system to a single from headers back and I still have this ridiculously annoying noise mid rpm range, not quite as loud as the twin system. Its rather embarrassing.

I'd like to know whether other members have encountered this problem and what they did to achieve a far better exhaust noise. I've checked out plenty of youtube vids with the same system sizings but from different manufacturers which sound amazing and left me wondering where I went wrong with mine & what I can do to fix. Money is not an issue if more changes need to happen.

Any help would be greatly appreciated.
Cheers, Mick.

A lot of people are going pacemaker headers, and high flow cats, it appears that the high flow cats are causing the 'wet fart' sound and the extractors are amplifying it with a little more flow..

"I" Reccomend Pacemaker headers, standard cats with a widened housing, 2.25 inch exhaust to one 2.5 inch single, straight through hi-flow muffler and resignator at the end..

Although it does sound good in real life i havent managed to get a decent video up of it..

The other option i have heard is good is the X-Force 2.25" twin catback with Pacemakers and hiflow cats..

[BLAKVZ]

Okay, thanks for the reply mate.
I had the idea to change back to standard cats, but a bloke from a local exhaust shop told me the price of standard cats and I thought shit, might as well just keep the highflows on. However if it wil rule out the noise Im happy to spend & change.

Thanks for heads up mate

[bigdaddycool]

I'll 100% agree with Impulsive on this one.

In the same boat BlakVZ. To cut a long story short. I got VZ Exec, pacemaker headers, 150cell high flows....... into single middle muffer and rear resonator but I also have 2 glass packed straight thru resonators on mine just after the cats before the center joint to solve this problem.

The problem is the cats, you probably didn't get the pacemaker cats designed for the headers like me I'm guessing and thats where the problem is coming from.

You can either do what I did if you want a quick fix, just get two tiny glass packed straight thru resonators added just after the cats.......... which will solve that problem.......... or get the right cats designed for the headers.

Check out this link >

Pacemaker Headers PH5367

I'm gunna get those eventually and get rid of my current ones.

[BLAKVZ]

Great, thanks mate. Appreciate the help

[Verds]

How much is it for the paceie setup. I had pacemakers on my old falcon inc high flow cats etc... and it sounded and performed awesome ... for just an exhaust ... with an upgrade on the CAI it was even better

[impulsive]

How much is it for the paceie setup. I had pacemakers on my old falcon inc high flow cats etc... and it sounded and performed awesome ... for just an exhaust ... with an upgrade on the CAI it was even better

i think i paid bout a $700 for them fitted, i know i got it pretty cheap, not exactly positive though

[Kal123]

$850 for Ceramic Coated Pacies Installed..

[impulsive]

dont ceramic coated pacies stuff with the 02 sensors?

[Kal123]

Nope not that I've heard, I know of a few people with CC Pacies on Alloytec's and they are fine..

[Kal123]

I'm now in the same boat as you BLACKVZ.

Today I had CC Pacemakers installed, and after 3000rpm, the note turns to shit, and sounds like a lancer with a canon...

So far my system is CC Pacies into standard cats, into twin 2.25.

I've reread a million exhaust threads, but they all seam to contradict each other lol. Most people blame the high-flow cats for this horric note after 3k, but i've kept standard cats... So this can't be the case.

I'll try and post a vid/sound clip of my exhaust, just need to find some time.

[Kal123]

"I" Reccomend Pacemaker headers, standard cats with a widened housing, 2.25 inch exhaust to one 2.5 inch single, straight through hi-flow muffler and resignator at the end..

Although it does sound good in real life i havent managed to get a decent video up of it..

The other option i have heard is good is the X-Force 2.25" twin catback with Pacemakers and hiflow cats..

Hey Impulsive, are you able to make me a vid or sound file? Andrew from hi-flow widened my cats as well... So our systems should be pretty similar....

I may just have to get rid of the twin system completely, and try something similar to yours...

[Not_An_Abba_Fan]

I am experimenting with an SV6 at the moment. It has stainless Hi Tech headers, hi flow cats, a twin 2 1/4" into single 3". The system goes twin off the cats into two straight through mufflers, out of the mufflers into a collector into 3" then into a 12" long 6" round resonator with twin 2 1/4" outlets.

That gave a huge improvement in torque right across the range, but it was quiet. I removed the front mufflers and replaced them with hot dogs, this made it louder but also higher pitched and developed that raspy note above 3000 rpm.

The next step is to replace the rear with a smaller resonator and a single 3" outlet. We took the rear muffler off and just had it running out of the 3" pipe under the car, it was loud and deep, but still had a weird note accelerating through 2500-3000rpm, once it was cruising it sounded nice. The single outlet rear with a resonator may work, I'll keep you posted.

kal123, do you still have the resonators after the cats? They look like cats as well, they are just in front of the two flanges that the exhaust bolts to.

[Kal123]

kal123, do you still have the resonators after the cats? They look like cats as well, they are just in front of the two flanges that the exhaust bolts to.

As far as I can tell, it doesn't...

[Not_An_Abba_Fan]

I think they may be the key. Removing them causes the poxy note.

[Kal123]

Ooooooh awesome, might look at getting some put back in. Will this make it much quieter?

[Not_An_Abba_Fan]

No, not a lot quieter, just a bit smoother and hopefully get rid of that raspiness.

[Kal123]

Sweet as, do you have a rough idea of the cost and time it'll take to put them in?

[Not_An_Abba_Fan]

Any small resonator should work. The originals are spiral louvre so a spiral louvre hotdog should be fine. Just make sure they are fitted with the openings on the louvres facing backwards. They are around $35 each. Should only take about an hour or so to fit them.

[Kal123]

Sweet, the exhaust note has actually changed a little after the first few days.. It's no as raspy at high rpm's now.. But still has that annoying tone..

[bigdaddycool]

yeh putting two resonators (straight thru glass packed) before the front flange peices will quiten down any exhaust and smooth the note out.

However that said, it didn't fix my problem when I had twin 2.5" ...... it quitened it a bit, but it was still loud.

I was impressed tho when I bolted my old system back on which had the rear resonator sounding like a tin can....... it removed the sound and just made it sound nice........ girgly air.

[mdmatt]

I've got the pacemaker headers to twin 2 1/2" exhaust... standard cats.. on my alloytec(190) SVZ ute.. sounds wicked and the performance is sweet.