V6 Aftermarket exhaust, making it quieter.

[acarmody]

So I have a V6 with a normal 2.5" exhaust, single through muffler and resi on the back, and I have just bought myself a new exhaust, from what I can gather its a Cobra Performance 3" system with single straight-through muffler. I would like to make this exhaust quieter than my current one.

This is the exhaust I bought, http://cobraperformanceexhaust.com.a...Y_V8_Sedan.pdf, twin magnaflow 91006M cats, but the rear is straight pipe, no resi or anything. So possibly put a muffler on the rear too? Any advice would be helpful.

[2DIE]

3" is pretty big for a V6.

You should easily be able to get a muffler fitted to the rear at any exhaust shop. Possibly you could find the 3" clamp type muffler and you could do it yourself with a hacksaw and C clamps.

[acarmody]

3" for a cammed V6, a few people have said it will be alright.

It is a LS1 system so I suspect the cat pipes will be the wrong size to hook up to my extractor, and I don't have a welder.

I'm going to talk to my local exhaust shop tomorrow and see what they recommend, but I also want to know what people here think.

[TI3VOM]

I would still think that a single 3" would be too big for a cammed ecotec! What other mods do you have and how aggressive is the cam?

[acarmody]

A few other minor mods, and the cams not that aggressive, on last dyno run it made about 150rwkw.

Meh the exhaust was cheap, and it allows me to run dual cats, which it came with. I paid $315 (bless you eBay) for the whole exhaust, the cats plus LS1 pacemaker extractors, I then sold the extractors for $300, so really I paid $15 for this exhaust. I'm willing to give it a crack.

[TI3VOM]

A few other minor mods, and the cams not that aggressive, on last dyno run it made about 150rwkw.

Meh the exhaust was cheap, and it allows me to run dual cats, which it came with. I paid $315 (bless you eBay) for the whole exhaust, the cats plus LS1 pacemaker extractors, I then sold the extractors for $300, so really I paid $15 for this exhaust. I'm willing to give it a crack.

Hahaha got to love ebay, I just bought a powerdyne supercharger for $855 postage included, it just needs a filter.
Definantly give it a crack as for $15 plus some more it wont hurt!

[acarmody]

Hahaha got to love ebay, I just bought a powerdyne supercharger for $855 postage included, it just needs a filter.
Definantly give it a crack as for $15 plus some more it wont hurt!

You bastard LOL. For the VT V6? I how offically hate you LOL.

[TI3VOM]

Hahaha I know that's how I felt when bidding ended, but I contacted him and he held onto it for me for about 2 weeks, I paid and within 3 and a half days of paying it was here lol

Yeah mate it's for the VT, it will soon make enough power to match the suspension setup, then it will be onto the brakes.

[acarmody]

Well have fun drifting up those hill climbs!

[2DIE]

Not that its any use to you but I saw some Jap car while surfing the net years ago, the whole exhaust was 2.5 or 3" hotdogs welded together. Apparently it was pretty quiet and flowed like there was no mufflers on it.

[acarmody]

HAHA thats pretty fun, wonder how they thought that up?

[TI3VOM]

Well have fun drifting up those hill climbs!

Haha cheers mate I will.

[2DIE]

Found it, quote from the website:

"The car is deathly quiet and sounds stock - you can't tell its a modified exhaust and yet is 2.5" straight through. The car (4G93T powered) makes 200kW at the front wheels on pump 95."

[acarmody]

Thats an easy car to make an exhaust for, straight with one bend.

Man my thread went sideways, LOL.

[2DIE]

Sorry

How about a 3" rear muffler and a single hotdog as well as your front muffler? Id think that should tone it down a fair bit.

[acarmody]

Don't know if there is room for a muffler and a hotdog on the rear. I'm thinking just a second muffler on the rear, gotta be quieter than a hotdog?

[soop]

I can only suggest that you run a TWIN system. Even if its twin 2.5".

[Tsunamix]

Ok I run a sort of 3" / 2.5" hybrid system on a v6. The trick is to merge the gas flows BEFORE the cat. So you need a single cat, a single front muffler and a single resi. This is actually a reasonably quiet system. Full system is Extractors into y pipe into 3" Hi perf Cat, into 2.5" muffler into 2.5" resi.

3" is fine for the hotter gases. As they cool, they condense so the smaller 2.5 works well at the reare end.

Single 3" systems are fine for Supercharged / Turbocharged applications. Over exhausted for NA though. When the budget frees up enough to go FI I will replace the 2.5" sections with a 3".

[acarmody]

Ok so I visited a few local exhausts places today.

Place 1: 2 hours work at $77/h plus $35 for a resi for the back = $300. WTF. Either he meant $135 for the resi or MATHS FAIL. I even asked if he meant $200 or $300 and he said $300

Place 2: The cats will hang substantially lower than what it is now, so go a single 100cpi cat and retain your 2.5" system (or go the 3" system to lose street torque but gain high rpm power). $325 to supply and install cat and about $100 to install the 3" system if I want. OK so illegal here, with a fine that costs more than my car is worth. Also I can't see how the cats will hang about 2" lower when they will be about the same height as the extractor pipes??.

Can anyone recommend an exhaust place in Brisbane that won't try and up-sell or rip me off.

Ok I run a sort of 3" / 2.5" hybrid system on a v6. The trick is to merge the gas flows BEFORE the cat. So you need a single cat, a single front muffler and a single resi. This is actually a reasonably quiet system. Full system is Extractors into y pipe into 3" Hi perf Cat, into 2.5" muffler into 2.5" resi.

3" is fine for the hotter gases. As they cool, they condense so the smaller 2.5 works well at the reare end.

The second one option sound like what you said. Onlu I'm guessing with maybe a good 200cpi cat.

[don0xer]

if your worried about illegal exhaust, even if you had a stock exhaust you probably wont past an emissions test with a cam. iirc a few yrs ago somone did an emissions test on a stock as a rock ls1 and it didnt even pass....

[acarmody]

If you get tested and you fail emissions with a crap cat, thats just old and FUBAR you might get out of a fine, if you have a brand new 100cpi cat you might as well bitch slap the inspector at the same time because you have blatantly broken the law.

[2004_VZ_Acclaim]

Can anyone recommend an exhaust place in Brisbane that won't try and up-sell or rip me off.

I recommend Fat Pipes in Kallangur, myself and 5 mates/people i associate with have had happy results coming out of here, friendly guys, great prices (got a quote for some work yesterday, had it done today and gave me a better sounding and cheaper alternative instead) and they get the job done quick as well

A bit of overkill but if still in doubt

Fat Pipes Custom Exhausts
Fat Pipes Feedback. - CruisingBrisbane.com
Fat Pipes Custom Exhausts | Facebook

And Les, the owners own Chevelle SS, just because it's so awesome :P

YouTube - Black Chevelle TUF454 powerskid at Queensland Powercruise 2010

[acarmody]

HAHA one of my customers at work last night highly recommended Fat Pipes and said Les was a top bloke. Also said Rob Bliss at Geebung, but told me to definitely talk to Les. This customer owns some hotrods so I'm guessing he know what hes talking about.

[acarmody]

Talked to the boys at Fat Pipes, he goes about $50 to modify the cat pipes, another $50 for a rear resi fitted, so about $100 all fitted, maybe a bit more if any more work has to be done. F'ing good deal to me.

Also I didn't see the Chev SS, but I did see two awesome customer cars.





Yes that is a Rolls-Royce and yes it does have a crank-start handle at the front. F'ing AWESOME.

[Tsunamix]

Funnily enough - My system was done by Rob Bliss. @ votes for him.

DONT DONT DONT use Jack Beedhams at Redcliffe. Chheap as chips, and will bash your chassis rails with a hammer to get the clearance to easily fit shit.