Sooner or later I will be getting another exhaust system made up to suit my supercharged inline 6.

I currently have pacemaker 4480s, hiflow metal core cat, 2.5" mandrel bent redback system consisting of hot dog resi, straight thru offset muffler, and rear resi in tail pipe. At the moment its very quiet. Not quite as quiet as a stock system, but quiet compared to most performance applications out there. It currently maxed out power wise and I cannot get anymore power out of my existing setup. A higher flowing system is definitely required.

Suggestions of a 3" system and modifying the collector on the headers to accept a proper 3" in/out cat was recommended. The flow of this sounds great, but I do not want to risk the extra noise.

I know I will need to accept a bit more Db from a new system, but I'd like to research the options on what system I can have or what I can do to keep noise levels to a minimum and still maintain maximum flow.

Can anyone suggest good options for my application?

It needs the following:
- maintain same cross sectional area as a 3" single system
- minimize Db level to a moderate level
- minimum cost by looking at possible option of 2nd hand mufflers, cats and resi's.

Does anyone know of alternate systems other than a single 3" all the way?
Could I use say a second hand xr6 turbo cat with the single 2" inlet and 3" outlet? (refer to pics)




Could running twin 2" pipes to a large muffler with a 3" outlet be of any benefit as shown above?

Maintaining similar or better cross sectional flow to a 3" single system is a must, and it needs to flow up to 250rwkw. 250rwkw is pretty much my limit on a stock intech motor and auto. I plan on fitting a bigger cam later on as a possibility so that power is basically what it could be eventually once the cam is fitted with more boost. But that is something Id like the room for later on. This current exhaust has reached its full potential now and cannot flow anymore without removing resi's which I do not want to do. So it needs to go.

If there is any other critical information I have missed from this, please let me know.

Shav, mine is 3 inch and very quiet on my AU.

It goes Pacemakers, 3" cat, hotdog, then system splits into two pipes (2.5" I think), through two big straight thru mufflers, system then rejoins to 3" and finishes with a muffler just behind rear bumper.

This system I think has a nice note, is relatively quiet, and has plenty of flow for more power. Its currently making 220rwkw and the restriction is not in the exhaust.

Cheers,

Joe

that sounds great joe. You wouldn't have any sound files would you? Also what brand parts did u use? I'm intrigued... Lol

No sound files sorry Shav. Not that in to recordings of falcon exhausts! And not sure of parts fitted, other than the cat, as it was all on the car when I bought it 4 years ago. The cat I think is a magnaflow....or maybe 'steelcat'? I can't remember!

I don't think the muffler brand is so important....more so that the cross sectional area remains large, there are lots of mufflers, two of them are big, and everything is straight through. The previous owner requested a high flowing quiet exhaust (he was 75!) and this is what the exhaust shop fitted.

Joe

interesting indeed. So if I'm reading this correct, you have a twin system coming from the hot dog which is after the cat, then the splits to twins which go into 2 large chamber straight thru mufflers, then back into single 3' tail pipe with a resi? Sorry if I sound demented but I'm just trying to picture what it looks like in my head.

How does the pipes rejoin to form the single 3'? Is it via a collector or via the resi?

Yes that's kind of right Shav. It splits into two pipes after the hotdog, and rejoins to a single system after the two large mufflers. Both times it splits/rejoins is via a collector, rather than two pipes coming out a hotdog or muffler.

Basically the purpose of the split is so the exhaust gas has to travel through more mufflers, which reduces the noise without impeding flow.

Joe

Id definatly be using magnaflow or lukey products if u want high flow with a nice note and not loud

thanks fellas, this sounds like a top idea. If its ok with you Joe, I'd like to replicate this system for my car.

Shav I have no ownership over the path of a few pipes! Go for it...it works well for me.

Just thought Id run it past ya mate. Some people get funny about it. You know how it is.