Headers/Cats Question

[jbray1984]

This has probably been covered and if so, Sorry... Just link me to where I can find it. As my searches came up pretty dry..
But what's the difference between


4 into 1: 1”5/8 primary , 2.5” secondary;
4 into 1: 1”3/4 primary , 3” secondary;
4 into 1: Step-up (1"5/8 to 1”3/4) primary , 3” secondary;


I wanna get extractors/cats etc for my SS but I don't understand the whole difference and what I should be going for.
And as for cats is there something I want to be looking for or staying away from? 100 rating on the cats alright?

Bit dumb on this side of things, so thought I'd jump on here and ask
Hopefully there's no stupid questions

 

[Not_An_Abba_Fan]

Depends on what system you have. Match the headers and cats to that.

But really, it makes no real noticeable difference what size you go for on the extractors. With modern EFI engines, the PCM has a range of maps it references when calculating how much fuel and timing to throw at the engine. I say go big. 1 7/8" primay 4-1 with either a 3" or 2 1/2" outlet depending on the system. Don't go 100 cell cats, they are illegal.

 

[jbray1984]

I was looking at this is all..

Xforce Commodore VE V8 Stainless Headers HI Flow Cats | eBay

Says it comes with 100 cats.
It's currently got a 3" Xforce cat back system on it. So this should match up pretty alright.
But is 3/4

 

[Not_An_Abba_Fan]

No comment....

 

[jbray1984]

That's helpful.
Lol.

Also, how much louder would something like this be?
Like.. Illegal amounts of loud?

VE SS SV6 Sedan Wagon UTE 3" Tailpipes | eBay

 

[anarklov3r]

I wouldn't bother with buying XFORCE gear brand new. They're honestly built pretty poorly. Not an Abba Fan (who is JC Forums go-to exhaust guy) can get you quality australia made and developed exhausts (not cheap asian copies like xforce) for a very similar price. I've had a Manta twin 2.5" exhaust from NAAF and honestly, best exhaust ive ever had and sounds awesome with zero drone.

Those 3" tailpipes will sound tough at idle, but thats about it. Will be raspy as hell and drone like crazy. There's no real performance plus of going for a 100cell cat, so keep it legal and geta 200cell (factory is like 400-600?)

I'm sure NAAF will be willing to hook you up with a quality exhaust. He will even ship it straight out to you for peanuts.

 

[jbray1984]

Oh okay, well fair enough.
The reason I'm asking is I currently have a 3" Xforce Stainless Cat back, but the rear mufflers are rusted out to no end so need replacing.

 

[Black X]

That hasn't lasted too long. I was considering an X Force even though people were saying how crap they were. I think this has convinced me to look elsewhere.

 

[Slick6]

My manta 3" stainless has been on my VE car for 6 years and about 80,000km and is still in great condition.

I live close to the coast and it hasn't rusted out, ironically i gave my stock rear mufflers to my old man for his SV6 and they have since rusted through.

Would buy another Manta tomorrow with no hesitation

 

[Slick6]

I've also got Pacemaker 1 3/4 and Manta cats which mate up to the catback no problems. Great system, great sound!