I understand exhausts have been posted to death on here, but my question is more of a what to do, rather than what to buy.

I've needed a new cat for a while now. I've wanted a cat-back for quite a while too. Thought I'd kill two stones with one bird and do 'em both, and find a nice 2nd hand set of extractors to go along with them. But most extractors apart from the Genies seem to be much longer than the stock manifold, and even then Genies seem to have a different flange?

I'm not too fussed about a hi-flow cat. If it's easier and not too much more expensive I'll pick one up, but I'm assuming they're gonna need flanges welded onto them, or else straight onto the headers and zorst? If I was to get, for example, some Pacey 4499s, a cat back and a relatively good nic stock cat, could I cut the excess pipe off the engine side of the cat, weld the flange back on and Bob's you're uncle? But I guess either way, it's gonna need some welding.

I know you can get cats like this that apparently bolt straight on, but I don't want to spend heaps if I can get away with it.

The other alternative is getting all the work done by a pro, but where's the fun in that?

unless you can weld, fitting extractors is not a home job.

I've got an uncle who's good with his metalwork and could do it for me in exchange for a sixer, but it's a 45 minute drive :/

But the actual question is what is required. Which parts would weld up, and which would bolt on, ie an exhaust that bolts up to the standard cat, would I just need to reposition the flange on the other side?

Do you know much about the 'direct fit' cats designed for the paceys?

cat back bolts to the cat with no problem.
Need to modify the cat in order to fit any extractors.

Well in that case, if it needs to be modified regardless and I'm in need of a new cat anyway, is it worth forking out the extra whatever and getting a higher flow cat?

Then if I test fit the system and measure where the cat flanges need to be, once they're welded on its bolt on and ready to go. Sounds like a plan

The flanges need to be welded on the car. You will never measure and weld off the car and have it fit properly.

As mentioned...

If you have a std cat... You cut front and rear pipes off the cat... Grind all the back of the cat back out with a die grinder so the rear pipe you cut off will slide into the back of the cat... Cut the rear section to the required length by pacemaker and slide into the back of the cat, we also "knife edged" the front of the pipe where it goes inside the back of the cat to give it that "high flow" effect (probably sweet stuff all in reality, but we weren't paying for labour)... You align it and tack it in place...

You chop the front pipe to the angle required and bolt all into the car... align the exhaust and then tack the front flange to the cat...

Once you're happy then remove the cat and weld the outsides and inside the front flange and again we ground it down with a die grinder to help funnel the air and make sure no parts protruded...

If you want to you can spend half to 3/4 of a day doing it just fiddling around to get it right... And a hoist is going to make welding upside down under a car a hell of a lot easier too I might add...

Pacemaker instructions straight off their website...
http://www.pacemaker.com.au/FittingInst ... 204499.pdf
(Note two per page so pacemaker can save on paper, this is what will be included in your extractors)

Make sure you clip a battery minder on the car battery when you weld on the car to protect the electronics...

Cheers,
Tim

Just the answer I was looking for, thanks! I imagined that was what's needed but wanted to check with someone who has done it. Ill follow what you did, with the tack welds and stuff. I did a little with the school's MIG last year, but not enough to say I 'know' how to weld, so looks like I'm making the 45 minute drive. But it doesn't seem too difficult (for someone who knows how to weld) by the sounds of it to justify paying too much extra for labour. Once those flanges are done it sounds a piece of piss bolting it on