How to install a cat (convertor)

JMO · 10-07-2008, 01:22 PM

Just wanted to know what is involved in installing a high flow cat to the standard headers and a 2.5" cat back. Is it bolt on or is there welding/cutting involved?

Cheers.

**Peuty** · 10-07-2008, 01:47 PM

Quote:

Originally Posted by JMO

Is it bolt on or is there welding/cutting involved?

That all depends on what you have currently, some systems have the cat botled on, others have it welded.

JMO · 10-07-2008, 06:27 PM

I currently have the stock headers (manifold) and a 2.5" redback. the redback is bolted onto the current cat. I'm not sure how it is attached to the stock headers.

Assuming the stock cat isn't welded to the stock headers, is it possible to bolt a new high flow (or even a standard cat) into the system?

howesy · 10-07-2008, 07:14 PM

Just had 2 fitted and the original cats were welded to the headers and flange bolted at the rear to the rest of the system. The exhaust guy cut them off directly in front and behind and welded in new ones after flaring the pipe end on the flange side and the cat on the header side. Of course he had to unbolt and rebolt the flange to do this.

JMO · 10-07-2008, 08:09 PM

All the pics I've seen of magnaflows etc have just pipes either end. I just had a look-feel :P and it seems the standard cat has an extended pipe that curls up towards the standard headers and then bolts on. Unless anyone know if there is an AU specific cat, it looks like I'll have to take it to a shop.

bodes-sh · 10-07-2008, 08:35 PM

all cats are the same from ea - au, all same shape piping wise, if you really wanted to you could get it cut off, get a flange welded on and then new cat bolted in, probably cheaper than getting a factory one and makes it easier to replace if you have to again

JMO · 10-07-2008, 08:56 PM

Excuse the crappy paint image :P

So from what you're saying, I'd have the cat pipe cut on the red line in the image and have a flange welded onto the remaining pipe that leads up to the headers? As I said, I haven't seen any aftermarket cats that have the flanges either end, so I'd have to have them welded onto the cat I did buy anyway...

bodes-sh · 10-07-2008, 09:14 PM

yes, that's correct...they are pretty cheap tho, but as far as the cutting goes, that's the right spot

JMO · 10-07-2008, 09:20 PM

What's cheap? The cat? The welding of the flanges would have to be done by a shop because I haven't got the equipment or the skill to do it myself. :( It would also have to be done to each new cat I'd have installed (not that I'm planning on constantly buying knew ones) so that would cost me labor every time. I'm guessing that's what you're trying to say?

bodes-sh · 10-07-2008, 10:31 PM

i meant the flanges would be cheap. the welding wouldn't be much either....look at is this way, even if you get a cat just welded in you are going to have to pay to have it cut out and welded in again if you need to replace it again. but if you get flanges put on, then the next time, if there is one, you can just take the cat into a shop, get them to weld flanges on and then bolt it in yourself, it saves on labour for them doing it...

JMO · 10-07-2008, 10:45 PM

ok. makes sense. Basically I still need to take it into a shop and tell them to do it the way you've described.

Thanks for the info