Welding 2.5" outlet to 172 ph2 cat

[Gaverick]

Anybody done this? I've read the threads about modding the 182 cat with a 2.5" pipe but nothing on the 172 cat.

The flange on my cat is warped in the middle so blows like a good 'un, currently caked in exhaust putty but it cracks off and leaks again after a week or so.

Thinking of cutting off the current cat outlet and welding on a 2.5" piece of pipe as I have a KTEC Stealth so I can sleeve it straight on to that by taking the adapter out.

 

[1812lsd]

Not sure about the 172 cat, but, High Temp Silicon is your friend, ditch the exhaust putty.

 

[Gaverick]

Used that originally, still didn't hold up. I'm sick of temporary repairs now it's about time I fixed it once and for all. I've ordered a 500mm length of 63.5mm tube so will start on this soon.

 

[viperjsy]

all I can sugest is give it TRY

 

[Gaverick]

Will be trying it shortly, will keep this updated and try and get some pics for future reference.

 

[viperjsy]

I will look forward to see how you get on

 

[Gaverick]

Some preliminary mock up done today and I don't see any major obstacles, looking for a spare cat to practice on.

 

[Gaverick]

So I managed to get hold of a second hand cat and set about chopping last night. I cut the standard outlet off just before the weld and then put a couple of notches down each side to allow the bigger diameter pipe to sit flush. First impressions are good, looks a nice fit and will seal well. It's off with a friend for welding at the moment, I'll hopefully have it back for the weekend.

Cut off standard outlet


Notched the sides


Mocked up the new pipe for fitment

 

[viperjsy]

that's looking good m8

 

[Gaverick]

Got the cat back today welded up. My friend had some trouble with the welding with the stainless pipe being thin (1.5mm) and the cat being mild steel, but it's on there now. If you are thinking about doing this I would suggest slightly thicker pipe or a mild steel pipe instead of stainless. Forgot to take any pics sorry.

I'm now going to wait until payday before fitting as I want to get a genuine cat fitting kit and a couple of new clamps.