Exhaust Cat Gasket

[Hansfishberg]

Just fitted a new catback exhaust and it seems to be blowing from where the catback connects to the catalytic converter. Had a look inside and the gasket is completely worn, which would explain the blowing. The catalytic converter is stock however the exhaust system is 3". Could anyone advise me on which gasket I should be looking to buy? Does it only depend on diameter?

Edit:

This what I'm after?

http://www.camskill.co.uk/m22b0s1400p56463/MITSUBISHI_LEGNUM_GALANT_VR4_%28EC5W_EC5A%29_-_SERVICING_PARTS_TUNING_SPARES_and_SERVICE_ACCESSO RIES_-_Middle_Section_to_Catalyst_Gasket_-_Legnum_VR4_EC5W_Galant_VR4_EC5A

[Colin Wiltshire]

I'd say a normal 3" gasket will be fine, I've used that on mine. I go on Ebay normally

[Hansfishberg]

Will this do?

http://www.ebay.co.uk/itm/3-76mm-Universal-Performance-Exhaust-Gasket-2-Hole-/220693109699?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3362559bc3

[Colin Wiltshire]

That's fine

[Hansfishberg]

Hmm it seems like this didn't fit as the cat is 2" whereas the exhaust is 3" so it just gives enough clearance but am doubtful it would seal properly. For now my mechanic just sealed it using exhaust sealant and this seems to have done the trick (dont think this will last imho). Does anyone know if anywhere I can purchase a 2" gasket with really thick outer edge that will seal a 3" pipe?

[Colin Wiltshire]

I thought the cat used 3" flanges, so the fact that it is mating to a 3" pipe shouldn't matter. I use 3" gaskets when putting my cat back on with no problems.

[Hansfishberg]

It did fit however the edge of the 3" gasket had very little leeway for movement when covering the 2" pipe, any movement and the pipe would not be sitting coincident with the inner radius of the gasket.

I don't think the CAT uses 3" flanges?