Factory exhaust diameter

[sakis]

Hello all,

I recently bought a milltek downpipe for my mk2 tt-s, however I am fitting it onto the standard cat-back and need to buy a reducer but I am not certain of the factory cat-back diameter. Some say 63.5 while others say 60mm, anyone who can confirm?(assuming it's same size as s3, if some knows otherwise please tell)

Regards

 

[Kaine19]

If its same size as s3 then mine was 2.34mm if i remember rightly. I did same thing as you

 

[nluk100]

Well it's definitely not 2.34mm lol.

I think the differences come from inside bore diameter and outside diameter. You need a reducer to go from the 3" (?) Milltek to then slide over the outside of the catback, which IIRC is 63.5mm.

 

[Kaine19]

I meant inch lol