1.8 downpipe on 1.6
 

Anyone know if I can use a NA [turbo] 1.8 DP on a 1.6 if I have a custom exhaust made?

Downpipe clearance is good?

I've done the swap myself...

The downpipes will swap if you swap the cat with them as the 1.8 cat is longer.

The only snag is the O2 bung on the 1.8 is on the downpipe vs. the header collector on the 1.6.

The downstream end of the cat ends at the same position on the 1.8 and 1.6. This is on NA's.

/thread

I assume we're talking about turbo downpipes, right? I don't think it makes any difference though.

I always understood the 1.8 dp to be longer than the 1.6 dp (from Sam01's thread). Since you say the cat is also longer on the 1.8, how can the 1.6 & 1.8 cat end at the same location?

Longer dp (1.8) and longer cat (1.8) can't be the same as the 1.6 end position of the cat, right? Unless I'm mistaken and the DP is shorter on the 1.8.

Woops. I assumed you were talking about the stock downpipes.

I know for a fact that the 1.8 cat is longer, and in stock form the 1.8 pipe is shorter to accommodate for said difference. The 1.6 and 1.8 cats end in the same position as I've swapped cat and downpipe from a 1.8 for emissions purposes. Actually less than a week ago.