I need to find out if N/a S4 cats will fit S5 N/a cars.

Searching didn't help me much as most of it was gutting cats and buying high flow units.



Santiago

 

I believe that they do not fit....the S5 has one Precat and one main cat, while the S4 has 2 pre-cats, and one main cat.........there might be a length difference because of that.....I am not 100% positive though.

 

i was trying to figure this one out too. my cousin has an s4 that needs to pass smog and i have the cats for my s5. haven't tried to swap them out yet though.

john

 

Some one has to have the measurements on whether or not it can be done

 

bump!

 

i know the anwser...they are the same. i had an 87 n/a before i got my s5 and i took off the s4's emmisions before i sold it so i had the old cats layin around for a few years, but i compared the two when i removed all the s5 stuff. the s4 stuff might of had more shielding but it all was the same, fit the same atleast. also the s4 emmisions are as equally worthless as the s5 emmisions...

 

Well, we know they didnt change the cat back portion of the exhaust, and im PRETTY sure the n/a exhaust manifold outlet wasnt changed, that being said s5 cats SHOULD fit between a s4 exhaust manifold and y-pipe. Now the split air pipe is another story.