I have the Megan cat-back which is 3" with no taper, how do I mount it to the stock cat which is 2.5"? Does it have to be cut or modified? Anyone else with this problem? I don't want to add anymore to the exhaust (cat-delete,3" cat, or another downpipe). Please help!!!!!!!!!! Thanks

 

they didnt come with nuts and bolts? catbacks are just direct bolt on usually

 

Yes it came with all the hardware, the issue is that the stock cat is 2.5" and the exhaust, which has no taper, is 3"

 

I have the full megan turbo back. when I first got it the test pipe was on back order. I put the rest on anyway with the stock cat. I didn't have any problems with the cat back part. I did have to enlarge the bolt holes on the dp side though.

 

it should just bolt right up even though the exhaust is a diff. size then the cat

 

I had the same problem before I got my testpipe. You will need to make the holes bigger if you want to mount it to the stock cat. You may get an exhaust leak bolting the 3in to the 2.5 cat though.

 

Thanks everybody. Sorry to sound ignorant, but larger holes on the cat flange or the exhaust?

 

I did exhaust.

 

Won't there be a huge exhaust leak goin from 3 inch flange to the 2.5 inch flange?

 

If I put a new stock cat gasket on and bolt the exhaust to it, the exhaust flange has enough coverage to prevent leak? What did all you Megan cat-back only exhaust owners do? (that diden't add the dp and testpipe)?

 

i put a 3" testpipe on a stock exhaust and everything worked fine. i know this is kinda backwards from what ur doing, but same difference. everything really should bolt up fine. have u gone underneath the car and tried it yet, or ur just talking about it?

 

You will need to dremel about 2mm out of the inside of the Megan bolt holes... with the OE cat gasket, it should not leak. I ran to inspection this way. The OE cat chokes flow on a Turbo back enough to easily "feel" though.