DIY downpipe questions.......

i am going to make my own downpipe w/ parts from kteller. for right now i’m keeping my cat, so i was wondering if 2.5 piping will bolt up to my stock cat. ok? i was going to get the 2 bolt 2.5 flange, and the 2 bolt 2.5 gasket. will that gasket work since it’s not a donut type like oem? also, does anyone know the nut size for an o2 bung? i have a regular garrett t3 w/ .42/.48 and wanted to make sure i ordered the right exhaust flange. kteller list a big and small t3 discharge flange, how do i know if mine is a mercedes type etc.?

thanx for the help guys!

A 2.5" will not bolt up to your stock cat. You’ll need some sort of reducer.

02 bung thread is M18 x 1.5

thanx chris! places to get a reducer? local parts store maybe?

local retail performance shops should have mandrel bends in stock. if your not running a/c, I’d reccomend a 3"DP for a decrease in spool time. 3" u/j bend is maybe $8-10 more than a 2.5". for an a/c compatible system 2.5" is the easiest to fit.

edit 3" is a bitch to fit, if your compressor is facing the passanger side. I forgot how shitty the stock crossmember is.

yeah, i’m trying to keep a/c. so, i should use the reducer and a regular donut gasket?