EK1 High flow cat Q's

[PHD]

has anyone know about the stock size cat for EK1?

if i want to get aftermarket high flow cat with stock pipe, is there any gain?
what will be the best size for aftermarket high flow cat in EK1?

PHD

[Jord]

i didnt think that high flow cats made a huge difference on NA cars... i have always been told they should be left for turbo cars?! stock it is a 2inch pipe im pretty sure just got mine replaced. i just used a Cat off a VTIR teg and modified it to fit! cheap and easy fix if your cat is ****ed!

[turtleEK1]

The y4 exhaust it quite restrictive because was built for economy in mind, not performance.

So even if you do put in a high flow cat, will free up a little, but nothing you will really notice.

To get full potential, will require full exhaust upgrade!

[Limbo]

You prob have 1 3/4" piping and cat.
You will see a difference in the highflow cat, as the cat is the most restrictive in the exhaust.
A 2" highflow/metal cat will give slight improvements, and will match future exhaust mods for D series engines (NA motors anyway)