Compliance Cat Flange Size?

[kidafa]

Hi All,

Was just wondering what size the compliances cats are in our cars? Im thinking they'd be 2.5" hay? Ive got a full 3" system with a Hi-Flowed compliance cat .....

If its a 2.5" flanged cat it would be the equivalent of having a baffle plate in their and hold me back a bit would it? Would it be worth pissing it off and getting a 3 inch flanged cat and "hi flowing" it

[Daleo]

Has it been "hi flowed" properly? They should have a pipe sleeve running through the middle. If not, the change in internal size will be a restriction. You'd be better off with a quality Hi flow 3" cat, they don't hurt power that much. And it's all legit then

Note; No responsibility will be taken if you use this post to render a cat inoperative. It's there for a reason, if you're that worried about the extra couple of hp, turn off your aircon, or go on a diet.

Be aware that the EPA in NSW do trawl the forums looking for just this type of post to find people breaking the law.

[BensDR30]

Chris, I bought a 3" Catco one from JJR - at less than $220 delivered, you can't go wrong.

Yes, the ID of the flanges is 2.5", and a 'gutted' cat does screw up the flow - simply by being an awfully shaped vessel.

If you really don't want to run a cat (remember that it is a Stagea, not a 400R ), get a decat pipe (for the track) or one of these:

http://www.frozenboost.com/product_info.ph...products_id=320

[kidafa]

When I hi flowed it, it upped boost and was providing smoother power (used to have a bit or jerk). Many mixed opinions on gutted cats from different mechanics and stag drivers. Im more for it but I may get a catco then and prob bash its guts out aswell.

[DSTROY]

Get a Catco 3inch cat but don't bash the insides out, it wont make any difference. Only thing you'll gain from no cat is a dirty stain on the back of your car. Hence why i still run a cat in my 300+kw skyline on the street.