Kerngator

I have 1998 z28 with normal cats on my car and I'm looking to upgrade to some spintech high flow cats, but is it worth the cost for the gains?

redtan

iTrader: (5)

Depends on what you consider "worth".

To some people, $200 is worth the 10hp you might gain with HF cats. To some, it's not. All up to you really.

RPM WS6

iTrader: (3)

Is the car completely stock otherwise?

If so, the gain would be marginal at best and not worth the cost IMO. Even complete cat delete on an otherwise stock exhaust manifold/stock engine car isn't going to provide big gains. So I wouldn't expect much at all from a "hi-flow" cat swap unless yours are clogged.

demonspeed

iTrader: (7)

I certainly wouldn't even bother unless I was doing long tubes.

MonmouthCtyLS7

iTrader: (6)

Unless your pushing serious power the gains will be minimal at best.

WS6wanted

To give you an idea of numbers, i have 2 magnaflow hi flow 3inch cats, texas speed 1 3/4 longtubes with magnaflow catback and lid and got 310 whp on my 98. I doubt you would get more than a couple of hp unless you get into heads and cam.

American Psycho

Do you live in an area where you have to pass emissions? That is the only reason why I would leave cats on my car.

MadFirehawk86

iTrader: (2)

IMHO dont even bother....if you do not live in a place that has inspections just save up for some long tubes or spend the money else where... the money spent on "high flow" cats is not worth the gain that you will get...it will be marginal at best. Even if you went with a cat less y pipe with the factory exhaust manifolds you wouldnt get much of a gain...longtube headers is where its at.

99Bluz28

iTrader: (35)

IMO, if the factory cats are damaged and need to be replaced, and you don't live in California then yes the swap to high/flow less expensive cats is worth it. Otherwise no, leave the factory cats on the car.