Quote:
Originally Posted by CamaroCracka
If I used a shorty header, I would not bother with a hi-flow cat. Stock cats are not that restrictive to notice a power difference if you are only using shorty headers.
|
I think you reversed the recommendation. The factory high flow cats are the biggest restrictive piece in the entire factory exhaust system.
OP, welcome to the forums and congrats on your new to you ride. Unfortunately for modifying your new ride you are in the most restrictive state in the union. Unless you're buying long tube headers second hand you won't get a manufacturer to send them to you, from what I understand. Many have tried, but they are illegal in CA. If you can get away with high flow cats in CA I'd do them first or at all over shorty headers. If you can't get away with them then shorty headers are said to have some gains, but it's very marginal. They get maybe as much gain as a cold air intake, if that.
As for cutting down noise, put the factory cats back in with stock manifolds or shorty headers and that should get you legal or close to legal. Long tube headers with or without high flow cats and high flow cats by themselves will make the car louder than factory. Shorty headers might add some volume, but not a crazy amount when paired with factory cats.
As others have said, make sure you get CARB compliant shortys if you get them and whatever you do, if it's not 100% CA compliant, plan on a day/afternoon to swap them over and another day/afternoon to swap them back.