My sisters husband has a 2003 nissan sentra spec v...he is about to buy the nismo header and he was wandering which one he should get...theres one with a cat built into the header and he dont know if he should get the one with no cat or with a cat...as far as performance what kind of differences does it make...?
Thanks

 

On the factory exhaust with the cat in the manifold, the cat has been breaking up and then getting sucked back into the engine and wrecking the exhaust valves. This happens because Nissan uses the variable cam timing to bring exhaust back into the engine instead of an EGR valve. I have not heard if the aftermarket ones do the same. Does the one with no cat in the header have one further down the exhaust? If not cat, the check engine light will not be happy.

My guess is the one with no cat in the header will make more power due to being able to have longer pipes before the collector but if no cat at all will not be street legal. The cat up close is to heat it up really fast for cold start emmisions, one further down will just take slightly longer to heat up and work.

 

Thanks man which one would you recommend??