If I remove the hi-flow cat and put a straight pipe on will the SES light go on???

 

Nope. No o2 sensors after the y-pipe. I'm running catless.

 

Thats untrue. If you have a FedSpec car, putting in a racing pipe will cause an SES because there is an 02 sensor right after the cat. The reason why the CaliSpec cars dont get the SES lights is because the O2 sensors are looking at the precats. FedSpec doesnt have precats.

Dixit

 

What are those small boxy looking thingys coming off the exhaust manifolds then ??

 

Freeflow is always better

 

Well my fault in not making myself clear, it has a small precat, but nothing like the calispec one where it has a LARGE precat that is basically the size of the main cat.

Dixit

 

No its not - removing the cat typically has no power increase whatsoever. Sometimes you actually lose a horse or two.

 

Not when he is boosted. Any boosted car is going to gain from free flow.

 

Yup. Cats are designed for a certain amount of exhaust flow, and once you start to seriously exceed that flow they become a more noticeable restriction.