After a lot of reading and homework, I'm still stumped regarding my FB exhaust.

I want to free up some flow and HP while still keeping the air pump and cat.

I know the back-pressure activated 6PORT is connected to the exhaust and I'm worried that hollowing out / replacing the pre-cats or main-cat will change the back-pressure profile, resulting in the 6 port not actuating properly and reducing top end power.

Can anyone make a recommendation or dispel this myth for me? Thank you!
I want to keep the car relatively stock and original so I can get collectors plates.

(So visually, hollowing out the precats would look nice, but I'm totally okay with a pipe if it works better, I will just keep the parts I take off incase I need them later).

Thanks!

 

You can delete the pre-cats as they are just an added function on a warm up phase anyways.
Even if you go to a header you can set the exhaust up with a presilencer that has the split air tube to activate the ports.

 

Just clarifying,

For 13B FB,

So hollowing out the pre cats and then putting them back on, won't cause any back pressure issues and affect the 6 port?

What changes can be made to the exhaust before you need to worry about this 6 port exhaust back pressure problem? Can you increase the ID of the pipes?

I saw that racing beat has a header and nice exhaust set up but I kind of want to keep the "thermal reactor" for emissions and am considering replacing old cat with a new hi-flo one.

Thank you

 

then get a cat with a split air pipe attachment.