Is there any advantage to adding a Catalytic Bypass? I have heard that it improves flow and adds HP but in some cases the difference in nominal and not worth the mod.

 

My supercharged F20B didn't benefit at all from the BYS straightpipe cat replacement... I have similar HP numbers to those who have "stock + SC" cars. Plus, my exhaust pipes are stained with black soot...

Our stock catalyst is probably a very high flow unit, so I would keep it and do the environment good

 

no advantage on n/a cars
i dynoed mine with and without cat with onl;y enough down time btwn dynos tyo swap parts 10-15 min
with the test pipe i gaine 1-2 horse everywhere in v-tec lost 1-2 everywhere not in v-tec
lost 3-8 torque EVERYWHERE - i was told this is due to no back pressure

btw this was done with spoon headerr and exhaust and injen cai

 

btw exhaust fumes where terrible smelling without cat especially in a convertible!!!!!

 

Great information everyone! Thanks.

 

uhear, that use to be a great mod on alot of cars but now adays it doesn't pay, especially in Cal. you could get a $10k fine for it. Most cars built anymore loose HP then gain and the little you get any more doesn't do anything that you could notice.

 

When I bring my car out of storage next spring, I will put my catalyst back on... and get the car dyno-ed to see if there are any changes.

In addition to the harm I am doing to the environment + the nasty exhaust smell, I will not miss the black soot stain on my exhaust tips...