threw a code p0420, which means smoke weed everyday....wait, it actually means that my cat is performing below its threshold(this would explain the plumes of exhaust my car has been emitting whenever i press the throttle more than half way). im going to go ahead and replace it with a highflow cat. my question is, which cat should i get if i have a 99em1, BUT the header i have on my car is for a 97-01 gsr teg. logically i would think that the cat made for the 97-01 teg would be fine, but i want to ask before i buy. i also have stock exhaust piping, so im assuming the 2.25 cat should work ok. any input is appreciated.

 

what year/model car does your cat come from and you have your answer...

 

my cat is oem em1, but i had a shop modify it to fit the gsr header, so i wasnt sure if i could get a universal fit, or if i had to specify the model of cat regarding the length

 

ttt

 

what about an o2 sim and a test pipe or gut the cat you have. i have a 99 em1 and a header, gutted cat,greddy evo, and an o2 sim will be in on monday and the engine light will be gone.