Short story, have a b18c sleeved to 84 mm with 10:1 piston. I was plan on going turbo, but lack of steady funds, its not going to happen yet. So i wanted to just get a header to get a little hp gain, im not spending crazy amount just going to get something better than my stock.

Right now i have a stock USDM ITR header + exhaust. But my header is cracked also so trying to upgrade. Im going to get a 4-2-1 header i think it will serve me better, i don't really race, just drive fast here and there, and race friends for fun sometimes.

Here is my question. If i get this header lets say the header i get is a 2.5 in collector, and the USDM exhaust is 2.25 in. How am i going to get the 2.5 to fit the 2.25? Do i have to get an exhaust system to? I know something about this adjustable test pipes, but idk if it accomodates the 2.5 to 2.25

 

bumpp

 

Hood exit **** all this hype "exhaust" **** or just get a cheap 2.5'' exhaust. Or if you want to be real cheap just get one of those telescoping test pipes that's how ppl bridge the gap to 3'' in the case of all motor b-series. K series 3'' collectors are the norm so this issue doesn't exist, plm makes great manifolds for the price and are decent quality.