Ok so as some of you know, I recently put on a Megan header that changed my beautiful exhaust tone to crap. Today it went into the shop and got a resonator welded onto the mid pipe that completely took away the rasp. I am curious about a couple of things however. First because I opened up the header and my piping is 2.5", would I benefit from upgrading the down pipe as well to keep the air flow an even 2.5"? And if I do decide to upgrade this piece, will it create rasp all over again?

 

Since you are naturally-aspirated you're talking about the S-pipe, down pipe is a turbo exhaust pipe. And because you are not turbo you don't need a full 2.5" exhaust. People forget this engine is just a Camry 4-banger. 2.25" is the ideal pipe size for aftermarket exhaust on a n/a tC.

Although the inside diameter of the S-pipe actually necks down to about 2" at one point, it's still just an empty pipe. After you have replaced the restrictive stock muffler & exhaust manifold you have maxed out your exhaust HP gains.

Spending $150-200 on a 2.5" S-pipe MAY gain you 1-2whp (equivalent of a dyno error) at high RPM's but it will surely ruin your low-end torque. At the tC's relatively low horsepower / exhaust flow the increase in pipe area from 2" to 2.5" (or even from 2.25" to 2.5") is dramatic enough to kill exhaust scavenging in the low end.

 

Well I do have intentions of going turbo in the nearby future. I only put a I/H/E on because I needed something. Right now I don't have the cash to spend on Turbo but I figured I would ask.

 

get a 2.25 inch pipe. do they make that? or do they only come in 2.5?