I wonder will the TRD exhaust help the TC gain horsePower? does anybody know

I suppose it does since it may allow a more free-flowing exhaust. Not much though, since there is still restriction in the rest of the exhaust.

i just installed the TRD exhaust couple days ago. Certainly sounds better but as for the HP gain, i'm sure there is a gain but not sure how much, and is it just me or does anyone feels like the whistle sounds louder and feels like the air flows smoother?

Maybe like .5 hp or 1 hp at absolute best. Nothing noticable. It's an axle back system, so the real exhaust restriction is from the header back (mainly the s-pipe off of the header). So the restriction still exists. You might notice some gain with a cat-back system... but axle-back is really just for the sound.

Moved to PH... :lalala:

I've had mine for a couple days and it seems like the throttle response may be marginally better. Then again, that's probably because I can hear the engine revving up much more now, plus I like to drive a little quicker to hear the marvelous sound.

.5-1.5 hp

I wonder will the TRD exhaust help the TC gain horsePower? does anybody know

Axlebacks yield from 4 to 5.66hp on the TC. Go to this link and read the graphs. http://www.scionlife.com/forums/viewtopic.php?t=80070