Older Gens where the precats are in the y-pipes are seeing a 15whp increase. I am thinking gutting the headers and adding a y-pipe should compare to, if not exceed, those gains. I am just concerned if I gut the manifold there will be an noticable increase in cabin sound. Although I guess as long as I leave the exhaust somewhat stock it should be negligable. I own a cougar (and 02 6spd Maxima) currently and I gutted my precats and saw a little increase in power. I am thinking of not only gutting the manifold but porting the exhaust opening of the manifold that bolts tto the heads. I am new to these cars and if somebody can please chime in who has experience with Maximas it would be a big help. With these mods (manifold gutted and ported, y-pipe) I think I could see some good gains (even on a stock exhaust).

People please chime in

I have personally done this to other cars and seen gains

 

I have not heard of that being done on an 02+. But if you are willing to take the risk... Id say stay safe and buy some headers and a B-pipe. That should give you plenty of gain.

Hotshot (headers), and Budget (bpipe) are 2 good places to get the parts.

 

sr20den and hitmanse contact them

 

Agreed. I think this is the way to go if you are concerned about excess noise. The Hotshot headers eliminate the precats completely. If don't want to mess with the emissions system than a Y(Cattman) and B pipe with stock muffler would be your alternative.

PhxBlue, did you install your headers yet?

 

No, gotta wait a few more weeks for the next batch to show up at SWA.