Did up a 2 1/4" y-pipe on Saturday, a beaute of a pipe. Nice clean lines, dumped into a single 3" to the cat. It didn't work!! Lost torque everywhere from zero to limiter. I could feel the difference. Pulled off battery terminal overnight, tried on Sunday, same thing. Never got a check engine light so I know everything was working, just not as well. Put stock "T-pipe" back in at lunch today, and the torque came back too. I guess that wierd pipe is there for a reason. Anyone else find this out the hard way also?

 

No, I have the "Y" pipe mod on my 5.4L and I gained torque. I have 2.5" going into the Y and a single 3" coming out into a 18" long magnaflow muffler and then 3" out to behind the rear tire. I have a F150 though which has a different setup on it. I have 4 cats up by the engine and I left those alone. Maybe since you only have one big one and you put on a high flow that is what is hurting your torque. What kind of muffler do you have? If you have no muffler or a flowmaster, then that is your problem. Get a magnaflow.

Jake

 

I plan on changing out my y pipe when ig et my exhaust done with a magnaflow y-pipe. is this guy's experience just reverse from everyone elses?