Factory Y-pipe - what's the story?
 

Hi.

Well, lots to read about y-pipes... even pictures of some cut open to show the extreme restriction in some cases caused by the poor design, where the two pipes are joined.

My question is: what will be the real-world benefits of replacing an otherwise intact and sound factory 'Y'-pipe ( 2000/4.6) with something like a Magnaflow (2.5" in/3" out) 'Y' pipe? Stock cats, Magnaflow SISO 3" catback comprise the rest of the system.

Truck seems to run just fine, so I can't really tell without disassembly if I have the dreaded restriction or if an aftermarket replacement will result in any gains, other than bragging rights ;-)).

Anyone here done this mod?

And, how did you alter the mounting to account for the removal of the tranny-mount hanger?

Thanks in advance for your insight, guys.

Cheers

Lots of people have done this. do a search and you'll find them.

The factory y-pipe is very restrictive, it really chokes-down inside - you can't tell from the outside but it does. Here's a pic of one:

https://www.f150online.com/galleries...3029&anum=2504

Mine was even more restrictive than that pic.

The benefit is better flow. :beers:

Thanks..
 

Thanks Jordan;

Yeah, that was the pic I was referring to. But my question is, how many are actually like that, and if the Maggie 'Y' or another ( better) one is used, how is that whole section supported?The guys who have done this really didn't go into that detail.

I'd rather know in advance before some muffler monkey arbitrarily bolts hangers to my frame. I mean, the factory setup had a specific mounting arrangement from both a support and resonance suppression perspective. I'd just like to know the best method with an aftermarket 'Y'.

Thanks again.

Cheers

The Magnaflow #15609 is a 3" system, with a flange to conenct to the stock 2.5" system. Replacignthe stock y-pipe with a 90 degree elbow and better designed y-pipe with dual 2.5" inadn 3" out and removing the 2.5"-3" flange on the Maggie would be a good idea. Depending on what the inside of yours actualyl looks like, you could get 5-15 ft-pounds.