furiousbob wrote:Also I've been pondering over a 2 1/4" exhaust system. My welding skills are not up to par so I'll be taking it down to my local shop. The only question I have is... what mufflers are most people using for these trucks? I would be expanding the Y-pipe to 2.25 and then running 2.25 through a (probably new, universal) cat and there on down to a new muffler.
I cut out the "wye" and cut the downpipe on the pssgr's side back to the 1st flange, then installed a cat with 2-2: dual inlets. Which works out great because the downpipes are 2". Run a 90-deg elbow off the flange on the pssgr's side to the cat, and the driver's side pipe needs a couple of angles to get to the other inlet. Of course a muffler shop could probably run brand new pipes from the flanges on both sides to the cat, and make it look real purty/ Mine isn't purty but it works!
The wye is very restrictive, as the outlet is not much bigger than 1-7/8". The way it's built, I don't think you could spread it, either. Huge bottleneck when you're installing a larger system.
With the cat in, have them eliminate the big "kink" in the pipe between cat & muffler; the pipe goes thru the frame x-member hole and the new muffler will hang in roughly the original position. Then you'll have to get 'em to bend a new tailpipe to complete the job.
Here's the parts I'd suggest, the Walker 15022 dual-inlet cat with a 2-1/2" outlet (just use a reducer down to the 2-1/4" exhaust, aft of the cat); Dynomax 17747 long-body muffler, nice n' quiet at speed with a throaty growl at lower speeds & idle:
Here are some links for a cat and 2-1/4" Dynomax muffler:http://www.ebay.com/itm/Catalytic-Conve ... 0p&vxp=mtrhttp://www.ebay.com/itm/Dynomax-17747-A ... Sz&vxp=mtr
This is as large of an exhaust your 2.8 will ever need, and if you should ever want to upgrade to a performance-built "3.2 Stroker" or Camaro/Firebird 3.4, you won't have to change anything, as it'll be perfect for the larger engine, too.
It won't be cheap unless you have a welder buddy like I do, but you'll like the results!!
Added benefit of the Walker cat is that there's an O2 sensor bung built into the casing, so the sensor will get hotter faster and stay hotter. Add that heater O2 sensor mod and it'll be Primo!
All that being said, I don't know what you can get away with in CommieFornia!
If you have to have a certified cat, I guess the dual-inlet cat wouldn't work. You could have the muffler shop modify the wye or replace it with a better junction of pipes, then plumb in the certified cat of your choice with a Dynomax muffer. Have the shop weld in an O2 sensor bung at the outlet of the new/modified wye and it'll work as good or better than the original.
I've added some pics of various wyes I saved during research, maybe one of those would work for you. The first pic is not of mine but another member's exhaust, you can see how the wye pipe sits and check out the great big exhaust pipe going to that itty bitty wye!
You do not have the required permissions to view the files attached to this post.