Just got a set of pacesetter longtubes for my 2500 rclb,the truck has true duals to a flowmaster with dual outlets,should i remove the cats or keep them i use the truck to tow a 8-10,000lb trailer,and need more towing power,BTW.I could not afford a duramax.after i install the longtubes i will get a mail order tune from jesse.I also have a TR 224 on114 i can put in the truck but wilkl this hurt my towing.Thanks

 

The exhaust on your truck has dual 3" cats as well as dual 3" headpipes(pipes from manifolds to the cats).
The only onther part to change on a stock 2500 exhaust is the muffler. Once you replace the manifolds and mufflers the exhaust will flow very well.
exit and the 2.5" for about 2" then the tubing steps up to 3".

if you are getting a tune, tell Jesse to delete the rear O2 sensor reporting. The sensors are $100 a pice so if you never have to replace a rear O2 sensor again, you will have saved $200 and your tune will be more than paid for.
You will only need to replace the front two O2 sensors.

from the factory the 3/4 ton exhaust exits the exhaust manifold with about two inches of 2.5" pipe that expands intp dual 3"tubing into dual 3" cats, the cats exit intp dual 3' tubing into a dual 3" inlet muffler with a single 3.5" outlet into a single 3.5" tailpipe.
You could simply install smaller less restrictive mufflers along with your long tubes and you will have a killer hi performance exhaust.


In the shop right now on the frame rack, is a 2006 2500 6.0L truck. I just measured the exhaust, I cant beleive that the 3/4 ton trucks and Vans use a dual 3" exhaust that is mandrel bent. These newer trucks have a much much more hi flow exhaust than the older 88-99 old body style OBS trucks did.

My Vortec 350 headpipes were crimp bent dual 1 7/8" pipes into dual 17/8" inlet/outlet cats. there were areas of the headpipes that were crimped down to an 1 1/2" or less. This is part of the reason why adding longtubes on my truck worked so very good.

The OBS 88-99 2500 trucks with the Vortec 350 trucks used a 2 1/4" headpipe into cat setup, along with larger pipe. At least the Vortec equipped trucks did, I have not seen a 3/4 ton TBI truck exhaust persoally, I have seen everything else in this post with my own eyes and used a Vernier caliper for all measurements.

It seems as though GM makes it a practice to use larger exhaust systems for their 3/4 ton and 1 ton truck platforms.. I would hate to guess what a complete manifold to tailpipe exhaust replacement from GM would be. It would be very expensive.

peace
Hog

 

Thanks hog kinda what i was thinkin on,true duals,no cats,later on the tr 224,and a stall.but then the truck still wont perform like a chipped duramax willit????

 

The exhaust on my 04 2500 is only 2 3/4 from the manifolds back to the muffler.