GREENMILE

iTrader: (8)

well i currently running tsp lt headers with a full 3" ypipe n borla muffler. now it bothers me that where the ypipe angles n all is crimped which make it a 2.5" so has anyone done a full 4" y pipe n cat back? im thinking of buying pipe from summit n find angle n clamp them on or maybe modify a duramax exhaust system has anyone done a 4" exhaust system?

low2001gmc

iTrader: (137)

I think you mean dual 3 into single 4.

If so...i have
ran both dual 3 into single 3.5 and dual 3 into single 4. 3.5 better for under 500 rwhp and 4 for 500+rwhp provided all pipes mandrel bend and free flowing muffler.

I have available for sale some mandrel 3 inch pieces of pipe good to make a y pipe, a dual 3 into 3.5 y merge, a magnaflow 22 3.5 inch muffler, 3.5 inch tailpipe and soon a magnaflow 30 4 inch muffler. NO CRIMPS TO SUFFOCATE, CHOKE!!!

If interested, feel free to text me for more info and pics...Rob 956 802 7700

GREENMILE

iTrader: (8)

u think running a tsp 3" ypipe with a 4" cat back would work as well? its really just the ypipe that bothers me.

low2001gmc

iTrader: (137)

I prefer homemade y pipe with mandrel bends and better y merge...

Noah Burns

iTrader: (5)

I'd take the 3" Y pipe if I already had it and cut the 3" collector off and buy one of the 3" in to 4" merge Y's on the market and then build a 4" cat back.

hemiexp04

Look up chucks tuning...he's been doing a lot of 4in catbacks lately

GREENMILE

iTrader: (8)

just looked into it. hes been modifying duramax cat backs. im going to redo ypipe to true mandrel pipping use a 3" to a 4" y collector n go from there. ebay has the mbrp 4" muffler for 120 n 4" x 4' pipe for $15 so i think i have it figured out now. lol. thanks for the input guys.

Choda

iTrader: (1)

full 4 inch is a huge exghaust. I have a single 3 into a 4 inch diesel tail pipe ( for looks ) and its great and fits with no prob. U guys using 4 inch full exhaust must be moving a ton of air.

GREENMILE

iTrader: (8)

yea i decided to do a true mandrel 3" ypipe n merge to a 4" catback. cant wait.

oldred95

Even if you use a duramax exhaust there is going to be some cutting and fitting since those systems are designed with the extra clearance of a 2 inch taller frame in mind.

I made a single 3 1/2 for mine.

https://www.performancetrucks.net/fo...t-99-a-516965/