PDA

View Full Version : Exhaust cat BAck Question

-=Jeff=-
09-27-2008, 09:14 PM
What are the main differences between the LT4 and LT5 cat backs.. I heard it is mainly with the head pipes, but what exactly is the difference?
jonszr1
09-27-2008, 10:33 PM
are you talking aboput stk or aftermarket. i know for sure its just the headpipes on the flowmaster believe it the same on the band b . stk they may have used a differenjt resonator but not sure
-=Jeff=-
09-27-2008, 10:50 PM
I guess mainly just the head pipes.. if I bought a LT4 aftermarket exhaust for my Z 9 assume used) what will I need to do to make it work on my car?? ( Assume OEM cats and manifolds)
GOLDCYLON
09-28-2008, 12:13 AM
Head pipes only from my understanding
jonszr1
09-28-2008, 12:18 AM
yyes i believe so . all the spring mounts and muffler mounts are the same. the big choice is 21/2 in or 3 in . also do you want the excedrin type or the quiet type .i have a 21/2 in on my blk car that traps 119-120 at the strip i dont know if there really is extra power in the 3 in or if you lose low end . i had mine custom built @ spin tech dr gas x pipe and their mufflers . maybe someone has actuall test results .i lost mine and cant remember , gettin old i guess
-=Jeff=-
09-28-2008, 12:24 AM
Head pipes only from my understanding


So what is differnet with the head pipes, that is more what I want to know
GOLDCYLON
09-28-2008, 12:43 AM
How they connect and sizes thats all
-=Jeff=-
09-28-2008, 01:11 AM
How they connect and sizes thats all

so the lengths are the same ont he LT5 vs LT4?
Ccmano
09-28-2008, 10:16 AM
The LT4 is similar to the 92-95' LT5 systems. The eariler 90-91 Lt5 systems had a different muffler (internally and externally) The piping also necked down more severely at the resonator and mufflers. In addition the LT4 system utiized an H pipe behind the resonator that the LT5 did not have. And yes the head pipe hookups are slightly different. Any good muffler shop should be able to adapt the Lt4 system to a ZR-1.

Hans
:cheers:
Pete
09-28-2008, 03:27 PM
Jeff,Like Hans mentioned about the early and later years.
The 90-91's have 3 bolt flat flange right side,the later years have a slip fit on the right side.
The left side is all the same ball flange.

I would go/do it like the early year 3 bolt flat flange on the right side,left side and leave the left side alone (ball flange)

The early year flat flange with ball flange makes R&R'ing the exhuast much easier.

Pete