Exhaust cat BAck Question - ZR-1 Net Registry Forums

-=Jeff=- · 09-27-2008

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

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

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

Head pipes only from my understanding

jonszr1 · 09-28-2008

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

Quote:

Originally Posted by GOLDCYLON

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

How they connect and sizes thats all

-=Jeff=- · 09-28-2008

Quote:

Originally Posted by GOLDCYLON

How they connect and sizes thats all

so the lengths are the same ont he LT5 vs LT4?

Ccmano · 09-28-2008

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

Pete · 09-28-2008

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

09-27-2008	#1
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,169	Exhaust cat BAck Question 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? __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978

09-27-2008	#2
jonszr1 Join Date: Sep 2006 Location: lone pine and mammoth lakes Posts: 1,407	Re: Exhaust cat BAck Question 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

09-27-2008	#3
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,169	Re: Exhaust cat BAck Question 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) __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978

09-28-2008	#4
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,155	Re: Exhaust cat Back Question Head pipes only from my understanding __________________ GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V

09-28-2008	#5
jonszr1 Join Date: Sep 2006 Location: lone pine and mammoth lakes Posts: 1,407	Re: Exhaust cat BAck Question 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

09-28-2008	#7
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,155	Re: Exhaust cat BAck Question How they connect and sizes thats all __________________ GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V

09-28-2008	#9
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: Exhaust cat BAck Question 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 __________________ 90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold.

09-28-2008	#10
Pete Join Date: Dec 2003 Location: Chicagoland,IL Posts: 2,679	Re: Exhaust cat BAck Question 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 __________________ '91 #1635 PoloGreen 350 LT5 11.09 @ 129.27 11.04 @ 128.86 474RWHP 400RWTQ http://www.youtube.com/watch?v=SFNFOhGGlR4 http://www.youtube.com/watch?v=ZlRIOMwaDYY https://sites.google.com/site/peteszr1garage