LT Headers with stock cats? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

OPP · 10-21-2012, 10:14 AM

Tomorrow I'm having my Doug Thorley LT headers installed. Jannetty found no difference in HP with or without cats. The difference is the smell. Any opinions on re-using the stock cats (or one of the two) with the LT headers? Difference in sound, smell?

14pilot · 10-21-2012, 10:23 AM

Important to note that Jannetty found no diff with High-Flow cats. The OEM cats are Low-Flow. And the Magnaflow's marketed as High-Flow are really Medium-Flow.

FWIW, get real High-Flow cats behind those DTs.

Camper · 10-21-2012, 10:28 AM

I think he found no real difference in aftermarket Hi-Flow cats and no cats. I dont think factory Cats were part of that scenario.

with that being said, if you are in an area in which you have easy inspections, I'd go no cats if you want max performance.

SGOS252382 · 10-21-2012, 10:30 AM

Main reasons to go catless
1. Less weight - cats are pretty heavy
2. More sound - catless increases the volume
3. Save money - cat pipes are expensive

For what it's worth, Kooks Headers told me overy the phone a while back that their catless pipes usually show a few HP gain over their catted pipes.

Even though others have reported no gains.

ZeuSS2011 · 10-21-2012, 11:02 AM

I had LT's with catless pipes. The smell was too much for me and the wife, especially at idle. Reminded me of riding in an old pick up truck with a bad exhaust smell. Some people like that smell, but we didn't. I installed some hi flo cats along with a tune and the smell went away. There was a slight difference in sound. Nothing major in my opinion.

SGOS252382 · 10-21-2012, 11:32 AM

Quote:

Originally Posted by ZeuSS2011

I had LT's with catless pipes. The smell was too much for me and the wife, especially at idle. Reminded me of riding in an old pick up truck with a bad exhaust smell. Some people like that smell, but we didn't. I installed some hi flo cats along with a tune and the smell went away. There was a slight difference in sound. Nothing major in my opinion.

Good tune should fix that. My car has no issues like you described (catless). If my car had a "old pick up truck exhaust smell" I'd hate it.

Ice Demon · 10-21-2012, 11:33 AM

Stock cats are crap get high flow cats or catless connection pipes.

litle88 · 10-21-2012, 12:53 PM

Pointless for using cats. Especially stock crap cats! How do you plan on installing those lol. That means hacking something lol, sorry but many wont do that, do it once and do it right just my .2

kenkartasasmita · 10-21-2012, 01:47 PM

but they said its illegal to have catless pipe in tx.

OPP · 10-21-2012, 08:36 PM

Thanks ya'll for the info. I'll go catless for now and see how it goes.

LSxJunkie · 10-21-2012, 09:22 PM

With no other mods or just boltons, you're not going to see gains with HFCs vs. catless pipes. However, when you get into bigger cams or power adders, you may find HFCs to be a bottleneck.

Badbubba · 10-21-2012, 10:30 PM

Smell isn't bad at all. Although, without a tune it may be worse. My hf cats blew out, so keep that in mind for future mods.

OPP · 10-22-2012, 08:16 PM

Got them installed today. I really can't smell anything different.
No Cats it is!!!

litle88 · 10-22-2012, 08:27 PM

Lol
Gooooood!
There you go.

10-21-2012, 10:14 AM	#1
OPP Drives: 2018 MBM ZL1 Auto Join Date: Sep 2009 Location: San Juan, Puerto Rico Posts: 960 View My Garage	LT Headers with stock cats? Tomorrow I'm having my Doug Thorley LT headers installed. Jannetty found no difference in HP with or without cats. The difference is the smell. Any opinions on re-using the stock cats (or one of the two) with the LT headers? Difference in sound, smell? __________________ .

10-21-2012, 11:33 AM	#7
Ice Demon Drives: 2010 Camaro SS Join Date: Oct 2011 Location: Memphis, TN Posts: 1,098 View My Garage	Stock cats are crap get high flow cats or catless connection pipes. __________________ Mods: "Cam Only"

10-21-2012, 12:53 PM	#8
litle88 V8 Lounge member #2 Drives: 2001 Ws6 Join Date: Sep 2009 Location: Burbank,IL Posts: 6,373	Pointless for using cats. Especially stock crap cats! How do you plan on installing those lol. That means hacking something lol, sorry but many wont do that, do it once and do it right just my .2 __________________ 2001 ws6, 40k miles, Ls3 416 stroker, short block built by PER the rest by me. LPE Ls3 heads milled to 12-1 comp, FAST 102, NW 102, kooks 2", dual DMH cutouts, Magnaflow C/B, BTR cam + springs. Full UMI suspension.

10-21-2012, 08:36 PM	#10
OPP Drives: 2018 MBM ZL1 Auto Join Date: Sep 2009 Location: San Juan, Puerto Rico Posts: 960 View My Garage	Thanks ya'll for the info. I'll go catless for now and see how it goes. __________________ .

10-21-2012, 09:22 PM	#11
LSxJunkie Snark snark snark Drives: RX350 Join Date: Sep 2008 Location: 3L Hell Posts: 555	With no other mods or just boltons, you're not going to see gains with HFCs vs. catless pipes. However, when you get into bigger cams or power adders, you may find HFCs to be a bottleneck. __________________ What is this, CorvetteForum Lite?

10-21-2012, 10:28 AM	#3
Camper Banned Drives: 10' 2SS LS3 M6 Join Date: May 2012 Location: Phoenix,AZ Posts: 1,370	I think he found no real difference in aftermarket Hi-Flow cats and no cats. I dont think factory Cats were part of that scenario. with that being said, if you are in an area in which you have easy inspections, I'd go no cats if you want max performance.

10-21-2012, 10:30 AM	#4
SGOS252382 Drives: 2010 Camaro 2SS/RS Join Date: Mar 2008 Location: S.W. Florida Posts: 6,294	Main reasons to go catless 1. Less weight - cats are pretty heavy 2. More sound - catless increases the volume 3. Save money - cat pipes are expensive For what it's worth, Kooks Headers told me overy the phone a while back that their catless pipes usually show a few HP gain over their catted pipes. Even though others have reported no gains.

10-21-2012, 11:02 AM	#5
ZeuSS2011 Drives: Black 2011 2SS/RS / Black 2013 ZL1 Join Date: Feb 2012 Location: El Paso, Texas Posts: 314 View My Garage	I had LT's with catless pipes. The smell was too much for me and the wife, especially at idle. Reminded me of riding in an old pick up truck with a bad exhaust smell. Some people like that smell, but we didn't. I installed some hi flo cats along with a tune and the smell went away. There was a slight difference in sound. Nothing major in my opinion.

10-21-2012, 10:30 PM	#12
Badbubba GrINned & JUICEd Drives: 15STI, 10Expy, 10 2SS/RS M6, 47KB1 Join Date: Nov 2009 Location: Pittsburgh, PA Posts: 1,247	Smell isn't bad at all. Although, without a tune it may be worse. My hf cats blew out, so keep that in mind for future mods. __________________ GPI SS3 Cam & stuff,N.O. Plate(dedicated fuel tank,progressive,fuel hose upgrade,remote opener,heater,console switches),LNC2000,CTAP,ARH 1 7/8" LTs/gutted cats/X pipe/mufflers,Jet Hot coated LTs,GPI HPT Tune,CAI, Scoop,Rx Catch Can,Gates heater hose relocation, Remote clutch & auto brake res,Metco loop,Momentum Tunnel Brace,TSW Nurb 18",555 & 05,Pfadt trailing arms & toe rods,Autometer WB,Fesler Pillar Pod,LED strips (int),Lloyds floor & trunk mats,LED DRL/front turn & license plate,DRL harness,VLEDs tail lights,Plasticoat Bowties. Ord: Oct 5, 2009 Rec: Nov 19, 2009 13.17@112.6 stock Last edited by Badbubba; 10-21-2012 at 10:30 PM. Reason: proofing

10-22-2012, 08:16 PM	#13
OPP Drives: 2018 MBM ZL1 Auto Join Date: Sep 2009 Location: San Juan, Puerto Rico Posts: 960 View My Garage	Got them installed today. I really can't smell anything different. No Cats it is!!! __________________ .

10-22-2012, 08:27 PM	#14
litle88 V8 Lounge member #2 Drives: 2001 Ws6 Join Date: Sep 2009 Location: Burbank,IL Posts: 6,373	Lol Gooooood! There you go. __________________ 2001 ws6, 40k miles, Ls3 416 stroker, short block built by PER the rest by me. LPE Ls3 heads milled to 12-1 comp, FAST 102, NW 102, kooks 2", dual DMH cutouts, Magnaflow C/B, BTR cam + springs. Full UMI suspension.