Modifying for " Dummies" - Page 6 - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Dr Jkel · 05-08-2010, 07:12 PM

Does it hurt the cats wth a 160* thermo

DSteck · 05-08-2010, 07:31 PM

Quote:

Originally Posted by Dr Jekel

Does it hurt the cats wth a 160* thermo

No.

Dr Jkel · 05-08-2010, 07:35 PM

so is it more of preferance or performance, I have some recommend it and others don't, but no real reason given

DSteck · 05-08-2010, 08:21 PM

Your cats aren't going to function as well as stock with headers since they get put outside of their efficient temperature operating range. They'll dampen some raspiness to the exhaust note and get rid of a little smell, but ultimately aren't going to function like your factory exhaust. It's preference. You should definitely not have cats if you intend to run leaded gas, or intend to spray your car... because it will destroy them pretty quick.

As far as the thermostat, I put a lower one in to keep my engine temperature down, consequently lowering underhood temperature a bit. My LS7 gets crazy hot in an extremely short amount of abuse time, so it still operates "hot" while loaded up anyway. I just wanted to combat high temperature under the hood while the car is sitting still.

Dr Jkel · 05-08-2010, 08:36 PM

so if you add headers it's a good idea to add high flow cats?

DSteck · 05-08-2010, 09:33 PM

Quote:

Originally Posted by Dr Jekel

so if you add headers it's a good idea to add high flow cats?

I usually throw cats in the garbage.

Darth_Emma · 05-09-2010, 11:12 AM

I am having Kooks LT headers with high-flow cats installed with a Borla Touring exhaust on Tuesday. The guys at the performance shop said I should use the cats. Why do you say they are not a good idea?

DSteck · 05-09-2010, 02:29 PM

I'm not saying they are a bad idea unless you plan to run leaded gas or nitrous. I just don't use them because I don't care about the extra noise and smell.

camarohead · 05-09-2010, 03:41 PM

Ok. For the most horsepower and torque. High flow cats or no cats.

JR-Vette · 05-09-2010, 07:21 PM

CAT designs of today cost very little to performance over the old brick types of years ago.
EPA being they make the nameplates warranty CATs for 8 years state being they are replaced for free to the car owner that only OEM CAT be used.

Most so called high flow CATs do nothing for performance and in many cases go bad in much shorter timeframe then the stock OEMs.
I see them all the time that get plugged up and effect AFR left/right banks.
Vendors like to sell them for the profit but if maintaining CATs for legal purposes then stick with the stock ones.
Some are ill designed and cause O2 Sensor tests to fail causing DTC error codes.
Being the PCM monitors the CAT temps it is better to use stock ones that maintain the proper heat range the PCM monitors for. Incorrect CAT temp can cause PCM to switch into Cat Over Temp (COT) and dump excess fuel in to cool the CATs to prevent CAT failures and ruin proper AFR for power enrichment or WOT.

Consider Corvette C6 Z06 or even ZR1 with 640 HP uses stock CATs so they are not delimiting the performance.

Dr Jkel · 05-10-2010, 08:20 AM

So are you saying that if you add headers to your car that you need no cats or just use the stock ones. I am a little confused on this, Thanks

DSteck · 05-10-2010, 08:54 AM

If you put headers on your car, then the cats that are designed to be used with the headers will barely function. Looking at stock exhaust, I don't think you'd be able to retrofit the stock cats to work with headers... headers will position them too far back to be in an effective operating temperature range.

JANNETTYRACING · 05-10-2010, 09:37 AM

Quote:

Originally Posted by Dr Jekel

So are you saying that if you add headers to your car that you need no cats or just use the stock ones. I am a little confused on this, Thanks

Manifolds and Stock Cats get replaced as an assembly by Long Tube Headers and High Flow Cats.

The connection points are your cylinder heads and the Clamps right under the Transmission crossmember.

Ted.

Dr Jkel · 05-10-2010, 09:45 AM

Quote:

Originally Posted by DSteck

If you put headers on your car, then the cats that are designed to be used with the headers will barely function. Looking at stock exhaust, I don't think you'd be able to retrofit the stock cats to work with headers... headers will position them too far back to be in an effective operating temperature range.

What do you mean by barely function?

05-08-2010, 07:12 PM	#71
Dr Jkel Roll Tide Drives: 2010 2SS RJT/BLK 6Spd Man Join Date: May 2009 Location: Talladega, Alabama Posts: 4,378	Does it hurt the cats wth a 160* thermo __________________ MUSTANG...Like Bringing a Hot Dog to a Steak Dinner....There is no comparison.

05-08-2010, 07:35 PM	#73
Dr Jkel Roll Tide Drives: 2010 2SS RJT/BLK 6Spd Man Join Date: May 2009 Location: Talladega, Alabama Posts: 4,378	so is it more of preferance or performance, I have some recommend it and others don't, but no real reason given __________________ MUSTANG...Like Bringing a Hot Dog to a Steak Dinner....There is no comparison.

05-08-2010, 08:36 PM	#75
Dr Jkel Roll Tide Drives: 2010 2SS RJT/BLK 6Spd Man Join Date: May 2009 Location: Talladega, Alabama Posts: 4,378	so if you add headers it's a good idea to add high flow cats? __________________ MUSTANG...Like Bringing a Hot Dog to a Steak Dinner....There is no comparison.

05-10-2010, 08:20 AM	#81
Dr Jkel Roll Tide Drives: 2010 2SS RJT/BLK 6Spd Man Join Date: May 2009 Location: Talladega, Alabama Posts: 4,378	So are you saying that if you add headers to your car that you need no cats or just use the stock ones. I am a little confused on this, Thanks __________________ MUSTANG...Like Bringing a Hot Dog to a Steak Dinner....There is no comparison.

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05-08-2010, 08:21 PM	#74
DSteck Account Suspended Drives: 2006 Corvette Z06 Join Date: Feb 2010 Location: St. Louis, MO Posts: 587	Your cats aren't going to function as well as stock with headers since they get put outside of their efficient temperature operating range. They'll dampen some raspiness to the exhaust note and get rid of a little smell, but ultimately aren't going to function like your factory exhaust. It's preference. You should definitely not have cats if you intend to run leaded gas, or intend to spray your car... because it will destroy them pretty quick. As far as the thermostat, I put a lower one in to keep my engine temperature down, consequently lowering underhood temperature a bit. My LS7 gets crazy hot in an extremely short amount of abuse time, so it still operates "hot" while loaded up anyway. I just wanted to combat high temperature under the hood while the car is sitting still.

05-09-2010, 11:12 AM	#77
Darth_Emma Psssssssssshhhhhhhhhhhhh! Drives: under contruction Join Date: Nov 2009 Location: Marysville, Ohio Posts: 12,996 View My Garage	I am having Kooks LT headers with high-flow cats installed with a Borla Touring exhaust on Tuesday. The guys at the performance shop said I should use the cats. Why do you say they are not a good idea?

05-09-2010, 02:29 PM	#78
DSteck Account Suspended Drives: 2006 Corvette Z06 Join Date: Feb 2010 Location: St. Louis, MO Posts: 587	I'm not saying they are a bad idea unless you plan to run leaded gas or nitrous. I just don't use them because I don't care about the extra noise and smell.

05-09-2010, 03:41 PM	#79
camarohead Drives: 2010 ss rs ls3 red-white rallys Join Date: Oct 2008 Location: Mississippi Posts: 729	Ok. For the most horsepower and torque. High flow cats or no cats.

05-09-2010, 07:21 PM	#80
JR-Vette Drives: 1999 500 HP Corvette Join Date: Jan 2010 Location: West Coast Posts: 164	CAT designs of today cost very little to performance over the old brick types of years ago. EPA being they make the nameplates warranty CATs for 8 years state being they are replaced for free to the car owner that only OEM CAT be used. Most so called high flow CATs do nothing for performance and in many cases go bad in much shorter timeframe then the stock OEMs. I see them all the time that get plugged up and effect AFR left/right banks. Vendors like to sell them for the profit but if maintaining CATs for legal purposes then stick with the stock ones. Some are ill designed and cause O2 Sensor tests to fail causing DTC error codes. Being the PCM monitors the CAT temps it is better to use stock ones that maintain the proper heat range the PCM monitors for. Incorrect CAT temp can cause PCM to switch into Cat Over Temp (COT) and dump excess fuel in to cool the CATs to prevent CAT failures and ruin proper AFR for power enrichment or WOT. Consider Corvette C6 Z06 or even ZR1 with 640 HP uses stock CATs so they are not delimiting the performance.

05-10-2010, 08:54 AM	#82
DSteck Account Suspended Drives: 2006 Corvette Z06 Join Date: Feb 2010 Location: St. Louis, MO Posts: 587	If you put headers on your car, then the cats that are designed to be used with the headers will barely function. Looking at stock exhaust, I don't think you'd be able to retrofit the stock cats to work with headers... headers will position them too far back to be in an effective operating temperature range.