Arh headers to npp exhaust question - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

scottm078 · 06-18-2023, 07:00 AM

I picked up a used set of arh headers. Does anyone know what hi flow cats I could use? Also do I need an adapter? I think the stock exhaust is 2.5 inches. The collector is 3 inch. When I look on summit I’m not sure what part number to get.

scottm078 · 06-20-2023, 12:36 PM

i reached out to ARH but havent heard back from them yet. looks like the tsp ones would work. if i go that route how are you guys hooking up your rear o2 sensors. Catless is not an option. i need to pass a visual and obd2 inspection in NH.

Joe.G · 06-20-2023, 06:41 PM

I got mine from Stainless works/Stainless power, you can order from any company just need to match up the pipe size. With headers you need to get the rear o2 sensors either tuned so they are less sensitive or turned completely off. My Header set up came with the cats and the o2 bungs front and rear.

scottm078 · 07-03-2023, 12:12 PM

anyone know what catalytic converter would work?

Joe.G · 07-03-2023, 01:10 PM

You just need to order a Hi Flow that has the inlet and outlet to match your set up

scottm078 · 07-03-2023, 01:19 PM

Quote:

Originally Posted by Joe.G

You just need to order a Hi Flow that has the inlet and outlet to match your set up

I was looking at the texas speed ones pn: #25-TSP20103x2.5CatConn pretty sure those would work. i think the texas speed headers and the arh are the same size and shape.

Joe.G · 07-03-2023, 01:21 PM

They're are different size outlet options on certain headers, and inlets on exhaust. You need to verify.

scottm078 · 07-03-2023, 02:00 PM

Quote:

Originally Posted by Joe.G

They're are different size outlet options on certain headers, and inlets on exhaust. You need to verify.

the headers have a 3 inch collector outlet and the stock exhaust (npp) is 2.5. at least thats what ive read on the internet so it must be true. the tsp headers are slip fit and so arent the arh. I got the headers cheap so im just trying to find a way to get them on the car. thank you for your help btw.

Joe.G · 07-03-2023, 02:13 PM

I just looked on ARH site and they do say it's 3" out, they list cats as an option Texas speed is probably cheaper.

morepowerjoe · 07-04-2023, 05:15 AM

I'm sure the outlet on the headers are 3" and the stock exhaust on your car is
2.5" so, yes those TSP cats will work. And as far as your rear o2's go they either have to be on or off and with most aftermarket cats I don't believe that they will be sufficient for the ecm to work with a stock calibration so, you will need a tune to turn the rear o2's off.

06-18-2023, 07:00 AM	#1
scottm078 Drives: 2013 Camaro ss 1le Join Date: Jun 2022 Location: New Hampshire Posts: 20	Arh headers to npp exhaust question I picked up a used set of arh headers. Does anyone know what hi flow cats I could use? Also do I need an adapter? I think the stock exhaust is 2.5 inches. The collector is 3 inch. When I look on summit I’m not sure what part number to get.

06-20-2023, 06:41 PM	#3
Joe.G Drives: 2014 2SS/RS 6SP Ashen Grey Join Date: Aug 2021 Location: NY Posts: 1,763	I got mine from Stainless works/Stainless power, you can order from any company just need to match up the pipe size. With headers you need to get the rear o2 sensors either tuned so they are less sensitive or turned completely off. My Header set up came with the cats and the o2 bungs front and rear. __________________ GM 3.91/TrueTrac OEM ZL1 Rims, 6 Piston Brakes & Side Skirts.ACST4 Splitter/Deflectors NPP M2W,GM Short Throw,GPI Ported Rod Mod,BO White PTB,CAI/JRE Scoop, GC Aluminum DS,Stainless Works Ceramic LTH/HiFlo Cats, Hotckis 1" Springs & Chassis Max Brace BMR Adjustable Swaybars,Trailing Arms, Adjustable Toe Rod, LCA & Z28 UCA Bushings Hendrix Solid Cradle Bushings Pedders Radius Rod Inserts Strut tower brace, Moroso Catch Can,SCT X4 Dynosteve,Remote Clutch reservoir,Hero Smoked Tail and 3rd Brake Light, Diode Dynamic SL1 Fog Lights AeroForce Dual gauge/Autometer pillar mount.

07-03-2023, 01:10 PM	#5
Joe.G Drives: 2014 2SS/RS 6SP Ashen Grey Join Date: Aug 2021 Location: NY Posts: 1,763	You just need to order a Hi Flow that has the inlet and outlet to match your set up __________________ GM 3.91/TrueTrac OEM ZL1 Rims, 6 Piston Brakes & Side Skirts.ACST4 Splitter/Deflectors NPP M2W,GM Short Throw,GPI Ported Rod Mod,BO White PTB,CAI/JRE Scoop, GC Aluminum DS,Stainless Works Ceramic LTH/HiFlo Cats, Hotckis 1" Springs & Chassis Max Brace BMR Adjustable Swaybars,Trailing Arms, Adjustable Toe Rod, LCA & Z28 UCA Bushings Hendrix Solid Cradle Bushings Pedders Radius Rod Inserts Strut tower brace, Moroso Catch Can,SCT X4 Dynosteve,Remote Clutch reservoir,Hero Smoked Tail and 3rd Brake Light, Diode Dynamic SL1 Fog Lights AeroForce Dual gauge/Autometer pillar mount.

07-03-2023, 01:21 PM	#7
Joe.G Drives: 2014 2SS/RS 6SP Ashen Grey Join Date: Aug 2021 Location: NY Posts: 1,763	They're are different size outlet options on certain headers, and inlets on exhaust. You need to verify. __________________ GM 3.91/TrueTrac OEM ZL1 Rims, 6 Piston Brakes & Side Skirts.ACST4 Splitter/Deflectors NPP M2W,GM Short Throw,GPI Ported Rod Mod,BO White PTB,CAI/JRE Scoop, GC Aluminum DS,Stainless Works Ceramic LTH/HiFlo Cats, Hotckis 1" Springs & Chassis Max Brace BMR Adjustable Swaybars,Trailing Arms, Adjustable Toe Rod, LCA & Z28 UCA Bushings Hendrix Solid Cradle Bushings Pedders Radius Rod Inserts Strut tower brace, Moroso Catch Can,SCT X4 Dynosteve,Remote Clutch reservoir,Hero Smoked Tail and 3rd Brake Light, Diode Dynamic SL1 Fog Lights AeroForce Dual gauge/Autometer pillar mount.

07-03-2023, 02:13 PM	#9
Joe.G Drives: 2014 2SS/RS 6SP Ashen Grey Join Date: Aug 2021 Location: NY Posts: 1,763	I just looked on ARH site and they do say it's 3" out, they list cats as an option Texas speed is probably cheaper. __________________ GM 3.91/TrueTrac OEM ZL1 Rims, 6 Piston Brakes & Side Skirts.ACST4 Splitter/Deflectors NPP M2W,GM Short Throw,GPI Ported Rod Mod,BO White PTB,CAI/JRE Scoop, GC Aluminum DS,Stainless Works Ceramic LTH/HiFlo Cats, Hotckis 1" Springs & Chassis Max Brace BMR Adjustable Swaybars,Trailing Arms, Adjustable Toe Rod, LCA & Z28 UCA Bushings Hendrix Solid Cradle Bushings Pedders Radius Rod Inserts Strut tower brace, Moroso Catch Can,SCT X4 Dynosteve,Remote Clutch reservoir,Hero Smoked Tail and 3rd Brake Light, Diode Dynamic SL1 Fog Lights AeroForce Dual gauge/Autometer pillar mount.

06-20-2023, 12:36 PM	#2
scottm078 Drives: 2013 Camaro ss 1le Join Date: Jun 2022 Location: New Hampshire Posts: 20	i reached out to ARH but havent heard back from them yet. looks like the tsp ones would work. if i go that route how are you guys hooking up your rear o2 sensors. Catless is not an option. i need to pass a visual and obd2 inspection in NH.

07-03-2023, 12:12 PM	#4
scottm078 Drives: 2013 Camaro ss 1le Join Date: Jun 2022 Location: New Hampshire Posts: 20	anyone know what catalytic converter would work?

07-04-2023, 05:15 AM	#10
morepowerjoe Drives: 2012 Chevrolet Camaro l99 Join Date: Aug 2020 Location: Austin, TX Posts: 2,232	I'm sure the outlet on the headers are 3" and the stock exhaust on your car is 2.5" so, yes those TSP cats will work. And as far as your rear o2's go they either have to be on or off and with most aftermarket cats I don't believe that they will be sufficient for the ecm to work with a stock calibration so, you will need a tune to turn the rear o2's off. __________________ DSS Pistons, Eagle ESP L19 Rods, ARP Head and Main Studs, TSP PRC CNC Ported Heads milled .030, Cometic .040 Head Gaskets, GPI SS3 VVT Camshaft, GM Racing Lifters, CHE Trunnions, Melling 10355HV Oil Pump, Cold Air Inductions CAI, Fast LSXR Intake Manifold, Nick Williams 103 TB, TSP Longtubes, ZL1 Fuel Pump, Mishimoto Radiator and Oil Cooler, 3600 Circle D Converter, Tru Cool 40k Tranny Cooler, Fluid Dynamics Balancer, EBC 3GD Rotors with EBC Bluestuff NDX Pads, Bilstein B6 Shocks / Struts with Eibach ZL1 Drop Springs Build Thread https://www.camaro5.com/forums/showthread.php?t=609817