Calling all owners with Long Tube Headers

[maxpower5]

Originally Posted by Hicompression

The front O2 sensors are before the cats. They are the air/fuel sensors. It doesn't matter if you remove the cats or not. The front sensors don't know whether they are there or not anyway. They are the ones controlling the air/fuel mixture by sampling the exhaust gases coming straight out of the combustion chamber.

The O2 sensors behind the cats are checking to see if the cats are working. That's all they do. They sample the exhaust gases after the cats and tell the computer to pop a code if they sense too much pollutants. They don't control air fuel.

So, no. You will not run lean by installing longtube headers with no cats.

thank you and might i add, well put.

[McBeevee]

I can tell you that you can run lean after LT's and a cai. I just had my car tuned on Thursday and it was lean at idle and at steady cruising speeds. Mike Norris did my tune and here is what he found.......

http://www.camaro5.com/forums/showpo...7&postcount=10

[Hicompression]

Originally Posted by Never Satisfied

I can tell you that you can run lean after LT's and a cai. I just had my car tuned on Thursday and it was lean at idle and at steady cruising speeds.

I'll guarantee you that the CAI led to the lean condition. I am running the stock airbox with headers and I am not lean.

So back to the question...will longtubes by themselves (with no other mods) lead to a lean condition? Absolutely not.

[McBeevee]

Originally Posted by Hicompression

I'll guarantee you that the CAI led to the lean condition. I am running the stock airbox with headers and I am not lean.

So back to the question...will longtubes by themselves (with no other mods) lead to a lean condition? Absolutely not.

Please explain to me how you can guarantee that?

[Hicompression]

Originally Posted by Never Satisfied

Please explain to me how you can guarantee that?

See post #42.

[McBeevee]

Thanks, but I'm well aware of how the upstream & downstream sensors work. An O2 sensor is not the only thing that can cause a lean condition. Don't forget the sizeable increase in airflow by removing the stock iron manifolds and adding a free flowing long tube header. That's where the increased power comes from. The stock tune in the ECM can only compensate so much for the increased flow.

[Ronn]

Originally Posted by Ronn

I was always under the impression that if you are installing LT's a tune was a must because there's a possibility of running lean because the stock prog can't compensate enough. Is this true with our cars? Or can you run the common bolt ons of intake, LT's and exhaust without a tune and not see any long term problems. A little off topic but i think it applies.

Originally Posted by Never Satisfied

Thanks, but I'm well aware of how the upstream & downstream sensors work. An O2 sensor is not the only thing that can cause a lean condition. Don't forget the sizeable increase in airflow by removing the stock iron manifolds and adding a free flowing long tube header. That's where the increased power comes from. The stock tune in the ECM can only compensate so much for the increased flow.

This was what I was originally wondering about, the stock tune can only adjust fuel so much. There's a point where the ECM basically says "ok that's too much flow, I can't deliver anymore fuel" etc.

So to sum it up, we may not be OK with an intake, LT's and catback without a tune.