I know that for a catalytic converter to work properly it needs to be heated to its operating temperature. I see there is a problem with long tubes and placement of the cats after the collector. Suppose I run the Pacesetter long tube headers and want to make sure these cats get to the proper temperature. Would the use of header wrap help keep the exhaust temperatures under the hood down and move that heat to the cats where it should be? I'd also think that pulling that heat away from the primaries and down into the collectors that it would help with scavenging. Any ideas?

 

That's why you use cera-metallic coatings on headers... to keep the heat in the tubes, rather than in your engine compartment. While header wrap will also keep the heat in the tubes, unfortunately it elevates the tube metal temperatures and causes faster oxidation (rust) and cracking of the welds and tubes. Mild steel was not intended to operate at the temperatures it will see with header wrap. You might also want to check T. Byrne Motorsports site... not sure if he still has the pic's of his first LT1, burned to a cinder by a fire he attributed to oil soaked header wrap.

what makes you think your cats are not getting hot enough? ... emissions failure?

 

No this exhaust set up hasn't been assembled. I just want to make sure that the cats have the proper temperature to work properly. I want this car to pass emissions easily with the LE2 package.

 

Anything else I can do to get the under hood temps lower? I want to get all the heat I can out of the engine compartment.

 

I tried running without the rubber weather strip that seals the rear edge of the hood to the cowl. It removed heat, but it also let a lot of water in, particularly on the PCM. Might be OK to remove it for a "track" car, but not for a daily driver that sees rain, or gets run through a car wash.