While doing some calibration on my twin-turbo GTO, I noticed one bank had some odd narrow-band sensor behavior. After a bit of looking and listening I figured out there was an exhaust leak between the header and the uppipe to the right side turbo.

I removed said turbo, plus the manifold and pipes, and sure enough it was loose in the connection point. While doing that I also inspected the lines I had running from the engine to the heater box. These lines have been problematic because they run directly underneath the turbo uppipe. In the past I replaced the lines with high temp Aeroquip lines and used a fiberglass high heat insulation, but when I inspected the lines they were both directly damaged and discolored because of heat.

The root cause is the contact with the header. Insulation works great if there is some gap between the two objects, but when the lines directly rest against the red hot exhaust pipe the insulation is not sufficient.

It is such a tight space that I think the best answer to us use some stainless steel tubes in place of the lines. The stainless will not be damaged by the heat, and is more compact in terms of space usage. I should be able to run the lines down close to the frame rail so as to not be in direct contact with the header.

I ordered some stainless 5/8s hard line and fittings from McMasterCarr, so in a few days I’ll give it a shot.