Hello Lancairians,

I was recently shown soot marks on my exhaust stacks by a former Continental employee.  He said those are defined by the angle of the exit gases direction on climb out.  He advised to cut the stacks back to the line defined by these marks.  Doing so, he said would result in more efficient performance and cooler CHTs.  

I may or may not have remembered the benefits or rationale correctly.

I set out to do this today and marked the stacks with masking tape and it looks like the resulting trim will position the face of the stack exit about 20 to 30 degrees different from existing.

I am wondering if others are aware of this, understand the concept, have done this, or have opinions/data about it.  

I have no reason to distrust the advice given and I believe the individual who gave the recommendation is extremely knowledgable.  I would just like to know if there is a body of knowledge and experience among our group.

Thanks,

John Barrett
N31VP - about 80% or more finished with body work in prep for paint.

Sent from my iPad