[Alan Roehrich]

The best I've seen with my stuff is around 4% or so. Knowing how little blow by there is on the dyno, I'm okay with that. A leak down test is a diagnostic test to locate a problem if something is wrong. Given that it is a static test, you're just finding where the leak is, and what the likely component is. I only leak an engine to see what is wrong with it in most cases. I suppose you could leak an engine fresh off the dyno, establish a baseline, then use that to see what the ring seal is after a given number of passes. The problem is accurately duplicating the conditions.