Scott, I'm not clear on the physical process(es) you call "heat soak" and "over spin" on the turbo hot side. Would you please be kind enough to elaborate? Is this some sort of thermal transient or is it more in the domain of acoustics? If I had a better picture of this concept, I would get more from your recent turbo post.Thanks, DeWitt Harrison de@aztek.com Boulder, CO 88 5kcstq