Some info the Bronco Tech block (more tech) on the left side of this page.
Use the Search feature near the top right side of this page. I almost always use the advanced search. On the left side of that page (Key Words) type in Astro, or Astro Van. Then click on Bronco Tech on the right side in the Search Forums. Click on search at the bottom center of the page. That should give you about a weeks worth of reading about the hydro-boost.