Related Photo Galleries
The Ratio: Cranking compression can give an indication of the trapping efficiency of the cam/compression combination, especially at lower engine speeds. How much pressure can be run on pump gas? Commonly, a cranking compression of 180 psi is considered the upper limit for pump gas octane. With attention to the factors discussed here, we have run 200 psi successfully, and are looking for more by employing every trick in the book.