I'm trying to pinpoint my compression ratio in my 1990 525i (M20B25). problem is my searches are coming up with 8.8:1 for US and 9.7:1 for euro, thats fine, but since my car was a japanese import it makes it tricky...is there any markings on the engine anywhere to distinguish between the two ratios?
see if this helps http://www.bmwe34.net/e34main/other/Models.htmOriginally Posted by luke01
here is one more http://www.vrchlabi.cz/e30/ruzne/enginenumber/
Last edited by M20Turbo; 01-28-2008 at 09:51 PM.
M20 525/7 Bore: 84.50mm Stroke 81mm CR 8.5:1, blue printed/dyno & custom chip. Boost @ 6.5psi ~246hp @ 5300rpm / torque @ 269ftlbs. @ 4250rpm