CM871 vs CM2250 bottom end

[Rawze]

(03-14-2017 )Running rough Wrote:  it would be interesting to know the compression ratio of my cm2250 cpl3606, i have heard the 2350 engines run at 18.9 to 1 ratio and i heard the new x15 effiecty series runs at 19.7 to 1, that is quite high, i belive 870 and 871 engines run at arount 17 to 1 while the austrailian isx e5 cm2250 runs around 17 to 1 compresion as well

2250 is 17.4:1 (some documents say 17.3:1). blanket statements simply 17:1 - They respond like they are 17.4:1 so that is what I go by.


871 and older compression ratios have never been widely publicized. It is close to the 2250 but definitely responds like it is a bit less overall, hence the low-end torque response is not quite as good on them. I would bet it is 16 something, and this is what the tuning on them reflects too. Newer documentation says 17:1 but it is mostly a blanket statement. - I was told it is more like 16.3 from an ex-instructor but am not sure I trust that 100%.