Being an engineer that often works with the metric system that's just one conversion factor that I committed to memory years ago (4.45 N = 1 pound force). If you google metric conversions you should be able to find it.

You have to be careful of the manufacturer's and distributor's advertised specs. They often fudge the numbers to make their products competitive. Also some include the weight of the starter, mount and wiring harness in their engine weights and some don't. I have even noticed discrepancies amongst engines from the same manufacturer.

The P80, P120, P140 & P160 are all the same size. If you look at the Jetcat Germany website it says that the P140RX weighs 1590 gm. and the P160SX weighs 1530 gm. The difference most likely is primarily due to the fact that the solenoids are mounted under the front engine cover on the P140RX. If you look at total installed weight of the turbine and equipment there should be a minor weight advantage for the P140 due to the new smaller ECU.

Joe