What's the difference between BMW models? (what do all the numbers mean?)?

I'm searching for a used BMW and I see 525i, 325i, 328i, 325i, 318i etc etc. I'm sure it's engine related, but what's the difference?

What's the difference between BMW models? (what do all the numbers mean?)?nortin

BMW has four primary lines, the 3 Series, 5 Series, 6 Series and 7 Series cars. The first number (as in 325i) represents the model line, the second two numbers (25) represents the the engine displacement, in this case 2.5 liters. A 745 is a seven series car with a 4.5 liter motor.

What's the difference between BMW models? (what do all the numbers mean?)?pc security

the first digit always represent the model, as in 3 series, 5 series, etc. in the past 15 years bwm has produced the 1, 3, 5, 6 and 7 series. the last two digits are meant to denote a the grade of the vehicle as compared to the others in its series. often the 30 will have a 3.0 liter engine, but not always. currently the 325 has 2.8 liter engine previously the 545/745 had a 4.4 liter engine. suffice it to say, the higher the number, the bigger, more powerful the engine.

bmw chose to use a different scheme with the Z3/Z4, X3, X5 and earlier the Z1 and Z8. no engine reference except in the accompanying badging on the vehicle.