The official BMW code for the 2.7 liter Eta engine is M20/B27. Because it was designed during the Seventies’ fuel crunch, the Eta (Greek letter denoting effeciency to engineers) was tuned for maximum effeciency and fuel savings. The BMW engineers used fewer cam bearings, softer valve springs, and a cam/chip package which was tuned for lean running to accomplish their goal of good fuel economy.
However, as not to strip all of the fun from the car, the Eta motors were tuned to maximize torque. As you can see in the following specifications, they don’t have too much horsepower, but they have gobs of torque. The torque curve is also very flat. This is readily noticeable, as you can pull almost any gear, regardless of speed.
|1984-1987 325, 325e, 325es||1988 325|
|Number of Cylinders||6||6|
|Horsepower SAE net @RPM||121 @ 4250||127 @ 4800|
|Torque lbs.-ft. SAE net @RPM||170 @ 3250||170 @ 3200|
|Fuel injection system||Bosch Motronic||Bosch Motronic 1.1|
|Fuel Required||unleaded 87 octane||unleaded 87 octane|