Metric Mechanic m3 engine series e30 Magazines/Books/Booklets...

[Peter]

General Engine Description



Straight from the factory, BMW M3’s are great

performance sedans! With their bigger brakes, better

suspension and more powerful high rev engines, the

M3 engine is strong, well built and reliable even

though more aggressively driven. The average engine

life expectancy is about 140,000 to 150,000 miles.

But some owners feel the M3 lacks low to midrange rpm “grunt”. In other words, it doesn’t pull

to their liking below 4,500 rpms. Metric Mechanic’s “fix” is to enlarge the engine. We up the bore

from 93.4 mm to 95 mm and increase the stock 84

mm stroke to 87 mm. Enlarging the intake ports

from 26 mm to 29.5 mm, helps the engine breath.

The net result is a bigger engine with improved

low end and mid range torque, and expanded top

end breathing - in other words - a 2.5 liter M3