Fri Aug 23, 2013 12:15 am by Slim Jim
Narrow angle is good for packaging efficiency. Wider angle engines have a lower center of gravity.
Some engines are basically cut down versions of other engines (ie. a V8 turned V6 by chopping off two cylinders)... so instead of the more balanced 60* V6, you get a 90* V6. Other engines still, are V8s with extra cylinders grafted on (V8 turned V10 = Viper)... so instead of the more balanced 72* V10, you get a 90* V10. etc. By maintaining the same bank angle, you can use the same tooling and manufacturing processes which saves money.
Changing the angle pros & cons:
PROS: increased smoothness (depending on cylinder count), easier to fit in engine bay
CONS: expensive
NOT changing the angle, but changing the number of cylinders pros & cons:
PROS: wider variety of engines, easier to make on the same assembly line, cheaper
CONS: requires balance shaft for smoothness, takes up more engine bay space