Volkswagen VR6, W12 and W16 engines

For conventional V6, a narrow 15° Vee angle would have required extraordinarily large spray angle between split crank pins, hence special strengthening. However, in contrast to many beliefs a, VR6’s crankshaft is more like an inline-6. It has 7 main bearings and independent crank throws for each cylinder, (this is possible because VR6 is longer than a conventional V6), thus avoiding the crank pin problem.

Don’t think a 15° V6 must generate a lot of vibration ! 

on the contrary, the VR6 is inherently a well-balanced configuration because it is nearly identical to an inline-6, just differing from the latter by a very narrow angle separating each pair of 3 cylinders. As a result, it generates no end-to-end vibration like conventional V6s and is actually almost as smooth as an inline-6.
 

Cut-away VR6. Note the 7-main bearing crankshaft

W12's cylinder block   W12's crankshaft. Note the  slightly split crank pins

 

If VR6 is a version of inline-6, then W12 must be a version of V12. 

It is made by mating two VR6 at 72°. The corresponding cylinders in different banks share the same split crank pins. Thanks to the 72° V-angle, the splay angle between split crank pins can be so small that no additional strengthening is required. (see photo), the short engine with 7 main bearings can hardly find space to add strengthened flying webs between the split crank pins.

W16 is identical to W12 except that each bank consists of 4 cylinders instead of 3. In other words, it is made from 2 VR8 engines.

The only mystery left  is the V5 (formerly called VR5). It's also 15°, but how can it manage to balance between the banks ? one bank has 2 cylinders and another has 3 cylinders. 

If you have its detailed technical specifications or even service manual, or can explain it, please inform us : help@ukcar.com)