Cracked two-part manifold

[Phil Payne]

> My own question still
> remains Phil:  The urS4 uses the exact same motor mount, and it fails
> regularly without manifold cracking.

No, but it's a completely different design.  You might as well say manifolds don't crack on Harley Davidsons.

> I expect that all 5k/200/urq's without manifold/turbo support will cause
> manifolds (single or 2pc) to crack, some faster than others (as you noted)

Not happening here.  I have dozens of personally fitted single-piece manifolds running round the UK, some on daily drivers, and no
complaints.  I've never refitted a support bracket to an MB (despite ETKA, you don't usually encounter them on MBs) and there isn't
one either on my MB ur-quattro or on the Bus - which runs a damn sight hotter than stock thanks to SJM.  I discard them on WRs
unless the car is a 'Concourse' car.

> Why don't the 20vt motor mount failures cause cracking?

Because the 20V engine has a completely different moment about its own axis - the 20V head adds mass on the left of the centreline,
not only for itself (including the second cam) but also because both the inlet manifold and the cooling manifold are to the left of
the centreline.  This is incredibly obvious as you crane a 20V lump into a car - the balance is completely different to a 10V.  Not
only that - the 20V exhaust system is laid out COMPLETELY differently and the moments between the major masses (turbo, wastegate)
and th emanifold are a fraction of what they are on a 10V.

--
  Phil Payne
  http://www.isham-research.com/quattro
  +44 7785 302 803
  +49 173 6242039