I wrote this on Facebook at the weekend:-
Will Grossbauer
I am curious what you have against poly though, I havent done a ton of research but from what Ive seen people seem to like poly? Whats pros/cons?
John Robinson
I am a Mechanical Design engineer with 4 patents to my name.
To design an engine mount - it has complicated requirements. On one hand it needs to support the engine on various planes, and on the other hand it needs to isolate the car from vibration. This isn't just a comfort issue - vibration brakes things. Everything from motors, to electonics to causing metal fatigue.
Some mount designs are ingenious - using oil filling, carefully designed rubber sections from materials with high internal damping, shapes and forms that are strong in one direction and not another.
These solid designs are an insult to the engineering that goes into 'proper' parts. Its what you would expect from a 10 year old asked to solve the problem.
They suit ONLY drag racing because of the high load and short duration.
Otherwise they totally fail to isolate the cabin from vibration which is incredibly loud and unpleasant, but also disasterous for the life and reliability of every other system in the vehicle.