Bore vs Stroke

[SteveSRT8]

Originally Posted By: dparm
Don't ask what the replacement cost is. Or the labor involved with extracting a 4.2L V8 from a tiny A4...


I've seen the engine bay. One scary tight package!

 

[Shannow]

A guy I know hydrauliced the engine in his Commodore (G8 for US folks)...$21k to get it fixed.

 

[Shannow]

Originally Posted By: mechanicx
I think 5-valves is the max and if you add more you get diminishing returns.


Yep, more means smaller, means more frictional losses per area of opening

 

[Cujet]

Originally Posted By: dparm
Originally Posted By: Cujet
Minutia aside, bore and stroke relationships have no affect on torque. Valve size does.


In that case, what do I win?


Damage notwithstanding, you have an engine design that is unable to match the wide torque curve and peak HP of a well designed 4 valve head...

 

[SteveSRT8]

Originally Posted By: Shannow
Originally Posted By: mechanicx
I think 5-valves is the max and if you add more you get diminishing returns.


Yep, more means smaller, means more frictional losses per area of opening


Don't forget leak down. More valves equals much worse leak down figures, especially as the engine ages a bit. Plus there's additional turbulence/interference from competing flows