12-06-2012, 02:59 PM
Great limit basic guide 
The limit of the engine internals on the HDi is probably 230bhp but in practice many people may not have new internals in there either.
The kinetic energy of the rotating parts is also more costly than the torque loading on those rotating parts as the revs rise, so in practice 300bhp at 3000rpm may be possible, while 200bhp at 4500rpm might be catastrophic!
The same is probably true of the Td engine too. It likes revs more than the HDi but that is also where the KE goes through the roof (remember KE ~ v.squared, so double the rpm and you quadruple the load on the bearings!)
Dave
The limit of the engine internals on the HDi is probably 230bhp but in practice many people may not have new internals in there either.
The kinetic energy of the rotating parts is also more costly than the torque loading on those rotating parts as the revs rise, so in practice 300bhp at 3000rpm may be possible, while 200bhp at 4500rpm might be catastrophic!
The same is probably true of the Td engine too. It likes revs more than the HDi but that is also where the KE goes through the roof (remember KE ~ v.squared, so double the rpm and you quadruple the load on the bearings!)
Dave