Quote:
Originally Posted by Robin Hood
No offence, but you didn't study engineering did you? 
I have.
Edit: If a N20 rates at 275HP at the crankshaft, then a N55 could do 275:2(litres)=137.5 x 3(litres)= 412.5 HP.
That's a lot.
Cheers
Robin |
Sigh. The internet call out. I did. University of Michigan. Sorry to disappoint.
The comparison is not valid as they are not the same engine and more importantly, likely do not share many components. They are almost certainly using different injectors to support the higher flow rate per cylinder due to the higher boost. Are the piston rods thicker in the N20 than the N55 to support the higher boost level? Does the N20 have piston oil squirters? The N55? How many mL of oil is moved by them per stroke of the engine to cool the piston bottom? What is the actual heat transfer of that volume of oil from the piston to the oil? What is the cooling capacity of the oil cooling system that in turn removes that heat from the system?
BTW, if we're using the HP/L logic, the 328i engine made 193 hp / 2.8L = 69 hp/L. The N55 makes 100 hp/L. This dramatic difference in hp/L MUST mean the N55 is less reliable. Likewise, all newer engines MUST be less reliable than older engines that made less HP/L. See? The logic doesn't hold up.
There are many factors which I'm sure the BMW engineers have data on and have run through MANY complex simulations that we do not possess and are not running through ANY simulations. This has turned into just another internet debate - a lot of opinion backed by very little data. I'm just acknowledging we have very little data from which to draw a conclusion.