sorry, compressor will be the same size and the turbine will be bigger, since less boost is required to achieve the same power at +50% rpm. I would tend to think that this design will allow the turbo to spool up faster and hence more MGU-H energy available?TurboLag wrote:How would the turbo be smaller if it needs to deliver the same amount of air, although on a higher rpm? Wouldn't the inducer/exducer size be the same? And why would a smaller turbo be better? Doesn't Mercedes (the best PU this year) already have the biggest turbo already?
Not a true statement necessarilymike wrote:IF you are making the same power, 15,000 rpm with low boost and 10,000 rpm with high boost will consume the same amount of fuel
The friction in the engine will be higher at higher RPMs, so you'll likely need more fuel or make less power.mike wrote:IF you are making the same power, 15,000 rpm with low boost and 10,000 rpm with high boost will consume the same amount of fuel
The friction created by all the moving parts in an ICE increases with an increase in rpm. An engine will have less frictional losses at 10,000 rpm than at 15,000 rpm. Since the fuel flow stays the same between 10,000 rpm and 15,000 rpm, mass flow stays the same. Because none of this changes except frictional losses as the rpm is increased above 10,000 rpm then it makes sense that the brake thermal efficiency will drop above that value.mike wrote:friction is a function of normal load and velocity, lower boost will reduce normal load and increase relative velocity, I see friction being similar between the 2 designs
Increase in rpm mainly comes from plain bearings which acts with respect to normal load (boost pressure) and piston rings. lower boost means that rings does not have to be set as tight, hence 50% increase in rpm may only result in 15% increase in friction. lets assume 10% of the energy is used to overcome friction, thats 1.5% energy increase. The benefit will be at a lower boost pressure and higher rpm MGU-H can recover more energy back to the drivetrain.trinidefender wrote:The friction created by all the moving parts in an ICE increases with an increase in rpm. An engine will have less frictional losses at 10,000 rpm than at 15,000 rpm. Since the fuel flow stays the same between 10,000 rpm and 15,000 rpm, mass flow stays the same. Because none of this changes except frictional losses as the rpm is increased above 10,000 rpm then it makes sense that the brake thermal efficiency will drop above that value.mike wrote:friction is a function of normal load and velocity, lower boost will reduce normal load and increase relative velocity, I see friction being similar between the 2 designs
