Hi,

The modifications to the MTU were software only which increased the RPM. Its not possible to change the turbos or intercoolers etc.

Hi Rik,
Thanks for your reply.

Having crunched some numbers I think new ratios in the ZF will cause problems with engine overload and or sequential turbo issues so thats a non starter.

The new MTU and gearbox configuration will actually output 2600 hp (existing is 2400 hp) but that realistically is all that will fit in the footprint available.

The numbers look like this -
Existing MTU 2500 RPM through ZF produces 13804 Nm (10181 lb/ft) at the Arneson (Prop speed 1231 RPM)
New MTU 2450 RPM through ZF produces 15340 Nm (11314 lb/ft) at the Arneson (Prop speed 1206 RPM)

If my sums are correct!

Now the Arneson site states that our ASD 15 BiL can take a max input torque of 16948 Nm so after getting them checked out that should be OK.

Now with this additional power, to increase the speed (and considering the reduction in prop RPM) we will need to up the props?

I am at a bit of a loss how MTU suggest I will get more speed with a lower prop speed?

Any suggestions are very welcome!