Hi all,

My team is trying to throw a turbo on our R6 for the first time this year and are having a tough time finding the mechanical efficiency and the total inertia of the turbo for Virtual 4Stroke modeling. If anyone is willing to share some numbers they have been using we'd appreciate it a ton.

Thanks a lot,

Mike

A 3d model would be great too, if anyone has one lying around.

I dont have any specs, but when you get some can you e-mail them to me as well.
Our team is doing the same thing

The total inertia (compressor wheel + turbine shaft wheel) for the GT12 is 4.41x10^-6 kg*m^2. Bless CatiaV5. The number should be almost identical for the GT15V.

I'll ask Gerry to chime in tomorrow about the mechanical efficiency.

I forgot about it for a few months, but I'll see if I can get the packaging model (filled end housings and center housing) together this week. I shouldn't have put that off for so long. Sorry guys.

-Kirk

GT12 mechanical efficiency? A difficult question to answer in general because it depends on your operating conditions. Unlike a ball bearing, the hydrodynamic bearing losses depend on the oil inlet conditions (ie, viscosity) and operating speed (plus other operating conditions).

Generally speaking, the mechanical losses will vary as the 1.5 power of turbo speed for this type bearing.

If you look at the GT12 turbine map you will see that the turbine-mechanical efficiency is not great--about 60 percent, maybe 65 percent max at low speed. This is because its size is so small and clearance losses, etc hurt the efficiency.

Note that on the turbine map, the turbine adiabatic losses and the mechanical losses are lumped together into this single turbine-mechanical efficiency.

For a rough estimate of the mechanical losses, calculate the ideal and the actual power (using the 60 percent turbine-mechanical efficiency) at max turbo speed. The difference is the power loss due to combined adiabatic and bearing losses. Assume the mechanical (ie, bearing) efficiency is 90 to 95 percent, and compute the bearing loss alone. Assume this varies with the 1.5 power of speed for other conditions.

Sorry if this sounds cryptic but that's how I would do the calculation myself. You'll have to work out the equations but that's the fun of engineering!

Thanks for the help! Should get those simulations running any day now...

Don't know if this helps but you might want to check THIS POST