Bring down oil temperature on a 912 Vz

You have a turbocharger, start with cooling the incoming air with an intercooler like a type 915 or 916 engine.  If the inlet air temp is excessive this will make a huge difference.  Engine coolant temp on the injected engine is important, keep it lower.  I would ask your turbo suppler what they recommend.

Cheers

You could add a second oil cooler to get oil temperature down. You didn't mention what kind of water temps you are seeing, but if the water is staying cool enough an oil to water heat exchanger might be good. There are expensive aircraft ones like Luminova, or I opted for one from a marine application: https://www.fredwarner.net/product/seakamp-26143-marine-oil-cooler-2x6-body-12-npt-1-hose-copper/?srsltid=AfmBOorJlpcgP4RKly4nGkDd9seDLyzk4nA72VmvHmMNaU6_bWdlnpaz

If your water is also running on the edge, this would not be a good idea. 

That is an approach making a lot of sense but making for a lot of work, too :-) Thanks for sharing! I have just bought the XL original Rotax oil cooler which should have around 40% more surface than what is installed now. I will report here what effect that has after I managed to install it.

Unfortunately the supplier is not very helpful when it comes to questions around their engine and this sort of issues.

My experience; Sonex Legacy/Rotax 912 ULS

When first flew, major problems with oil/coolant overheating.

Tried all sorts of cowling modifications, to get temp under control. All ideas worked a little. None enough to be sustainable.

Grounded the girl & returned to workshop for a complete rethink.

Relocated coolant radiator to very front of cowl & added a dedicated air scoop.

Purchased the largest Rotax oil cooler & located it in exit air flow, bottom of firewall.

Increased exit air flow.

Now all heat exchangers over cooling (below 90C) . This is better than overheating, as easy to progressively blank of  heat exchangers with adhesive/metallic air-conditioning tape, until desirable temperature reached.

Longer term -I am well into installing a cowl flap, that will control exit air at the pilots discretion.😈