Multigrade mineral oil, say 10w60, behaves like a 10 grade oil at low temperatures (around -30c) and a 60 grade oil at high temperatures (around 140c). Temperatures in turbochargers are far higher than 140c, so the viscosity of oil is a bit irrelevant under those conditions. This is where synthetic oils come into their own, they hold their viscosity at much higher temperatures. So you are far better to use a fully synthetic oil, than a part synthetic oil in a turbocharged car.
Higher viscosity oil is more sticky and hence more difficult for the piston oil control rings to scrape it to where it should be - hence oil burn.
If you are going to rag your car to its limits, use 10/60 fully synthetic, but you will have to suffer the oil consumption. Take it a little easier and a 10/40 or 5/40 fully synthetic will give good protection and low oil consumption.
The engine oil is almost the cheapest part of the car to replace - so do it regularly and it will pay dividends.
As an aside. Many years ago I bought a cheap high mileage Vauxhall Carlton 4 cylinder 1800cc car. I drove it 1000 miles a week. I changed the oil and filter every 5000 miles, the oil, filter and spark plugs every 10000 miles and additionally, the air filter every 20000 miles. Within a year, the fuel consumption had increased by 10% and oil consumption decreased by 10%. A year after I bought it, with 45000 extra miles on the clock, I sold the car for more than I paid for it because the engine was so sweet.
Duncan