I'm not a big fan of oil additives, as I prefer Mobil-1 or Amsoil synthetic products which certainly don't need any additives.

For a turbo it's very important to get oil to the turbo bearings quickly, upon starting, and also get oil that has good film strength. Amsoil recommends their 10W30 Turbo Formulated Motor Oil (ATM) product for the new turbo cars, and I'm not sure what would be recommended for a high milage turbo, but I'd suspect it would be nearly the same regardless, as the start up on a turbo really spins the cold bearings, and when it's working at 120,000 RPM it's working very hard (and hot) too, so synthetic is highly recommended.

I recently contacted Amsoil's tech department and asked them which of their products they would recommend for a new Volvo 5-cylinder turbo (XC90 in this case). They recommended the product noted here-in,.

I've used Mobil-1 15W50 in my three normally aspirated Porsches with good results: 1983 928-S 5-speed; 1984 944, 1990 944 S2 Cabriolet, however, that oil is probably "too thick" for turbo use.

I'm interested in hearing what others have used with good results, and what the recommendations are out there.

Regards, Mr. P

http://www.amsoil.com/products/atm.html


http://www.amsoil.com/products/prodpics/2003/atm_qt_600pxh.jpg

Mr. P