I just got a volvo 850t. It smoke really bad.And there is oil on top of the v\c but not in the plug.
1. What mods can I do on this wagon?
2. How much boost can I run?
3. The turbo is a to4d 13g right??
can I upgrade if so to what (something with little to no mods to install)

 

Before you do anything, change the pcv system. That's why you have the smoke and oil. I wouldn't wait either.

 

Some oil on top isn't anything to worry about. Inspect the pcv system, could be something as simple as the cap gasket. Turbo might be on the way out and odds are it is a 15g. After getting the car running right you can start with simple panel filter, OBX exhaust, and boost gauge/mbc. Some cars seem to have a touchier fuel cut off but i think that is at ~1bar. Our turbos start to run out of steam at about 18psi.

Factory turbos from our cars that are upgrades are 16t,18t, and 19t are factory offered turbos that are essentially bolt on. the 18t is starting to get powerful enough on low end that you have to start acquiring supporting mods for proper boost control and fueling. Check out volvospeed.com

 

Thanks for the info!!