I have been wondering, does the b230f engine handle a turbo that boosts like
8-10 psi or about 0.55 bar whit out any modifications

 

An n/a motor converted to +T, right? That's a simple question but it's not a simple answer. In theory, yes...and that's about the max because of the higher static compression of the n/a motor. In practice, so much depends on the health of the engine. Boosting an n/a motor with 200k on the clock without first bringing the motor back up to stage zero is a great way to learn about the B230F. Soon you will be examining all sorts of misshapen objects that once worked harmoniously within your engine! After this many years, any engine still running around with its original head gasket is a leak or worse waiting to happen. Boosting such an engine is a surefire way to blow the HG. If you want to boost the motor, it can certainly be done. How long it lasts is another question. A far superior method is to get a late model 740/940T motor. Beginning in 91, the motors went back to a heavier 13mm rod. In 93 or 94 they added piston skirt oilers to reduce heat. These later motors are far superior in handling boost. Regardless, it is a major undertaking to remotor a car. It is relatively simple to turbo an n/a car...you just need to know upfront you will dramatically shorten the motor's life if you don't do a rebuild.

 

what do you mean to do a rebuild. like new pistons, connecting rods, valves, camshaft, crankshaft. ???

 

Well, assuming the engine isn't worn beyond specs to the point where you have to do a re-bore, the existing pistons and rods should be fine. It's the rod and main bearings, crank bearings, valve guides, oil pump seals and most of all the head gasket. Most young folks get their first Volvo nowadays and the car has quite a few miles on it. With miles comes wear, with wear comes "slop"...the space between the crank bearings and crank shaft gets larger so oil pressure goes down. Lower oil pressure means less oiling for the top end i.e. cam, lifters, valves and guides. Running boost forces more air and fuel into the combustion chamber than n/a. This extra fuel provides extra power...and heat. Lots of heat. Cramming more fuel into the combustion chamber and the resultant more powerful output means more pressure against an aging head gasket. The head gasket is always a critical component of any engine but particularly so when the cylinder head is of different composition than the block. Like metals contract and expand at the same rate; unlike metals have a disparate rate. That's why old timers like me run iron heads on V8's. The Volvo motor has an aluminum head on an iron block. Because the aluminum contracts and expands at a different rate than the cast iron, the head gasket, which seals the two, has to be in good shape. And...when it's a turbo motor with the extra boost pressure and power, the head gasket is even more critical.
Now, here's the issue...no one would rebuild an n/a motor and then turbo it. If one is going to spend the money and effort to rebuild a motor then start with a turbo motor! I'm saying, slap a turbo on your car if you want to. Have a blast! All I was trying to do is let you know up front that if you drive like stole the car, the engine is going to take a dump on you sooner rather than later!