Ok, sorry for the noob question, but can someone please fully explain PSI to me? What PSI is good? What's bad? What does it effect? It has something to do with turbo right?
Thanks

 

PSI, or pounds per square inch, is just a measurement of air pressure. It's basically the amount of pressurized air that is being forced into your engine by the turbo or supercharger. Smaller turbos build less boost pressure. Bigger turbos build more boost pressure. The more pressurized air, the more power. But there are limitations.

The stock block sleeves can only handle so much before the engine blows up. I've seen Honda blocks resleeved to withstand 60 PSI of boost though. (That's insane, by the way.) The stock internals can only withstand so much pressure before they bend or break, sending a rod through the side of the block for example. That's why its important to set power goals when starting a boost project. You must understand the limitations of stock parts. If your plans call for more than stock can handle, you have to replace with aftermarket. This includes block sleeves, crankshaft, rods, pistons, cam shaft, valves... basically everything.

That's an EXTREMELY basic sample of info.

 

Alright, awesome
tyvm

 

I would like to add that PSI is not the lone determinant of power with a turbo. A large turbo at low PSI could make the same power as a small turbo on moderate PSI. Turbo specs are very important when determining how much PSI you need to reach a certain power goal. Also important of course are the other modifications to the engine and drivetrain.