I have been working on this for some time now looking over all aspects of how the components on the car works, looking at wiring schematics and component flow and so far this is what I have on Turbocharging the M54 successfully with little to no check engine lights and decent fuel trims. Also making sure some components are not pressurized under boost. In the Diagram we also changed/deleted the OEM CCV system to a more simplified DIY Air & Oil Separator using fast acting check valves.

The wires to the MAF will need to be extended.

   The 2 Vacuum hoses that went to the “F” connector on the original OEM intake boot are now on the vacuum block. The hose to the fuel pressure regulator has an inline check valve so it does not see pressure and fuel pressure stays static.

   The wastegate is ran off the vacuum block, do this if you have a low pressure wastegate spring under 9psi. This way you will not need to spend money on a boost controller. Make SURE to use PTFE stainless Steel Lines. You can do a -4 Line, -4 an to 1/8″ NPT fitting (you will need 2) and the -4 an hose ends for the PTFE Stainless Steel line. Anfittingsdirect.com has them.

   The By-pass valve is also run off the vacuum block. DO NOT in any case vent the metered air into atmosphere, the car will bog, stall during shifts due to the rich condition when venting metered air out of the closed system. DO NOT use a Blow Off Valve.

   On my diagram you see that I use a high flow catalytic converter, this is to keep things clean and keep the post cat Oxygen sensors happy and we comply with local / Federal laws. The cat is on 2 V-Bands so it is removable.

   My wastegate is venting to atmosphere, back pressure is less and usually you get more efficiency this way out of the external gate as you do not get reverson from the exhaust gas. If you want it back into the exhaust, route it so the tube going back into the exhaust is at an angle and not “Teed” into it.

   The fuel tank breather valve, also known as the purge valve needs a check valve so we don’t send pressure to it. It needs to be under vacuum to pull fumes out of the tank not pressure.

   This Diagram can/will change as I find more efficient ways to make things work. But this is the starting point of going turbo on a non turbo car.

The Air & Oil separator is a basic $30 ebay catch can.

M54B30 Turbo Diagram

Updated 7/19/2012