Never done this.

[The Collector]

Hello I'm looking to turbo my m42. I'd like around 260 + rear wheel HP. I have never done a turbo build. Please help. Any advice is appreciated.  My M42 is in a 91 318is. The Block has around 300000 miles.  I am in the process of rebuilding my motor so. I wanna do a turbo build for sure. Just need help and advics

[i8ur911]

Rebuild the engine top to bottom with all new bearings first. If you can, buy new lower compression pistons; 8.5:1 or 9:1 would be good. Use a better head gasket than stock. Purchase a stand alone management set up (megasquirt, AEM, VEMS, etc). Buy all turbo components (turbo, intercooler, intercooler piping, injectors, etc). Spend many weeks putting together and many, many more tuning. And try not to blow everything up after finishing

[The Collector]

What if I was looking at around 10 psi or 30

[wazzu70]

From what turbo? 10psi from different turbos can be a large difference in airflow. Psi in the manifold really does not tell you anything.

You can make that power on the stock rods, but its not worth it IMO. While you have the engine apart upgrade the rods and pistons. I dont think you need to run a different headgasket.

As mentioned previously, tuning is the most crucial part of the puzzle. Figure that out first.

[The Collector]

Never done tuneing I am completely new in a world of unknowns. When it comes to turbos tuning etc. I am a tool salesmen during the day mechanic at night. Not a performance builder. I'm looking for advice. Help and anything from fellow m42 enthusiasts. Brands to look into. Tunes ? I do not know

[fumstoo]

megasquirt, injectors, meth and call it a day. Im betting you could hit 260whp on a stock m42.

[bme30]

Get the standalone first.. Get the stock motor running.  That will be your baseline tune to build from when you build the boost motor.