M20 2.5L performance build

[ADEN]

You either do an optimized NA build with the headers etc. or do a turbo build. Not both.

If you're a reasonably proficient Wrench, piecing together a turbo setup is not hard. Lots of examples on here. Otherwise, a kit is the way to go. Don't use a huge turbo. Smaller is better. Check the turbo map and size it to M20 flow.

We had a lot of success with Megasquirt plus MAP.

I am interested in the smaller turbo idea but need to know the smallest turbo i can use @ 6k or even 5.5k RPM without causing bad exhaust restriction?

[dvallis]

So, it's not about exhaust restriction. You need to use a turbo properly sized for the expected boost and flow CFM of an M20. Read up on Turbo Maps.

We're using a Garrett GT3076R T4 0.63 A/R turbine, 0.60 A/R compressor, ball bearing CHRA, water/oil cooled. Not cheap but bullet proof.

Specs are here. Including the turbo map.

https://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=tp&Product_Code=GRT-TBO-H31&Category_Code=GTOTHS