Now we get into turbo upgrades. Turbos capable of delivering the higher boost and airflow you need to safely get more power.
First you need to plot out your airflow demands. Then you need to go hunting through a massive library of compressor flow maps.
Like here: Big Collection of Compressor Maps
Then if you're lucky, you can find one that the points fit and which fit your engine.
If you're not lucky, you need to revise your boost and power goals to fit the available compressors.
For this one we get lucky. Here is the map for a garrett GT2056 compressor with a 55trim. I have placed the same green, red and pink dots on it, along with an extra in grey:
https://www.aulro.com/afvb/images/im...13/09/1382.jpg
Some of you may recognise the name attached to the grey point. I crunched the numbers on that years ago when many were refusing to believe Lara's power claims. Suffice to say, they checked out completely. Back then he was acheiving a safe, if not completely clean, 180kw at the crank with his TD5.
That is ~424Nm at 4000rpm on 38psi boost and an A/F ratio of ~17:1.
The interesting point here is that this garrett 56mm compressor comes attached to the same GT20 turbine as the stock TD5. This means a competent turbo shop can literally rebuild your turbo (or an exchange turbo) with this larger compressor. Virtually a bolt on.
What this larger compressor cannot do is deliver more low end boost cleanly. To do that you need a VNT turbo. But VNT turbos do bring their own compromises. Not the least of which no compressor maps are publicly available.
