01-08-2014, 09:59 AM
For the record, they don't truly compound, Chris...
They're a compound-sequential setup...
They only compound until the big turbo is up to speed - it's not designed to produce insane pressures, more reduce lag on an engine with a larger turbocharger. That's why they have the bypass valves in place to stop the smaller turbo from being worked at high engine speeds. They do have a very small primary turbo and quite a large secondary turbo, hence they only compound for a short period of time.
Unless you understand how to properly read compressor maps and understand the relationship between boost, flow and pressure ratios - trying to size turbochargers is a nightmare... That's before even beginning to understand how turbine flow will affect this. I don't really 100% understand it at times, it's such a minefield.
They're a compound-sequential setup...
They only compound until the big turbo is up to speed - it's not designed to produce insane pressures, more reduce lag on an engine with a larger turbocharger. That's why they have the bypass valves in place to stop the smaller turbo from being worked at high engine speeds. They do have a very small primary turbo and quite a large secondary turbo, hence they only compound for a short period of time.
Unless you understand how to properly read compressor maps and understand the relationship between boost, flow and pressure ratios - trying to size turbochargers is a nightmare... That's before even beginning to understand how turbine flow will affect this. I don't really 100% understand it at times, it's such a minefield.
