Understanding Turbocharger Maps

How can we know if the turbocharger we wish to fit to an engine is the right one?

Introduction

This article covers the process for understanding the manufacturer data for turbocharger compressor and turbine. It is based on the author’s experience with the Garrett T28 of the Nissan 200SX and the Borg Warner BV50 of the Porsche 997

Turbo (for which there are unfortunately no maps!). The maps are a vital surce of information and should be used to understand the matching between the hot and cold side. After this process is done, there is nonetheless a requirement for a good amount of real testing (on-dyno, on-vehicle) in order to validate in real life the choices made. More often than not, a hybrid turbo is a viable solution to match the best possible turbine and compressor.

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