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Barra Turbo Selection – Finding the Best Size

Barra turbo selection. Airflow points plotted

To find the optimum Barra turbo size we’ll use the calculators on StrikeEngine and follow the usual turbo selection process.

Step 1

Step 1 is to find the volumetric efficiency of the engine. We’ll use this calculator and the data points from this dyno graph

Comments – Very low volumetric efficiency. I wonder what the compression ratio the engine has. And generally how the plumbing is set up, exhaust manifold, intake, intercooler, stock turbo size etc.

Step 2

Step 2 is to bolt the VE numbers into the turbo size calculator with our boost target. For this article we want 30 PSI at 3830 and 5390 RPM.

PRCFMlbs/ftBoostRPMPower Predicted
Comments – Despite the boost targets for our Garrett turbo being similar to the stock. Our power predictions with the G30 turbo are much much higher. It makes me wonder if the source dynograph we are using makes sense…..


Barra Turbo Analysis

The G30-990 seems very well suited to the Barra at 30PSI. The two points are close to the efficiency island and additionally, there is headroom to improve the volumetric efficiency of the engine while maintaining the same boost pressure and improve the performance of the turbo.

In short, for stock engine efficiency, the 990 turbo is a good fit and if we improve the engine later, the turbo will still be suitable. And one more plus with the G-Series, there is some room to turn up the boost to 35PSI.

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This page was last modified Jul 3, 2024 @ 8:38 pm

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