ENGINE TESTING ON THE FLOW METER TEST BENCH

Max Bernardi

19 April 2019

The analysis of fluid dynamics, both during the design phase and during performance optimisation, is crucial when building a competitive engine. A flow meter is required in order to test the quantity and speed of a fluid in a component: let’s see how this highly professional instrument works with the help of Galiffa Kart.

THE THEORY

To understand the importance of flow meter testing, you need to know the basics of fluid dynamics and the role it plays in the design of an engine and its subsequent tuning to increase performance. In terms of fluid dynamics, an engine can be considered a set of components cyclically passed through by a fluid: in fact, at each cycle, the air enters the intake and, after having completed all the phases, exits via the exhaust. The reduction of fluid dynamic losses, with the aim of having a greater flow rate, is crucial to improving performance.

At the Galiffa Kart, they often repeat: the main objective of engine tuning is to reduce fluid dynamic losses

FLUID DYNAMIC LOSSES

What are fluid dynamic losses? The answer is quite intuitive: when a fluid passes through a component, it is inevitable that, due to the shape of the passage, the friction and obstacles it encounters, it loses some of its power and reduces its flow rate. Keeping losses to a minimum is one of the crucial aspects which a high-level engine tuner has to concentrate on.

Gianfranco Galiffa sets up the carburettor for the flow meter testing

FLOW METER TEST BENCH

To experimentally test a flow rate, you can use a flow meter test bench, an instrument that allows you to create a predetermined difference in pressure in the input and output of a component and measure the flow rate of the air passing through it. To do so, the flow meter uses analysis software, a blower and an electrical part made up of an inverter for pressure stabilisation, a pressure sensor, a flow sensor and a Type T thermocouple. Usually, these checks are performed on cylinders, reed valve packs and carburettors, crucial components in the tuning of an engine and, therefore, which need to be optimised to reduce fluid dynamic losses.

The flow meter test bench at Galiffa Kart

Gianfranco Galiffa sets the program for the component to be tested by flushing

The software has a function that allows you to compare tests, checking the modifications carried out on various components

CYLINDER - THE TEST

Modifications to a cylinder can include the size of the intake and exhaust ports, as well as cleaning and optimising the boosters. A thorough job involves removing the aluminium residues left after casting, connecting the various areas and removing any shavings to obtain a clean surface: even a simple chamfer of the chrome plating, on the cylinder wall that comes into contact with the piston, if performed at 45 or 70 degrees, changes its effectiveness. The flow meter allows us to analyse the air flow that circulates inside the intake and exhaust ports, comparing, for example, a cylinder with tuning step 1 to one with tuning step 2, therefore theoretically with better performance.