TURBO LAG

Fitting a larger turbo can increase turbo lag, which means it takes more time to spool up and provide boost. A smaller turbo has smaller parts, so it takes less energy to spin them and produce boost.

While a smaller turbo will reduce turbo lag, it also limits the amount of boost it can produce. A larger turbo will take longer to produce boost, but once it does, it can produce a lot more and at higher rpm.

The size of a turbo is determined by the diameter of its compressor and exhaust turbine wheels. A turbo’s size can also be measured by its rate of airflow, which is calculated in kg per second.

Turbo lag can be reduced by changing to a ball bearing designed turbo. Such turbos use hard-wearing ball bearings capable of producing minimal friction, which can spool up quicker than a fluid type bearing, so lag is less, especially on larger turbos.