The 61mm frame GBT is the mid-sized option in the range. This unit will typically suit 1.8-3.0 litre engines providing outputs from 400-670bhp. With crossover in power figures from the 54mm to the 61mm, the operating compressor efficiency can always be high with the correct unit selection. An added advantage to the Ma5 cover is that it has the same fitment as the Ma7 cover. They have been designed to be interchangeable.
Turbine: Trim = 81.1 Inducer = 61.0mm Exducer = 55.0mm.