Garrett GT4094R Turbochargers

What the Garrett GT4094R is

The GT4094R is a Garrett GT40-series dual ball-bearing turbo, oil and water cooled, that Garrett described as ideal where a GT4294R will not fit but more flow than a GT4088R is needed, with the same outline as the GT4088R. Garrett rated it at 450 to 800 horsepower on engines of 2.0 to 5.7 liters (6.0 in its 2015 catalog), with a 67.8 / 94.0 mm, 52 trim compressor wheel in a 0.72 A/R housing and a 77 mm, 78 trim turbine wheel; turbos 751470-19 to -22 have turbine housings of 0.85 to 1.19 A/R.

This page lists a complete GT4094R turbo, a CHRA and housings and parts for it. Garrett’s own guidance on turbine housings: a smaller A/R gives quicker boost response and more turbine power at low engine speed; a larger A/R lets the wheel flow more, with lower back pressure and more power at high engine speed.

Sources: Garrett GT4094R (archived 2007) · Garrett catalog volume 5 (2015, archived) · Garrett: Turbine Housings 101