Garrett GTX4718R Turbochargers

What the Garrett GTX4718R is

The GTX4718R is a Garrett GTX-series turbo for large engines: Garrett rated it at 900 to 1,600 horsepower on 2.5 to 10.0 liters. Garrett’s 2012 catalog describes a dual ball bearing, oil-cooled center housing, compressor wheels from 81.8 to 87.8 mm inducer with a 117.6 mm exducer, and a 92.7 mm, 82 trim turbine wheel, sold as a supercore with free-float, non-wastegated T6-inlet turbine housings (0.96 to 1.39 A/R) bought separately. Garrett’s current catalog lists the GTX4709R and GTX4720R Gen II in the GTX47 size.

This page lists GTX4718R supercores without turbine housing (81.8, 84.8, 85.8 and 87.8 mm inducers, including drag-race and class-legal versions), complete 88 mm turbos with T6 V-band turbine housings in 1.08, 1.23 and 1.39 A/R, and a partial turbo. 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 GTX4718R page (archived, 2016) · Garrett catalog Vol. 5 (archived PDF) · Garrett: Turbine Housings 101

GTX4718R models compared

Wheel sizes are inducer / exducer, taken from the specification published for each part number. The turbine housing sizes are the ones on the listings above; the same turbo is sold with several.