Subaru EZ engine
was introduced in 2001 in the Japanese market, in the Legacy RS30 (Sedan) and Legacy GT30 (Station Wagon), and in 2001 in the United States market. It is a flat-six, 24-valve, quad cam motor with an aluminium block and heads. The number of exhaust ports per cylinder varies. It is available in EZ30 and EZ36 variants.
The later EZ30R used from 2003 to 2009 was heavily updated from the early EZ30D used from 2001 to 2004. It received new cylinder heads with 3 exhaust ports per head and variable intake valve timing. All use dual timing chains and coil-on-plug ignition.
- EZ30D: 2999 cc DOHC, 220ps (161 kW) @6000 rpm, 289Nm@4400 rpm. Bore 89.2 mm, Stroke 80 mm. Compression 10.7:1. This version uses one exhaust port per head, a cable throttle, variable intake geometry, cast aluminium intake manifold, and has a 6500 rpm rev limit. It was only available with an automatic transmission. Found in the 2001–2004 Outback H6, 2001-2002 Legacy GT30, 2001-2002 Legacy RS30 and 2001-2002 Legacy Lancaster 6.
- EZ30R: 2999CC DOHC, 245ps (180 kW) @6600 rpm, 297Nm@4200 rpm. Bore 89.2 mm, Stroke 80 mm. Compression 10.7:1. This version had one exhaust port per cylinder, a drive-by-wire throttle, a black plastic intake manifold, VVL and AVCS. It was available in manual and automatic unlike the old EZ30D. Found in the 2003–2009 Legacy 3.0R, Outback 3.0R and 2006–2007 Tribeca.
- EZ36R: 3629CC DOHC, 260ps (191 kW) @6000 rpm, 335Nm@4400 rpm. Bore 92 mm, Stroke 91 mm. Compression 10.5:1. Found in the 2010-current Legacy, Outback and 2008-current Tribeca. The EZ36R incorporates possibly the only implementation of an asymmetrical connecting rod in a modern application. The offset connecting rod was designed to allow additional displacement from the same exterior dimensions.