Nissan QR engine
The QR family of straight-4 piston engines by Nissan were introduced in 2000 and range from 2.0 L to 2.5 L in displacement. These motors are aluminum, dual overhead camshaft (DOHC), four-valve designs with variable valve timing and optional direct injection.
The 2.0 L (1998 cc) QR20DE produces 147 hp (110 kW) and 148 lb·ft (200 N·m) The bore is 89 mm with a stroke of 80.3 mm and a compression ratio of 9.9:1. The QR20DE was replaced with the MR20DE.
- 2001-2007 Nissan X-Trail T30 (140 hp)
- 2001-2007 Nissan Primera P12
- 2002–present Nissan Serena C24, 145 hp (108 kW)
- 2003-2008 Nissan Teana J31, 145 hp (108 kW)
- 2001-2005 Nissan Wingroad Y11
- 2002-2005 Nissan Avenir W11
- 2001-2004 Nissan Prairie M12
- 2000-2004 Nissan Bluebird Sylphy
The QR25DE is a 2.5 L (2488 cc) variant built in Decherd, TN with cast steel connecting rods, a steel timing chain, counter-rotating balance shafts, and an aluminum intake manifold. The engine bore is 89 mm with a stroke of 100 mm and a compression ratio ranging from 9.5:1 to 10.5:1 depending on the vehicle.
Output is rated 175 hp (130 kW) at 6000 rpm with 180 lb·ft (244 N·m) of torque at 4000 rpm in the Altima 2.5 and Sentra SE-R models. Altimas that are PZEV compliant create 170 hp (130 kW) and 175 lb·ft (237 N·m) of torque. In the 2005+ Nissan Frontier the QR25DE generates 154 hp (115 kW) and 173 lb·ft (235 N·m) of torque. The crankshaft comes fully balanced allowing removal of the counter shafts built into the older style QR25. The newer versions are also equipped with a composite intake manifold and compression has been bumped up to 10.5:1 
- 2002-2006 Nissan Sentra SE-R 165 hp & SE-R Spec V 175 hp
- 2007–2012 Nissan Sentra SE-R 177 hp & SE-R Spec V 200 hp
- 2002–present Nissan Altima 2.5, 2.5S, 2.5SL 165 hp, Hybrid 158 hp
- 2001–present Nissan Serena C24, 158 hp (118 kW)
- 1999-2003 Nissan Bassara
- 2001-2007 Nissan X-Trail T30 APEC export version, 178 hp (133 kW)
- 2005–present Nissan Frontier King Cab XE 4x2 154 hp
- 2003-2005 Nissan Teana 160 hp (120 kW) and 240 nm
- 2008–present Nissan Rogue 170 hp (130 kW)
- 2007–present Nissan X-Trail T31 169 hp (126 kW)
- 2009–present Suzuki Equator Extended Cab 4x2 152 hp
- 2002-2009 Nissan Presage
- 2013-present Nissan Teana
2007+ QR25DE 
The revised QR25DE found in the 2007+ Sentra, Altima, Rogue, etc. has a number of improvements over the older QR25DE. These include:
- A simpler, larger diameter single path resin intake manifold replaced the old dual path design. (Note: California emissions models do have a swirl control valve located in the intake)
- Revised piston crown shape to support a higher compression ratio of 9.6:1.(10.5:1 in Sentra SE-R Spec V.)
- The balancer system has been moved back slightly from the crank pulley to a more central location in the block.
- Revised cam shaft profile.
- Reinforced connecting rods.
- Reduced friction likely through Nissan's extensive use of coatings on pistons, journal bearings, etc.
- Additional engine mount on the top of the motor, pulley side.
- Higher rev limit and improved power output.
- 2002-2006 Nissan Primera P12 (JDM)
See also 
- "2007 Nissan Altima overview"
- "2007 Nissan Altima specifications"
- "2006 Nissan Altima specifications"
- "2006 Nissan Frontier specifications
- "2006 Nissan Sentra specifications"
- "Global Vehicles", by Jack Yamaguchi, "Automotive Engineering International", June 2001, retrieved June 29, 2006
- "NTB03070 Nissan technical service bulletin regarding engine precatalyst failure"
- "NTB06045 Nissan technical service bulletin regarding low oil levels"
- "NTB05058 Nissan technical service bulletin regarding power valve screws"
- "Road Test: 2002 Nissan Sentra SE-R" by Josh Jacquot, "SportCompactCar", December 2001, retrieved June 26, 2006
- "Technobabble: December 2001 by Dave Coleman, "SportCompactCar", December 2001, retrieved June 26, 2006