Nissan QR engine

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The QR family of straight-4 piston engines by Nissan 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.

[edit] QR20DE

The 2.0 L (1998 cc) QR20DE produces 147 hp (110 kW) and 148 ft·lbf (200 N·m) The bore is 89 mm with a stroke of 80.3 mm and a compression ratio of 9.9:1.[1]

Vehicle applications:

• 2001-present Nissan X-Trail (140 hp)
• 2001-2007 Nissan Primera P12
• 2002-present Nissan Serena C24, 145 hp (108 kW)

[edit] QR20DD

The QR20DD is similar to the QR20DE but features NEO direct injection to improve fuel economy and to reduce emissions.[2] It produces 150 hp (110 kW).

Vehicle applications:

• 2000-2004 Nissan Bluebird Sylphy

[edit] QR25DE

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 of 9.0:1.[3] Output is rated 175 hp (130 kW) at 6000 rpm with 180 ft·lbf (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 ft·lbf (237 N·m) of torque.[4] In the 2005+ Nissan Frontier the QR25DE generates 154 hp (115 kW) and 173 ft·lbf (235 N·m) of torque.[5] More recently, in the Nissan SE-R Spec V 2007+ the QR25DE generates 200 hp (150 kW) @ 6600 rpm and 180 ft·lbf (240 N·m) of torque @ 5200 rpm with a 7000 rpm redline. The crankshaft comes fully balanced allowing removal of the counter-shafts built into the older style QR25. The newer version is also equipped with a composite intake manifold and compression has been bumped up to 9.5:1[6]

Vehicle applications:

• 2002-present Nissan Sentra SE-R & SE-R Spec V
• 2002-present Nissan Altima 2.5, 2.5S , 2.5SL, Hybrid
• 2001-present Nissan Serena C24, 158 hp (118 kW)
• 2001-present Nissan XTrail APEC export version, 178 hp (133 kW)
• 2005-present Nissan Frontier King Cab XE 4x2
• 2003-2005 Nissan Teana 160 hp (120 kW) and 240 nm
• 2008-present Nissan Rogue 170 hp (130 kW)

[edit] Concerns

[edit] Manufacturing, design, and assembly flaws

The QR25DE sold in the United States has been subject to a significant number of problems in its short lifetime. A variety of mechanical flaws have led to numerous technical service bulletins, recalls, repairs, and outright engine replacements.

• Vehicles with the QR25DE may ingest material from a damaged pre-catalyst resulting in increased oil consumption.[7]
• Power valve screws in the intake manifold may become loose and result in unstable idling or power loss.[8]
• In June 2006, it came to Nissan's attention that approximately 85,000 Altimas and 2,000 Sentra SE-Rs equipped with the QR25DE and built between January and May 2006 may experience unusually high oil consumption. This can lead to premature engine failure and possibly a fire. While Nissan investigates the problem, owners of the affected vehicles are being advised to check their oil frequently (every 700 mi (1,100 km) [1127 km]), and dealers have been instructed to place the affected vehicles on sales hold.[9]

[edit] Stated versus observed power

In addition to the physical problems suffered by the QR25DE, Nissan's official stated power and torque numbers seem to disconnect from power measurements taken by the general public. Though rated for 175 hp (130 kW) and 180 ft·lbf (240 N·m) of torque in the Nissan Altima and Sentra SE-R Spec-V, the actual power of the engine may be significantly lower. Multiple dynamometer readings performed by a range of people in an assortment of cars over several years have shown that the engine more than likely produces ~160 hp and ~170 ft·lbf of torque. Parasitic loss alone seems an unlikely candidate for the discrepancy as automatic transmission loss would be approximately 28% and manual transmission loss 19%.[10][11]

Nissan's revised power claim of 175 hp (130 kW) at 6000 rpm is more realistic than the original 180 hp (130 kW) claim, but is still a long way from the 160 hp (120 kW) produced on the dyno. Our experience with the drivetrain loss varies greatly (see "Technobabble", page 22), but it seems unlikely any front-drive transaxle could make 34 hp (25 kW) evaporate into thin air. | Josh Jacquot | SportCompactCarWeb, 2001'}} Nissan has since revised power and torque values for the modified QR25DE that will be featured in the redesigned 2007 Altima. This new estimate of 175 hp (130 kW) and 180 ft·lbf (240 N·m) is based on a revised balancer system, larger intake manifold, and a slightly increased compression ratio of 9.6:1.[12] Moreover, the new figures adhere to the stricter SAE requirements published in 2004 whereas the older numbers were published under the much more lax 1995 SAE standards.

[edit] QR25DD

The QR25DD is similar to the QR25DE but increases the compression ratio to 10.5:1 and includes direct injection. It produces 170 hp (125 kW) and 181 ft·lbf (245 N·m).[13]

Vehicle applications:

• 2002-2006 Nissan Primera P12 (JDM)

[edit] See also

• List of Nissan engines

[edit] References

• "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