The QR family of inline-fourpiston engines by Nissan were introduced in 2000 and range from 2.0 to 2.5 L (1,998 to 2,488 cc) in displacement. These motors are aluminum, dual overhead camshaft (DOHC), four-valve designs with variable valve timing and optional direct injection. The engine shares much of its architecture with the YD diesel engine.
QR20DE
QR20DE
The 2.0 L (1,998 cc) QR20DE produces 140 PS (103 kW; 138 hp) at 6000 rpm and 200 N⋅m (148 lb⋅ft) at 4000 rpm. The bore and stroke is 89 mm × 80.3 mm (3.50 in × 3.16 in) and a compression ratio of 9.9:1.[1] The QR20DE was replaced with the MR20DE engine in most applications in early 2005.
The QR20DD is similar to the QR20DE but features NEO direct injection to improve fuel economy and to reduce emissions.[1] It produces 150 PS (110 kW; 148 hp) at 6000 rpm and 200 N⋅m (148 lb⋅ft) at 4400 rpm.[1]
The QR25DE is a 2.5 L (2,488 cc) variant built with cast steel connecting rods, a steel timing chain, counter-rotating balance shafts, and an aluminum intake manifold. The engine bore and stroke is 89 mm × 100 mm (3.50 in × 3.94 in) and a compression ratio ranging from 9.5:1 to 10.5:1 depending on the vehicle.[2]
Output is rated 175 hp (130 kW; 177 PS) at 6000 rpm with 244 N⋅m (180 lb⋅ft) of torque at 4000 rpm in the Altima 2.5 and Sentra SE-R models. The Sentra SE-R Spec V originally claimed 180 hp, but this was adjusted downward to 175 once production started in late 2001.[3] The redline is 6100 rpm.[3] Altimas that are PZEV compliant create 170 hp (127 kW; 172 PS) and 175 lb⋅ft (237 N⋅m) of torque.[2] In the 2005+ Nissan Frontier the QR25DE generates 152 hp (113 kW; 154 PS) and 171 lb⋅ft (232 N⋅m) of torque.[3]
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 centric location in the block.
Revised cam shaft profile.
Reinforced connecting rods only available in the Sentra SE-R Spec V 2007-2012 .
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.
The QR25DD is similar to the QR25DE but increases the compression ratio to 10.5:1 and includes direct injection. This engine is also the first QR to use DLC coating on the valve lifter buckets for reduced friction. It produces 125 kW (170 PS; 168 hp) at 5600 rpm and 245 N⋅m (181 lb⋅ft) at 4000 rpm.[1]
The QR25DER is similar to the QR25DE but has a supercharger for increased power and is coupled with a 15 kW (20 hp) electric motor, Dual Clutch System, and lithium-ion battery for increased fuel efficiency. The engine has a compression ratio of 9.1:1 (10.0:1 in 2014 Infiniti QX70[4]) and produces a combined 250 hp (186 kW; 253 PS) at 5600 rpm and 243 lb⋅ft (329 N⋅m) at 3600 rpm.[5]
