Editing Quad 4 engine (section)

==Versions==
=== LD2 ===
[[File:Quad4-89Calais.jpg|thumb|right|280 px|A 2.3-liter Quad&nbsp;4 in 1989 Cutlass Calais]]
The LD2 is the original version of the Quad&nbsp;4, introduced in 1987 for the 1988 model year. Bore × stroke are {{cvt|92| × |85|mm|in|1}}, for a displacement of {{cvt|2260|cc|cuin|1}}. In base form it put out {{cvt|150|bhp|kW|0}} from 1988 to 1989 and {{cvt|160|bhp|kW|0}} from 1990 to 1992. The naturally aspirated Quad&nbsp;4 was able to produce that power with a 9.5:1 [[compression ratio]], and was able to meet [[emission standards]] without using an [[Exhaust gas recirculation|EGR]] system. 

Minor running changes to the base Quad&nbsp;4 included different crankshafts, cams, and [[manifold (automotive)|manifold]]s, all meant to increase torque and reduce NVH. 

A slightly augmented version of the LD2 was offered in some [[Oldsmobile Achieva]] models with the SC (and possibly SL) trim packages. In this application the LD2 engine had a device called a vortex valve installed in the throttle body, and a ram-air cold-air intake was installed near the driver's side headlamp with ducting to direct the air to the engine intake.<ref name="mcg-scc"/><ref name="bf-jul2022"/> While some references rate this engine at 180&nbsp;hp, Oldsmobile's own literature reports a number of {{cvt|170|hp|kW}}.<ref name="brochure-1994"/>

Applications:
* 1988–1991 [[Buick Skylark]]
* 1992–1994 [[Oldsmobile Achieva]]
* 1988–1991 [[Oldsmobile Cutlass Calais]]
* 1990–1991 [[Oldsmobile Cutlass Supreme]]
* 1988–1994 [[Pontiac Grand Am]]
* 1990–1991 [[Pontiac Grand Prix]]
* 1993–1997 [[Pontiac Trans Sport]] (Europe only)

==== 1995 ====
[[File:Quad4-95Z24.jpg|thumb|right|240 px|A 2.3-liter Quad&nbsp;4 in 1995 Chevrolet Cavalier Z24]]
For 1995 only, a balance shaft-equipped version of the 2.3-liter engine was produced. This arrangement ensures a constant load on the shafts: the crank drives one shaft, which drives the second, which then drives the [[Oil pump (internal combustion engine)|oil pump]]. The shafts spin at twice the engine [[Revolutions per minute|rpm]], forcing the [[redline]] to be reduced from 6800 to 6500&nbsp;rpm. Output is {{cvt|150|bhp|kW|0}} and {{cvt|150|lbft|Nm|0}}. This was the only Quad&nbsp;4 produced in 1995, and was known as a transitional year for the engine family.

Applications:
* 1995 [[Pontiac Sunfire]] GT
* 1995 [[Chevrolet Cavalier]] Z24
* 1995 [[Pontiac Grand Am]]
* 1995 [[Oldsmobile Achieva]]
* 1995 [[Buick Skylark]]
{{clear}}

=== LG0 ===
The "high output" 2.3-liter LG0 was rated at {{cvt|180|hp|kW|0}} from 1989 to 1992, {{cvt|175|hp|kW|0}} in 1993 and {{cvt|170|hp|kW|0}} in 1994. Both the 1993 and 1994 power reductions were a direct result of the first two rounds of exhaust port size reductions for NVH control. The LG0 is differentiated from the LD2 engine by aggressive camshafts and an extra half point of compression; 9.5:1 to 10.0:1. Premium fuel with a 91 [[octane rating]] or higher was recommended for these engines due to the compression ratio.

The LG0 was introduced with special production runs of 200 Cutlass Calais International Series coupes, and 200 Grand Am SE coupes, all featuring bright red paint and gray interiors. It was only available when paired with the heavy-duty [[Getrag]]-designed [[Getrag 282 transmission|HM-282/NVG-T550]] five-speed [[manual transmission]].

A limited production version of the LG0 engine was offered in select Oldsmobiles with the designation "W41" (listed below).

LG0 applications:
* 1990–1993 [[Chevrolet Beretta]] GTZ
* 1994 Chevrolet Beretta Z26
* 1989–1991 [[Pontiac Grand Am]] SE
* 1990–1991 Pontiac Grand Am LE with the "sport performance package" (RPO: W32)
* 1992–1994 Pontiac Grand Am GT
* 1989–1991 [[Oldsmobile Cutlass Calais]] International Series
* 1990–1991 Oldsmobile Cutlass Calais Quad&nbsp;442
* 1992–1994 [[Oldsmobile Achieva]] SC
* 1990 [[Oldsmobile Cutlass Supreme]] International Series

==== W41 ====
[[File:W41engine.jpg|thumb|right|A 2.3-liter Quad&nbsp;4 W41 engine]]
The W41 was the most powerful Quad&nbsp;4. The 1991–1992 W41s were rated at {{cvt|190|hp|kW|0}}, while the 1993 W41 was rated at {{cvt|185|hp|kW|0}} as a result of the first round of exhaust port size reduction to improve emissions and other changes to the Quad&nbsp;4 architecture to reduce NVH. The additional {{cvt|10|hp|kW|0}} came from longer duration cams and a different [[Engine control unit|PROM]].

Part of the W41 drivetrain was a specific version of the HM-282/NVG-T550 with a gear set otherwise unavailable. All W41 five-speed transmissions had a final drive ratio (FDR) of 3.94:1 whereas the 1988–1992½ LD2 and LG0 transmissions all used a 3.61:1 FDR; the 3.94:1 FDR was used on all 1992½–1994 LG0 transmissions, but retained the standard HM-282/NVG-T550 gear set.

W41 applications:
* 1991 [[Oldsmobile Cutlass Calais]]
* 1992–1993 [[Oldsmobile Achieva]] SCX
{{clear}}

=== L40 ===
[[File:Quad OHC I4 engine.jpg|thumb|right|Quad OHC engine]]
This SOHC variant of the Quad&nbsp;4 was intended to replace the Pontiac 2.5&nbsp;L [[GM Iron Duke engine#Tech IV|Tech IV]] [[Overhead valve engine|OHV]] "Iron Duke" engine. Debuting in 1992 and called the Quad OHC, this eight-valve engine produced {{cvt|120|hp|kW|0}}, {{cvt|40|hp|kW|0}} less than the Quad&nbsp;4s of the same era. [[Torque]] was {{cvt|140|lbft|Nm|0}}. Power dropped to {{cvt|115|hp|kW|0}} in 1993 with an attempt by GM to reduce the NVH of the engine.

Although power and [[Fuel economy in automobiles|fuel economy]] were better than the Tech IV, the Quad OHC was retired after 1994 when the DOHC version became standard.

Applications:
* 1992–1994 [[Oldsmobile Achieva]]
* 1992–1994 [[Pontiac Grand Am]]
* 1992–1994 [[Buick Skylark]]
{{clear}}

=== LD9 ===
[[File:2.4L Twin Cam.jpg|thumb|right|A 2.4-liter Twin Cam in 1997 Pontiac Sunfire]]
The LD9 Twin Cam was a 2.4-liter Quad&nbsp;4 variant which debuted in 1996 with balance shafts and a redesigned cylinder head. In the mid-1990s, these engines, like their earlier 2.3-liter counterparts, were known for timing chain failures, as well as water pump failures, in which the water pumps were often difficult and costly to access and replace. LD9s also had very small oil passages, making for less than adequate lubrication, and costly engine repairs if not maintained properly. Bore was decreased from {{cvt|92|to|90|mm|in|2}} and stroke increased from {{cvt|85|to|94|mm|in|2}} for better torque. Power came in at {{cvt|150|bhp|kW|0}}.<ref name="mgc-96cavalier"/> This engine received a minor update halfway through the 1999 model year that eliminated the exhaust gas recirculation, increased the compression ratio from 9.5:1 to 9.7:1, and switched from low [[Electrical impedance|impedance]] [[Fuel injector#Typical EFI components|fuel injectors]] to high impedance. For increased reliability this engine also saw other minor updates in the 2000s towards the end of its use in General Motors vehicles. In 2001, changes included a smaller knock sensor, flat-top pistons instead of dished, new oiling passages, newer stronger timing chain, a redesigned water pump, a redesigned starter motor, and a higher capacity [[catalytic converter]]. An improved belt-tensioner was introduced in 2002.

==== Specifications post-1999 ====
{| class="wikitable" style="width:70%;"
|-
| Engine type
| [[Multi-valve#Four valves|Multivalve]] [[Overhead camshaft engine#Dual overhead camshaft (DOHC)|DOHC]] [[straight-four engine]]
|-
| Bore × Stroke
| {{cvt|90| × |94|mm|in|2}}
|-
| Displacement
| {{cvt|2392|cc|cuin|1}}
|-
| Compression ratio
| 9.7:1
|-
| Fuel delivery
| Sequential fuel injection (SFI)
|-
| Peak power
| {{cvt|150|hp|kW|0}} at 5600&nbsp;rpm
|-
| Peak torque
| {{cvt|155|lbft|Nm|0}} at 4400&nbsp;rpm
|-
| Estimated fuel economy
| {{cvt|23|mpgus}} city / {{cvt|33|mpgus}} highway{{citation needed|date=June 2012}}
|}

Applications:
* 1996–2002 [[Chevrolet Cavalier]] Z24
* 1996–2002 [[Pontiac Sunfire]] GT
* 1996–2001 [[Pontiac Grand Am]]
* 1996–1998 [[Oldsmobile Achieva]]
* 1999–2001 [[Oldsmobile Alero]]
* 1997–2000 [[Chevrolet Malibu]]
* 1996–1998 [[Buick Skylark]]
{{clear}}