Editing Quad 4 engine (section)

=== 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}}