Editing Quad 4 engine

{{short description|Inline four-cylinder automobile engine}}
{{original research|date=April 2021}}
{{Infobox automobile engine
| name          = Oldsmobile Quad&nbsp;4
| image         = Quad4Engine.jpg
| caption       = 
| manufacturer  = [[Oldsmobile]] division of [[General Motors|GM]]
| aka           = Quad OHC<br />Twin Cam
| production    = 1987–2002
| predecessor   = 
| successor     = [[L850 engine|Ecotec engine]]
| configuration = [[Straight-four engine|I4]]
| displacement  = {{ubl |{{cvt|2260|cc|cuin|1}}|{{cvt|2392|cc|cuin|1}}}}
| bore          = {{ubl |{{cvt|92|mm|in|2}}|{{cvt|90|mm|in|2}}}}
| stroke        = {{ubl |{{cvt|85|mm|in|2}}|{{cvt|94|mm|in}}}}
| block         = [[Cast iron]]
| head          = [[Aluminum]]
| valvetrain    = {{ubl |[[Dual overhead cam|DOHC]] [[Multi-valve#Four valves|4 valves per cyl.]]|[[Single overhead cam|SOHC]], 2 valves per cyl.}}
| compression   = 9.5:1, 9.7:1, 10.0:1
| fuelsystem    = [[Sequential multi-port fuel injection|Sequential MPFI]]
| turbocharger  = Experimental engines only
| fueltype      = [[Gasoline]]
| oilsystem     = [[Wet sump]]
| coolingsystem = [[Radiator (engine cooling)|Water-cooled]]
| power         = {{cvt|150–190|bhp|kW|0}}
| specpower     = 
| torque        = {{cvt|160|lbft|Nm|0}}
| length        = 
| width         = 
| height        = 
| weight        = 
}}

The '''Quad&nbsp;4''' is a family of [[straight-four engine]]s produced by [[General Motors]]' [[Oldsmobile]] division. Several [[Overhead camshaft engine#Dual overhead camshaft (DOHC)|double overhead camshaft]] (DOHC) versions were produced between 1987 and 2002, and one [[Overhead camshaft engine#Single overhead camshaft (SOHC)|single overhead camshaft]] (SOHC) model was built from 1992 to 1994. 

==History==
The Quad&nbsp;4 is the first domestic regular production DOHC four-cylinder engine wholly designed and built by GM, the only similar prior example being the [[Chevrolet Cosworth Vega]], whose DOHC head was designed by [[Cosworth]] in England. In addition to the 2.3-liter DOHC Quad&nbsp;4s, there was also a short-lived 2.3-liter SOHC variant called the "Quad OHC", available from 1992 to 1994, and the 2.4-liter Twin Cam, available from 1996 to 2002.

The Quad&nbsp;4 was originally expected to debut in 1987, but was delayed for one year. From as early as 1988, Oldsmobile announced that a high-output "HO" Quad&nbsp;4 with {{cvt|180|bhp|kW|0}} was forthcoming.<ref name="jalopnik-mar2019"/>

All Quad&nbsp;4 family engines were produced at the [[Lansing Engine Plant]] (plant five) in [[Delta Charter Township, Michigan|Delta Township]] near [[Lansing, Michigan]]. The Twin Cam was the last engine that was engineered and produced solely by Oldsmobile; the [[Oldsmobile Aurora engine|Aurora V8]] and [[Northstar engine series#LX5 (Shortstar)|Shortstar V6]] were based on the [[Cadillac]] [[Northstar engine series|Northstar V8]] architecture.

First released to the public as a regular production option for the 1988 [[Oldsmobile Cutlass Calais]] and [[Pontiac Grand Am#1985–1991|Pontiac Grand Am]], the engine's availability expanded to [[Buick]] in late 1988 and [[Chevrolet]] in 1990, after which it became a mainstay in GM's lineup.

The Quad&nbsp;4 underwent two rounds of [[Cylinder head porting|exhaust port size reductions]], followed by the addition of [[balance shafts]] in 1995 to address its levels of [[noise, vibration, and harshness]] (NVH). Further changes were made for the 1996 model year when the engine's [[Bore (engine)|bore]] and [[Stroke (engine)|stroke]] were changed, and the engine was subsequently renamed the "Twin Cam".

The Quad&nbsp;4 engine lineup was cancelled after the 2002 [[model year]]. It was replaced by the [[GM Ecotec engine|Ecotec]] for the 2003 model year.

==Common features==
The Quad&nbsp;4 name is derived from the engine's four-cylinder, [[Multi-valve#Four valves|four valve-per-cylinder]] layout.<ref name="dl-jun2019"/> The engine has a [[cast iron]] [[Cylinder block|block]]. The [[Cylinder head|head]], camshaft carriers, and timing chain cover are aluminum, and the sump is die-cast aluminum.<ref name="jalopnik-mar2019"/>

Although [[toothed belt|cogged]] [[Timing belt (camshaft)|timing belt]]s were becoming popular among contemporary overhead cam designs, the Quad&nbsp;4 uses timing chains to drive both camshafts, as well as the water pump. Engine accessories are driven by a single-plane serpentine belt.<ref name="hrm-apr1987a"/>

Fuel is delivered by an electronic fuel injection system, and spark is produced by a distributorless ignition system called "direct-fire", that alternately fires two ignition coils located under the cast aluminum engine cover.<ref name="jalopnik-mar2019"/>

==Reception==
Following the engine's release in 1988, Oldsmobile promoted the Quad&nbsp;4 name with cars like the [[Oldsmobile Aerotech]]. Although the engines in the Oldsmobile Aerotechs were purpose-built and turbocharged, they were meant to showcase the design's capability. At the 1988 [[Indianapolis 500]], the [[pace car]] was an Oldsmobile [[Cutlass Supreme#Fifth generation|Cutlass Supreme]] convertible powered by a [[Turbocharger|turbocharged]] production Quad&nbsp;4.

After positive reviews for the first few years of sales, the automotive press began to criticize the Quad&nbsp;4 for its NVH levels when compared to turbocharged four-cylinders, [[V6 engine|V6]]es, and occasionally [[V8 engine|V8]]s.

The design gained a minor following in [[hot rod]]ding circles due to its resemblance to a 1930s [[Offenhauser]] engine once the ribbed aluminum cover was removed, exposing the tall cam towers and deep valley between them holding the spark plugs.<ref name="hemmings-mar2012"/><ref name="srm-mar2007"/>

==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}}

==Prototypes and experimental engines==
===Factory prototypes===
At the same time that Oldsmobile announced the planned high-output "HO" Quad&nbsp;4 in 1988, they suggested that a turbocharged version producing up to {{cvt|250|bhp|kW|0}} was planned. A turbocharged Quad&nbsp;4 with a reported {{cvt|200|hp|0}} was installed in an Oldsmobile 98 that was previewed by [[MotorWeek]]. A turbocharged Quad&nbsp;4 was never released as a production option.<ref name="jalopnik-mar2019"/><ref name="mw-feb2020"/>

The pace car for the 1988 Indianapolis 500 was an Oldsmobile Cutlass Supreme that had been converted into an open car by Cars and Concepts. The engine was a turbocharged 2.3-liter Quad&nbsp;4 built mainly with factory parts that produced {{cvt|250|hp|kW}} at 6400&nbsp;rpm.<ref name="wbody-1988pace"/>

The Oldsmobile Aerotech II and Aerotech III were both released in 1989. The Aerotech II is a wagon-back sports coupe concept with a 2.3-liter Quad&nbsp;4 making {{cvt|230|hp|kW}} with some form of forced induction. The Aerotech III is essentially a preview of the 1990 Oldsmobile Cutlass Supreme sedan, and came with a supercharged 2.3-litre Quad&nbsp;4 that developed {{cvt|230|hp|kW}}.<ref name="oo-concepts"/>

===Aerotech engines===
Even before the production Quad&nbsp;4 was released, Oldsmobile engineering's Chief Engineer Ted Louckes and Future Systems and Technology engineer Bill Porterfield had begun a program looking for more power and higher efficiency from the engine. Part of the project included building the Oldsmobile Aerotechs in pursuit of new land speed records. Two new twin-cam four-cylinder engines were built, based not on production Quad&nbsp;4 parts, but on a set of engineering parameters derived from the engine, which Oldsmobile referred to as the "production architecture." Under this scheme the derivative engines had to keep the Quad&nbsp;4's four-stroke combustion cycle, double overhead cams, multi-valve cylinder head and, significantly, {{cvt|100|mm|in|2}} bore spacing.<ref name="hrm-apr1987b"/>

====Batten RE engine====
[[File:Quad4-900-2.JPG|thumb|right|Batten RE engine with single turbo]]
The Batten RE engine was designed by Rudy Sayn and Andy Schwartz of Batten Heads in Detroit, and followed the restrictions set out by Oldsmobile. The engine's cylinder head, block, and sump are all of aluminum alloy, with the sump also able to handle structural loads. The RE also has an unusual coolant distribution manifold. The RE's designers retained the valve angles and sizes, pent-roof combustion chambers, dual chain-driven camshafts, and stock piston crown shapes of the production Quad&nbsp;4.<ref name="hrm-apr1987b"/>

The RE is a [[Cylinder (engine)#Sleeve|wet sleeve]] design, with four cast iron cylinder liners attached to an upper cylinder block deck plate. With a bore of {{cvt|3.5|in|mm|0}} and a stroke of {{cvt|3.1|in|mm|0}}, the engine displaced {{cvt|1955|cc|cuin|2}}.<ref name="hrm-apr1987b"/>

The electronic fuel injection system came from Rochester Products, while Delco Electronics provided the engine's high-voltage ignition system. The RE was fitted with a single turbocharger from [[Garrett AiResearch]].<ref name="hrm-apr1987b"/>

Output estimates for the Batten RE engine range from {{cvt|750| to |900|hp|kW}}. A Batten RE engine powered the short-tail Aerotech car.<ref name="oo-aerotech"/>

Applications:
[[Oldsmobile Aerotech]] short-tail

====Feuling BE engine====
[[File:Quad4-1000.JPG|thumb|right|Twin-turbo Feuling BE engine with one external port per valve]]
In Ventura, California, Feuling Engineering undertook development of an experimental engine subject to the same set of restrictions set by Oldsmobile. Feuling's design focused on thermal efficiency and heat rejection. Like the Batten engine, Feuling's BE is an all-aluminum design, with an alloy sump able to handle structural loads. The Feuling block was developed by Keith Black Racing Engines, who produced a Y-block with deep skirts. This engine was also linered — in this case by a set of aluminum/[[Nikasil]] liners courtesy of [[Mahle GmbH|Mahle]].<ref name="hrm-apr1987b"/>

The engine's camshaft profiles were the result of a collaboration between Feuling, Engle Manufacturing Company, and Dick Jones Camshafts. In the BE, the camshafts are driven by timing belts rather than chains. Each intake and exhaust valve has its own external port. External manifolding connects each exhaust port to one of two different turbochargers.<ref name="hrm-apr1987b"/>

Feuling later used a similar cylinder head design on what is reported to be a Cosworth block to create a Feuling/Oldsmobile V8 engine intended for Indianapolis.<ref name="mas-fov8"/> This was a different engine than Oldsmobile's own Aurora IMSA/IRL racing V8.

Output of the Feuling BE engine is estimated to have been approximately {{cvt|1000|hp|kW}}. It was used in the long-tail Aerotech car.<ref name="oo-aerotech"/>

Applications:
[[Oldsmobile Aerotech]] long-tail

===Quad&nbsp;8===
In an episode of [[MotorWeek]] from early 1988, a photo is shown of an Oldsmobile V8 engine developed using Quad&nbsp;4 technology. The engine is called the Quad&nbsp;8.<ref name="aw-1988"/> What was shown was apparently a mock-up of the engine, possibly built by Feuling Engineering.<ref name="hotrod-jan2023"/><ref name="cyclenews-apr2002"/> The engine made an appearance at a Specialty Equipment Market Association ([[SEMA (association)|SEMA]]) show in Las Vegas, but did not go into production.<ref name="hagerty-apr2020"/> The Quad&nbsp;8 was featured in an article in the June 1993 issue of [[American Rodder (magazine)|American Rodder]] magazine.<ref name="ar-jun1993"/>

== See also ==
* [[List of GM engines]]

== References ==
{{reflist|refs=

<ref name="jalopnik-mar2019">{{Cite web |url=https://jalopnik.com/heres-why-the-quad-4-was-one-of-gms-most-important-engi-1829719965 |title=Here's Why the Quad 4 Was One of GM's Most Important Engines Ever |last=Tracy |first=David |date=4 March 2019 |website=jalopnik.com |publisher= |access-date= }}</ref>

<ref name="dl-jun2019">{{Cite web |url=https://www.drivingline.com/articles/gms-quad-4-engine-was-a-high-tech-light-at-the-end-of-a-long-long-tunnel/ |title=GM's Quad 4 Engine Was a High-Tech Light at the End of a Long, Long Tunnel |last=Hunting |first=Benjamin |date=3 June 2019 |website=www.drivingline.com |publisher= |access-date= }}</ref>

<ref name="hrm-apr1987a">{{cite magazine |author=<!--Staff writer(s); no by-line.--> |title=Oldsmobile's All-New Production Quad-4 |url=https://www.motortrend.com/features/oldsmobiles-all-new-production-quad-4-april-1987-982-1324-116-1/ |magazine=[[Hot Rod (magazine)|Hot Rod]] |location= |publisher= |date=April 1987 |access-date=2024-10-30}}</ref>

<ref name="hemmings-mar2012">{{Cite web |url=https://www.hemmings.com/stories/class-of-87-quad-4-edition/ |title=Class of '87 — Quad 4 Edition |last=Bumbeck |first=Mike |date=23 March 2012 |website=www.hemmings.com |publisher= |access-date= }}</ref>

<ref name="srm-mar2007">{{cite web |url=http://www.streetrodderweb.com/tech/0703sr_fabricating_tapered_cones/index.html |title=Fabricating Tapered Tubes — Cool Cones |date=March 2007 |publisher=Source Interlink Media, Inc. |access-date=2024-10-23 |archive-url=https://web.archive.org/web/20071221002016/http://www.streetrodderweb.com/tech/0703sr_fabricating_tapered_cones/index.html |archive-date=2007-12-21 |work=[[Street Rodder (magazine)|Street Rodder]] |first=Jay |last=Storer }}</ref>

<ref name="mcg-scc">{{Cite web |url=https://inventory.motorcargroup.com/vehicles/255/1992-oldsmobile-achieva-coupe-sc |title= 1992 Oldsmobile Achieva Coupe SC |author=<!--Not stated--> |date= |website=inventory.motorcargroup.com |publisher= |access-date= }}</ref>

<ref name="bf-jul2022">{{Cite web |url=https://barnfinds.com/quad-4-equipped-1992-oldsmobile-achieva-sc/ |title=Quad 4 Equipped: 1992 Oldsmobile Achieva SC |last=Lavery |first=Jeff |date=15 July 2022 |website=barnfinds.com |publisher= |access-date= }}</ref>

<ref name="brochure-1994">{{Cite web |url=https://xr793.com/wp-content/uploads/2017/02/1994-Oldsmobile-Achieva.pdf |title=1994 Achieva By Oldsmobile |author=<!--Not stated--> |date= |website=xr793.com |publisher=[[Oldsmobile]] |access-date= }}</ref>

<ref name="mgc-96cavalier">{{cite web |url=http://media.gm.com/division/chevrolet/products/archive_prod_info/pguide/cavalier/cavspec3.htm |title=1996 Cavalier Specifications — Engine, Capacities and Transmission |website=media.gm.com |date= |publisher= |access-date=2024-10-23 |archive-url=https://web.archive.org/web/20040511063941/http://media.gm.com/division/chevrolet/products/archive_prod_info/pguide/cavalier/cavspec3.htm |archive-date=2004-05-11 }}</ref>

<ref name="mw-feb2020">{{Cite AV media |url=https://www.youtube.com/watch?v=cublVH6LtVg |title=Olds Quad 4 Prototypes {{!}} Retro Review |date=2020-02-13 |publisher=[[MotorWeek]] |via=Youtube |people=[[John Davis (television personality)|John Davis]]}}</ref>

<ref name="wbody-1988pace">{{Cite web |url=https://www.w-body.com/oldsite/pace-car/index.html |title=1988 Oldsmobile Cutlass Supreme — Indy 500 Official Pace Car |author=<!--Not stated--> |date= |website=www.w-body.com |publisher= |access-date= }}</ref>

<ref name="oo-concepts">{{Cite web |url=https://www.outrightolds.com/concepts-and-show-cars/oldsmobile-concept-cars |title=Oldsmobile Concept Cars |last=Kerr |first=Sean |date= |website=www.outrightolds.com |publisher= |access-date= }}</ref>

<ref name="hrm-apr1987b">{{cite magazine |author=<!--Staff writer(s); no by-line.--> |title=Oldsmobiles Next-Generation Hot Rod Engines. Are They Here Now? |url=https://www.motortrend.com/features/quad-4-april-1987-982-1324-112-1/ |magazine=[[Hot Rod (magazine)|Hot Rod]] |location= |publisher= |date=April 1987 |access-date=2024-10-30}}</ref>

<ref name="oo-aerotech">{{Cite web |url=https://www.outrightolds.com/spotlight-on/olds-aerotech |title=Oldsmobile Aerotech |last=Kerr |first=Sean |date= |website=www.outrightolds.com |publisher= |access-date= }}</ref>

<ref name="mas-fov8">{{Cite web |url=https://www.museumofamericanspeed.org/fuelingoldsmobile.html |title=Fueling Oldsmobile Indy Engine |author=<!--Not stated--> |date= |website=www.museumofamericanspeed.org |publisher= |access-date= }}</ref>

<ref name="aw-1988">{{Cite AV media |url=https://www.youtube.com/watch?v=ZDFmhPZOGjI |title=Olds Aerotech {{!}} Retro Review |date=2020-04-28 |publisher=[[MotorWeek]] |via=Youtube |people=[[John Davis (television personality)|John Davis]]}}</ref>

<ref name="hagerty-apr2020">{{Cite web |url=https://www.hagerty.com/media/automotive-history/the-oldsmobile-aerotechs-were-perhaps-americas-hottest-prototypes/ |title=The Oldsmobile Aerotechs were perhaps America's hottest prototypes |last=Petrány |first=Máté |date=28 April 2020 |website=www.hagerty.com |publisher= |access-date= }}</ref>

<ref name="hotrod-jan2023">{{Cite web |url=https://www.hotrod.com/features/deeper-breathing-982-1641-18-2/ |title=Deeper Breathing |author=<!--Not stated--> |date=1 January 2023 |website=www.hotrod.com |publisher= |access-date= }}</ref>

<ref name="cyclenews-apr2002">{{cite magazine |author=<!--Staff writer(s); no by-line.--> |title=Jim Feuling: Mechanically Insane |url=https://magazine.cyclenews.com/i/128148-cycle-news-2002-04-03/49? |magazine=[[Cycle News]] |page=45 |location= |publisher= |date=3 April 2002 |access-date=}}</ref>

<ref name="ar-jun1993">{{cite magazine |last= |first= |date=June 1993 |title=The Top-Secret V8 |url= |magazine=[[American Rodder]] |page=92 |location= |publisher= |access-date=}}</ref>

}}

== External links ==
{{Commons category|GM Quad 4 engine}}
* {{cite web |url=http://www.quad4forums.com/ |title=Quad4forums.com |date=2005-04-30 |publisher= |access-date=2024-10-23 |archive-url=https://web.archive.org/web/20080530045938/http://www.quad4forums.com/ |archive-date=2008-05-30 }}
* {{cite web |url=http://autos.groups.yahoo.com/group/quadfourm/ |title=Yahoo group QuadForum mailing list |date= |publisher= |access-date=2024-10-23 |archive-url=https://archive.today/20130105132545/http://autos.groups.yahoo.com/group/quadfourm/ |archive-date=2013-01-05 }}

{{DEFAULTSORT:Quad 4 engine}}
[[Category:Oldsmobile engines]]
[[Category:Straight-four engines]]
[[Category:Gasoline engines by model]]