Editing Porsche 924 (section)

==924 Turbo==
[[File:Porsche 924 Turbo (3740494673).jpg|thumb|Porsche 924 Turbo (Canada). [[NACA duct]] and front fascia vents are typical of all Turbo models. Large round [[Automotive_lighting#Side_marker_lights_and_reflectors|side-marker lights]] and prominent bumpers with separate [[Automotive_lighting#Front_fog_lights|fog lights]] are typical of all North American 924 models.]]
Porsche executives soon recognised the need for a higher-performance version of the 924 that could take advantage of the model's excellent balance and bridge the gap between the standard 924 and the 911. Having already found the benefits of turbochargers on several race cars and the 1975 911 Turbo (930), Porsche chose to use this technology for the 924, eventually introducing the 924 Turbo in 1978.

On release the 924 Turbo was met with high praise from the automotive community and journalists alike. It was celebrated for its supercar-like performance and impeccable handling, with build quality, general attention to proportion and more purposeful aesthetics garnering universal approval. Some criticised the turbocharged I4 for its coarseness, but critics forgave it in exchange for its economy and remarkable power increase over the naturally-aspirated car. In their comparison against the Aston Martin V8, Porsche 928, Porsche 911 3.0SC, BMW 635 CSI and Lotus Eclat 523, Motor Magazine found the 924 Turbo to be joint second in top-speed (achieving an average of 142&nbsp;mph) and second in 0-60&nbsp;mph acceleration (achieving a time of 6.9 seconds) being topped only by the Aston V8 at 145&nbsp;mph and Porsche 911 at 6.5 seconds respectively, a remarkable feat considering the difference in displacement and price between the models.<ref>{{cite magazine |author=<!--Staff writer(s); no by-line.--> |title=Motor |url= |magazine=Motor |location=United Kingdom |publisher= |date=1980-01-26 }}</ref>

To power the 924 Turbo, Porsche heavily revised the [[VW EA831]] 2.0&nbsp;L I4 motor already used in the naturally aspirated 924, opting to hand assemble the engine at the Porsche factory in Zuffenhausen, Stuttgart. Porsche engineers designed and equipped it with a revised crankcase, connecting rods, cylinder-head gasket, crankshaft and an all new aluminium-silicon alloy cylinder head. With the use of dished combustion chambers and specially shaped pistons  the compression ratio was reduced to 7.5:1, this helped better accommodate the [[Kühnle, Kopp & Kausch|KK&K]] K-26 [[turbocharger]] without inducing pre-ignition. Platinum tipped spark plugs were also used and exhaust valve diameter was increased over the n/a engine.{{sfn|Morgan|1998}} With {{convert|10|psi|kPa|abbr=on}} of boost, output increased to {{convert|170|hp|kW|0|abbr=on}} at 5,500 rpm and {{convert|181|lbft|Nm|abbr=on|0|lk=}} of torque at 3,500 rpm. The 924 Turbo's engine assembly weighed about {{convert|65|lb|kg|0|abbr=on}} more, so front spring rates and anti-roll bars were revised. Weight distribution was now 49/51 compared to the original 924 figure of 48/52 front to rear.<ref>{{Cite news|url=https://www.motorsportmagazine.com/archive/article/march-1980/82/porsche-924-turbo|title=The Porsche 924 Turbo {{!}} Motor Sport Magazine Archive|date=2014-07-07|work=Motor Sport Magazine|access-date=2018-07-16|language=en}}</ref>

In order to aid cooling, as well as to distinguish it from the standard 924, Porsche added a [[NACA duct]] in the hood, this helped heat escape when stationary and caused hot air to be drawn out of the engine compartment due to low pressure induced by the louvred alloy engine under-tray when on the move. In addition to the NACA duct, four slotted air vents were installed in the badge panel, with open ducts added to either side the front valance so to aid cooling of the front brakes. 15-inch spoke-style [[alloy wheel]]s, four-wheel disc brakes with five-stud hubs and a five-speed racing pattern 'dog-leg' transmission was fitted as standard. Power was transferred from the clutch plate to the gearbox through a larger diameter torque tube. Forged 16-inch flat wheels of the style used on the 928 were optional, but fitment specification was that of the 911 which the 924 shared wheel offsets with. A rubber duck-tail spoiler was fitted to the rear hatch, reducing the already low drag coefficient from .36 to .33.  Internally, Porsche called the 924 Turbo the "931", much like the 911 Carrera Turbo which had been known as "Type 930". Although right hand drive specific parts were denoted by the prefix "932" both left hand drive and right hand drive cars are referred to as "931", this designation remains in common use by Porsche enthusiasts today.<ref>{{Cite web|url=http://www.924.org/models/931_overview.htm|title=931 Overview|website=www.924.org|access-date=2021-01-14}}</ref>

The turbocharged [[VW EA831]] engine allowed the 924 Turbo to accelerate to 60 mph in a similar time to the early iterations of the bigger, more powerful Porsche 928, and [[Porsche 911|911]] SC ({{Convert|180|bhp|kW|0|abbr=on}}), thanks in part to a lighter [[curb weight]], but it also brought reliability problems as was often seen in other turbocharged cars of the era.<ref>{{Cite web|url=https://www.classiccarsforsale.co.uk/reviews/classic-porsche-reviews-924|title=Porsche 924 Review {{!}} CCFS UK|website=www.classiccarsforsale.co.uk|access-date=2018-07-16}}</ref> This was mostly due to the fact that the general public did not know how to operate or care for such an early oil cooled turbo setup. Allowing the engine to idle and turbo to cool before shutdown helps prevent turbo seal and component failure and as such greatly extends the turbo's lifespan.<ref>{{cite web|url=https://www.autocar.co.uk/car-news/advice/how-look-after-your-turbocharged-car |title=How to look after your turbocharged car |website=www.autocar.co.uk|date=July 15, 2020 |access-date=January 21, 2021 }}</ref>

For the 1981 model year Porsche released a revised 924 Turbo Series 2 (although badging still read "924 turbo"). By using a revised turbocharger with a larger compressor and a smaller turbine running at increased boost, slightly higher compression of 8:1 and an improved [[fuel injection]] system with DITC (Digital Ignition Timing Control) ignition triggered by the flywheel, peak power rose to {{convert|177|hp|kW|abbr=on}}.

In North America, the 924 Turbo arrived in late 1979 for the 1980 model year. It was saddled with extra weight compared to Euro-spec cars, due to the federally mandated large bumpers and other safety equipment, and less power due to stringent emissions controls. Power was {{convert|143|hp|kW|abbr=on}}, nearly twenty percent down on the European model. For the 1981 model year, power increased slightly to {{convert|154|hp|kW|abbr=on}} and the transmission was switched to one with a regular H-pattern layout (North America only).<ref name=RT82>{{cite journal | ref = 81bg | journal = Road & Track's Road Test Annual & Buyer's Guide 1981 | issue = January–February 1981 | title = 1981 Buyer's Guide | editor-first = Tony | editor-last = Hogg | page = 112 }}</ref>

The 924 Turbo also saw success in Motorsport, mainly in rally guise, preceding the introduction of the 924 Carrera GT. Between 1977 and 1980 [[Jürgen Barth]] and Roland Kussmaul headed a project to develop a competition specification 924 Turbo. The competition cars were based on prototype 931s purchased from the factory by the Porsche head of motorsport Peter Falk, modifications included but were not limited to a wider track, Rallye arches and auxiliary light pods. The car first competed in the 1979 [[Monte Carlo Rally]] and with Barth and his co-driver Kussmaul at the helm, the car finished 4th in the GT4 class, despite being de-specced due to homologation requirements. The 1979 season continued with the same car and drivers taking part in the famous 19,000&nbsp;km [[1979 Round Australia Trial]]. Impressively the car won its class, completing the trial with accumulated penalties of 13 hours and 9 minutes across the 134 stages.<ref>{{cite web|url=https://petrolicious.com/articles/history-will-repeat-itself-in-monte-carlo-when-this-porsche-924-turbo-returns-in-2019|title=History Will Repeat Itself In Monte-Carlo When This Porsche 924 Turbo Returns In 2019 |date=2021-01-14}}</ref>

The 1981 season saw the 924 Turbo make history when it carried a JVC camera inside the cabin, capturing the first ever in car footage of the famous Monte Carlo Rally. This was its final season, retiring to make way for the intercooled 924 Carrera GT.

===Carrera GT===
{{Distinguish|Porsche Carrera GT}}
[[File:1980 Porsche 924 Carrera GT front.jpg|thumb|1980 924 Carrera GT]]
[[File:Porsche 924 GTS - 2008 Rallye Deutschland.jpg|thumb|[[Walter Röhrl]]'s 1981 924 Carrera GTS driven during the [[2008 Rallye Deutschland]].]]
In 1979, Porsche unveiled a concept version of the 924 at the [[Frankfurt Auto show]] wearing Carrera badges. One year later, in 1980, Porsche released the 924 Carrera GT, making clear their intention to enter the 924 in competition. By adding an [[intercooler]], increasing compression to 8.5:1, lowering the suspension as well as various other little changes, Porsche was able to develop the 924 Turbo into the race car they had wanted, dubbing it the "924 Carrera GT". 406 examples (including prototypes) of the Carrera GT were built to qualify it for [[Group 4 (racing)|Group 4]] racing requirements.<ref>{{Cite news|url=https://rmsothebys.com/en/auctions/PA17/Paris/lots/r153-1981-porsche-924-carrera-gt/412135|title=RM Sotheby's – 1981 Porsche 924 Carrera GT {{!}} Paris 2017|date=2017-07-19|work=RM Sotheby's|access-date=2018-08-06|language=en}}</ref> Of the 400 roadgoing examples, 75 were made in right hand drive for the UK market. In 1981 Porsche released the limited production 924 Carrera GTS. 59 GTS models were built, all in left hand drive, with 15 of the 59 being race prepared Clubsport versions.<ref name="evo.co.uk">{{Cite news|url=https://www.evo.co.uk/porsche/porsche-924/21017/porsche-924-carrera-gt-review-history-and-specs-of-an-icon|title=Porsche 924 Carrera GT: review, history and specs of an icon|work=Evo|access-date=2018-08-06|language=en}}</ref>

Visually, the Carrera GT differed from the standard 924 Turbo in that it had polyurethane plastic front and rear flared guards, a polyurethane plastic front spoiler, a top mounted air scoop for the intercooler, a much larger rubber rear spoiler and a flush mounted front windscreen. It also featured [[Recaro]] seats with fine red pinstripes and body paint was available in black, "Guards Red" and "Diamond Silver". It featured [[Pirelli]] P6 tires as standard, and [[Pirelli]] P7 tires were available as an option along with a limited slip differential.<ref>{{Cite news|url=https://www.carmagazine.co.uk/car-reviews/magazine-reviews/midnight-special-porsches-race-bred-924-carrera-gt-driven-car-archive-1981/|title=Midnight special: Porsche's race-bred 924 Carrera GT driven (CAR archive, 1981)|work=CAR Magazine|access-date=2018-08-06|language=en}}</ref> It lost the 924 Turbo's NACA duct in the hood but retained the air intakes in the badge panel. This more aggressive styling was later used for as motivation for the 944. The later Carrera GTS differed stylistically from the GT with fixed headlamps under Perspex covers (instead of the GT's pop up units). GTS models were also {{Convert|59|kg|lb|abbr=on}} lighter than their GT counterparts at {{Convert|1121|kg|lb|abbr=on}}, and Clubsport versions were even lighter at {{Convert|1060|kg|0|abbr=on}}.<ref name="evo.co.uk" />

In order to comply with the homologation regulations, the 924 Carrera GT and later 924 Carrera GTS were offered as road cars, producing 210 and 245&nbsp;hp (157 and 183&nbsp;kW) respectively.<ref>{{Cite news|url=https://www.supercars.net/blog/1981-porsche-924-carrera-gts/|title=1981 Porsche 924 Carrera GTS {{!}} Classic {{!}} SuperCars.net|date=2016-04-27|work=Supercars.net|access-date=2018-08-06|language=en-US}}</ref> Clubsport versions of the GTS were also available with {{convert|280|hp|kW PS|0|abbr=on}}, and factory included Matter [[roll cage]] and race seats. 924 Carrera GT variations were known by model numbers 937 (left hand drive) and 938 (right hand drive).

=== Carrera GTR ===
[[File:GTI 924 Carrera GTR.jpg|thumb|right|A 924 Carrera GTR campaigned by [[GTi Engineering]] in 1981 and 1982.]]
The ultimate development of the 924 in its race trim was the 924 Carrera GTR race car, which produced {{convert|375|hp|kW PS|abbr=on|0|lk=}} from a highly modified version of the 2.0&nbsp;L I4 used in all 924s, and weighed in at {{Convert|930|kg|lb|0|abbr=on}}.<ref>{{Cite news|url=https://www.topgear.com/car-news/classic/you-need-porsche-924-gtr-heres-why#1|title=You need this Porsche 924 GTR. Here's why|date=2016-06-23|work=Top Gear|access-date=2018-08-06|language=en}}</ref> This allowed for a 0–60&nbsp;mph (97&nbsp;km/h) time of 4.7 seconds and a top speed of {{Convert|180|mph|km/h|0|abbr=on}}.<ref>{{Cite news|url=https://www.topspeed.com/cars/porsche/1981-porsche-924-gtr/|title=1981 Porsche 924 GTR @ Top Speed|work=Top Speed|access-date=2018-08-06|language=en-US}}</ref> In 1980, Porsche entered three 924 GTRs at the 24 hours of Le Mans, which went on to finish 6th, 12th and 13th overall. Also building a 924GTR rally race car, and two other GTRs (Miller and BF Goodrich). 17 fully assembled 924 GTRs were built , with chassis numbers 18 and 19 as spares for the private racing teams. A limited number of special series parts were produced to support the teams.

Lastly, in 1981, Porsche entered one of two specially built 924 Carrera GTPs (the "944GTP Le Mans") in which Porsche Motorsports introduced a new prototype highly modified 2.5 liter I4 engine. This engine sported four valves per cylinder, dual over head camshafts, twin balance shafts and a single turbocharger K28 to produce {{convert|420|hp|kW PS|0|abbr=on}}. This last variant managed a seventh place overall finish and spent the least time out of any other car in the pits. This new 2.5 liter configuration engine is the predecessor of the 944 platforms and the later 1987–88 944S 16V M44/40 power-plant.

Production of the 924 Turbo ceased in 1982 except for the Italian market which lasted until 1984. This was due to the restrictions on engines larger than two liters, putting the forthcoming 2.5 liter 944 into a much higher tax category.