This identification guide has been written to assist people in determining the authenticity of a Nissan Skyline R31 GTS-R, as distinguished from others in the R31 series such as the GTS, GTS-X and GTS-Autech. Classic Register also keeps an informal register of GTS-Rs which can be viewed by clicking here.

The R31 GTS-R was a ‘Group A’ homologation ‘evolution’ car. In order to qualify for Group A racing in 1987, manufacturers were required to produce a minimum of 5,000 base model vehicles. For Nissan, the Skyline GTS and GTS-X represented that base model for the R31 series, and easily met the minimum production number requirements. However, when the ‘Group A’ rules changed for the 1987 year, several modifications needed to be made which were not reflected on the existing GTS models. For example, the rules no longer allowed for electronic wings, an item which was present on the GTS coupe. Instead of requiring manufacturers to produce an additional 5,000 units complying with the new rules, manufacturers need only produce a minimum of 500 ‘evolution’ models reflecting the new changes, and were then allowed to compete in the category. This is precisely the reason Nissan produced the GTS-R, and the car is said to have provided vital test data and preparation for the re-introduction of the GT-R nameplate on the R32 series. The GTS-R performed particularly well in the Japanese and Australian touring car championships, as well as having a number of significant achievements through Nissan Motorsport Europe.

The superior performance of the GTS-R, its low production numbers and thoroughbred racing link as a ‘Group A evolution’ car have made it the most desirable vehicle in the R31 Skyline range. As GTS-Rs generally bring higher prices than other R31 models, it is therefore important as a prospective purchaser or restorer, to know the relevant features which confirm a car’s authenticity. This guide provides a range of detailed information on the Skyline GTS-R’s original specifications and features, including its exterior features, interior features, mechanical features and of course the relevant chassis and model codes.

Number built:

800 units is commonly quoted as the production number. However, GTR-Registry.com has since undertaken research and confirmed that 823 were produced, including 4 prototypes. As a side note, the minimum requirement for Group A qualification at the time was 500 units.

Period of manufacture:

Official production commenced in August 1987, however, GTR-Registry.com has confirmed that the several prototypes were built earlier in 1987. Production ended in November 1987, prior to the GTS-R's ‘Group A’ race debut.

Please note, this guide has been written based on a variety of online sources and enthusiast input. You should not rely on this guide to make any purchasing decision and we make no representation that all information is accurate. You should always seek independent professional advice when looking to purchase a unique car. If you have additional information, photographs or corrections you believe need to be made to this page, please contact us by clicking the button at the top of this page, or comment below.

 

1. Exterior Features - 1987 Nissan Skyline R31 GTS-R

The GTS-R's exterior features are listed below. As noted where relevant, many of these features were shared with the GTS and GTS-X models, and therefore may not necessarily be unique to the GTS-R (unless specifically stated).

  • All production GTS-Rs were painted “Bluish Black (Code BG8). The paint code can be found on the vehicles data plate, located on the passenger side of the bulkhead in the engine bay (see images for the specific location).
  • Projector headlights (These were fitted to all JDM R31s from August 1987).
  • Fixed front spoiler (In line with Group A rules, this was not electronically adjustable as on the GTS / GTS-X models). The lip is was made from a coated rubberised foam approximately 10mm thick.
  • Unique ‘Group A’ rear spoiler made from fibre reinforced plastic (FRP).
  • Revised unique front bumper including vents under both of the front indicator lenses (GTS / GTS-X only have one vent on the passenger side).
  • 15” steel rims with wheel covers were available as standard.
  • As an option (and most commonly applied) were 15” x 6.5” silver ‘BBS’ wheels. These had ‘Skyline’ badged centre caps. Original wheels should have “BBS” embossed on the face of the rim. The ‘BBS’ wheels were originally fitted with 205/60 R15 tyres front and rear.
  • Series III GTS grille was applied with “GTS” embossed in large text on the passenger side of the vent mould.
  • “GT” badges underneath side repeaters/indicators (The same as the GTS / GTS-X).
  • Decals on the rear of the car include:
    • “Nissan Motorsport International” decal on the left side of rear spoiler.
    • “GTS-R” decal on the left side of the rear boot lid (between the tail light and spoiler).
    • “Nissan” decal on the right side of the rear boot lid (between the tail light and spoiler - same as applied to GTS / GTS-X).
    • Large “Skyline” decal on panel below number plate - same as applied to GTS / GTS-X.
  • Twin 1 ¾” exhaust pipes exit from the muffler with chrome tips.
2. Interior Features - 1987 Nissan Skyline R31 GTS-R

The GTS-R's interior features are listed below. As noted where relevant, many of these features were shared with the GTS and GTS-X models, and therefore may not necessarily be unique to the GTS-R (unless specifically stated).

  • Leather bound ‘Hartge’ steering wheel, featuring dual horns. This steering wheel was unique to the GTS-R.
  • Like the GTS / GTS-X, the GTS-R was fitted with electric windows, air-conditioning and AM/FM radio and tape deck (The original radio / cassette system is believed to be a  unit built by National, which later became Panasonic. The original units have the antenna up / down buttons on the right hand side of the unit, which we have cited on many cars.) If anyone has a better image of an original, please pass it on so we can include it in this section.
  • Optionally fitted with a 260km/h “Impul” instrument cluster (However, the standard 180km/h JDM dash was fitted to the GTS-R in most cases).
  • The turbo boost gauge is integrated within the main instrument cluster at the top left (same cluster as the GTS / GTS-X).
  • Space saver spare wheel (same as available on the GTS / GTS-X).
  • “Skyline” labelled floor mats (same as available on the GTS / GTS-X).
  • Unique mono-form grey cloth bucket seats. The door card trim inserts and rear quarter panel inserts matched the grey cloth seat material. Note, the same interior trim and seats were applied to the “Tommy Kiara M30” special edition, and were a "Nismo" option for the GTS / GTS-X (the Nismo option seats will have a small nismo label in the centre of the back rest). Other than those two exceptions, these seats are unique to the GTS-R.
  • Interior colour will be specified as “G” (believed to mean ‘grey’) on the vehicle’s chassis plate (See location on images shown). During their research, GTR-Registry have confirmed that 60 GTS-Rs did not have the "G" code applied. It not yet confirmed why Nissan omitted the G from these cars, but please contact us if you have any additional information.
  • Dark grey carpet was fitted to all GTS-Rs.

 

3. Model Number and Chassis Number - 1987 Nissan Skyline R31 GTS-R

Model Number:

The model number will confirm whether the vehicle is a GTS-R, and should read as follows:

KRR31RHFSM GR

The model number will be displayed on the vehicle’s blue data plate (located on the passenger side firewall/bulkhead in the engine bay). See the images for a better description of the specific location. Note: GTR-Registry.com during their research have confirmed that 3 of the 4 prototype vehicles built had a different model code to that noted above.

 

Chassis Number:

The chassis number will be in a standard format for the R31 Skyline as follows:

HR31-###### (where “#” represents each unique chassis digit)

The chassis number will be printed in two locations. Firstly, it will be noted on the vehicle’s blue data plate (located on the passenger side firewall/bulkhead in the engine bay). The same code should be stamped into the firewall/bulkhead on the driver’s side of the engine bay. See the images for a better description.

 

For full confirmation, we recommend that you check the vehicle’s identity through Nissan’s ‘FAST’ software. 

4. Engine Number - 1987 Nissan Skyline R31 GTS-R

The engine number on the R31 GTS-R is located in the same position as all RB20 engines, and unfortunately, the engine number itself will not confirm the engine is the RB20DET-R. Instead, you must rely on engine components and other features to confirm with some certainty that the engine is genuine. These are outlined in the ‘Mechanical features’ section of this guide.

Nonetheless, the engine number is located on the passenger side of the engine block, close to where the block flange meets the gearbox (i.e., rear end of the block). You will see a smooth ground down area in two distinct rectangular / square shapes. The smaller ‘front’ ground area will have “RB20” stamped into it, and the larger ground down area on the flange edge will have the unique engine code stamped into it. Our research so far indicates that this code should be 6 digits followed by the letter A, noting that the same pattern appears on several types of car that use the RB20.

Examples of the locations and typeface have been provided in the images. Note, to see the number clearly, you will need to use a flashlight, and look behind the extractors which will likely impede your view. It may also be necessary to clean off the area with degreaser to clearly see the stampings. If anyone has better images available please pass them on so we can improve this section.

5. Mechanical Features - 1987 Nissan Skyline R31 GTS-R

The GTS-R had the following mechanical features:

  • 1998cc 6-cylinder 24-valve turbocharged DOHC engine (Code: RB20DET-R) producing 210ps/154kw. The RB20DET-R engine was distinguished visually by the “Nissan RB20DET-R” bonded badge which is mounted on the top of the inlet manifold, as opposed to the “ECCS” badge on the standard GTS / GTS-X models.
  • Early RB20 engines (including the RB20DET-R) were known as ‘red top’ engines – a reference to the rocker cover colour.
  • Factory tubular stainless steel equal length exhaust manifold. The J-pipe casting and bracket is unique to the GTS-R to make clearance for the different exhaust manifold. The regular RB20DET J-pipe has a single 90° bend, whilst the GTS-R has two 45° + 45° bends in the design.
  • The GTS-R will have a small gearbox casing breather next to the wiper motor.
  • Unique moulded heat shield above exhaust manifold.
  • T04E Garratt turbocharger (larger turbo than the GTS / GTS-X).
  • Larger throttle body than the standard GTS / GTS-X.
  • Lightened flywheel.
  • Larger intercooler (4 times larger than the standard GTS/GTS-X intercooler).
  • Tweaked ECU (unique to the GTS-R).
  • HICAS four-wheel steering system.
  • 5-speed manual transmission and limited slip differential.
  • The GTS-R had a front-mounted intercooler located under the radiator support panel. The A/C condensers are positioned behind the driver's side bumper vent, and another is mounted vertically in front of the intercooler. This is different to the standard GTS/GTS-X which had a smaller intercooler positioned close to the passenger side bumper vent. The passenger side vent is not directly utilised in the GTS-R, and only has intercooler pipes running behind it.
  • Factory front suspension strut tower brace. Skyline badged plastic covers should appear over the tower brace ends where they project from the strut top (see images).
  • Original suspension was made by Tokiko for Nismo. (see example in images of front and rear shocks).
  • The GTS-R carried over the same KYB electronically adjustable suspension as earlier GTS models.
  • Front ventilated disc brakes (274mm diameter, 22mm thick), rear solid disc brakes (260mm diameter, 10.4mm thick).
  • Exhaust system is believed to be 2.5” stock.
6. Documentation and Articles - 1987 Nissan Skyline R31 GTS-R

We have collected a number of original magazine articles / brochures relating to the GTS-R, and have displayed them here for historical reference and educational purposes.

If anyone has access to any original advertisements, documentation or other material that may be relevant in this section for historical purposes, please send them through to us so we can place this documentation here.

Please note, all documentation placed here are not owned by Classic Register, and is for historical reference and educational purposes only. Upon request from any original copyright owner, the material will be removed. 

7. References - 1987 Nissan Skyline R31 GTS-R

The following sources, among input from many owners and enthusiasts, have contributed to the creation of this page. If you have any further information you believe can be added, please let us know by contacting us or commenting below.

http://gtr-registry.com/index.php

http://forum.r31skylineclub.com/

http://www.gtr.co.uk/

http://www.r31house.co.jp/

http://www.sau.com.au/

https://ja.wikipedia.org

https://en.wikipedia.org

http://jdm-expo.com/

http://car-me.jp/

http://minkara.carview.co.jp/

http://www.goo-net.com/

http://www.jdm-option.com/