Help me make the definitive S-Chassis VIN/Model decoder

[InvisibleHand]

Hey! Long time lurker here. I mostly come here to search for answers for my S14 build, but today I want to ask the community to help me with something directly.

I am building an S-Chassis registry app that decodes VIN and Model codes and provides all the factory specs of the car (from S12 to S15). Then based on the number of cars registered and the specific configuration of each car, it tells you the rarity of any specific option, and the rarity of the overall configuration.

I have been doing extensive research to document every digit's purpose and all possible S-Chassis-related variables per digit. Unfortunately, there is a lot of conflicting or outright missing information out there. The primary resources I am using are:

nissanhelp.com VIN decoder
gtr-registry.com S-Chassis portals
240sx.org S-14 Model Identification document
Various VIN related posts here on zilvia.net

If you don't have any specific knowledge, the next best thing you can do is list your car's VIN (minus the last 6 digits which are the serial number, for your privacy) as well as your Model Code, along with the year, model and factory options of your car so I can begin to identify the pattern within the code.

Here is what I have so far. Please help me fill in the gaps and correct any errors.

Let's begin with the VIN.

All S-Chassis' will begin with:

• JN1: Japanese Nissan Passenger Vehicle
• JN3: Japanese Nissan Convertible

Digits 4-9 are the VDS or Vehicle Description Section:

• 4th Digit: The VIN decoder claims this is the engine option but I don't think this is right. For instance, my 240sx has A here and came stock with a KA24DE. But the site says A is for VG, VK and VQ motors. The list has the KA24DE as D. What's the truth about this digit?
• 5th Digit: Chassis code - All S-Chassis will have S here, with the exception of S12's which I believe have a C. Please correct me if I'm wrong.
• 6th Digit: VIN decoder calls this the "model change" but the info is lacking. Looking at some info this may denote models in the following format:

  180sx = 3
  200sx = 2
  240sx = 4 (This is consistent with my car)
  Silvia = 6

• 7th Digit: Body Type - 4 is 2-Dr Coupe and 6 is 2-Dr Vert and Fastback
• 8th Digit: Misc, primarily focused on safety features from what I can tell. My car has D which according to the VIN decoder means "Driver & Front Passenger Air Bag + 3 Point Seat Belt". I will need some help determining how many of these variables will apply to our cars.
• 9th Digit: Check Digit - Of no real significance.

Digits 10-17 are the VIS or Vehicle Identifier Section:

• 10th Digit: Model Year - I have info for S13 through S15, but am missing S12. It is as follows:

  L = 1990
  M = 1991
  N = 1992
  P = 1993
  R = 1994
  S = 1995
  T = 1996
  V = 1997 (consistent with my car)
  W = 1998
  X = 1999
  Y = 2000
  1 = 2001
  2 = 2002

• 11th Digit: Plant Code - I believe all S-Chassis were build in Kyushyu, Japan, which is represented by W.
• 12th-17th Digits: Serial Number specific to each individual car.

Additionally, I have found that Japanese market car VINs or Chassis Numbers are structured differently with just 9-10 digits vs 17 in the U.S. Are there any other differences like this in other markets such as Europe and Australia?

On to the Model Code:
I have only been able to find the S14 code breakdown from 240sx.org (linked above) This looks very accurate to me. But I need similar resources for S12, S13 and S15. If anyone has a similar doc to the S14 one please link it here. Otherwise, this is where listing your specific code, configuration and options will help me decipher it for all S-Chassis.

Thanks in advance for your help! Let's make the most comprehensive database of code specs and the most efficient car registry on the internet! The registry app is just the start but is the biggest hurdle. I think the whole S-Chassis community will like what I have planned once that's launched!

Cheers!