NSX-R Differences

The modulator, master cylinder, and brake booster differ between the 02R and other models (the 92R is the same as the other models).
The brake booster side flange of the master cylinder is slightly angled for models other than the 02R, while it is horizontal for the 02R. Therefore, the 02R master cylinder can likely only be used in combination with the 02R brake booster.

Use the Complete 02R System

Although it is possible to use only the modulator, it is difficult to determine how it differs from those of other models. Therefore, unless the master cylinder and brake booster are also changed to 02R specifications, it is preferable to select a modulator for the standard model.
In addition, because the master cylinder is different, the shape of the two brake pipes connected to the modulator also differs, and their part numbers are therefore different.

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Master cylinder for 02R (46100-SL0-N12)

1. Photo: KUSAKA Studioopen_in_new(Licensed for use)
   Comparing the master cylinders for the 02R and other models, there is a significant difference: the 02R has two passages connecting to the reservoir, while the other models have only one.
   At first glance, it might seem that only the 02R has a tandem type, but even the master cylinders for other models with one passage have both a primary and a secondary piston inside. Therefore, all models are tandem type regardless of the number of passages, and the difference is likely only slight in braking feel, such as improved brake touch.

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Brake booster for 02R (46400-SL0-N11)

1. Photo: KUSAKA Studioopen_in_new(Licensed for use)
   Regarding the brake booster, the following is stated in the press information for 02Ropen_in_new, so this difference appears to be more significant. 02R Press Information:
   Brake booster response improves by increasing the valve body diameter, and also improves linearity by increasing the assist ratio.

1. I bought all the parts new except for the modulator.
   The clamp rubber (rubber, pipe clamp) and bracket (clamp, brake pipe) that secure the brake pipe to the back of the blower unit are the same for the early ALB and late ABS models, but since I'm unlikely to ever remove them again, I decided to replace them as part of a refresh.
   
   When I bought the car, the parts other than the modulator weren't that expensive, but now that parts prices have skyrocketed, even just buying the pipes has become an expensive purchase.
   
   I used the master cylinder and brake booster from the first-generation coupe, so I bought the pipes for the standard model, but if you use the master cylinder and brake booster from the 02R, the piping shape is different, so you will need to change the "brake pipe COMP.U" and "brake pipe COMP.V" to the 02R version.

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Complete New Parts Set (Excluding Modulator)

Use the AP1 modulator

The "NK8A" modulator used in the later model NSX ABS was used in many vehicles sold between around 1999 and 2004.
At the time, it was possible to purchase a new genuine NSX modulator, but I wanted to try a low-cost replacement method, so I decided to try replacing it with an NK8A modulator from another vehicle.
At the time, I didn't anticipate that obtaining the genuine modulator would become difficult, and I had planned to replace it with an NSX one later, but it was discontinued and became unavailable.
After checking the wiring diagram, it appears that Step Wagon and other vehicles can be used with the same wiring modifications as the AP1, but the AP1, being rear-wheel drive, is considered more likely to be suitable for use in the NSX.

The AP1 ABS modulator is the same "NK8A" as the later NSX up to the 120 model, but it was changed to the "NK11A" unit from the 130 model onwards.
The NK11A seems like the ideal solution for NSX parts due to its improved response speed and approximately 700g lighter weight, but the differences in bracket shape, pipe tip shape, and routing make it difficult to adapt.
Even with the NK8A, there are two versions: "57110-S2A-952" for the AP1 100 model and "57110-S2A-J51" for the 110-120 models. The difference between 952 and J51 is unclear, but it might be better to choose the newer J51 model.
The 57110-S2A-950 and 57110-S2A-951 found in the used market are likely part numbers integrated into 57110-S2A-952, and 57110-S2A-J50 is likely integrated into 57110-S2A-J51.
For the AP1, the NK8A part number can be identified by the label attached to the computer section. However, the part number shown on this label refers to the computer itself, which is a component of the modulator assembly. Therefore, the number begins with 57105 rather than the complete modulator assembly part number 57110.

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Modulator Temporarily Mounted on Bracket

1. I cleaned the bracket removed from the earlier ALB unit and temporarily assembled the NK8A modulator, proportioning valve, and brake pipe.
   I intended to install it on the vehicle as is, but since the pipe between the modulator and proportioning valve would get in the way when installing the other pipes if it was assembled first, I removed it for the time being.