909 Motorsport M5 ABS Kit
Nissan S Chassis S14-S15

Bosch Motorsport M5 ABS Integration Kit for Nissan S14 / S15

This is a highly integrated Bosch Motorsport M5 ABS system designed for the Nissan S14 and S15 chassis.

At the heart of this package is the Bosch Motorsport M5 ABS, a professional-level motorsport unit used in racing worldwide. The M5 system provides ultra-fast processing, highly accurate wheel slip control, and configurable ABS strategies for track use. Eleven selectable calibrations on a 12-position map switch allow the ABS behaviour to be tuned for tyres, surface conditions, and driving style.

Most competition S-chassis cars either never had ABS or lost it long ago, and the ones that kept it are running a mid-1990s road-car system behind modern tyres and brakes. This kit brings the platform a current motorsport ABS, with the sensing solved from a standard driveline through to a full aftermarket hub package, and with the cabin hardware integrated where the stereo used to live.

What’s Included

• Bosch Motorsport M5 ABS control unit
• Front wheel speed sensors and adapters to suit standard or fabricated front hubs, using the factory ABS sensor location
• Outboard wheel speed sensor and tone ring relocation kit for R200 axles, suits either the stock cast steel hubs and wheel bearings, or aftermarket hubs (tested with ACOSTAL) running R35 wheel bearings
• Front passenger floor mounting plate for the ABS hydraulic unit
• Mounting hardware throughout

Cabin mounting is handled per build. We’ve made a clean single-DIN installation for the S-chassis before, map switch and bias valve in the original stereo slot, no cutting, nothing hanging off the dash, and can reproduce it as custom work alongside your kit. The bias valve itself is specified per car: pedal-box builds don’t need one.

Brake lines from the master cylinder to the hydraulic unit are made to suit the vehicle at install: 909 specifications call for Goodridge or Speedflow hardware.

Why the wheel speed sensing moves outboard

ABS is only ever as good as its picture of what each wheel is doing. The control loop works by detecting the very start of a wheel locking, releasing pressure, and reapplying it, many times a second. All of that depends on the wheel speed signal being an honest, immediate account of the wheel itself.

Measuring inboard, at the driveshaft end, puts the whole driveline between the sensor and the tyre:

• Compliance. An axle shaft winds up under braking torque and unwinds as it releases. The inboard end and the wheel are not doing quite the same thing at quite the same moment.
• Backlash. Splines, CV joints and the differential all carry lash. Under ABS pressure cycling the driveline oscillates back and forth through it, and the sensor reads that motion as though it were the wheel.
• Sensor gap stability. An inboard sensor reads off a driveshaft that moves. Yoke deflection under load, wheelspin and changing conditions all vary the gap between sensor and ring, and a wandering gap gives a signal the ABS cannot reconcile against the other three wheels. The system does the responsible thing: it flags a sensor fault, lights the warning lamp and takes itself offline. A sequential gearbox sharpens all of this: dog engagement lands as a shock through the driveline dozens of times a lap, including on downshifts in the braking zone, which is why inboard sensing often works until the season a sequential goes in.

The result isn’t just a noisier signal; it’s a mistimed one, and at worst no ABS at all. The system releases a moment late and reapplies against a wheel that isn’t where it thinks it is, and the phasing that makes ABS work quietly comes apart.

Relocating the tone ring and sensor outboard puts the measurement at the wheel, past the compliance and past the lash, with a gap that stays where it was set.

None of this is a criticism of Nissan. A factory-ABS S14 or S15 measured the whole rear axle with a single tone ring on the differential input flange, workable for a three-channel system that treated both rear wheels as one, reading variable-reluctance sensors whose signal grew with speed. The M5 controls each rear wheel individually through active sensors with a defined gap window, so this kit isn’t second-guessing the factory, it’s updating a 1990s measuring point to the standard the new system is designed around.

The parking brake stays

Our outboard sensing package is designed around the factory parking brake rather than in place of it. That keeps the car legal for scrutineering where a functioning handbrake is required, keeps it usable on a trailer or in the paddock, and for tarmac rally, keeps the handbrake doing its job.

Key Benefits

• Clean cabin control: the map switch mounts to suit your build, and our single-DIN stereo-slot installation (switch and bias valve, no cutting) is available as custom work
• Wheel speed sensing solved from a standard driveline through to aftermarket hubs with R35 bearings on R200 axles
• Front sensing uses the factory ABS sensor location, suiting standard or fabricated hubs
• Purpose-made floor mounting plate for the hydraulic unit rather than an improvised bracket
• Eleven selectable ABS calibrations for slicks, semi-slicks and wet circuit work
• Proven Bosch Motorsport reliability

Technical Specifications: Bosch Motorsport M5 ABS

• Control Strategy: High-speed multi-channel wheel slip control
• Maps: Eleven selectable calibrations on a 12-position map switch
• Inputs: 4x wheel speed sensors
• Outputs: Hydraulic modulation via Bosch Motorsport valve block

Bosch Motorsport M5 vs Factory ABS

FAQs

Q: Which cars does this kit suit?
A: The Nissan S14 and S15. The kit works whether or not the car still has its factory ABS.

Q: What about an S13?
A: Most S13s built to this level are already running S15 hubs. That upgrade brings a larger wheel bearing and spindle and more favourable suspension geometry, and it’s normally done well before motorsport ABS is on the list, so a car ready for this system has usually made the change already. This kit suits that setup. Sensing for factory S13 hubs isn’t offered.

Q: Do I have to change my hubs or axles?
A: No. The rear outboard sensing kit is designed for R200 axles and suits either the stock cast steel hubs and wheel bearings, or aftermarket hubs (tested with ACOSTAL) running R35 wheel bearings. At the front, the sensors and adapters use the factory ABS sensor location and suit standard or fabricated hubs.

Q: Do I lose the handbrake?
A: No. The sensing package is designed around the factory parking brake, so it stays and keeps working.

Q: Do I need special tools or skills to install the kit?
A: Some expertise is required, and brake lines from the master cylinder to the hydraulic unit are made to suit at install. Professional installation is recommended. We can install and commission the system in our Newcastle workshop, or supply the kit with our guidance behind your own builder. We cover the whole job, brackets to commissioning, in what a Bosch Motorsport ABS M5 install actually involves.

Q: Can you ship this kit overseas?
A: Yes. These are 909 vehicle-specific kits and we ship them worldwide. Contact us for freight to your country.

Q: Is the system validated for road use?
A: No, Bosch Motorsport ABS is for track usage only.

Q: Can I adjust the ABS behaviour?
A: Yes. The kit includes a driver-selectable map switch with eleven selectable calibrations, allowing ABS response to be tuned for dry, wet or low-grip conditions.

Q: Will this kit suit a LHD car?
A: We have not had access to a LHD vehicle for testing. For the right pilot customer we would be willing to work together on testing, please get in touch via the contact page.

Q: What's the difference between the Clubsport, Kit 1 and Kit 2 core options?
A: Every option includes the same M5 system and the same 909 platform hardware. The Clubsport core uses Bosch's universal harness, the right choice for most club and time-attack builds. Kit 1 moves to a vehicle-specific loom and supports the M5's advanced control functions for cars with real aero or braking beyond about −2 g, and Kit 2 adds Autosport-specification connectors at the wheel-speed sensor leads for endurance-style service schedules. Our kit comparison guide covers the choice in detail.