Bosch Motorsport M5 ABS Integration Kit for Lotus Exige S Series 3 V6
This is a highly integrated Bosch Motorsport M5 ABS system designed to replace the factory ABS in the Series 3 V6 Lotus Exige S.
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.
The Exige is already a circuit car with numberplates, so the conversion is held to that standard: the hydraulic unit goes in the standard location, the factory wheel hard lines and wheel speed sensors stay, and the cabin hardware is bracketed into the console and dash rather than hung off them. The yaw sensor mount is designed for the parcel shelf with provision for a VBOX recorder, because on this car the data logger was always going to be fitted anyway.
The problem with factory ABS in competition: what track drivers call “ice mode”
ABS works by holding each tyre near a target slip ratio, the difference between wheel speed and vehicle speed, where 0% is a freely rolling tyre and 100% is a locked one. Peak braking force sits somewhere between the two, and exactly where depends on the tyre and the surface. The cycling you feel through the pedal is the system chasing its target, and while it’s in slip control, pressing harder adds nothing; extra pedal force won’t be sent to a tyre the system already considers at its limit.
Road-car calibrations have to be built conservatively: one calibration must stay safe on every surface a road car can meet, down to the very worst. Under genuine circuit braking (real speed, semis or slicks, kerbs and bumps working the tyre) that conservative logic can settle on a slip target far below the grip actually available. The result is what drivers call ice mode: the system refuses to build brake pressure no matter how hard you stand on the pedal, and the only way out is to come almost completely off the brake, let the wheels match the car’s speed, and reapply. If you braked at the limit for the corner, that margin doesn’t exist.
It isn’t a fault, and pads, fluid or bigger discs won’t touch it. It’s a road calibration operating outside the envelope it was designed for.
Motorsport ABS approaches the problem from the other direction: the driver selects the calibration for the tyre and conditions actually in use, and the system controls to a slip target appropriate for genuine circuit grip. Eleven selectable calibrations on the 12-position map switch cover the range from wet circuit to slicks, chosen before the braking zone, not discovered during it.
Brake balance: what the factory system quietly manages for you
On a platform like this the ABS/ESP doesn’t just prevent lock-ups; it actively manages front-to-rear brake distribution. Under light braking the system can run more rear brake than the hydraulics alone would give, keeping the car flat; under hard braking it bleeds rear pressure down as weight transfers forward. The distribution your car actually runs is electronic, not mechanical.
That has two consequences for a competition build. Unplugging the ABS doesn’t return the car to some honest pre-electronic state; it removes the brakeforce distribution the base hardware was designed around, and can leave the car with a hard pedal and a rear balance never intended to stand on its own. And altering mechanical bias underneath a stock system means fighting a computer that’s redistributing pressure on top of your changes.
A motorsport ABS conversion makes brake balance deliberate again: the overall front-to-rear balance is set properly in hardware, which is why this kit includes a bias valve mounting solution beside the master cylinder, and the M5 then controls slip at each wheel from that correct baseline, rather than papering over an incorrect one.
What’s Included
- Bosch Motorsport M5 ABS control unit
- Hydraulic unit mounting in the standard location
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Factory wheel hard lines retained: only the master-cylinder pipes need to be made
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Factory wheel speed sensors retained: harness connectors supplied, trimmed and terminated
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ABS harness re-orientated to suit the standard hydraulic unit location
- Bias valve mounting beside the master cylinder
- Map switch and MIL bracket in the centre console
- Diagnostic port and main switch bracket, LHS dash
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Factory ABS ECU cover retained, preserving the steering angle communications
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Yaw sensor mount for the parcel shelf: available with or without VBOX recorder provision
- Mounting hardware throughout
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.
What you give up: factory torque vectoring
The factory torque vectoring function is delivered by the standard ESP system, and it cannot be retained once that system is replaced. We’d rather put that at the top of the page than in the fine print.
For a car being driven on circuit, that is usually the trade people are looking to make, motorsport slip control that can be matched to the tyre in front of you, with brake balance set deliberately in hardware, in place of a road-biased stability package that intervenes on its own terms. If your Exige is primarily a road car, it is a genuine consideration and worth a conversation before you order.
Key Benefits
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Standard hydraulic unit location, factory wheel hard lines and factory sensors retained: only the master-cylinder pipes are made at install
- Harness arrives orientated for the car and terminated for the factory sensors, not a bag of connectors
- Cabin hardware properly bracketed: map switch and MIL in the console, diagnostic port and main switch on the LHS dash
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VBOX-ready yaw sensor mount: data logger integration designed in, not zip-tied on
- Steering angle communications preserved through the retained ABS ECU cover
- Bias valve mounting beside the master cylinder for a deliberate mechanical balance
- Eleven selectable ABS calibrations for slicks, semi-slicks and wet circuit work
- Proven Bosch Motorsport reliability
Technical Specifications: Bosch Motorsport M5 ABS
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Control Strategy: High-speed multi-channel wheel slip control
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Maps: Eleven selectable calibrations on a 12-position map switch
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Inputs: 4x wheel speed sensors
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Outputs: Hydraulic modulation via Bosch Motorsport valve block
Bosch Motorsport M5 vs Factory ABS
|
Factory Exige S V6 ABS/ESP |
Bosch Motorsport M5 ABS Kit |
| Technology |
Road-car ABS/ESP module with stability and torque vectoring functions |
Modern, high-speed multi-channel motorsport ABS |
| Processing Speed |
Limited, slower ECU response |
Ultra-fast ECU with real-time wheel slip control |
| ABS Maps |
Fixed road calibration with selectable driving modes |
Eleven selectable calibrations for different tyres and conditions |
| Torque vectoring |
Factory ESP-based function |
Not retained; see the note above |
| Brake balance |
Electronically distributed by the factory module |
Set deliberately in hardware via the bias valve beside the master cylinder |
| Wheel Speed Sensing |
Factory sensors and tone rings |
Factory sensors retained; harness connectors trimmed and terminated |
| Driver Control |
Driving mode selection only |
Map switch in the centre console, adjustable between sessions |
| Data logging |
None |
Yaw sensor mount with VBOX recorder provision |
| Installation |
Factory fit |
Standard location mounting, factory wheel lines retained. Master-cylinder lines will need to be made. |
| Performance |
Adequate for road use; limited under hard braking/track |
Motorsport-level braking performance for the track |
FAQs
Q: Which cars does this kit suit?
A: The Series 3 V6 Lotus Exige S.
Q: Do I lose the factory torque vectoring?
A: Yes. That function belongs to the factory ESP system and cannot be carried across. For a circuit car it is usually the intended trade, see the section above.
Q: My factory ABS has never caused a problem. Why replace it?
A: Because the problem shows up at circuit pace under maximum braking, which is precisely when you can’t afford it. A road calibration has to stay safe on every surface a road car might meet, so at real speed on semis or slicks it can settle on a slip target well below the grip you actually have, and refuse to build pressure no matter how hard you push the pedal.
Q: Why not just unplug the ABS instead?
A: On this platform that also deletes the electronic brake distribution the car was designed around, leaving a rear balance that was never meant to stand on its own. A motorsport system with properly set mechanical balance is the engineered path, not the workaround.
Q: What does the VBOX provision actually do?
A: The parcel shelf yaw sensor mount is offered in two forms: one that carries the yaw sensor alone, and one that also locates a VBOX recorder. If the logger is going in the car anyway, having both mounted properly from the same bracket beats finding somewhere for it later.
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.
