Ultra Racing 4-point middle lower chassis brace for Mazda MX-5 MK1 / NA and MK2 / MK2.5 / NB models listed in the compatibility table.
The Ultra Racing ML4-300 is a middle lower bar / middle member brace designed as an aftermarket chassis reinforcement upgrade for first- and second-generation Mazda MX-5 models.
Mounted beneath the centre section of the vehicle, this four-point brace links key lower chassis and suspension mounting areas around the central floor and transmission tunnel. By reinforcing these points, the brace is designed to reduce unwanted chassis flex and help the suspension operate more consistently under cornering and changing loads.
Product details:
- Brand: Ultra Racing
- Part number: ML4-300
- Product type: Middle Lower Bar / Middle Member Brace
- Position: Centre / middle lower chassis
- Brace specification: 4 Point
- Construction: One-piece welded steel
- Finish: Ultra Racing white
- Installation method: Bolt-on using OEM mounting points
- Ultra Racing accessory reference: BC043
- Approximate dimensions: 95cm x 84cm x 5cm
- Approximate weight: 3.4kg
- Quantity required per vehicle: 1
- Quantity supplied: 1 middle lower brace
- Required mounting hardware: Supplied
Common reasons for fitting:
- Reduce unwanted flex through the centre section of the chassis
- Reinforce the floor and transmission tunnel area
- Help maintain more consistent suspension geometry under load
- Improve overall chassis response during enthusiastic road or track driving
- Complement front and rear Ultra Racing chassis reinforcement components
Fitment advice:
Ultra Racing application data identifies ML4-300 for Mazda MX-5 MK1 / NA and MK2 / MK2.5 / NB models. Ultra Racing Malaysia specifically confirms 1.8-litre NA and NB applications, while broader Ultra Racing and MazSpec catalogue data list the brace across the full NA / NB platform range. Some aftermarket exhaust systems may reduce clearance around the brace, and Ultra Racing specifically notes that shorter exhaust hangers may be required in some installations.
Other items to consider purchasing:
- Ultra Racing front strut brace
- Ultra Racing front lower brace
- Ultra Racing rear lower brace
- Ultra Racing rear torsion brace
- Ultra Racing anti-roll bars
- Replacement chassis fasteners where existing hardware shows wear or corrosion
Useful tools / consumables:
- Socket and ratchet set
- Torque wrench
- Suitable vehicle lift or axle stands
- Penetrating fluid where existing underbody fasteners are corroded
Difficulty guide: Intermediate DIY / workshop installation. Safe access beneath the centre of the vehicle is required.
Why Ultra Racing?
Ultra Racing specialises in aftermarket chassis and handling upgrades. Its middle lower braces reinforce structural areas through the centre of the vehicle, helping reduce unwanted chassis movement and allowing the suspension to operate more consistently under load.
What's in the box:
- 1 x Ultra Racing ML4-300 4-point middle lower chassis brace
- Required mounting hardware as supplied by Ultra Racing
Installation notes:
Ultra Racing specifies ML4-300 as a bolt-on installation using OEM mounting points. The vehicle must be safely raised to access the lower mounting positions. Position the brace correctly and check clearance around the exhaust, transmission and surrounding underbody components before final tightening. Ultra Racing notes that some aftermarket exhaust systems may require shorter exhaust hangers to provide sufficient clearance. Reassemble and tighten all mounting hardware to the appropriate vehicle or manufacturer specification.
| Make | Model | Sub Variant | Chassis / Code | Years | Power (PS) | Engine Codes | Fuel | Transmission | Notes |
|---|---|---|---|---|---|---|---|---|---|
| Mazda | MX-5 MK1 / NA | 1.6 | NA6C | 1990-1993 | 115 | B6ZE | Petrol | Manual / Automatic where fitted | 4-point middle lower brace; generation-wide NA application. |
| Mazda | MX-5 MK1 / NA | 1.6 | NA6C | 1994-1998 | 90 | B6ZE | Petrol | Manual | 4-point middle lower brace; generation-wide NA application. |
| Mazda | MX-5 MK1 / NA | 1.8 | NA8C | 1994-1998 | 130 | BP-ZE | Petrol | Manual / Automatic where fitted | NA 1.8 application directly confirmed by Ultra Racing Malaysia. |
| Mazda | MX-5 MK2 / NB | 1.6 | NB6C | 1998-2002 | 110 | B6ZE | Petrol | Manual | Included within Ultra Racing's NB 1998-2005 application. |
| Mazda | MX-5 MK2 / NB | 1.8 | NB8C | 1998-2002 | 140 | BP-ZE | Petrol | Manual / Automatic where fitted | NB 1.8 application directly confirmed by Ultra Racing Malaysia. |
| Mazda | MX-5 MK2.5 / NB-FL | 1.6 | NB6C | 2002-2005 | 110 | B6ZE | Petrol | Manual | Included within Ultra Racing's NB 1998-2005 application. |
| Mazda | MX-5 MK2.5 / NB-FL | 1.8 VVTi | NB8C | 2002-2005 | 146 | BP-Z3 | Petrol | Manual / Automatic where fitted | Included within Ultra Racing's NB 1998-2005 application. |
| Mazda | MX-5 MK2.5 / NB-FL | 1.8i Turbo | NB8C | 2004-2005 | 178 | BP-Z3 Turbo | Petrol | Manual | NB-generation application; no turbo-specific exclusion stated. |
| Reference Type | Reference Number | Notes |
|---|---|---|
| Mazda OE | N/A | No direct Mazda OE reference - aftermarket chassis reinforcement part |