Description
BMW E46 M3 Convertible (00-06) BC Racing ZX coilover kit 6/9 kg/mm
The BC Racing ZX coilover kit E46 M3 Convertible (part number I-121-ZX) is a coilover kit adjustable in height and damping, also simply called a coilover, for the BMW E46 M3 Convertible, model years 2000 to 2006. The spring rate is 6 kg/mm front and 9 kg/mm rear.
This kit is 3-way adjustable. BC Racing uses the ZX for competitive track driving, long sessions and demanding drifting, and supplies its own part number for the Convertible.
The ZX combines two well-known series: the digressive base of the DS and the dual piston with external reservoir of the ER. Each damper is an upright monotube. You adjust the low-speed compression in 20 clicks, the high-speed compression in 12 clicks and the rebound in 30 clicks.
The spring rate is 6/9 kg/mm front/rear. The dampers are filled with race oil with an ultra-high viscosity index and the ride height is infinitely adjustable via the damper body.
Key benefits
- Three separate adjustments: low-speed compression, high-speed compression and rebound.
- External reservoir: extra oil for sessions in which the dampers have to work hard.
- Combination of DS and ER: digressive character with dual piston.
- Race oil with ultra-high VI: consistent behaviour as temperatures rise.
- Replaceable upper mount: easier to maintain.
- Specific to the M3 Convertible: its own BC Racing part number.
- Spring rate 6/9 kg/mm: front/rear.
- Rebuildable: made to last.
Suitable for
BMW M3 E46 Convertible, model years 2000 to 2006
- Long track day sessions
- Competitive track driving
- Demanding drifting with an open-top M3
Technical specifications
- Manufacturer: BC Racing
- Part number: I-121-ZX
- Series: ZX, 3-way with external reservoir
- Spring rate front/rear: 6/9 kg/mm
- Damper design: upright monotube with dual piston and external reservoir, digressive, race oil with ultra-high viscosity index
- Damping: 3-way, 20 clicks low-speed compression, 12 clicks high-speed compression, 30 clicks rebound
- Ride height: infinitely adjustable via the damper body
- Top mounts: replaceable upper mount, camber plates on suitable kits, rubber top mounts optional
- Contents: dampers and springs front and rear, lower mounts, top mounts where applicable, adjustment spanners and warranty card with serial number
- Warranty: 1 year on manufacturing defects. Noise from track-focused series is not covered by the warranty
Fitting and delivery
When fitting, choose a safe location for the reservoirs and check that lines and reservoirs stay clear during steering and compression. Then set the ride height and have a wheel alignment done on the M3 Convertible. The delivery time is 1 to 2 weeks as long as the manufacturer has stock. If the manufacturer is temporarily out of stock, you can still order and we will keep you informed.
Three adjustments per damper give an M3 Convertible the adjustment range of a real track car.
Why choose this ZX coilover kit E46 M3 Convertible?
Because the separate high-speed and low-speed compression lets you choose exactly how the car reacts to bumps and kerbs, independently of how it sits in the corner. Anyone who really puts their M3 Convertible to work on the circuit or when drifting can use the ZX to tune compression and rebound separately to the use.
BC Racing coilover kits for the BMW E46 M3 Convertible
Overview of the BC Racing series for the BMW E46 M3 Convertible supplied by Race4DriftParts, with the BC Racing part number. Spring rates in kg/mm, front/rear.
| Series | Part number | Springs f/r | Damping | Intended for |
|---|---|---|---|---|
| BR | I-121-BR-RA | 6/9 | 30 clicks, linear | Road with the occasional track day |
| DS | I-121-DS-DA | 6/9 | 30 clicks, digressive | Track-focused, sporty road use |
| RM | I-121-RM-MA | 6/9 | 30 clicks, digressive, synthetic oil | Track days, hill climbs, tarmac rally |
| ER | I-121-ER | 6/9 | 2-way, 30 clicks per direction, external reservoir | Serious track and competition use |
| HM | I-121-HM | 6/9 | 2-way, 30 clicks per direction, external reservoir | Serious track use |
| ZX (this kit) | I-121-ZX | 6/9 | 3-way (20/12/30 clicks), external reservoir | Competition, long sessions, drift |
| ZR | I-121-ZR | 6/9 | 3-way (20/12/30 clicks), external reservoir | Competitive motorsport |
Frequently asked questions
What is the difference between the BC Racing ZX and DS for the E46 M3 Convertible?
The DS is 1-way without a reservoir; the ZX coilover kit E46 M3 Convertible adds an external reservoir, a dual piston and 3-way adjustment.
What do I adjust with the high-speed compression of the BC Racing ZX?
The high-speed compression determines how the damper reacts to fast wheel movements, such as kerbs and bumps. The low-speed compression mainly controls body movement under braking and turn-in.
What is the delivery time of this BC Racing ZX coilover kit?
The delivery time is 1 to 2 weeks as long as the manufacturer has stock. Even without stock you can order; we will let you know when the kit is in.
Delivery outside the European Union: different shipping costs may apply. Don’t worry: we will email you as soon as possible after your order and agree the shipping with you. You are not committed to anything without your consent.






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