Wavetrac ATB Helical LSD Limited Slip Differential for BMW E9X 335i (E90 E92 E93) & E8X 135i (E82 E88) | 215K Large Case | 3.08 Final Drive | For Welded OEM Ring Gear/Crownwheel | N54 N55 Diff Upgrade Torsen-Style

Wavetrac ATB Limited Slip Upgrade for BMW E9X 335i and E8X 135i — 215K, 3.08, welded OEM crownwheel

If you are chasing real-world traction, faster corner exits and consistent power to the tarmac, this Wavetrac automatic torque-biasing differential is the go-to upgrade for BMW 335i and 135i drivers. Built for the 215K large-case final drive with a 3.08 ratio and designed for factory welded ring gears, it transforms how your car puts power down on fast road and track days.

Unlike ordinary helical units, the patented Wavetrac mechanism maintains drive even when one side goes light over kerbs, cambers or slick surfaces. That means confident acceleration out of bends, reduced wheelspin and rock-solid stability in the wet, without the on-off behaviour or understeer you get from clutch-pack diffs.

Why enthusiasts choose Wavetrac for BMW 335i and 135i

• Delivers traction when an inside wheel unloads over a kerb or bump, keeping the outside wheel driving you forward
• Predictable, smooth power delivery for quicker lap times and sharper road response
• No clutches to wear, no chatter, minimal maintenance compared to plated LSDs
• Friendly with factory stability systems and daily driving

Engineering highlights

• Patented wave-cam device maintains bias under near zero-load conditions for uninterrupted drive
• Carbon fibre bias plates keep performance consistent from new to high mileage
• 9310 high-strength gears inside a forged or billet steel body for durability
• ARP fasteners throughout for long-term reliability
• Designed and manufactured in the USA

Real results on road and track

We have fitted and driven these units on customer 335i and 135i builds. Feedback is consistently the same — far better traction in the wet, cleaner corner exits, improved stability on bumpy B-roads and a more confidence-inspiring balance on circuit. It simply puts power down where other diffs give up.

Fitment and compatibility

• BMW 3 Series E9X 335i
• BMW 1 Series E8X 135i
• Diff size: 215K large case
• Final drive: 3.08
• For factory welded OEM ring gears

Part reference: 215K

Ideal for

• Fast road builds seeking stronger acceleration and stability
• Track days where inside wheel lift over kerbs kills drive
• Turbocharged N54 and N55 cars needing reliable grip to match power

Professional installation

We strongly recommend expert fitting and correct setup of backlash and preload for best results. MJ Modifications offers full installation services in Warwickshire. Email info@mjmodifications.co.uk for a fitting quote, availability and advice.

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