3J Driveline NXG Plate-Type Limited Slip Differential for Mazda MX-5 NA 1.8 & All NB

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3J Driveline NXG Plate-Type Limited Slip Differential for Mazda MX-5 NA 1.8 & All NB

From fast-road and track day to all-out race or drift applications, the 3J Driveline NXG Plate-Type Limited Slip Differential can be set up exactly to suit your requirements. The amount of pre-load and ramp angles are fine-tuned for each application, affecting how the differential locks under acceleration and braking.

3J Driveline differentials are designed and manufactured in the UK, meaning the warranty and after-sales support are exceptional. Each plate-type differential is fully rebuildable, so if it is used in extreme operating conditions—such as racing and time attack—it can be serviced instead of replaced. Furthermore, 3J diffs are designed with two different ramp angle specs on each bevel gear, so the behaviour of the differential can be fine-tuned without purchasing any new parts.

Plate-type Limited Slip Differentials have a cross pin that rides up a ramp on the bevel gear, applying pressure to the friction plates and locking both sides of the differential together. For example, a shallow ramp angle of 25 degrees will allow the cross pin to slide up the bevel gear easily, applying more locking force to the differential. Steep 90-degree ramp angles prevent any additional load from being applied, relying on pre-load to lock the differential instead.

Pre-load is used to set how much force is applied to the friction plates before any engine torque is applied to the differential. More pre-load requires less effort to lock the differential, locking it sooner. Due to how plate-type differentials lock, slight noise and wheel judder can be expected at low speeds.


Accel/Decel Ramp Angle (degrees) Preload (lb-ft) Diff Way Notes
Fast Road 50/90 25-35 1-way
Track 40/90 55-65 1-way
Race 30/90 65-75 1-way
Rally 30/90 65-75 1-way For more oversteer bias 30/60 or 45/45 ramp angles can be specified.
Sprint 40/90 65-75 1-way
Kaaz Style Road/Track 40/60 40-45 1.5-way Ideal Fast Road/Track combination option
Drift 45/45 65-75 2-way

Suits NA 1.8 & all NB MX-5s with push-in driveshafts

For a full breakdown, see our plate type blog here

Please note unless a stock figure is shown, 3J diffs are made to order. The usual lead time is around 4 weeks.

Additional information

Shipping Weight 8.2 kg
Shipping Dimensions 20 × 20 × 20 cm

3J Driveline




Track, Race, Rally, Sprint, Drift, Fast Road, Kaaz Style

Add Sintered Plate

Yes, No


Mk1 (89-98), Mk2 (98-05)

Warranty information

Warranties cover defects in materials and workmanship only. Warranty is for replacement of a similar product, repair of the original product or refund of the purchase value only and excludes all labour and incurred charges including towing, fitting, inconvenience, and purchases of other manufacturer's products. The warranty is good for the period stated in the additional info tab from the date of purchase. Mileage warranties are for road use only and proof of mileage is required. Products must be installed by an independent experienced professional mechanic and the suspected defect must be present at the outset. The warranty does not cover damage caused by incorrect installation, failure to comply with the maintenance requirements of the vehicle, processing or otherwise changing the product, ordinary wear and tear, or any other external influences. Warranties are invalid if the product is used for racing, rallying, drifting, track days or any other form of motorsport or competition. Please refer to the manufacturer's own warranty documentation for more information.

Making a warranty claim

Proof of purchase receipt showing the date of purchase, proof of mileage at installation, proof of current mileage and invoice of the work undertaken by an independent experienced professional mechanic must be supplied along with the returned products for a warranty claim to be considered. If your vehicle needs to be used whilst your warranty claim is considered replacement parts from the same manufacturer should be purchased through BOFI Racing. In the event of a successful warranty claim, we will refund the card that was originally used to purchase the replacement parts, in full or in part depending on the nature of the claim. BOFI Racing reserves the right to make full or partial compensation at its sole discretion depending on the condition and mileage use of the returned suspect parts. For example, if you have used the part for several thousand miles before a defect is noticed, only partial compensation may be offered.

Make Model Year
Mazda MX-5 I (NA) 1993 - 1998
Mazda MX-5 II (NB) 1998 - 2005