Which MINI’s is the Quaife ATB differential compatible with
Part Number: QDF22N
Retail Price: £645 + VAT (UK price £774)
The QDF22N fits the following MINI manual transmission models:
- MINI F56 3 Door Hatch Cooper S 2013 – onwards
- MINI F56 3 Door Hatch JCW 2013 – onwards
- MINI F55 5 Door Hatch Cooper S 2013 – onwards
- MINI F55 5 Door Hatch JCW 2013 – onwards
- MINI F54 Clubman Cooper S 2WD 2014 – onwards
- MINI F57 Convertible Cooper S 2014 – onwards
- MINI F57 Convertible JCW 2014 – onwards
Part Number: QDF38Z
Retail Price: £605 + VAT (UK price £726)
The QDFF38Z fits the following MINI manual transmission models:
- MINI R53 3 Door Hatch Cooper S/ JCWGP 2002 – 2006
- MINI R52 Convertible Cooper S/JCW 2002 - 2008
- MINI R55 Clubman Cooper S/JCW 2007 – 2013
- MINI R57 Convertible Cooper S/JCW 2007 – 2015
- MINI R58 Coupe Cooper S/JCW 2007 – 2015
- MINI R59 Roadster Cooper S/JCW 2007 – 2015
- MINI R60 Countryman Cooper S 2WD only 2010 – 2015
- MINI R61 Paceman Cooper S 2WD only 2010 – 2015
What Is a Quaife ATB Differential
"The Automatic Torque Biasing (ATB) Helical LSD differential is QUAIFE’s unique design and is an after-market differential that provides smooth, constant traction for racing or slippery road conditions. This differential has the added benefit of no adverse effect on the steering of a front-wheel-drive vehicle. QUAIFE ATB differentials have been used in a wide array of applications, from Formula 1 cars to emergency and public utility vehicles, where all-weather mobility is essential and where the product must perform in the most demanding of conditions." (Lohen, 2019).
The differential progressively locks as torque increases; there are no plates or clutches to wear out, unlike the more conventional limited-slip designs. The QUAIFE differential is particularly effective in combating the effects of FWD torque steer and understeer.
As engine power outputs through modification increase even further, the ability to use this extra performance becomes more important. Wheelspin may look spectacular, but such loss of traction from either a standing start or exiting a bend wastes time, whether driving on the road, circuit, rally stage or drag strip. Fortunately, QUAIFE's patented Automatic Torque Biasing (ATB) Helical Limited Slip Differential (LSD) is an effective, well-proven, low-cost solution.
As a direct replacement for the standard, factory-fitted ‘open' differential, QUAIFE's unit can transform the performance of any MINI. Unlike a conventional plate-type limited-slip unit, QUAIFE's item relies on gears rather than clutch plates for its operation. That means it’s much smoother in operation, as it never locks harshly with a set pre-load of wheel slip across the driven axle. Rather, it automatically biases the torque away from the spinning wheel across the axle, to a constantly varying degree.
How Does a Quaife Differential Work?
Sets of floating helical gear pinions mesh to provide the normal speed differential action. In the event of wheel slip, torque bias is generated by the axial and radial thrusts of the pinions in their pockets. The resultant friction forces enable the differential to transmit a greater proportion of the torque to the appropriate wheel. The effect is progressive and at no stage does the differential lock solid, hence the inherent safety and user-friendliness of the QUAIFE ATB Helical LSD unit.
To the driver, especially of a front-wheel-drive car like the MINI, the results are significant performance improvements; superior, controllable traction without the harsh steering wheel snatch or torque steer that have long been associated with performance differentials.
The QUAIFE differential is quiet in operation, requires no special maintenance or rebuilds, is long-lasting, and retains the standard method of lubrication, making for an easy, pain-free upgrade. Proven in rallying, racing and on the road, this differential offers safe, reliable, winning performance - everything you would expect from a QUAIFE product.
Warranty
The QUAIFE ATB Helical LSD differential is offered with a limited lifetime warranty as a demonstration of the quality of the product.
Why and when should I fit a QUAIFE differential to my MINI?
To help answer this question its important to first understand what is fitted to the MINI as standard and how this works. The standard differential is an open differential, this allows the drive wheels (in the case of MINI variants we are looking at, the front wheels) to rotate at different speeds which is essential for a vehicle to be able to corner.
The open differential does not allow for any sort of torque management and therefore transmits power to the wheel with the least resistance I.e. the wheel with the least traction so actually aiding the break-in traction.
This is where a limited-slip differential such as the Quaife automatic torque biassing (ATB) differentials benefit performance.
The Quaife ATB operates as an open differential would during normal driving conditions so you won't notice it. However when a wheel encounters a loss of traction the gears within the ATB work together to that reduce the load to that wheel and transfer the output to the wheel with the greatest resistance i.e. the greatest level of traction. Once traction is regained the gears disengage allowing normal operation.
Fitting a QUAIFE differential at any stage of modification will improve drivability, cornering, power application and performance under heavy acceleration. Under heavy braking, the differential works in reverse and transfers torque away from the locking wheel which delays the application of the ABS and improving deceleration allowing you to brake later than you could when running the standard differential.
For those who enjoy a spirited drive a Quaife ATB differential is recommended on all manual transmission Cooper S and JCW’s. It is highly recommended that a Quaife differential is fitted when carrying out any power-related performance upgrade, such as an ECU tune (remap). Tuning for additional engine performance increases torque and the demand for traction. A Quaife ATB differential can help make the most of the power improvements.
The Quaife ATB differential is suitable for road application being quiet and requiring no additional maintenance. It is also strong enough and performs well enough for track applications. MINI also chose to use the exact differential that Lohen offer in the F56 JCW Challenge limited edition production car so you can be assured of a very high-quality item that fits into the Cooper S and JCW manual gearbox perfectly.
MINI Installation
When Lohen installs the Quaife ATB differential we strongly recommend purchasing and installing new differential bearings to avoid any damage that may be caused to the original bearing when removing and also to refresh a moving wearable part that would otherwise be very difficult to access. Lohen recommends using high-quality gearbox oil during installation. We use Millers oil CRX 75W90, 2L will be required. Installation of a differential can be completed within one day so you can drive in and out the same day to notice the difference.
