The QUAIFE ATB differential is designed to prevent the complete loss of drive that occurs with a conventional differential when one wheel slips. Whilst requiring some torque in the slipping wheel, the QUAIFE unit is progressive in action but never locks – controlled power is transmitted to all the driving wheels. Ideally suited to high powered front wheel drive systems, QUAIFE ATB differentials are also used in rear and four wheel drive vehicles where optimum traction is required. Installation is identical to the normal differential with bearing pre-loads and pinion mesh being restored to the original manufacturers’ settings. Servicing of the unit is simple as all gear pinions are free fitting and normal final drive lubrication oils are retained.
Benefits
· All QUAIFE differentials come with a Life Time Warranty excluding specialised vehicles.
· Maximises traction and minimizes wheel spin
· Proven in drag and circuit racing, rallying and road use
· Eliminates torque steer and snatching in fwd cars compared to conventional LSD
· Maintenance free design and retains standard axle lubrication
· Produced from British Steel billets throughout
· CAD designed and CNC machined then inspected to ISO 9001 standards
· Used by Ford, GM and Daimler-Chrysler as original equipment
· Massive range available, from Alfa Romeo to Volvo
· Beware of cheap imitations!
More traction, more speed
As engine power outputs increase ever further, the ability to utilize this extra performance becomes more important. Wheel spin may look spectacular, but such losses of traction waste time either from a standing start or exiting a bend, whether driving on the road, circuit, rally stage or drag strip. Fortunately, QUAIFE’s patented Automatic Torque Biasing (ATB) Helical LSD differentialis an effective, well-proven, low-cost solution.
As a direct replacement for the standard, factory ‘open’ differential, QUAIFE’s ATB Helical LSD unit can transform the performance of your car. Unlike a conventional plate-style limited slip unit, QUAIFE’s ATB Helical LSD unit relies on gears, rather than clutch plates for its operation.
That means it is much smoother in operation, because unlike a conventional plate-style LSD, 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 and never locks.
To the driver (especially of a front-wheel drive car) 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. These traction benefits can also be utilised in rear wheel drive vehicles, while QUAIFE ATB Helical LSD units offer significant traction advantages fitted to the front of four wheel drive cars.
Reliability is total; the ATB Helical LSD units are designed using the latest CAD techniques and are CNC machined to ultra-tight tolerances from the very best CORUS steel billets. The completed units are then subject to rigorous in-house inspection on a tri-coordinate measuring machine before being dispatched to the customer.
Such quality means that unlike a conventional plate-style LSD the QUAIFE ATB Helical LSD unit requires no special maintenance or rebuilds, long lasting and it retains the standard method of lubrication, making for an easy, pain-free upgrade.
Proven in rallying, racing and on the road, the ATB Helical LSD differential offers safe, reliable, winning performance– everything you would expect from a QUAIFE product.
The requirement
In an age when power and torque outputs are rising rapidly thanks to the adoption of ever-advanced technology, harnessing engine performance to use it effectively in a user-friendly manner is huge challenge for engineers and powertrain designers. The problem is simple one – how do you effectively control the delivery of power through the driven wheels to maximize traction and minimize wheelspin.
The choices faced by OEM’s
Different car manufacturers have adopted different approaches. Some front wheel drive platforms (particularly from Ford and Opel/Vauxhall) have adopted the electronic traction control route, which offers safety benefits, but tends to compromise driver involvement and enjoyment, particularly if the vehicle is used for trackday work.
Others – such as Mitsubishi and Subaru – have invested heavily in developing four wheel drive systems for their high performance derivatives and while these total traction systems afford obvious benefits, the negative factors such as high transmission power losses and excessive weight mean that they will remain very much a niche market.
Which leaves vehicle designers in something of a quandary, as they are faced with just two choices for an effective, user-friendly and low-cost traction control system on a two-wheel drive high performance car. Interestingly, in an increasingly electronic age, both of these systems rely on mechanical methods to improve traction.
OEM Applications
In recent years the advantages of the Quaife ATB differential have been exploited by original equipment manufacturers in both front and rear wheel drive applications.
These include:
· Dodge (V10 Viper sports car)
· Dodge (Neon SRT-4 high performance sedan)
· Ford (Focus RS high performance hatch)
· GM F40 transmission (currently under development)
The Quaife Engineering Automatic Torque Biasing differential
The second mechanical method of improving traction is to use a Quaife Automatic Torque biasing differential. Rather than using clutch plates as a method of operation, the Quaife ATB uses sets of floating helical cut gear pinions that run in pockets and mesh during normal driving.
Should one of the driven wheels start to spin however, the helical gears start to generate a torque bias thanks to the axial and radial thrust of the helical gear pinions in their pockets. The result is a progressive transfer of torque away from the spinning side of the axle to the driven wheel, which is now capable of transmitting a greater proportion of torque.
i) Positive Dynamic Effects
Because the Quaife ATB differential’s design produces a progressive transfer of torque away from the spinning wheel to the wheel that is capable of driving, the effect is far more benign to the driver. For rear-wheel drive use the benefits of the Quaife ATB diff are obvious –
excellent traction qualities, combined with a progressive action, making for a benign, effective and involving package for those seeking the ultimate in safe high performance vehicle dynamics.
This has been proven by the interest shown by from Dodge for the adoption of the Quaife differential as an optional extra for the Viper V10 sports car. In this application, the Quaife ATB copes happily with 525lb/ft of torque at just 4,100rpm.
In a front wheel drive car harsh snatching and torque steer are eliminated, so much so that it is not uncommon for a Quaife ATB differential to cope with 350lb/ft of torque through the front wheels in aftermarket road applications.
ii) Maintenance Free Performance
Unlike a plate style LSD the Quaife unit delivers performance without the need for strip downs and rebuilds. There are no plates or gears to wear or break and the ATB units retain standard vehicle lubrication.
