Quaife ATB Limited Slip Differential Retrofit - BMW F2x M140i/M240i (Exchange)

The famous Quaife ATB limited slip differential is one of the world's most popular performance upgrade products for BMW. This unique device transforms the way your car applies power to the road, offering a stunning increase in traction, acceleration, cornering speeds and handling. The Quaife design will work flawlessly with all OE components, will not void your manufacturer's warranty, and comes with its own worldwide lifetime guarantee.

Available for both Manual & Automatic, please advise us after placing your order.

$500 Exchange (Refundable) Deposit required in addition to LSD. 

PRODUCT INFORMATION

The Quaife ATB (Automatic Torque Biasing) differential is a unique type of limited-slip diff that substantially improves traction for powerful vehicles using only gear mechanisms. This clever design revolutionised the differential market - offering a superior level of performance and warranties compared to its competitors.

In 2007, BMW began welding the crown wheel gear to the open differential instead of bolting them together. This means for models such as the F20 M140i and F22 F23 M240i we must now machine the crown wheel gear off, and drill it so that a Quaife ATB LSD can be bolted on in the open differential's place. This is specialist work that we only offer to be done in house. We offer two methods of upgrading - you can send up your differential for the retrofit to be performed or we offer an exchange program whereby we send you a pre-built differential with the Quaife ATB unit already inside.

Exchange Quaife Limited Slip Differential

An Exchange Quaife Limited Slip Differential is a complete BMW differential equipped with a Quaife ATB LSD. We offer these in exchange for your original differential so that you avoid the lengthy downtime and complications of a Quaife ATB installation. However, this is only offered to you if your vehicle has done less than 60,000kms and if it's done more you will need to send your differential in for conversion. SouthernBM guarantees the Exchange Quaife Limited Slip Differentials for 2 years, and the Quaife ATB itself comes with a limited lifetime warranty. The total cost is inclusive of delivery of the Exchange Quaife Limited Slip Differential and the return of your standard unit.

The Exchange Quaife LSD unit is also sold with an additional $500 core charge (not included in the purchase price). We will send you an invoice for this charge once your pre-built exchange differential is prepared and ready to send.  This amount will then be refunded upon the return of your standard differential to us in good working order.

Exchange Quaife Limited Slip Differentials are only available for certain models. If we don't have any exchange differential available to suit your car you will need to send us your differential for retrofitting.

Quaife Limited Slip Differential Retrofit

If your BMW has done more than 60,000kms or if you would prefer to have your own differential retrofitted with the Quaife ATB unit you can send it to us for converting. Depending on your location, the process can take 5-15 days including freight transit time. The cost is also fully inclusive of freight to bring your standard differential to us and the return. All you need to do is organise the removal of your differential (at your own cost) and we can take care of the rest.

MORE ABOUT THE QUAIFE ATB

Why do you need a limited slip differential?

All standard BMW models come from the factory fitted with the basic "open differential" - a simple device that allows the driving wheels to turn at different speeds (enabling the car to navigate around corners). The problem with the open diff is that it can only ever apply the same amount of torque to both driving wheels, so when a wheel slips, it will only put through the amount of torque it requires to power that spinning wheel (very little!). The car spins away power in these instances.

Additionally, BMW use various electronic traction systems that "curb" power to the drive wheels during traction loss (indicated by the flashing traction light on your dashboard). The Dynamic Stability Control system (DSC) is designed to "curb the engine output and stop slip on the wheels", a good feature in theory, but is still in its early stages of development and is way too intrusive, often frustrating the driver when trying to push on. If you accelerate hard from slow speeds, or try to power out of turns (especially in slippery conditions), the loss of traction will make the engine sap power away from the wheels. Turbocharged rear-wheel drive cars with high torque outputs suffer the most, such as BMW's M135i, and conditions are worsened by the fact they are equipped with run-flat tyres and stiff suspensions. Of course if you are lucky enough to have sufficiently deep pockets, all BMW M-Powers come from the factory with a mechanical limited-slip differential, demonstrating that even BMW themselves know that powerful cars need these important devices.

Fortunately, there are clever differentials out there on the aftermarket that will transfer torque to the wheel with more traction rather than take it away... 

How does a Quaife ATB differential improve performance?

The Quaife unit uses sets of floating helical cut gear pinions that run in pockets and mesh during normal driving, acting as an open diff. Should one of the driving 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 an instantaneous and progressive transfer of torque away from the spinning wheel to the one with more traction, always varying accordingly and automatically.

With the DSC and traction systems switched off during traction loss, you will feel the Quaife transferring the power to the wheel with more grip in a smooth and predictable manner. Any movement at the rear end is controlled and intuitive for the driver. With the traction systems switched on, you will rarely ever see the light flicker on your dashboard as the Quaife allows you to power through any loss of traction, working in perfect harmony with all of the BMW's standard equipment.

The car ultimately becomes easier to control and is able to apply its power to the tarmac with maximum effect. Acceleration, cornering speeds, handling, steering, and overall dynamics of the car are dramatically improved! The Quaife is capable of varying the torque split from 0-80%, and does this quietly and smoothly in operation. It does not affect any of the traction systems on the car, and does not affect the manufacturer's warranty. All backed by its own worldwide lifetime guarantee.

Watch BBC Top Gear's Chris Harris demonstrate the Quaife ATB in our 335i during his Autocar days.

How is the Quaife ATB superior?

The Quaife ATB Differential provides significantly improved traction and handling for powerful rear-wheel BMWs.

Once installed, drivers will notice an immediate difference as the Quaife automatically biases torque across the axle to the wheel with most grip. Unwanted wheel-slip is greatly reduced, enabling drivers to exploit the full potential of their machines for the first time, leading to a more exciting, rewarding and rapid driving experience.

Widely regarded as the differential upgrade of choice for road car owners, the Quaife ATB was designed to overcome the flaws of conventional clutch-plate limited-slip diffs. Quaife's patented design;

• requires no servicing or maintenance.
• is silent and smooth in operation.
• is guaranteed to work seamlessly with all electronics and OE components.
• uses a progressive, non-locking helical gear design - allowing for safe and predictable control during moments of oversteer.
• is capable of biasing up to 80% of torque to wheel with most grip.
• comes with a limited lifetime warranty.

The clutch-plate problem

'Clutch-plate' limited-slip diffs (BMW M Performance, Drexler, OS Giken, etc) operate using an internal spring pack and set of clutches that limit the amount of rotational difference between the driving wheels in low traction conditions. However, the wearing of clutches means that they require special lubricant changes throughout their lives, and will eventually need replacing. Due to their finite life, many of them can't be guaranteed for more than 12 months.

Additionally if high locking percentages are used they can cause abrupt locking of the rear axle and significant "snap-oversteer" out of slippery turns. While these characteristics might be beneficial in motorsport, they aren't ideal for road use.

The Quaife solution

The Quaife ATB Differential however uses a unique, non-wearing gear design that maximises traction by automatically biasing torque across the axle depending on which wheel is enjoying the most grip. The result in performance is huge amounts of grip, but in comparison to clutch-plate diffs offers an intuitively controllable rear end during any moments of oversteer. 

There are no clutches, ramps, springs or other wear prone components to replace at regular intervals, because the Quaife ATB’s well-proven system of helical gears is extremely durable. This makes the Quaife ATB a genuine 'fit and forget' upgrade that offers compromise-free performance and unbeatable reliability on the street, strip, stage or circuit, but most importantly, it can be accompanied with Quaife's famous limited lifetime warranty.

What is the Quaife warranty?

The Quaife ATB Limited-Slip Differential comes with a limited lifetime warranty. If damage is caused to the Quaife due to faulty installation or overheating, the warranty may be voided and repair costs charged.

Our Exchange Quaife Limited Slip Differentials include an additional 24 months warranty on all other final drive components, such as bearings and seals, or if the car is new we will match your manufacturer's warranty.

Will the Quaife ATB affect my new car warranty?

The Quaife ATB will not affect your manufacturer's warranty. Over 3,000 Quaife ATB differentials for BMWs have been sold worldwide, and not one of these has resulted in BMW claiming a fault or defect was as a result of the Quaife installation.

Key features

• Manufactured in Great Britain
• Precision manufactured from certified steel billets and inspected to ISO9001-2008 standards
• Direct replacement for factory standard open differential unit (no 'shims' required)
• Uses regular gear oil lubrications systems and maintenance schedule
• Has been consistently tested and improved since its launch in the 1980's
• Plug and play complete Quaife ATB-equipped differentials available via SouthernBM
• Comes with technical support by telephone or email via SouthernBM

Models

• 1 Series / F20 (2012-2019) / M140i
• 2 Series / F22 / F23 (2014-2021) / M240i

Return Policy

Shipping

We understand how difficult it can be to find good quality parts at affordable prices. Our goal is to offer reliable parts at a price everyone can afford. We send out hundreds of parts every week through various courier companies. Unfortunately these companies do not offer freight insurance on our larger product range. 

Please note that with this product range we do offer shipping, however, these items are sent at buyer risk. Therefore, if you have ordered one of these panels and it sustains any damage during transit the onus falls onto the buyer. Obviously we are supplying a brand-new product and we intend for the product to arrive in the same condition it leaves our distribution centre - in a perfect, untouched condition. We have various procedures in place for checking, packing and wrapping these items to ensure there is minimal risk of damage occurring during transit, however, damage can still occur. We endeavour to be as transparent as possible with our customers to ensure they are aware there is always a risk of damage occurring during transit and, if damage does occur, the liability falls onto the buyer.

Some shipping/courier companies offer an insurance for shipments. Please contact us within 24 hrs of a purchase if you’d like to pay for an additional insurance.

To return the item you purchased, please mail it to:

Refunds do not include any shipping and handling charges shown on the packaging slip or invoice. Shipping charges for all returns must be prepaid and insured by you. You are responsible for any loss or damage to hardware during shipment. We do not guarantee that we will receive your returned item. Shipping and handling charges are not refundable. Any amounts refunded will not include the cost of shipping.

 Returns, repairs and service

Until the nature of any fault is determined, the resolution Euro Kustoms can offer may vary. Where necessary, the item may need to be returned to determine fault/issue (see RETURNING ITEMS below regarding freight costs).

Once the fault/issue is clarified, Euro Kustoms may offer replacement parts to the customer. Other alternatives may be offered to the satisfaction of both parties.

Where replacement is not possible, any refund offered may be less than the sale price, depending upon any contribution the owner may have made to the fault/failing.

Where the customer has contributed to the failure, or been misleading in their description of their issues,  Euro Kustoms may not accept the warranty claim. If the warranty claim is rejected, the item is to be returned to the customer at the customer cost. Freight cost not to exceed original freight cost. Where item was purchased with free postage, freight costs are to be set at 20% of the item cost. Payment to be made to  Euro Kustoms within 14 days of being notified of warranty rejection. Storage fees to apply beyond this time.

Where money is owed to Euro Kustoms for replacement and postage due to incorrect fitting of product,  Euro Kustoms is entitled to hold onto the item until payment is made. Storage fees to apply beyond 14 days at 5% of the original product cost until the credit expires.

The warranty is considered void if the item has been modified, altered or tampered with by a person (or persons) not authorised by  Euro Kustoms service.

At no time is  Euro Kustoms liable to pay any labour cost to fitting or re-fitting of a faulty product.

If a part has been incorrecty purchased or incorrectly sent  Euro Kustoms will work with the customer and the costs of the order will be covered by whoever is at fault. If  Euro Kustoms is responsibile for sending the incorrect item we will work with the customer to either exchange it for the correct part or organise a refund for the order amount only. At no time is  Euro Kustoms liable to pay any additional labour costs incurred

If the part has been altered in anyway to its original state the warranty, return or exchange may be void

**Ensure you read the RETURNING ITEMS information below prior to returning any product.**

Returning Items

If for any of the above reasons you are required to return an item, the following steps need to be followed:

Email info@EuroKustoms.com.au stating your order number, the item/s you wish to return, and the reason for the return.

Our customer service department will review your email and, if applicable, issue you a return authorisation (invoice) number which must be included on the address label. All other relevant information will be sent to you at this time.

Euro Kustoms will not accept the return of any item/s without an RMA attached.

To enable  Euro Kustoms to continue offering the very best price, freight arrangements vary depending upon the time that has expired since purchase.

Dispatch

Items are generally dispatched within 1-5 business days after payment is cleared however, please allow approximately 7- 10 business days for it to arrive. Buyers will be able to trace the delivery online with a unique tracking number.

Buyers have the full responsibility to provide us with the correct delivery address and mobile phone number on the checkout page before payment. Courier providers (not Australia Post) normally contact the buyer prior to the delivery day, however this is not always the case.

Any changes to address after checkout will not be considered as valid.

Euro Kustoms is not liable for any delay, losses and/or damage of items due to changes of delivery address after checkout, or mistakes made by buyers. This also includes failure to provide an answered phone number which is essential to facilitate delivery of bulky freight. Please be aware that PO Boxes cannot receive items above 25kg or longer than 1 metre. We highly recommend that you change your delivery address to a workplace for items that are large and bulky.

Where goods are sent through Australia Post, the buyer may receive a card in their letterbox indicating their item is available for pickup from their local post office.

A redelivery fee will be charged to buyers for items that are undeliverable and/or returned to AGR due to incorrect delivery address or unsuccessful delivery. Items will only be delivered during normal business hours (9am to 5pm) on weekdays. Delivery is not available on weekends, public holidays or after business hours.