Quaife Limited Slip Differential Retrofit

Andrew Brien, the owner and director of SouthernBM, discusses the performance benefits and retrofit process of the Quaife LSD upgrade available for most current BMW models.

SouthernBM provide many services for their extensive list of clients. Apart from servicing BMWs, SouthernBM also specialises in performance modifications for all modern BMW models.

One of the most popular upgrades is shown on this M140i - a Quaife Limited Slip Differential (LSD) retrofit.

What is a Limited Slip Differential? 

An LSD is described as: “a differential that allows its two output shafts to rotate at different speeds but limits the maximum difference between the two shafts. In an automobile, such limited-slip differentials are sometimes used in place of a standard differential, where they convey certain dynamic advantages, at the expense of greater complexity.“

The Quaife Automatic Torque Biasing LSD 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.

Quaife themselves are a British based operation and specialise in components to upgrade the driven parts of a vehicle such as driveshafts, diffs, and steering racks.

What are the benefits of a Limited Slip Differential? 

The Quaife LSD unit specified for this upgrade allows for a driver to further exploit the mechanical ability of the car, whilst built so it fits inside the existing differential housing. This means that it will look factory fresh, and requires no extra engineering or modification. The differential ring gear also remains the same meaning there is no change to your final drive ratio and no reprogramming of the engine management computer required.

Andrew Brien, the owner and director of SouthernBM, explains that the extra performance a Quaife LSD provides allows for a car that's easier to control and is able to apply its power to the tarmac with maximum effect.

He says that in comparison to a normal diff, an LSD provides more mechanical grip across a varying range of conditions and gets more of the engine’s output to the driven wheels. This makes driving the car an easier and safer proposition.
Andrew then explains that the process to install the Quaife LSD into the housing requires some specific machining and mechanical work. In older vehicles the mechanism that makes up a differential and the process to disassemble and reassemble were, in comparison to today, far easier.

Manufacturers moved to provide a set and forget mechanism by welding components (crown wheel and carrier, says Andrew) together. This made for both strength and longevity, plus brought the manufacturing costs down. However, to replace or upgrade requires the components to be worked upon to separate them.

Limited Slip Differential Retrofit Process

When supplying a new LSD, the existing crown wheel requires some mechanical machining to accept the new Quaife ATB unit. This machining ensures the crown wheel and LSD are a bolt together fit, and will sit snugly, where possible, inside the existing housing before being refitted to the car.

This process has taken extensive research and development on SouthernBM’s part. Specific computer programs were written to suit the machinery used and this ensures millimetre perfect tolerances when drilling bolt holes to mount parts together, for example.

Andrew describes the Quaife unit fitted as a helical gear cut unit. These require less servicing, are quieter, and is torque biasing. Quaife describes this process as: “the limited slip differential automatically biases the torque across the axle to the wheel with the most grip.”

On high torque, turbocharged, rear wheel drive machines such as the BMW M140i, this dramatically improves rear end grip. This makes cornering on a slippery road surface driving safer and on a dry road, allows a driver to really utilise the full power and torque delivery of an engine.

SouthernBM clearly go the extra distance to provide a bespoke mechanical and upgrade service. Be sure to lodge an enquiry below if you have any questions.
If you enjoyed reading this article, you can subscribe below to receive more like this in your inbox as they are published.
For media enquiries please contact us.
Published Apr 30, 2020

Be the first to leave a comment

Thanks for posting your comment!
Please note, all comments must be approved before they are published.
First Name
Last Name
Email Address
Keep me updated with news and exclusive offers
Post Comment

The guys are great, definitely take your BMW there.

David Veeken
Google Review

Simply the best Independent BMW Service Centre in Melbourne.

Stewart Adam
Google Review

First time at Southern BM today and it won't be my last. Efficient and quality service as I'd expected at a much more reasonable price than a BMW Dealer. The only downside, you'll drop your car off and will end up drooling over the m3s and m4s out front!

Bobby Turner
Google Review

After 3 other BMW workshops couldn't fix the problem with my M3. SouthernBM sorted it. Excellent to deal with, great communication and customer service.

David Dean
Google Review

Thank you once again to John, Andrew and their team. Have been bringing our cars to them for several years now and have complete trust and faith in their workmanship and honesty.

Eugene Ooi
Google Review
Watch the video

Stay up to date

You've just been sent an email to confirm your email address. Please click on the link in this email to complete your subscription.

We respect your privacy − read our policy.

© 2024 SouthernBM. All Rights Reserved.

Please sign in

Email Address
Log In Forgot your password?
Don't have an account? Register

Stay up to date

You've just been sent an email to confirm your email address. Please click on the link in this email to complete your subscription.
First Name
Last Name
Email Address

We respect your privacy − read our policy.

Stock Availability

In Stock Items marked GREEN or 'In Stock' are currently in stock at SouthernBM. Most orders are shipped within 1-2 business days. ‘Click & Collect’ orders are usually ready within 1-2 hours during normal trading hours.
Available to Order Items marked YELLOW or ‘Available To Order’ are not currently in stock at SouthernBM, and need to be ordered in from the supplier. Please note the expected delivery time before placing an order.
No Longer Available Items marked RED or ‘No Longer Available’ have been discontinued and are no longer available to be ordered. Please contact us for an alternative.
All orders are dispatched from our Melbourne warehouse. Most orders are delivered within 1-3 business days Australia-wide after dispatch. The expected delivery time on all 'Available To Order' items is only an estimate and wait times may vary from those provided. Please contact us if you have any questions.

All items listed on our website are not available for in store pick up without prior purchase. Please use the ‘Click & Collect’ option at checkout and we will let you know as soon as your order is ready.

Make a booking

Thanks! We've received your request. We will be in touch within 1 business day to confirm your booking. If you do not see the email in this time, please check your JUNK/SPAM folder.
Preferred Date
Drop Off Time
Registration #
First Name
Last Name
Email Address
Keep me updated with news and exclusive offers
How can we help?
Send Request