AC Schnitzer Limited Slip Differential For BMW 3 Series F30/F31 (331010340-f)

The AC Schnitzer Limited Slip Differential (LSD) is one of the most meaningful drivetrain upgrades for a BMW F30/F31 when the goal is better traction, sharper corner exits and a more controlled rear axle. 

AC Schnitzer positions the F30/F31 as a modular performance platform, with its upgrades developed around improved driving dynamics and everyday usability. 

🧠 What does the LSD actually change?

A standard open differential basically says:

“Give each rear wheel whatever rotation it needs.”

That is excellent for normal driving, but under hard acceleration in a corner, the inside rear tyre can unload and begin spinning.

The AC Schnitzer LSD changes the philosophy:

“When one wheel loses grip, transfer more usable torque to the wheel that can still put power down.”

The published specification for this AC Schnitzer unit is approximately 40% locking under acceleration and 10% under deceleration/braking. 

Situation	Open differential	AC Schnitzer LSD
Straight-line acceleration	Good	Better traction potential
Tight corner exit	Inside wheel can spin	More controlled drive
Wet road	Easier to overwhelm one tyre	More balanced torque delivery
Track corner exit	Can waste traction	Stronger drive out of corner
Lift-off/braking	Relatively free	Mild stabilising lock
Driver feel	Open/rear-biased feel	More connected rear axle

🔥 Why 40% acceleration lock matters

Think of a F30 with a powerful engine exiting a second-gear corner.

As lateral load transfers to the outside:

Inside rear tyre ↓ load
Outside rear tyre ↑ load

With an open differential, the lightly loaded inside tyre can become the limiting factor.

With the LSD:

Engine torque → differential → both rear wheels → greater usable traction

That means the driver can begin applying throttle earlier and more confidently rather than waiting for the car to straighten.

The result isn’t simply “more horsepower.” It is better utilisation of the horsepower you already have.

🏁 On different driving styles

Spirited road: ⭐⭐⭐⭐⭐
The biggest benefit is confidence. Throttle application through bends becomes more predictable.

Track/circuit: ⭐⭐⭐⭐⭐
Corner exit is where the LSD earns its money. It helps convert engine torque into forward acceleration instead of allowing excessive inside-wheel slip.

Fast sweeping corners: ⭐⭐⭐⭐½
The controlled locking behaviour contributes to a more coherent rear axle.

Straight-line acceleration: ⭐⭐⭐⭐
Particularly useful when traction differs between the two rear tyres.

Daily driving: ⭐⭐⭐⭐
A properly calibrated clutch-type LSD can remain civilised while giving the chassis a more mechanical, connected character.

⚙️ Important 331010340 detail

The 331010340 application is associated with xDrive F30/F31/F34 applications, while the related 331010320 is listed for non-xDrive applications. 

AC Schnitzer’s product information specifically notes that the xDrive version requires the series differential to be supplied to Aachen for the conversion process. 

So do not order solely from the F30/F31 model name—the exact drivetrain, differential and vehicle data need to be confirmed before purchase.

🧩 The deeper engineering philosophy

The fascinating part of this modification is that it doesn’t try to make the BMW simply stiffer, louder or more powerful.

It improves the relationship between engine torque and tyre grip:

Engine → gearbox → driveshaft → differential → axles → tyres → road

Most power modifications attack the left side of that chain.

The LSD improves the final torque-distribution stage.

That’s why an LSD can make a moderately powered F30 feel substantially more capable without adding a single horsepower.

The verdict:
AC Schnitzer 331010340 = a traction-and-corner-exit upgrade rather than a power upgrade. For an F30/F31 being developed around enthusiastic driving, it is arguably more transformative than another small engine-power increase because it allows the chassis to use the available torque more effectively. 

AC Schnitzer Limited Slip Differential For BMW 3 Series F30/F31 (331010340-f)

Remus Racing Exhaust System for BMW M5 F90 Limo Decat Pipe | 4x 100mm Titanium Black Tips 1-089317-1000-7

At an engineering level, this is a high-flow, motorsport-oriented exhaust package for the F90 M5’s 4.4-liter twin-turbo S63 V8. 

REMUS describes the Racing system as using lightweight construction, high-grade materials, integrated exhaust valves and a non-resonated front section. 

🔥 What makes the system special

1. Non-resonated front section

The REMUS 089317 0000 replaces the front cat-back section and increases tubing from approximately 80 mm OEM → 84 mm REMUS. 

Removing the resonated section reduces restriction and gives the V8 a much more aggressive exhaust character. 

Think of it as:

S63 V8 → turbochargers → freer-flowing exhaust path → valves → four large tips

The reduced back-pressure is particularly interesting once the engine is producing substantially more power than stock.

2. Valve-controlled exhaust

The Racing axle-back uses integrated valves operated through the BMW’s original valve actuators/electronics. That means the system can retain the fundamental concept of factory valve control rather than simply being permanently loud. 

3. Titanium-black visual signature

The four large black titanium-style tips give the M5 a much more motorsport-oriented appearance. REMUS offers several tailpipe configurations, including titanium and black-finished options; the exact tip specification should therefore be checked against the seller’s 1-089317-1000-7 configuration because REMUS lists several interchangeable tailpipe packages. 

🧠 Engineering interpretation

The important part isn’t simply “bigger exhaust = more horsepower.”

The S63 is already a highly boosted V8. Exhaust design influences:

• Back-pressure
• Turbocharger pressure ratio
• Exhaust-gas energy
• Turbo response
• High-rpm flow
• Acoustic character
• Thermal management

A freer-flowing system can give the turbochargers an easier route to evacuate exhaust gas. The benefit becomes more meaningful as airflow increases with tuning.

REMUS itself claims performance and torque increases and lower back-pressure for its Racing system. 

📊 F90 M5 character

Area	OEM exhaust	REMUS Racing
Sound	Refined	Aggressive
Exhaust flow	OEM-oriented	Higher-flow
Valve operation	Factory	Retained
Turbo breathing	Conservative	Less restrictive
High-RPM character	Smooth	More intense
Weight	Higher	Weight-optimized
Appearance	OEM	Motorsport
Road legality	Depends on configuration	Racing components may not be road approved

REMUS explicitly states that its Racing components without EC approval are not intended for public-road use. 

⚠️ Important F90 compatibility point

There is a major distinction between pre-GPF/OPF and GPF/OPF-equipped F90s. REMUS lists the Racing system for specific F90 configurations, and its documentation notes different applications depending on whether the car has GPF/OPF. 

So the production year and emissions configuration of the M5 must be matched to the exact REMUS part number before purchase.

🏁 The final philosophy

The REMUS Racing system transforms the F90 M5 from a luxury super-sedan with a V8 into something acoustically and mechanically closer to a GT-style performance machine:

4.4L Twin-Turbo V8
↓
Lower exhaust restriction
↓
Better high-flow capability
↓
Sharper turbo/exhaust response
↓
Valve-controlled aggression
↓
Four large titanium/black outlets
↓

S63 V8 — executive sedan outside, race-bred soundtrack underneath.

For a closed-course/track-oriented build, this is considerably more interesting than simply changing the rear mufflers because the non-resonated front section changes the flow characteristics of the entire cat-back system. 

REMUS also recommends ECU calibration for closed-course applications when using its racing exhaust components to optimize performance and avoid warning-light issues. 

Remus Racing Exhaust System for BMW M5 F90 Limo Decat Pipe | 4x 100mm Titanium Black Tips 1-089317-1000-7