Carpokes

MFactory is offering to produce their Helical LSD for all 85.5+ 944 cars including the 951 with open differentials.

Price $1,125 plus shipping (around $40 depending on location) estimated delivery time 3 months.

If you have an open differential and your car was not optioned with code 220 LSD then this is a great option.

For more info look at the link. Their facility has modern tooling and the finish is high quality.

https://www.mfactoryeurope.com/products ... s=e&_v=1.0

There are only 7 buyers minimum needed since Tegiwa that owns Mfactory has a staff member who owns a 944 himself and will be purchasing one of the units for his car.

If you're interested please post here so we can get the minimum remaining units allocated.


features are:

Gain a prominent advantage over the competition with the MFactory Helical Limited Slip Differential. Through the smooth and constant distribution of power to the wheels, the MFactory Helical LSD puts the power-to-the-ground and maximises your vehicle's traction. A must for any race car, be it Street, Strip or Track!

Diamond Cut to exacting tolerances from Forged High-Nickel-Chromium-Molybdenum Steel
Perfect fitment & finish ensures hassle-free installation & maintenance, each and every time

Designed using leading-edge Solidworks 3D CAD & Cosmos FEA software
Advanced Gear Geometry minimizes parasitic drivetrain losses. Race transmissions built with MFactory components transfer, on average, 1-2% more power to the ground over our competitors!

Multiple Stages Available
Users can choose (and upgrade) between the various Stages available, which determine the Bias Ratios. With the MFactory Helical LSD, upto 75% torque can be transferred to the one wheel! A must-have for serious road-racers

2nd Generation Design
The MFactory v2 Helical LSD is lighter, stronger and more efficient than any other Torque-Biasing Differential on the market today!

Covered by the MFactory Lifetime, Globally Transferable Warranty
Whether used on the Street, Strip or Track, all MFactory Helical LSD's come with a Lifetime, No-Hassle, Globally Transferable Warranty

No-Load/One-Wheel Syndrome
A common misconception is that a Torsen-Style Differential is useless under a no-load situation (e.g One wheel in the air). Although true to an extent, this no-load situation does not apply to the modern day car with Traction Control (or eDiff). For those without traction control, there is a very commonly used solution to the problem (used by professional race car drivers over the past 30+ years) that our competitors will not tell you; simply left-foot brake

Specifications

Made from imported Japanese SAE 4320 & SAE 9310 Steel
Forged, Double Tempered and Super Sub-Zero treated for unsurpassed toughness
Advanced Shot Peening technology increases surface hardness
Designed to withstand the extreme shock loads of competition-level Drag Racing
Advanced gear geometry designed using industry-leading software puts more power to the ground
Only the highest quality Brighton-Best Hardware is used
Maintenance-free Gears eliminates the need for special fluids & rebuilds associated with plate-type LSDs
Lock-free operation ensures no adverse affect to steering response

Happy New year!

Interesting that it's referred to as an LSD when it clearly is not.

It’s better than having an open differential. It’s a Torque bias differential that limits the slipping of the wheels.

I’m sure people here would benefit from it instead of having to find a used LSD transmission that have been difficult to find and much more expensive.

A limited-slip differential (LSD) is a device that allows the wheels on an axle to rotate at different speeds (necessary for turning) while limiting excessive wheel spin by transferring torque to the wheel with more traction. This improves handling, acceleration, and stability compared to an open differential, which sends all power to the wheel with the least resistance.
Helical LSD Technology from MFactory
MFactory specializes in high-performance helical LSDs, which are a type of torque-biasing (or torque-sensing) differential, often referred to as Torsen-style. 1 These use a set of helical (worm-like) gears inside the differential housing to manage torque distribution. When one wheel loses traction and spins faster, the helical gears generate axial thrust forces that create friction against the housing, resisting the speed difference and biasing more torque (up to 75% in standard MFactory units) to the wheel with better grip. 0 This happens smoothly and progressively without any clutches or electronic intervention.
Key features of MFactory’s helical LSDs include:
• Forged construction: Made from imported Japanese SAE 4320 and SAE 9310 steel for superior strength and wear resistance, designed to handle extreme loads in racing environments like street, strip, or track. 4
• Advanced gear geometry: Minimizes parasitic drivetrain losses (1-2% more efficient power transfer to the ground compared to competitors) and reduces noise. 0
• Maintenance-free operation: No clutch packs to wear out or fluids to degrade over time; torque bias is inherent to the gear design and only activates when needed, without binding or inhibiting normal differentiation. 1
• VTB variant: MFactory’s newer Variable Torque Biasing (VTB) LSD is a hybrid evolution, incorporating a patent-pending coil spring preload system (instead of traditional Belleville washers) for adjustable bias up to 85%. 3 It functions both on- and off-throttle like a plate-type LSD but retains the smoothness, quietness, and no-maintenance benefits of a helical design. 2
Overall, MFactory’s units are engineered for motorsport, with revisions incorporating new heat treatments and forging technologies for better durability. 4
Differences from Other LSDs on the Market
Helical LSDs like MFactory’s differ fundamentally from other types in mechanism, behavior, and application. Here’s a breakdown of key comparisons:
• Vs. Clutch/Plate-Type LSDs (e.g., common in muscle cars or high-performance racing setups like those from Eaton or OS Giken):
◦ Mechanism: Clutch-type use friction plates or cones that engage under torque or speed differences, often preloaded with springs for constant partial lock. 20 Helical rely purely on gear geometry for torque transfer—no wear-prone clutches.
◦ Performance: Clutch-type can provide more aggressive locking (up to full lock in some designs) and better handle scenarios where one wheel has zero traction (e.g., off-road or curb-hopping), acting more like a locker. 15 25 Helical are torque-sensitive and may revert to open-diff behavior if one wheel is completely unloaded, but they excel in smooth, progressive torque biasing for road racing or street driving. 17 22
◦ Driving Feel and Maintenance: Helical are quieter, smoother, and less prone to torque steer or binding in turns, with no need for servicing or special fluids. 19 21 Clutch-type can be noisier (chattering), require periodic rebuilds due to plate wear, and often need friction-modifying additives in the gear oil. 16
◦ Best For: Helical suit daily drivers, autocross, or track days where predictability matters; clutch-type for drag racing or extreme off-road.
• Vs. Viscous LSDs (e.g., found in some AWD systems like older Subarus):
◦ Mechanism: Viscous use silicone fluid in a sealed chamber; heat from speed differences thickens the fluid to transfer torque. 23
◦ Performance: Slower response time and less torque transfer capability compared to helical, which react instantly via gears. 27 Viscous can overheat and fade under prolonged stress.
◦ Driving Feel and Maintenance: Viscous are smooth but less effective in high-performance scenarios; they require no maintenance but aren’t as durable in racing.
◦ Best For: Viscous for mild all-weather traction; helical for motorsport.
• Vs. Locking Differentials (Lockers) (e.g., Detroit Locker or lunchbox lockers):
◦ Mechanism: Lockers fully couple both wheels to spin at the same speed when engaged, either automatically (ratcheting) or manually/electronically. 18
◦ Performance: Maximum traction in off-road conditions but can cause harsh handling, tire chirp, or understeer on pavement. 23 Helical never fully lock, preserving differentiation for better on-road manners.
◦ Driving Feel and Maintenance: Lockers are clunky and unpredictable on streets; helical are seamless.
◦ Best For: Lockers for rock crawling; helical for balanced performance.
In summary, MFactory’s helical LSDs prioritize efficiency, durability, and smooth operation, making them ideal for enthusiasts seeking a set-it-and-forget-it upgrade over more aggressive or maintenance-heavy alternatives.

Do you have a price for the group buy, assuming you get 7?

I think it's fair to call it an LSD. Not the same as a clutch-based LSD, but it clearly offers a form of 'limited slip' and as you say clearly better than an open diff. To me, it would come down to price. I'd support the group buy, but my car has a factory LSD unit (thanks to Kevin Gross)....

Any idea how this new TB differential would compare to the Wavetrac? I have two Wavetracs in my A4, along with the center Torsen... and that car is incredibly stable and will drive through snow like "butta baby." The Wavetrac incorporates a design feature that partially compensates for the condition where one wheel is on a slippery surface. My Wavetracs are dead silent in operation.

I installed a Guard Transmission (GT) TB differential in my 944 S2 years ago. It was built like a tank but I didn't like how it reacted as you could feel the torque being shifted from one side to the other as it struggled for grip under hard acceleration. It also made some cracking sounds during that process. I pulled it out and installed a GT clutch type LSD. It's been working great since 2004. It will only make noise in very tight slow turns.

In my spare 968 trans (may go in the 951) I had Kevin at Catellus Engineering install an OS Giken LSD when he completely rebuilt the trans with a lot of new parts.

As an aside: I really like the MAGNA differential in my MK8 Golf R. In the rear it has a traditional open differential, combinded with electronically controlled wet clutch packs on each side that can transmitt 100% of torque to either side. During normal driving it constantly adjusts left/right torque, which you can see on the dash torque display. On the highway in cruise it will generally decouple and switch to FWD mode. The only maintenance required it changing the clutch pack fluid every 40K miles... or you can check the amount of energy input using OBDeleven and decide to change sooner if you do a lot of autocross or track work. Pretty slick and much, much better than the old viscous Haldex system.

I’m definitely interested.

Latitude48 wrote: Tue Feb 03, 2026 9:46 am Any idea how this new TB differential would compare to the Wavetrac? I have two Wavetracs in my A4, along with the center Torsen... and that car is incredibly stable and will drive through snow like "butta baby." The Wavetrac incorporates a design feature that partially compensates for the condition where one wheel is on a slippery surface. My Wavetracs are dead silent in operation.

I installed a Guard Transmission (GT) TB differential in my 944 S2 years ago. It was built like a tank but I didn't like how it reacted as you could feel the torque being shifted from one side to the other as it struggled for grip under hard acceleration. It also made some cracking sounds during that process. I pulled it out and installed a GT clutch type LSD. It's been working great since 2004. It will only make noise in very tight slow turns.

In my spare 968 trans (may go in the 951) I had Kevin at Catellus Engineering install an OS Giken LSD when he completely rebuilt the trans with a lot of new parts.

As an aside: I really like the MAGNA differential in my MK8 Golf R. In the rear it has a traditional open differential, combinded with electronically controlled wet clutch packs on each side that can transmitt 100% of torque to either side. During normal driving it constantly adjusts left/right torque, which you can see on the dash torque display. On the highway in cruise it will generally decouple and switch to FWD mode. The only maintenance required it changing the clutch pack fluid every 40K miles... or you can check the amount of energy input using OBDeleven and decide to change sooner if you do a lot of autocross or track work. Pretty slick and much, much better than the old viscous Haldex system.

I think it would probably be very similar in feel to a wavetrac or quaife.

So far there are 5 spots open. Anyone else interested? As far as price this would be the lowest cost LSD option I have seen so far coming in at around $1,165 shipped per unit.

1. Moemonney
2. 69fi
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5.
6.
7.

If this is coming from Europe, you will also have to pay import tariffs and duties.