Forged Motorsport Final Drive Gears & Pinions
YCW Engineering


Forged Motorsport Final Drive Gears & Pinions

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Background Research

I've documented my quest to reach the ultimate S65 response build by lightening the drivetrain with a billet carbon steel flywheel by TTV, and Carbon Fiber Driveshaft by Mfactoy.

The next step is to shorten gears by increasing the final drive ratio on our M cars. More torque through the differential means more power to the ground, staying in the power band of our highly strung engines. 

Unfortunately, sourcing gear & pinion sets is a difficult undertaking. Most options need to be bought used and reconditioned, or bought new at high prices from BMW. I have been looking for a factory to offer an aftermarket gear & pinion set for most BMW M cars in DCT, SMG and MT. 

I chatted with Michael at MFactory & YCW Engineering, and he immediately took notice of our interest. 

In the spirit of EuroConnex: this is a true factory direct connex. 

MFactory's Background

MFactory is a fundamental supplier to the OEM & aftermarket drivetrain industry. They are ISO regulated, 

Here are some highlights. 

  • Official OEM to Honda of America's Motorsports Divisions
  • Official OEM to Toyota Motorsports Europe
  • World's Largest Manufacturer of Forged Performance Transmission Components for Japanese and European Automobiles
  • North America's Largest Manufacturer of Limited Slip Differentials for Japanese and European Automobiles
  • North America's Largest Honda/Acura Performance Transmission Specialist
  • North America's Largest BMW Performance Drivetrain Specialist

Due to non-disclosures, MFactory cannot list all of their clients publicly. 

Every product within the MFactory catalog is designed in-house in the USA and manufactured in-house to our own specifications at both our US R&D Facility and in their Taiwan factory, before being tested & developed in the real-world on state-of-the-art race vehicles from North America, Europe and Asia-Pacific.

Product Information

Mfactory is looking to develop forged gears & pinions for the BMW M market in our desired final gears. Here are the design specifications. 

  • 3.45, 3.62, 3.91 and 4.10 ratios 
  • Compatible with OEM M Variable LSD or aftermarket LSD
  • Forged raw materials imported from Japan
  • SAE 8620 specifications: post-treatment Tensile U/Y Strength of over 900/550 MPa and HRC 61
  • CNC machined to precise specifications
  • Secondary Heat Treatment: State-of-the-art Case Hardening procedure achieved via computer-controlled Gas Carburization and Quenching
  • Double-Tempering: A superior heat treatment technique used to decrease the brittleness and increase the toughness of their parts
  • Surface Grinding: Through the use of state-of-the-art diamond grinding machines, they ensure all parts are smooth, precise and free of burrs
  • Super Sub-Zero Processing: An advanced treatment technique whereby the parts are cryogenically hardened at -300°F, realigning the steels crystalline structure for maximum strength, then heat tempered again for a 3rd time to ensure maximum toughness (resistance to fracture)
  • Micro-Peening Treatment: the parts are subject to a high speed shot blast with our proprietary micro media, creating a super smooth surface
  • WPC treatment optional 
  • 30 day money back guarantee

Installation Notes

  • 3.62 MDCT E9X M3 applications will require TCU remap and a new MT differential cover
  • Professional installation highly recommended. This is not a DIY. 
Factory Direct

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