Built to Survive the Torque Spikes of Modern BMW Turbo Sixes and Fours
The Pure Drivetrain Solutions 21-458-1000 SUPER-FLEX billet flexplate is engineered for BMW B48, B58, and S58 platforms that see track time, tuning, or high torque converter stall demands. Machined from hand selected aerospace grade alloy steel and hard machined to .002 TIR, the 21-458-1000 replaces the factory stamped steel flexplate with a one piece design rated well beyond OE limits. Every 21-458-1000 flexplate goes through a proprietary three stage heat treating process before being spin tested to 20,000 RPM, exceeding SFI safety standard 29.2. Enthusiasts running upgraded torque converters, higher stall speeds, or built engines choose the 21-458-1000 because it resists the flexing and cracking that leads to premature failure in factory plates.
Key Features
- One piece design with integral ring gear teeth matched to N57/B58/S58 bolt pattern
- Hand selected aerospace grade alloy steel sourced from USA steel mills
- Proprietary three stage heat treating process for long term durability
- Hard machined to exacting .002 TIR tolerances
- Lightening pockets for reduced rotating mass
- Tested to 20,000 RPM, exceeding SFI safety standard 29.2
- Multiple torque converter bolt patterns supported
- Matte black finish with laser etched logo on every 21-458-1000
Fitment
| Year Range | Make | Model | Trim |
|---|---|---|---|
| 2016-2019 | BMW | 340i | B58 |
| 2016-2019 | BMW | 440i | B58 |
| 2019-2025 | BMW | M340i | B58 |
| 2021-2025 | BMW | M440i | B58 |
| 2016-2021 | BMW | M240i | B58 |
| 2017-2023 | BMW | 540i | B58 |
| 2019-2026 | BMW | Z4 | M40i B58 |
| 2019-2020 | Toyota | Supra | B58 |
| 2018-2024 | BMW | 330i | B48 |
| 2017-2024 | BMW | 430i | B48 |
| 2021-2025 | BMW | M3 | S58 |
| 2021-2025 | BMW | M4 | S58 |
| 2023-2025 | BMW | M2 | S58 |
Specifications
| Detail | Value |
|---|---|
| MPN | 21-458-1000 |
| UPC | Not Provided |
| Material | Aerospace grade alloy steel |
| Finish | Matte black, laser etched logo |
| Design | One piece with integral ring gear |
| TIR Tolerance | .002 inch |
| Tested Speed Rating | 20,000 RPM |
| Safety Standard | Exceeds SFI 29.2 |
| Country of Origin | USA |
What’s Included
- (1) Pure Drivetrain Solutions 21-458-1000 SUPER-FLEX billet flexplate
About Pure Drivetrain Solutions
Pure Drivetrain Solutions designs and manufactures billet drivetrain components for enthusiasts who demand reliability under extreme power. Every part, including the 21-458-1000, is built in the USA to exacting tolerances and tested well beyond published industry safety standards before it reaches the customer.
FAQ
What is the 21-458-1000?
The 21-458-1000 is a billet steel flexplate built by Pure Drivetrain Solutions for BMW B48, B58, and S58 engine platforms. It replaces the factory flexplate with a stronger one piece design rated for high stall torque converters and tuned applications.
Which BMW engines use the 21-458-1000?
The 21-458-1000 fits vehicles equipped with the B48 four cylinder, B58 inline six, and S58 inline six engines found across 3, 4, 5 Series, Z4, M2, M3, and M4 models.
Does the 21-458-1000 fit the Toyota Supra?
Yes, the 21-458-1000 fits the 2019-2020 Toyota Supra equipped with the B58 engine shared with BMW platforms.
Is the 21-458-1000 SFI rated?
The 21-458-1000 is tested to 20,000 RPM, which exceeds SFI safety standard 29.2 for flexplates.
What material is the 21-458-1000 made from?
The 21-458-1000 is machined from hand selected aerospace grade alloy steel sourced from USA steel mills and finished with a three stage heat treating process.
Will the 21-458-1000 work with a stock torque converter?
Yes, the 21-458-1000 retains the factory bolt pattern layout and works with stock or upgraded torque converters.
Does the 21-458-1000 include installation hardware?
The 21-458-1000 ships as the flexplate only. Use OE spec or ARP bolts torqued to manufacturer specification during installation.
Why upgrade to the 21-458-1000 instead of running the factory flexplate?
The factory stamped flexplate can flex or crack under high stall torque converters and tuned power levels. The 21-458-1000 one piece billet design eliminates this failure point for track and high performance street use.
Install Instructions
- Support the transmission and remove the transmission from the vehicle following factory service procedures.
- Remove the factory flexplate bolts and separate the OE flexplate from the crankshaft flange.
- Clean the crankshaft flange mating surface and inspect for damage.
- Position the 21-458-1000 flexplate against the crankshaft flange, aligning the dowel pins.
- Install new or OE spec bolts and torque to manufacturer specification in the proper sequence.
- Reinstall the torque converter and transmission following factory service procedures.
- Verify proper flexplate to converter clearance before final assembly.
