• ARP B38 Main Stud Kit
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ARP Automotive Racing Products

BMW B48 ARP Main Stud Kit

BMW B48 ARP Main Stud Kit

$199.99 USD
$199.99 USD $199.99 USD
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This ARP Main Stud Kit is designed for the BMW B48 Engine 

Upgrading from factory main bolts to ARP Main Studs is a simple, yet greatly beneficial upgrade. ARP Main Studs offer the following benefits: 

- Uniform Clamping Force: ARP Main Studs provide a uniform clamping force that OEM bolts cannot. With the improved distribution of pressure across main bearing caps comes better, more precise crank alignment for stability and longevity. 
- Improved Block Stability and Rigidity: ARP Main Studs improve block rigidity and therefore stability. This ensures maximum power transfer from the crank to the drivetrain, which in turn ensures: 
- Improved Throttle Response
- Greater Horsepower
- Higher Torque Output
- Prevent Main Cap Walk: This occurs as main caps shift and move out of position, which can cause crank and engine damage
- Reduced Risk of Fastener Stretching: Under high RPM applications and high loads, factory main bolts are prone to stretching and deforming. ARP uses advanced manufacturing techniques and high quality materials for hardware that is much less prone to deformation under load.
- Safeguard Engine Block Threads: Because ARP Main Studs have unmatched tensile strength, they are much less likely to deform or strip block threads under high loads. Additionally, ARP’s precision machining and manufacturing ensures that stud threads are both highly accurate and consistent.

When opting for main studs instead of factory bolts, it's important to note that the engine builder should mic the bores. Using studs may require a line hone to ensure proper fitment and alignment. A line hone is a machining process that can be used to resize and reshape the main bearing bores, ensuring that they are perfectly round and concentric. This is crucial for ensuring proper oil clearance and preventing premature bearing wear. By mic'ing the bores and performing a line hone if necessary, engine builders can ensure that the main studs are installed correctly and that the engine will perform reliably and at its best.

Installation Instructions

  1. Thoroughly clean all threaded holes in the engine block. If necessary, use an ARP thread chaser to ensure clean threads and proper engagement.
  2. Inspect all studs, nuts, and washers for damage and verify proper fit, length, and dimensions before installation.
  3. Install the main studs into the engine block by hand until snug. Do not overtighten.
  4. Install the main caps and check for proper fit, alignment, and any binding.
  5. Apply ARP Ultra-Torque Fastener Assembly Lubricant to the stud threads, nuts, washers, and washer contact surfaces.
  6. Install the washers and nuts and tighten them by hand. Do not substitute motor oil or other lubricants for ARP Ultra-Torque.

  7. Following the manufacturer's recommended main-cap tightening sequence, torque all main stud nuts progressively in three steps using ARP Ultra-Torque:

    Step 1: 20 ft-lbs
    Step 2: 40 ft-lbs
    Step 3: 60 ft-lbs

  8. After final torque, measure the main bearing bores and verify proper size, roundness, and alignment.
  9. If necessary, line hone the main bores with the ARP main studs installed and torqued to specification.
  10. Verify final main bearing oil clearances before engine assembly.


BMW B48 Applications:

1 Series

2016-2019    F20    120i / 125i
2019-2023     F40     118i / 120i / 128ti / 135i / M135i
2024-Present     F70     120 / M135i 

2 Series

2014-2021     F22/F23     218i / 220i / 230i
2014-2017     F45     220 / 225i
2021-Present     G42     218i / 220i / 230i
2021-Present     U06     223i
2020-2024     F44     218i / 220i / 228i / M235i
2025-Present     F74     M235

3 Series

2015-2019     F30/F31/F34     320i / 330i / 330e
2018-Present     G20/G21     318i / 320i / 330i / 330e

4 Series

2016-2019    F32/F33/F36    420i / 430i
2020-Present     G22/G23/G26     420i / 430i / 430e

5 Series

2017-Present     G30/G31     520i / 530i / 530e

6 Series

2017-Present     G32     630i

7 Series

2015-2022     G11/G12     730i / 730Li / 740e / 740Le

X1 Series

2015-2022     F48     sDrive18i / sDrive20i / xDrive20i / 25i / xDrive25i / 28i
2022-Present     U11     sDrive18i / xDrive20i / xDrive28i / M35i

X2 Series

2018-2023     F39     sDrive18i / sDrive20i / xDrive20i / 25i / xDrive25i / 28i / M35i
2023-Present     U10     xDrive28i / M35i

X3 Series

2017-2024     G01     sDrive20i / xDrive20i / xDrive30i / xDrive30e
2025-Present     G45     xDrive20e / xDrive30e

X4 Series

2018-Present     G02     xDrive20i / xDrive30i

X5 Series

2018-Present     G05     xDrive25i / sDrive25i

Z Series

2018-Present     G29     Z4 sDrive20i / sDrive30i

Toyota B48 Applications:

A90 / A91 Supra

2019-Present     J29/DB82/DB22 Supra
2020-Present     GR Supra 2.0  

MINI B48 Applications:

MINI Hatch [F55/F56/F57]

2014-Present     Cooper S
2015-Present     John Cooper Works (JCW)

MINI Clubman [F54]

2015-Present     Cooper S
2016-Present     John Cooper Works (JCW)

MINI Convertible [F57]

2016-Present     Cooper S
2016-Present     John Cooper Works (JCW) 

ARP-MSK-B48

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