ARP reinforced head studs, BMW / MINI 2.0 16V B48A20 B48A20B

This kit of reinforced head studs for the BMW / Mini Cooper S / Toyota GR Supra 2.0L contains 10 ARP studs, 10 ARP washers and 10 ARP nuts.

Gary Holzapfel, who came from the aerospace industry, founded ARP (Automotive Racing Products) in the early 1970s to answer a major problem in motorsport: engine failures caused by bolts and studs that were not strong enough. At the time no manufacturer was able to meet that need. Today ARP offers thousands of part numbers across several ranges and product types, such as head bolts, main bearing bolts and connecting rod bolts. Depending on the application, ARP offers several material grades:

• 8740: a chrome-molybdenum steel whose standard strength properties are perfectly suited to modified engines. Tensile strength between 1240 and 1447 N/mm2.
• ARP2000: stronger than 8740, the ARP2000 alloy withstands clamping and tensile loads of up to 1516 N/mm2. This range is widely used on track and drag cars and can be used with hydrogen.
• L19: a premium treated steel whose tensile and fatigue strength is clearly above the 8740 and ARP2000 ranges, with a tensile strength of up to 1792 N/mm2. This material is more sensitive to corrosion, so it must be kept oiled and away from moisture. It is not recommended for use with hydrogen.
• CA625+ (Custom Age 625 Plus): this super alloy has clearly superior technical properties while resisting corrosion and oxidation. Its tensile strength reaches 1930 N/mm2.

All ARP fasteners are designed and made in the United States. Production starts with cold or hot forging, followed by a heat treatment that varies with the range, then shot peening to remove surface irregularities. Precision grinding follows to obtain perfect concentricity, then the thread is rolled. Finally comes the finish, with a coating such as chrome-molybdenum black oxide or polished stainless steel, depending on the product range.

Every kit comes with assembly lubricant and an instruction sheet stating:

• the fitting steps
• the thread of the bolts, studs and nuts
• the tightening torque
• the tightening procedure