Reinforced ARP cylinder head studs BMW S58B30

The engine concerned

The S58B30 is BMW's 3.0-litre twin-turbo inline six-cylinder petrol engine (2,993 cc, 84 mm bore, 90 mm stroke), in production since 2019. It powers the BMW M2 (G87), M3 (G80, G81), M4 (G82, G83), X3 M and X4 M.

As standard, the cylinder head is held by M11 bolts, 188 mm long (part number 11 12 8 644 675).

Reinforced ARP cylinder head studs

The job of the head fasteners is to keep the cylinder head locked to the block despite the pressure inside the combustion chambers. They keep the gasket compressed; as soon as their clamping force drops, leaks appear between head and block.

For this engine ARP lists the 201-4705 kit: M11 studs in ARP2000, with 12-point nuts. Developed by ARP, ARP2000 alloy steel is heat treated to 220,000 psi tensile strength, and its threads are rolled once the treatment is done. Compared with the 10.9 and 12.9 classes of standard fasteners, between 150,800 and 176,900 psi minimum tensile strength, the gap reaches 24 to 46 %. As an estimate, this ARP2000 M11 kit, heat-treated to 220,000 psi tensile strength, suits a six-cylinder engine producing up to 1,000 hp (calculated estimate).

Technical specifications

Tightening torque

Technical guide

When assembling, the threads and the nut bearing faces receive ARP Ultra-Torque lubricant rather than engine oil. The torque and tightening sequence are to be read in the instruction sheet supplied with the kit.

The ARP brand

ARP (Automotive Racing Products) was born in the early 1970s from the initiative of Gary Holzapfel, an engineer from the aerospace industry, determined to eliminate engine failures caused by weak fasteners in motorsport. The company designs and manufactures thousands of parts in California, in several material grades suited to each use.

Advantages over the original bolts

Criterion	Original head bolts	Reinforced ARP studs
Main fasteners	M11 bolts	M11 studs
Block threads	Stressed at every tightening	Preserved (studs fitted hand tight)

When studs become necessary

On an engine left standard, the original fasteners do their job. Switching to reinforced fasteners becomes worthwhile as soon as:

• S58B30 with higher boost pressure, through an engine remap or a turbo change
• The compression ratio is increased
• A reinforced MLS gasket is fitted, with its need for a high and even preload
• The head has already lifted or the gasket has already failed
• The engine is used in competition, with intense heat cycles and repeated teardowns

Vehicle compatibility

OEM reference: 11 12 8 644 675

Why is it the most cost-effective solution?

On a tuned S58B30, the original head fasteners cap the pressure the gasket can hold as soon as combustion pressure rises. ARP2000 studs with 12-point nuts push that cap back, for an outlay out of all proportion to opening up a twin-turbo six-cylinder after a blown head gasket.

Consider a reinforced head gasket

Reinforced fasteners are only fully worthwhile with a head gasket able to resist the same pressure. We offer the following part for this engine: