ARP

ARP for Porsche

Back the early 1970s, racing enthusiast Gary Holzapfel saw that many of his friends’ broken engines were caused by fastener failure. At the time, there were no commercially available studs and bolts up to the challenge so Holzapfel called upon his many years of fastener making experience for a leading aerospace subcontractor and founded ARP (Automotive Racing Products).In the ensuing years, the firm has grown from what was literally a backyard garage workshop into a highly diversified manufacturer. These include forging, heat-treating, machining, quality control finishing and packaging/warehousing facilities in Santa Paula and Ventura, California.Today, ARP’s product line contains thousands of part numbers, and has expanded to include virtually every fastener found in an engine and driveline and throughout the suspension and frame. These range from quality high performance OEM replacement Porsche parts to exotic specialty hardware for Formula 1, IndyCar, NASCAR and NHRA drag racing and marine applications.

A Quick Look at ARP

Back the early 1970s, racing enthusiast Gary Holzapfel saw that many of his friends’ broken engines were caused by fastener failure. At the time, there were no commercially available studs and bolts up to the challenge so Holzapfel called upon his many years of fastener making experience for a leading aerospace subcontractor and founded ARP (Automotive Racing Products).In the ensuing years, the firm has grown from what was literally a backyard garage workshop into a highly diversified manufacturer. These include forging, heat-treating, machining, quality control finishing and packaging/warehousing facilities in Santa Paula and Ventura, California.Today, ARP’s product line contains thousands of part numbers, and has expanded to include virtually every fastener found in an engine and driveline and throughout the suspension and frame. These range from quality high performance OEM replacement Porsche parts to exotic specialty hardware for Formula 1, IndyCar, NASCAR and NHRA drag racing and marine applications.

Choosing the Right Fit for Your Porsche

Where ARP is listed for Porsche, use the supplied model coverage and OE references to confirm suitability. Check details that commonly affect fitment such as model year, side/position, and connector type where relevant.

• Typical reasons to choose these parts include upgrading to higher-strength fasteners in critical engine and driveline areas, especially during rebuilds or when original hardware is a known weak point.
• Common triggers for replacement can be stripped threads, stretched bolts, head gasket issues, or evidence that previous torque procedures were incorrect.
• Watch for symptoms such as fasteners that no longer hold torque, signs of movement at gasket joints, or repeat leaks after correct installation with standard hardware.
• Before fitting, read and follow ARP’s torque and lubrication instructions carefully; use appropriate measuring and torque methods rather than mixing procedures.
• During planning, focus upgraded hardware on the most highly stressed fasteners rather than replacing everything without a clear reason.

Browse by Category

If you already know the area you are working on, start with the category and then filter by Porsche model. Where real-world symptoms and typical reasons to replace are provided, use them to keep the wording grounded.

Engine Rebuild Parts — Engine rebuild parts are typically renewed during a planned overhaul or when symptoms point to internal wear, such as loss of compression, heavy oil use, persistent leaks, abnormal noises, or contamination found during inspection. Where ARP fasteners are used in this area, they are usually chosen to improve clamp consistency and reliability while the engine is apart.

• Confirm the need for a rebuild with tests such as compression and leak-down, bore inspection, and oil/filter checks before committing to major work.
• Plan to replace chains, guides, tensioners, seals, gaskets, critical hardware, and other hard-to-access wear items while the engine is out.

Connecting Rod — Connecting rod components are replaced when bent, cracked, out of tolerance, or when upgrading for higher RPM, higher cylinder pressures, or improved durability. ARP hardware is often specified here to reduce the risk of bolt-related failures and to maintain consistent big-end clamping under high load.

• Inspect for big-end knock, low oil pressure from excessive clearance, metallic debris, vibration, or heat discolouration when deciding whether to renew rods and fasteners.
• Where permitted by the engine design, consider new rod bolts during any serious rebuild, and have rods properly measured and reconditioned.

Crankcase Parts — Crankcase parts are renewed when there is damage from bearing failure, stripped threads, oil leaks from case joints, or wear affecting clearances and oil pressure. In this area, ARP fasteners may be used to restore or improve joint integrity and resistance to movement under load.

• Check for low oil pressure, recurring metallic debris, abnormal crankcase pressure, case seam seepage, and alignment issues during strip-down.
• Prioritise cleaning of oil passages, bore alignment checks, sealing surface inspection, and thread repair or replacement where required.

Engine Tuning — Engine tuning components are selected to improve drivability, fuel economy, throttle response, or to support hardware changes such as intake, exhaust, or forced induction. Where higher loads are introduced, ARP fasteners can be used alongside tuning parts to keep key engine joints secure.

• Do not use tuning to mask underlying mechanical faults; confirm compression, fueling health, sensor function, and absence of boost or vacuum leaks first.
• Monitor for hesitation, flat spots, surging, inconsistent boost, or warning lights after changes, and resolve root causes before increasing stress further.

Engine Rods and Bolts — This category focuses on connecting rods and rod bolts, where ARP products are commonly used as a durability upgrade. Owners typically change these components when building for higher RPM or cylinder pressure, or after events that may have stretched standard bolts.

• Look out for bearing knock, low hot oil pressure, metallic debris, vibration, or signs of bolt stretch or oval big-end bores during inspection.
• Treat many rod bolts as single-use where specified, follow torque or stretch procedures precisely, and include rod balancing as part of good rebuild practice.

Explore ARP at Design911

View the current ARP range for Porsche at Design911, then filter by model and category to narrow down to the right parts.