SKU: 901-8150 | UPC: 672036022327
ARP 81.5mm Ring Compressor for VW/Audi 1.8T, Honda B18, BMW M42
ARP 81.5mm Ring Compressor (901-8150) simplifies piston installation in performance engines with 81.5mm pistons including VW/Audi 1.8T, Honda B18, and BMW M42 builds. This precision tool delivers even clamping force to slide pistons into cylinders without ring damage or wall scoring. Built for consistent results in street and race engine assemblies.
Key Features
- Precision Tapered Profile: Gradually squeezes rings evenly to avoid distortion or breakage during piston insertion
- Knurled Grip Surface: Provides firm hold in oily conditions for controlled placement
- Exact 81.5mm Fit: Matches oversized pistons in popular 81mm bore engines for seamless compatibility
- 6061-T6 Aluminum Build: Lightweight yet tough construction handles repeated professional use
- ARP Engineering: Application-matched design ensures reliable clamp load every time
Product Notes
- Confirm piston OD measures 81.5mm prior to use
- Lubricate rings lightly for optimal compression
- Store in dry area to maintain taper accuracy
Installation Notes
- Professional installation recommended.
- Slide compressor over piston rings and taper into cylinder bore
- Use ARP-recommended lubes on threads and rings if applicable
This Part Fits
| Year | Make | Model | Submodel |
|---|---|---|---|
| 1996-2006 | Audi | A4 | 1.8T |
| 1998-2005 | Audi | A6 | 1.8T |
| 1999-2006 | Volkswagen | Golf | GTI 1.8T |
| 1999-2005 | Volkswagen | Jetta | GLI 1.8T |
| 1994-2001 | Honda | Integra | GSR / Type R |
| 1992-1999 | BMW | 3 Series | 318i / 318is M42 |
Why Choose ARP?
- Trusted brand in performance engine components for decades
- Reliable tools match fastener quality standards
- Precision machined for pro-level engine work
Frequently Asked Questions
-
Q: Which piston sizes does it support?
A: Specifically for 81.5mm diameter pistons common in rebuilt VW/Audi 1.8T, Honda B18, BMW M42 engines. -
Q: What is the construction material?
A: Machined 6061-T6 aluminum with knurled finish for strength and secure grip. -
Q: What support does ARP provide?
A: ARP backs tools with satisfaction guarantee, contact for warranty claims.
Shipping & Handling
- Method: UPS Ground / USPS
- Availability: In stock - ships same or next business day
- Packaging: 5.8 x 5.3 x 1.2 inches box
- Weight: 4.8 oz
ARP
ARP (Automotive Racing Products) is the world’s premier manufacturer of high-strength engine and driveline fasteners—head studs and bolts, main studs, rod bolts, and more—engineered and manufactured in-house from start to finish for race-proven reliability. With vertically integrated processes that include cold heading, machining, heat-treating, thread rolling after heat treat, and rigorous QA, ARP maintains aerospace-level certifications (ISO 9001 and AS9100) and validates every part for repeatable clamp load and fatigue resistance. Signature alloys such as 8740 chromoly, ARP2000, L19, and Custom Age 625+ deliver ultimate tensile strengths up to the super-alloy range, while ARP Ultra-Torque fastener assembly lubricant helps achieve consistent pre-load during installation. From street performance builds to professional motorsport programs, ARP fasteners provide precise fitment, superior metallurgy, and the durability needed to keep engines together at elevated cylinder pressures and...
View ARP Products
ARP Head Studs
ARP head studs replace factory head bolts with precision-machined threaded studs that provide more consistent and repeatable clamping force on the cylinder head gasket. Unlike head bolts that apply torque through both rotational and tensile forces, head studs allow the nut to be torqued concentrically on a stud that is already stationary, producing more even clamping load across the entire head gasket surface. Popular ARP Head Stud Applications ARP head studs are available for a wide range of performance and turbocharged engines including the Subaru EJ series, Honda K series and B series, Mitsubishi 4G63 and 4B11, Honda Civic and Integra, Toyota 2JZ-GTE, Nissan SR20DET and RB series, GM LS series, Ford Coyote and 5.0, and Dodge/Chrysler HEMI applications. ARP offers both 8740 chromoly and ARP2000 alloy head stud kits, with the ARP2000 material providing approximately 20 percent higher tensile strength for high-boost applications above 30 psi. Why are head studs preferred over head b...
View ARP Head Studs Products
Fabrication
Shop Fabrication Parts & Materials at Black Ops Auto Works for stainless steel tubing, titanium tubing, aluminum charge piping, mandrel bends, V-band clamps, flanges, merge collectors, AN fittings, PTFE hose kits, braided fuel and oil lines, heat shields, welding supplies, brackets, bungs, and hardware for building custom exhaust systems, turbo plumbing, intercooler piping, fuel systems, and engine bay routing. Start with tubing (304 or 321 stainless, titanium, or aluminum) in the right diameter and wall thickness, then add mandrel bends, flanges, V-bands, and clamps to complete the joint work. AN plumbing follows the same pattern: match dash size to horsepower target, pair the right hose (PTFE or CPE) with matching hose ends, and use adapters, bulkheads, and distribution blocks to route fuel, oil, and coolant cleanly. Shop by material (stainless, titanium, aluminum), fitting type (AN, ORB, NPT), diameter, or brand (Vibrant, Ticon, Stainless Bros, Radium, Fragola, DEI, ATP). ...
View Fabrication Products
Tools
Welcome to our exclusive Tools Collection, where we offer a carefully curated selection of the best tools available in the market. Whether you're a professional tradesperson or a DIY enthusiast, our tools are designed to meet all your needs. Why Choose Our Tools? Quality: We prioritize high-quality materials and craftsmanship. Diversity: A wide range of tools for various applications, from woodworking to automotive. Affordability: Competitive prices without compromising on quality. Innovation: Stay ahead with the latest tools and technologies. Featured Categories Explore our featured categories within the Tools Collection: Hand Tools: Essential tools for precision and durability. Power Tools: Efficient tools for faster and easier work. Tool Accessories: Enhance your tools with high-quality accessories. Organizers: Keep your workspace tidy with our tool organizers. Shop with Confidence Our Tools Collection is backed by excellent customer service and a satisfactio...
View Tools Products


