AMSOIL DOMINATOR 20W-50 Competition Diesel Oil
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The Confidence to Compete, The Protection to Win
AMSOIL DOMINATOR 20W-50 Competition Diesel Oil is designed for professionals and enthusiasts who demand the absolute best protection for their high-performance engines. It is specifically engineered to deliver the most important benefits for high-horsepower and turbocharged competition diesel engines, including superior bearing protection and robust durability that withstands extreme pressures and temperatures.
Key Benefits
- 50% more film thickness than SAE 15W-40 HTHS limit
- HTHS viscosity of 5.5 cP for superior bearing protection
- Boosted zinc and phosphorus for extreme wear protection
- Offsets damaging effects of fuel dilution in high-HP engines
- Maximum oxidation inhibitors preserve turbocharger performance
- Durable 20W-50 synthetic formulation for competition diesel
- Lasting protection for multiple events
- Covers API CK-4, Cummins, Mack, Volvo, Caterpillar specifications
50% More Film Thickness and Boosted Zinc
DOMINATOR 20W-50 Competition Diesel Oil delivers 50% more film thickness compared to the 3.5 cP HTHS limit for SAE 15W-40, with an HTHS viscosity of 5.5 cP. It is heavily fortified with zinc and phosphorus anti-wear additives to provide additional protection against scuffing and wear in severe conditions.
High-horsepower diesel engines push a lot of fuel, leading to fuel dilution that reduces oil viscosity. DOMINATOR's robust formulation helps offset the damaging effects of fuel dilution by maintaining its protective viscosity longer.
Its extremely durable 20W-50 synthetic formulation contains maximum levels of oxidation-inhibitor additives to resist harmful oxidation and preserve turbocharger performance and life.
Technical Specifications
| Property | Value |
|---|---|
| Kinematic Viscosity @ 100°C, cSt | 18.5 |
| Kinematic Viscosity @ 40°C, cSt | 137.5 |
| Viscosity Index | 151 |
| CCS Viscosity, cP (°C) | 4118 (-15) |
| Pour Point | -37°C (-35°F) |
| NOACK Volatility, % weight loss | 3.7 |
| Total Base Number | 10.1 |
| High-Temperature/High-Shear Viscosity, cP | 5.5 |
| Sulfated Ash Content, wt. % | 1.0 |
Industry Certifications & OEM Approvals
API
- CK-4, CJ-4, CI-4+, CH-4
Cummins
- 20081/20086
Mack
- EO-O/EOS-4.5
Volvo
- VDS3/VDS4/VDS4.5
Caterpillar
- ECF-2, ECF-3, ECF-1-a
Renault
- RLD-3/RLD-4
Chrysler
- MS 10902
Ford
- WSS-M2C171-F1
Applications & Specifications
Use in performance-modified diesel engines that require: API CK-4, CJ-4, CI-4+, CH-4; Cummins 20081/20086; Mack EO-O/EOS-4.5; Volvo VDS3/VDS4/VDS4.5; Caterpillar ECF-2, ECF-3, ECF-1-a; Renault RLD-3/RLD-4; Chrysler MS 10902; Ford WSS-M2C171-F1.
Provides lasting protection for multiple events. Use oil analysis to determine appropriate drain interval. When not competing, follow OEM drain intervals or extend based on oil analysis.
Pros and Cons
Pros
- 50% more film thickness than SAE 15W-40 HTHS limit
- HTHS viscosity of 5.5 cP for superior bearing protection
- Boosted zinc and phosphorus for extreme wear protection
- Offsets damaging effects of fuel dilution in high-HP engines
- Maximum oxidation inhibitors preserve turbocharger performance
- Durable 20W-50 synthetic formulation for competition diesel
- Lasting protection for multiple events
- Covers API CK-4, Cummins, Mack, Volvo, Caterpillar specifications
Cons
- Premium Investment: Higher initial cost compared to conventional or "shelf-brand" synthetic oils.
- Limited Local Retail: Primarily available through authorized dealers and specialized synthetic outlets. National Synthetics is a local stocking dealer. Call 1-678-944-8816 to confirm in-stock items for same-day local pickup.
Order Through Your Independent AMSOIL Dealer
Get maximum protection for your competition diesel. As your Independent AMSOIL Dealer, we provide expert guidance and competitive pricing on all AMSOIL products.
Independent AMSOIL Dealer #30576570
Shipping & Returns
Fast, Reliable Shipping
- Free standard ground shipping on orders of $100 ($130 in Canada) or more.
- Orders under the threshold ship for a flat $9.99 ($12.99 in Canada) freight charge.
- In-stock items typically delivered in two to three business days.
- U.S. and Canada only — no shipments to PO Boxes.
30-Day Return Policy
- Return unopened, currently marketed products within 30 days for a full refund (minus freight).
- Exchange unopened products within 90 days with no restocking fee.
- Special-order items are non-returnable.
- Returns are handled directly by AMSOIL.
Frequently Asked Questions
DOMINATOR 20W-50 Competition Diesel Oil delivers 50% more film thickness compared to the HTHS limit for SAE 15W-40 (5.5 cP vs 3.5 cP). High-horsepower competition diesel engines generate extreme pressures that can shear thinner oils, leaving bearings and components vulnerable. The heavier 20W-50 grade maintains protective viscosity even under fuel dilution.
When not competing, follow OEM drain intervals or extend based on oil analysis. DOMINATOR Competition Diesel Oil meets API CK-4 and other major diesel specifications, so it can be used in street-driven diesel vehicles at OEM-recommended intervals.
Customer Reviews
See all 14 reviews20W50 competition diesel oil
This oil lowered my oil temps by 8-9 degrees Fahrenheit, and is heavy enough that none comes out of my crankcase tube. If your diesel has a little extra crankcase pressure I HIGHLY recommend this oil.
Independent AMSOIL Dealer #30576570. Product information sourced from AMSOIL. Visit AMSOIL.com for the most current product details and availability.