SK ZIC YUBASE+ VHVI vs Mineral Group II — Why Group III Outperforms and Costs Less

Why does one bottle of engine oil cost THB 800 / 4L and another costs THB 2,500 / 4L when they look the same?

The answer is in the base oil — the foundation that makes up 75–85% of the bottle. API 1509 classifies base oils into five Groups, with Group III (e.g. SK ZIC YUBASE+) hitting the "value sweet spot" of high performance at moderate cost — which is why Mercedes-Benz, Volvo, Cummins, and BMW choose it.

This article explains base oil Groups and why SK ZIC YUBASE+ (Group III VHVI) is the right fit for industrial fleets in Thailand.

API 1509 — Five Base Oil Groups

graph TD
    A[API 1509 Base Oil Groups] --> B[Group I: Solvent Refined]
    A --> C[Group II: Hydrocracked]
    A --> D[Group III: VHVI / Severely Hydrocracked]
    A --> E[Group IV: PAO Polyalphaolefin Synthetic]
    A --> F[Group V: Esters, Naphthenic, Others]
    B --> G[VI 80-120
Saturates <90%
Sulfur >0.03%]
    C --> H[VI 80-120
Saturates ≥90%
Sulfur <0.03%]
    D --> I[VI ≥120
Saturates ≥90%
Sulfur <0.03%
SK ZIC YUBASE+]
    E --> J[VI ≥130
True synthetic
premium price]
    F --> K[Specialty
Ester for racing
biodegradable]

Group I (Mineral, Solvent Refined)

• VI 80–120 — viscosity changes a lot with temperature
• Sulfur > 0.03% → faster oxidation
• Saturates < 90% — aromatic content causes sludge
• Use for: budget engine oil, older machinery, short drain intervals (3,000–5,000 km)

Group II (Mineral, Hydrocracked)

• VI 80–120 but saturates ≥90%, sulfur <0.03%
• ~30% longer life than Group I
• Use for: mainstream engine oils (most "synthetic blend" products)

Group III (VHVI = Very High Viscosity Index)

• VI ≥ 120 — viscosity stable across temperature swings
• Saturates ≥ 99% (nearly pure hydrocarbon)
• Sulfur < 0.03%
• Produced via severely hydrocracked + hydroisomerization — process similar to true synthetic
• Marketed as "Synthetic" in Thailand and EU (US calls it "Synthetic Blend" — definition under review)
• SK ZIC YUBASE+ — Group III produced in Korea by SK Energy → quality matches PAO Group IV at 30–50% lower cost

Group IV (PAO — True Synthetic)

• VI ≥ 130 — peak stability
• Petrochemical-derived, not from crude oil
• Premium pricing — used in Porsche, BMW M, F1 applications

Group V (Specialty)

• Esters, Naphthenic, Polyglycol — niche uses (food-grade, biodegradable, racing)

Why Group III VHVI is the "sweet spot"

Group III delivers 80% of PAO performance at 50% of the cost — hence the "sweet spot".

SK ZIC YUBASE+ — Technology from SK Energy Korea

SK Energy is the world's #1 producer of Group III VHVI base oil (Lubes'n'Greases 2022). Their Ulsan, Korea plant produces ~7,000 barrels/day and exports to Shell, Mobil, Total, and Castrol (i.e. it is the base stock inside many premium "fully synthetic" products).

SK ZIC is SK Energy's consumer brand using YUBASE+ as the base oil.

YUBASE+ properties

• VI 125–140 — stable viscosity from -40°C to 150°C
• Volatility (NOACK) ≤ 6% — low evaporation → reduces oil consumption
• Pour point ≤ -45°C — cold-start performance
• High aniline point → strong solvency for additive packages
• Cold cranking simulator (CCS) passes SAE J300 — supports 0W grades

SK ZIC Engine Oil — Product Family with OEM Approvals

Premium Synthetic (Group III + IV blend)

Synthetic (Group III VHVI)

Commercial Fleet (drum + pail)

Motorcycle (M-series)

Gear Oil (G-FF manual / G-EP differential)

ATF / CVT

• ZIC ATF Multi — Dexron VI, Mercon LV, Toyota WS, Nissan Matic-S
• ZIC ATF 3 — Dexron III (older vehicles)
• ZIC ATF SP4 — Hyundai/Kia SP-IV (6-speed automatic)
• ZIC CVTF Multi — Nissan NS-2/NS-3, Honda HMMF/HCF-2, Toyota TC, Subaru Lineartronic

Hydraulic (HYDRO)

• ZIC HYDRO 32 / 46 / 68 — DIN 51524 Part 2 HLP anti-wear — 18L pail + 200L drum

OEM Approvals — Why They Matter in B2B

OEM approval = the engine manufacturer (Mercedes, Volvo, Cummins, BMW) has lab-tested and certified a specific oil — not just an "API/ACEA grade".

Examples:

• MB 228.31 — Mercedes truck diesel oil (100,000 km extended drain) → ZIC X-9000 / X-7000 15W-40 approved
• Volvo VDS-4 / VDS-5 — Volvo truck diesel → ZIC X-7000 approved
• Cummins CES 20081 / 20086 — Cummins engines → ZIC X-7000 / X-9000 approved
• BMW LL-01 — BMW gasoline long-life → ZIC X-Top 0W-40 approved
• VW 502.00/505.00 — VW gasoline + light diesel → ZIC X-Top approved
• dexos2 — GM/Chevrolet → ZIC X-9000 5W-30 LS approved
• JASO MA2 — Japan motorcycle (wet clutch) → ZIC M9 4T approved

For government TOR procurement: if the TOR requires "engine oil meeting Cummins CES 20081", the supplier must submit a Letter of Approval from the engine OEM + Product Data Sheet — SK Lubricants provides complete documentation.

FAQ

Q: Do private passenger cars need Group IV PAO, or is Group III VHVI enough?

A: Group III VHVI is sufficient for 99% of passenger vehicles. Group IV PAO is appropriate for:

• Super-cars (Porsche GT3, BMW M)
• Racing
• Extended drain intervals over 30,000 km
• Sustained extreme temperatures (-40°C / 150°C)

Q: Are "Fully Synthetic" oils sold in Thailand Group III or Group IV?

A: Most are Group III (including SK ZIC, Mobil 1, Shell Helix Ultra, and most Castrol EDGE variants). True Group IV PAO is found only in premium top-tier oils priced above THB 1,000 / L.

Q: Is Semi-Synthetic / Synthetic Blend safe to use?

A: Yes — it is a Group II + Group III mix, suitable for standard vehicles without special OEM requirements. SK ZIC X-7 series is all Group III VHVI → quality exceeds most semi-synthetic offerings.

Q: If my Toyota normally uses Toyota Genuine oil — can I switch to SK ZIC?

A: Yes — Toyota Genuine SN GF-5 or SP GF-6 also uses Group III base oil. SK ZIC X-7 FE 0W-20 meets Toyota WS + ILSAC GF-6A → safe substitute, no warranty voiding (keep the receipt + product data sheet).

Q: For a fleet of diesel trucks, which grade should I order?

A:

• Volvo Euro 5 trucks → ZIC X-9000 15W-40 (VDS-4 + Volvo Euro 5 approved)
• Cummins trucks → ZIC X-9000 15W-40 or X-7000 10W-40 (CES 20081)
• 1-ton pickup → ZIC X-7 Diesel 10W-30 or 5W-30
• Older trucks (pre-Euro 5) → ZIC X-3000 15W-40 (economy fleet)

Quote Request

Sahawatthanakit stocks the full SK ZIC range in 800ml (motorcycle), 1L/4L/6L (passenger), 18L pail, and 200L drum (fleet/factory) — fleet pricing + nationwide delivery.

• Phone: +66-2-096-2118
• LINE: @sahawatt1988
• Email: info@sahawatthanakit1988.com
• Request quote: /en/quote?service=lubricant