5W-30 is the dominant factory-fill viscosity grade for modern BS-VI petrol passenger cars in India — specified by Maruti Suzuki, Hyundai, Kia, Toyota, Honda, Skoda, and Volkswagen for fuel-economy and emissions-system protection. This guide walks through the realistic composition of a 5W-30 API SP formulation — Group III / IV base oil selection, OCP / PMA viscosity modifier, low-SAPS detergent-inhibitor package, secondary alkyl ZDDP, friction modifier, and the four-step manufacturing process with BIS IS 13656 pass targets.
The “5W-30” designation comes from SAE J300, the Society of Automotive Engineers viscosity classification for engine oils. It is a multigrade oil — meeting viscosity requirements at both low and high operating temperatures and demanding considerably more from base oil chemistry than the older 15W-40 or 20W-50 grades.
5W is the winter rating — it commits the oil to a maximum cold-crank simulator viscosity of 6,600 cP at −30 °C (ASTM D5293) and a maximum mini-rotary viscosity of 60,000 cP at −35 °C (ASTM D4684). This low-temperature performance is unreachable with Group I or Group II base oils — it essentially forces Group III, Group III+, or Group IV PAO as the primary base oil.
30 is the high-temperature rating — KV100 between 9.3 and 12.5 cSt (ASTM D445) and HTHS viscosity of 2.9 cP minimum at 150 °C (ASTM D5481). The 2.9 HTHS floor — lower than 40-grade’s 3.5 — is what gives 5W-30 its 1.5 to 2.5% fuel-economy advantage over heavier grades. ILSAC GF-6A explicitly leverages this through the Sequence VIE / VIF fuel-economy engine tests.
A 5W-30 formulation lives or dies by three numbers: cold-crank viscosity at −30 °C, NOACK volatility (D5800, 13% max for SP), and HTHS at 150 °C. Hit those three and the rest of the formulation follows.
| Component | Function | Typical % (m/m) | Notes |
|---|---|---|---|
| Base oil — Group III 4 cSt | Light-cut backbone — cold-crank and NOACK control | 35–45% | Yubase 4 / Nexbase 3043 / SK 3 are workhorse |
| Base oil — Group III 6 cSt | Mid-cut viscosity backbone — KV100 contribution | 28–38% | Yubase 6 / Nexbase 3060 |
| Base oil — PAO 4 cSt (optional) | NOACK and pour-point boost for premium variant | 5–15% | Optional; required for ILSAC GF-6 NOACK headroom |
| VII — OCP polymer (8–12% active) | Viscosity index improvement; multigrade behaviour | 8–10% | OCP standard; star-polymer HSD for SP / GF-6 |
| Low-SAPS DI package (commercial) | Detergent + dispersant + antiwear + antioxidant + CI | 9–11.5% | Lubrizol LZ27000, Infineum P6700, Oronite OLOA 55500 series |
| Overbased Ca sulfonate (if component blend) | Detergent — piston deposit control, TBN reserve | 1.8–2.6% | TBN target 8 mgKOH/g in finish |
| PIBSI dispersant | Sludge control, deposit suppression | 3.5–5% | High-MW PIBSI preferred for sludge |
| Secondary alkyl ZDDP | Antiwear, antioxidant; TWC compatibility | 0.7–1.0% | Delivers 0.06–0.08% P (SP limit 0.08% max) |
| Alkylated diphenylamine (ADPA) | Primary antioxidant — oxidation control | 0.5–1.0% | Higher dose to compensate for reduced ZDDP |
| Hindered phenolic antioxidant | Synergistic antioxidant — low-temperature radical scavenge | 0.3–0.6% | Pairs with ADPA in synergistic system |
| Organic friction modifier (GMO / MoDTC) | Fuel-economy contribution — Sequence VIE / VIF | 0.2–0.6% | MoDTC delivers 0.5–1.2% FE gain; GMO is cheaper |
| Pour point depressant (PMA) | Lowers pour point of base oil blend | 0.1–0.3% | Lower treat rate vs Group I — Group III is already low pour |
| Silicone defoamer | Suppresses foaming during operation | 5–15 ppm | Dilute to dosable concentration before addition |
5W-30 is almost always formulated with a commercial low-SAPS DI package rather than component blending — the API SP / ILSAC GF-6A claim demands extensive engine testing that the additive companies have already done. Component blending makes sense only for very large producers or non-claimed economy variants.
| Property | API SN | API SN Plus | API SP | ILSAC GF-6A |
|---|---|---|---|---|
| Target engines | Pre-BS-VI petrol | BS-IV / early BS-VI petrol | BS-VI petrol & GDI turbo | BS-VI fuel-economy petrol |
| LSPI protection (Seq IX) | Not required | Required | Required (extended) | Required (extended) |
| Timing chain wear (Seq X) | Not required | Not required | Required | Required |
| Phosphorus (D5185) | 0.06–0.08% | 0.06–0.08% | 0.06–0.08% max | 0.06–0.08% max |
| Sulphated ash (D874) | 1.0–1.2% | 1.0–1.1% | 0.9–1.1% | 0.9–1.0% |
| NOACK volatility (D5800) | 15% max | 15% max | 13% max | 13% max |
| HTHS @ 150 °C | 2.9 cP min | 2.9 cP min | 2.9 cP min | 2.9–3.2 cP |
| Fuel-economy (Seq VIE/VIF) | Not required | Not required | Optional | Required |
| Typical DI pack treat rate | 8.5–10% | 9–10.5% | 10–11.5% | 10.5–12% |
| Indicative cost premium vs SN | Baseline | +Rs 8–14 / L | +Rs 18–28 / L | +Rs 25–38 / L |
API SP (introduced May 2020) is now the live current standard. Most new factory-fill specifications in India have moved from SN Plus to SP for the BS-VI petrol fleet. ILSAC GF-6A is the fuel-economy claim layered on top of API SP and is the right label for premium aftermarket retail products.
| Property | ASTM Method | IS 13656 Limit | Recommended Formulation Target |
|---|---|---|---|
| KV @ 100 °C | D445 | 9.3–12.5 cSt | 10.5–11.2 cSt |
| KV @ 40 °C | D445 | Report | 60–68 cSt |
| Viscosity Index | D2270 | 155 min | 165–175 |
| CCS @ −30 °C | D5293 | 6,600 cP max | 5,200–5,900 cP |
| MRV @ −35 °C | D4684 | 60,000 cP max, no yield | 28,000–38,000 cP |
| HTHS @ 150 °C | D4683 / D5481 | 2.9 cP min | 2.95–3.05 cP |
| Pour point | D97 | −30 °C max | −39 to −45 °C |
| Flash point (COC) | D92 | 200 °C min | 225–245 °C |
| TBN | D2896 | 7 mgKOH/g min | 7.5–8.5 mgKOH/g |
| Sulphated ash | D874 | 1.1% max | 0.85–0.95% |
| NOACK volatility | D5800 | 13% max | 8–11% |
| Phosphorus | D5185 | 0.08% max | 0.065–0.075% |
The “Recommended Formulation Target” column is the design target we work to in our 5W-30 SP formulations. The intent is to comfortably clear every IS 13656 limit so that production batch variation never threatens compliance.
Not reliably for an API SP / BS-VI claim. 5W-30 requires Group III (or Group III+ / IV PAO) base oil to meet the CCS limit of 6,600 cP at −30 °C and the NOACK volatility limit of 13% max. Group II base oils are typically too volatile (NOACK 16–22%) and their cold-crank performance struggles at −30 °C. An economy 5W-30 SN can be tried on a Group II + PAO blend but acceptance in the aftermarket is limited because all majors have moved to Group III.
ZDDP is added at 0.7 to 1.0% to deliver 0.06 to 0.08% phosphorus in finished oil — well below the API SP 0.08% P max limit. The secondary alkyl ZDDP is preferred for better thermal stability and three-way catalyst compatibility. The reduced ZDDP is balanced with ashless antioxidant (ADPA + hindered phenolic) and friction modifier chemistry to meet the antiwear and oxidation targets without exceeding the P limit.
Standard 5W-30 targets HTHS of 2.9 cP min at 150 °C (ASTM D4683). For ILSAC GF-6A fuel-economy claims the practical design target is 2.9 to 3.1 cP — just above the floor, to maximise fuel-economy contribution. For ACEA C2 / C3 claims targeting European OEMs the HTHS bumps to 3.5 cP min — that variant is a different formulation with heavier VII and slightly heavier base oil cut.
Direct material cost for an API SP 5W-30 ranges from Rs 195 to 230 per litre at current Group III base oil and additive prices — nearly double the cost of a CH-4 15W-40. Group IV PAO synthetic versions add Rs 35 to 65 per litre. A fully PAO + ester premium variant (positioned as full-synthetic shelf product) runs Rs 280 to 340 per litre. Add Rs 8 to 14 per litre for packaging, labour, utilities, and overhead.
5W-30 has thinner high-temperature viscosity (KV100 9.3–12.5 cSt) and lower HTHS (2.9 cP) than 5W-40 (KV100 12.5–16.3 cSt, HTHS 3.5 cP). 5W-30 is preferred for fuel-economy oriented petrol PCMO and modern Japanese / Korean OEMs. 5W-40 is preferred for European OEMs (VW, BMW, Mercedes) and turbocharged engines needing higher HTHS bearing protection. Cold-crank performance is identical (both 5W).
5W-30 in API SP grade is petrol-focused — the LSPI protection and TWC chemistry are tuned for spark-ignition. For diesel cars, look at API SP / CK-4 combined claim or ACEA C2 / C3 with mid-SAPS chemistry — these are specifically designed for modern BS-VI diesel with DPF and SCR. Many OEMs (Mahindra, Tata, Hyundai diesel) now specify 5W-30 ACEA C3 in BS-VI diesel service manuals; a separate formulation is needed rather than a relabelled SP product.
Target VI is 165 to 175 (IS 13656 limit is 155 min). The high VI is delivered by Group III / IV base oil chemistry (intrinsic VI 120–140) plus 8–12% OCP or star-polymer VII. A VI lower than 160 in a finished 5W-30 typically signals VII shortfall or base oil contamination — investigate before despatch.
Share your target API category (SN / SN Plus / SP / GF-6A), production scale, and price band. We’ll respond within one business day with an indicative formulation plan, BOM, base oil shortlist, and BIS certification roadmap.