NGK BKR5EIX Iridium Spark Plug (Set of 4) — BS4 & BS6 Compatible Cars in India

The NGK BKR5EIX is an iridium spark plug specified for a specific group of older Indian vehicles — the Toyota Corolla, Mitsubishi Cedia, Fiat Palio, Fiat Siena, and Tata Nano GenX. If you own one of these cars, this guide covers the exact part number you need, the suffix difference that matters, how many plugs to order, and what "BS4 & BS6 Compatible" actually means.

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In short: The NGK BKR5EIX (stock no. 6341) fits the Fiat Palio 1.6i.e, Fiat Siena 1.6i.e, Fiat Adventure, and Tata Nano GenX. The BKR5EIX-11 (stock no. 5464) is the correct variant for the Toyota Corolla and Mitsubishi Cedia 2.0. These are not interchangeable. The BPR5EIX is a different plug entirely with a shorter thread reach — do not substitute.

Shop NGK BKR5EIX and BKR5EIX-11 on AutoDecode — correct variant, verified sourcing, pan-India delivery.

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BKR5EIX vs BKR5EIX-11 — Which Suffix Does Your Car Need?

This is the most important distinction when buying this plug, and it is consistently overlooked in online listings.

The "-11" suffix denotes a factory pre-set electrode gap of 1.1mm. The base BKR5EIX has no pre-set gap and requires gap verification against your vehicle's service data before installation.

Fitment data sourced from the official NGK India 4-Wheeler Iridium Application Chart.

If your vehicle specifies the BKR5EIX-11 (Corolla, Cedia) and you install the base BKR5EIX without checking and setting the gap, the plug will not perform at the correct specification for your engine. Do not treat these two variants as interchangeable.

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⚠️ BKR5EIX vs BPR5EIX — A Different Plug Entirely

These part numbers look nearly identical but are not the same plug.

The BPR5EIX has a shorter thread reach and is specified for different vehicles — including older Maruti carburetor models (Gypsy 1.3, Omni, Zen 1.0, Maruti 800) and the Toyota Qualis.

Installing a plug with the wrong thread reach affects combustion chamber geometry, positions the electrode incorrectly relative to the piston, and in severe cases can cause electrode-to-piston contact damage. Always verify the full part number — not just the heat range — before purchasing.

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Technical Specifications

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How Many Plugs Do You Need?

Critical exception — Tata Nano GenX: The Nano engine is a 2-cylinder unit. You need only 2 plugs, not 4. A "set of 4" listing is double what you need for this vehicle.

Also note: The standard Tata Nano and Nano Twist use the BKR6EIX (heat range 6) — a different plug. The BKR5EIX applies specifically to the Nano GenX variant. These specifications are not interchangeable.

Toyota Corolla note: The Corolla has gone through multiple engine generations in India. The BKR5EIX-11 applies to specific generations. Confirm your engine code before ordering.

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What Does "BS4 & BS6 Compatible" Actually Mean?

This label causes unnecessary confusion and deserves a direct answer.

Spark plugs are not BS4 or BS6 certified. Bharat Stage emission norms apply to vehicles and their exhaust systems — not to individual components like spark plugs, filters, or oils.

When a listing says "BS4 & BS6 Compatible" for the BKR5EIX, it means the vehicles this plug is specified for include models produced under both emission standards. It is a vehicle compatibility descriptor, not a product certification.

What actually matters for a spark plug is thread size, thread reach, heat range, and electrode gap — all of which must match your engine's specification. That is what this guide helps you verify.

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Signs Your Spark Plug Needs Attention

For the older platforms in this fitment list — Corolla, Cedia, Fiat Palio, Siena, Nano GenX — watch for:

• Rough or uneven idle that has developed gradually
• Hesitation or stumble when pulling away from low speed
• Difficult cold starts, especially in cooler mornings or after the car has sat for several days
• Drop in fuel efficiency without another clear cause
• Engine vibration at idle that was not present before
• Check engine light — scan for misfire codes (P030X series)

Always scan for fault codes before replacing parts. Misfire codes identify the affected cylinder, directing inspection toward the relevant plug, coil, and injector. Blind replacement without diagnosis can miss the actual cause.

For vehicles with incomplete or unknown service history — common with used examples of these older platforms — removing the existing plugs and inspecting them is worth doing before ordering replacements. A healthy plug shows light tan or grey deposits. Black, sooty deposits suggest a rich mixture or prolonged low-load operation. Wet, oily deposits may indicate engine wear beyond the plug itself.

If plugs need replacement, find the correct NGK BKR5EIX or BKR5EIX-11 on AutoDecode for your specific vehicle.

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Buying Genuine Parts — Two Risks to Avoid

Risk 1 — Wrong suffix. Online listings sometimes combine BKR5EIX and BKR5EIX-11 under a single product or list them interchangeably. Confirm the exact part number — including whether the -11 suffix is present — before ordering.

Risk 2 — Counterfeit plugs. NGK is one of the most frequently counterfeited spark plug brands in India. For older, less commonly serviced vehicles like the Cedia and Palio, the supply chain is thinner and unverified grey-channel sellers are more common.

Signs of a genuine NGK BKR5EIX / BKR5EIX-11:

• Clear NGK logo on both the ceramic insulator and packaging
• Correct stock number (6341 or 5464) printed on the box
• "Made in Japan" on both plug and packaging
• Smooth, consistent ceramic insulator with no surface blemishes
• Precision-machined thread, hex, and metal shell

Buy from: NGK-authorised distributors, established automotive parts retailers with a verifiable supply chain, brand service centres (Toyota, Fiat, Mitsubishi) where stock is maintained, or verified online platforms with genuine sourcing policies and clear return terms.

Avoid: Unknown sellers with no transaction history, prices significantly below market rate for iridium plugs, or loose plugs sold without original NGK packaging.

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Fitment Checklist Before You Buy

• Vehicle model and correct generation confirmed
• Engine type: 4-cylinder petrol (or 2-cylinder for Nano GenX)
• Correct suffix: BKR5EIX-11 for Corolla and Cedia; BKR5EIX (no suffix) for Fiat models and Nano GenX
• Correct quantity: 4 plugs for 4-cylinder vehicles; 2 plugs for Nano GenX
• NGK stock number: 6341 (BKR5EIX) or 5464 (BKR5EIX-11)
• Not BKR5EIX — different thread reach, different vehicles
• Verified seller with return policy
• On delivery: check part number, stock number, "Made in Japan" marking
• Gap: BKR5EIX-11 is factory pre-set at 1.1mm; BKR5EIX requires gap verification before fitting
• Use a torque wrench at installation — do not over-tighten a 14mm thread into an aluminium cylinder head

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Conclusion

The NGK BKR5EIX and BKR5EIX-11 are correctly specified iridium plugs for their respective vehicles. The suffix distinction is real and matters. The BPR5EIX is a different plug with a shorter reach. The Nano GenX needs 2 plugs, not 4. And "BS4 & BS6 Compatible" is a vehicle descriptor, not a certification.

For older vehicles with less workshop familiarity, buying the exact correct part from a verified source matters more than ever — not less.

Shop NGK BKR5EIX and BKR5EIX-11 on AutoDecode with verified sourcing and vehicle-specific fitment guidance.

📱 WhatsApp: wa.me/917906442130

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FAQs

Q1: What is the difference between NGK BKR5EIX and BKR5EIX-11?
Both share the same thread size, reach, heat range, and iridium IX construction. The only difference is the electrode gap: BKR5EIX-11 comes factory pre-set to 1.1mm; the base BKR5EIX has no pre-set gap and requires gap verification against your vehicle's service data before fitting. 

Q2: Is the BKR5EIX the same as the BPR5EIX?
No. They have the same thread size (14mm) and heat range (5), but different thread reaches — BKR5EIX has a 3/4" (19.0mm) reach; BPR5EIX has a shorter 1/2" (12.7mm) reach. They are specified for different vehicles. Do not substitute one for the other.

Q3: Does the NGK BKR5EIX fit the Tata Nano or the Nano GenX?
The BKR5EIX is specified for the Nano GenX only. The standard Tata Nano and Nano Twist use the BKR6EIX (heat range 6), which is a different plug. Confirm your variant before ordering.

Q4: How many plugs do I need for a Tata Nano GenX?
Two. The Nano GenX has a 2-cylinder engine. Despite appearing in the same fitment list as 4-cylinder vehicles, it needs only 2 plugs per complete replacement — not 4.

Q5: What does "BS4 & BS6 Compatible" mean on a spark plug listing?
It means the vehicles this plug is specified for include models produced under both emission standards. Spark plugs are not BS4 or BS6 certified — emission norms apply to vehicles, not individual components.