Spark plugs — NGK, Denso and budget options

Tags: #spark-plugs

Part of the spark-plug series — overview: Spark plugs — options, prices, reliability.

Further alternatives — NGK reliability and outdated-NGK claim. Factory NGK QH6RTIP plugs are described by one source as outdated. Torch-brand direct replacements QH5RIU-13 and QH6RIU-11 are said to offer a higher octane/heat rating and a smaller gap (<1.1mm). Separately, NGK-brand plugs (iridium or standard) are confirmed reliable over 60,000 km with no degradation by another owner, who also noted the factory plugs had inconsistent gaps out of the box¹².

Torch QH6RTI (no platinum pad) and NGK long-term test. Torch-brand QH6RTI spark plugs are officially recommended for the X80. Unlike premium Torch variants, they lack the platinum pad on the outer electrode; community testing found no practical difference vs. iridium plugs on prior vehicles. Chinese Miles-brand plugs were tested as an economical alternative. Some vehicles still run OEM plugs from a 2013 factory batch^3456789. Separately, Miles ALSP067 iridium plugs were installed with a 1.2mm gap (a slight adjustment from the 1.15mm factory spec found on one plug), costing about 1,640 RUB for a set (RU market, 2025); the owner reported a possible reduction in misfires and was monitoring the fuel-economy impact¹⁰. NGK plugs tested to 70,000+ km in "excellent condition" — no need to replace until the engine runs rough; proactive replacement at 30,000 km is considered unnecessary if the engine runs smoothly^11121314.

Non-iridium budget alternatives also reported reliable. Beyond the iridium options covered on the Spark plugs — Torch, Miles and Ford cross-refs card, owners also report success with plain NGC-brand plugs (no unusual symptoms reported) and with generic Russian-made domestic plugs — one owner ran domestic plugs to 50,000 km without needing replacement. Overall community sentiment: this engine is not particularly picky about spark-plug brand compared to some other platforms^{1516171819202122232425}.

Field report — NGK plugs and a fuel smell (inconclusive, installation-related?). One owner (Aziz Marashly) reported that installing NGK ILTR5A-13G plugs caused a fuel smell from the engine and possible over-fueling, possibly related to improper thread fit or an installation error rather than the plug itself. The owner returned to factory Torch plugs, citing a thermal-range mismatch as the suspected cause. Not conclusively determined whether this was an NGK fitment issue specific to this plug or an installation error — worth a mechanical inspection if similar symptoms occur after an NGK swap²⁶.

Field debate — IXEH22TT, Torch, and Denso all reported working, with a personal-experience split. One owner asked whether IXEH22TT plugs would fit; a Mazda-mechanic acquaintance recommended them as "top" quality. Another member pushed back in favor of Torch, citing two separate bad personal experiences with Denso plugs and having since standardized on NGK, then switching to Torch — while acknowledging "to each their own." A third owner confirmed running Torch at a 1.3mm gap with good results, and pointed to the OEM plug's "-11" suffix digits as the reference marking to match when buying^{27282930313233}. This is a personal-preference/anecdote thread, not a resolved recommendation — it sits alongside, and does not override, the Torch QH6RTIP-13/QH6RIU-11 OEM-spec guidance documented on the Spark plugs — factory spec and gap disputes card.

DENSO ITV16TT — positive report. One owner installed DENSO ITV16TT (listing: "DENSO ITV16TT 4718 IRIDIUM" 4-plug set) and reports everything running well afterward³⁴³⁵.

ITV16TT (heat range 5) vs. ITV20TT (heat range 6) — reported fuel-economy and shift-smoothness gain. Denso ITV16TT (calorific number 5) and ITV20TT (calorific number 6) are both cited as compatible; heat range 5 suits city driving, heat range 6 suits sustained high-RPM/highway use. One owner reports that after switching, the car "came alive" — fuel consumption dropped from 13 L/100km to 10.5 L/100km at highway speeds (~150 km/h), and the transmission became noticeably smoother on every gear³⁶³⁷. A separate anecdote (different vehicle, same plug family debate) recounts a prior car where Denso plugs caused excessive fuel consumption in the city, resolved by switching to NGK³⁸ — offered as a data point that plug-brand results can vary by vehicle/engine rather than a direct X80 conflict.

Standard (non-iridium) plugs as a cost-effective baseline — Denso vs. iridium tradeoff. A separate, earlier report frames the choice more simply as standard vs. iridium: Denso standard (non-iridium) plugs are confirmed working and recommended as a cost-effective baseline. One owner switched from unknown/cheap plugs at 59,000 km to Denso standard after experiencing a cylinder-4 misfire. The stated tradeoff: iridium plugs (TORCH QH6RIU-11 OEM-type or similar) last longer but cost 2-3x more; standard plugs need more frequent replacement but are much cheaper — for typical driving, the benefit of iridium over quality standard plugs is described as marginal³⁹⁴⁰⁴¹.

DENSO TV16TT — an additional recommended cross-brand option. DENSO TV16TT spark plugs are recommended as a reliable option for X80 owners, expanding the cross-brand list beyond the Torch lines (see the Spark plugs — Torch, Miles and Ford cross-refs card) and the standard Denso plugs covered on this card. One owner (Эдуард Янонис) confirmed using this plug for a second time with normal operation, suggesting repeat satisfaction rather than a one-off trial. Suitable for the X80 2.0L engine⁴².

Media

Photo of spark plugs installed in the engine

Second photo of spark plugs installed in the engine

Torch QH6RTI iridium spark plug shown with 16mm and 25mm dimensional markings

Oxidized spark plug with granular residue on threads, suggesting improper storage or age-related degradation

Miles ALSP067 iridium spark plugs shown with packaging and installed components in the engine bay

Related pages

• Spark plugs — options, prices, reliability
• Torch spark plugs — codes, listings, gap rules
• Spark plugs — Torch, Miles and Ford cross-refs
• Spark plugs — factory spec and gap disputes
• OEM spark plug specifications

Sources

This page is compiled from 42 community messages. Every fact carries a numbered reference to its original author and message.

Last updated: 2026-10-29