{"product_id":"denso-iridium-spark-plugs-sc16hr11-3499-4-pk-4-pack-long-life-0-7mm-center-electrode-copper-core","title":"Denso Iridium Spark Plugs SC16HR11 3499-4 PK — 4‑Pack Long‑Life 0.7mm Center Electrode, Copper Core","description":"\u003cstrong\u003eDenso SC16HR11 iridium long-life spark plugs (3499-4 PK) are high-performance replacement plugs built for improved ignitability and extended service life.\u003c\/strong\u003e\n\n\u003cp\u003eEngineered with Denso's patented iridium alloy and a precision 0.7 mm center electrode, these plugs use the same laser-welding technology found in higher-performance Denso lines but tuned for durability and longevity. They pair a copper-core center electrode for efficient heat transfer with a five-rib insulator and dual sealing to reduce misfires and voltage loss. For drivers seeking dependable, long-lasting ignition components that OE manufacturers choose for luxury models, these plugs are a practical upgrade.\u003c\/p\u003e\n\n\u003ch3\u003eHow do these plugs improve starting and throttle response?\u003c\/h3\u003e\n\u003cp\u003eThe SC16HR11's slim iridium-tipped center electrode focuses the spark, which helps consistent ignition under varying conditions. Improved ignitability means more reliable combustion on initial startup and steadier throttle transitions during acceleration.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e0.7 mm iridium center electrode for concentrated spark delivery\u003c\/li\u003e\n  \u003cli\u003eCopper core for fast heat dissipation and stable operating temperature\u003c\/li\u003e\n  \u003cli\u003eLaser-welded tip to maintain a consistent gap over time\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat makes these plugs last longer than standard spark plugs?\u003c\/h3\u003e\n\u003cp\u003eDurability comes from Denso's iridium alloy and a robust construction that resists electrode wear. The tight laser weld and corrosion-resistant materials reduce erosion, helping the plug hold its gap and performance far longer than conventional designs.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003ePatented iridium alloy resists electrode wear\u003c\/li\u003e\n  \u003cli\u003eDual copper and glass seal creates a gas-tight bond to prevent leakage\u003c\/li\u003e\n  \u003cli\u003eManufacturing pre-fire testing ensures consistent quality out of the box\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eAre these plugs compatible with my vehicle and easy to install?\u003c\/h3\u003e\n\u003cp\u003eThe SC16HR11 is offered in the retail equivalent 3499-4 PK set and matches the specifications used as OE on many luxury and mainstream vehicles. Installation follows standard spark plug replacement procedures; torque specs and anti-seize practices from the vehicle manufacturer should be observed.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eSold as a four-pack (3499-4 PK) for multi-cylinder engines\u003c\/li\u003e\n  \u003cli\u003eMatches OEM fitment on numerous GM, Toyota, Honda and Mitsubishi applications\u003c\/li\u003e\n  \u003cli\u003ePre-fired and quality-checked for reliable plug-to-plug consistency\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat build features reduce misfires and voltage loss?\u003c\/h3\u003e\n\u003cp\u003eThe plug’s five-rib insulator geometry reduces the chance of flashover along the ceramic surface, and the copper core helps maintain thermal stability. Together these design choices lower stray voltage and keep the ignition system focused on creating a clean, stable spark at the electrode gap.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eUnique five-rib insulator minimizes flashover risk\u003c\/li\u003e\n  \u003cli\u003eCopper core center electrode improves thermal conductivity and stability\u003c\/li\u003e\n  \u003cli\u003eConsistent electrode gap thanks to precise welding and materials\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for? The Denso SC16HR11 iridium long-life plugs are aimed at drivers and technicians who want a reliable OE-quality replacement that balances performance and longevity. They suit owners of vehicles that originally came with iridium or fine-wire plugs, aftermarket enthusiasts who prefer extended service intervals, and fleet managers who value reduced maintenance frequency. If you want durable ignition parts with proven manufacturing controls, these plugs offer a strong, cost-effective option.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: How often should Denso SC16HR11 iridium plugs be replaced?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Iridium plugs typically last longer than conventional plugs; consult your vehicle manual, but many last much longer between services—often up to three times conventional plug intervals.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Can I use these plugs on engines that currently use platinum plugs?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes, if the plug specifications and thread\/gap match your engine. Confirm compatibility with your vehicle's recommended part numbers before switching.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"Denso","offers":[{"title":"Default Title","offer_id":48083868614814,"sku":"B083NJKY3Z","price":99.35,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0781\/2041\/9486\/files\/denso-sc16hr11-pack-front.jpg?v=1785837778","url":"https:\/\/northtrailauto.ca\/products\/denso-iridium-spark-plugs-sc16hr11-3499-4-pk-4-pack-long-life-0-7mm-center-electrode-copper-core","provider":"North Trail Auto","version":"1.0","type":"link"}