Ngk Or Denso In The Rx 300?

[nq517]

Do anyone know what is the original spark plug in the RX 300?

[GoldenStateSilverSport]

Do anyone know what is the original spark plug in the RX 300?

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Original spark plug is denso..toyota owns part of this company - they also make the oil filter among other things..

[bluestu]

I put NGK Iridium plugs in my RX300. The guys at the parts stores preferred them over the Bosch Platinum 4. They were about $7 a piece at Advance Auto.

[RX in NC]

I've used both NGK and Denso plugs in several Japanese vehicles over the past three decades. Both are top-quality and as long as you stick with the required iridium application in the RX series, you'll be fine. Do NOT downgrade to a platinum plug - stay with iridium.

[TunedRX300]

Denso has smaller center electrode for better performance but less service life.

It is also interested to note that even though the center electrode is Iridium, ground electrode seems to be Platinum. See this link and a direct quote

http://www.spark-plugs.co.uk/pages/technic...spark_plugs.htm

"Construction of NGK and Denso plugs is similar for the most part, the big difference being Denso's use of a 0.4mm Iridium tipped centre electrode - claimed to be the world's smallest production centre electrode, where NGK's IX centre electrode is 0.6mm. As with NGK Iridium, and indeed most other spark plugs, the narrower the centre electrode is, the lower the potential difference (voltage) that is required to jump the gap between centre and ground electrodes. It follows that the Denso plug will require an even lower 'spark jump' voltage than the NGK plug. The Denso plug also utilises a 'u-grooved' ground electrode which is claimed to aid in the production of a 'flame core' which further improves the combustion process. In theory, all the benefits offered by NGK Iridium plugs are further improved by the Denso Iridium plugs - with the exception of service life. The smaller diameter of the Denso centre electrode means that less wear can take place before the plugs' optimum service life is exceeded.

Denso also manufacture long life Iridium power plugs such as SVK20RZ8, VK22PR-Z11 etc. These maintain the 0.4mm Iridium centre electrode but also have a platinum 'chip' in the ground electrode to allow performance to be maintained for a much longer service life (up to 60000 miles). These plug types are usually recommended for high power turbo charged engines where wear may otherwise be accelerated."

[GoldenStateSilverSport]

I've used both NGK and Denso plugs in several Japanese vehicles over the past three decades.  Both are top-quality and as long as you stick with the required iridium application in the RX series, you'll be fine.  Do NOT downgrade to a platinum plug  -  stay with iridium.

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hey guys, is it true that we shouldn't be using platinum spark plugs in our rx? i have an 01 rx300 silversport and im about to get my 60k. im gonna getmy plugs replaced, and was considering "upgrading" to platinum, but it seems like from the comment above, i should stick with denso?..comments?

any help is appreciated.

[RX in NC]

Be aware that if you're currently running your original iridium plugs, it is unlikely that you need to change them now and if you do, you may see no improvement in performance or gas mileage whatsoever. These iridium plugs are very capable of going 100,000 to 120,000 miles in the RX300. If I were you I would pull them (at least the front three plugs which you can easily reach by removing the dust cover) and inspect them before you arbitrarily replace them simply because you've reached 60,000 miles on the vehicle. My wife's RX300 is approaching 97,000 miles and still runs the original Denso iridium plugs because they are clean and in great shape. I pull one at random every 20,000 miles or so and take a close look at it. There has been no reason to refresh the plugs on her vehicle thus far, so I'd be foolish to waste the money doing so. I won't be surprised if these plugs do indeed go 120,000 miles, and at that point I'll change them.

[GoldenStateSilverSport]

Be aware that if you're currently running your original iridium plugs, it is unlikely that you need to change them now and if you do, you may see no improvement in performance or gas mileage whatsoever.  These iridium plugs are very capable of going 100,000 to 120,000 miles in the RX300.  If I were you I would pull them (at least the front three plugs which you can easily reach by removing the dust cover) and inspect them before you arbitrarily replace them simply because you've reached 60,000 miles on the vehicle.  My wife's RX300 is approaching 97,000 miles and still runs the original Denso iridium plugs because they are clean and in great shape.  I pull one at random every 20,000 miles or so and take a close look at it.  There has been no reason to refresh the plugs on her vehicle thus far, so I'd be foolish to waste the money doing so.  I won't be surprised if these plugs do indeed go 120,000 miles, and at that point I'll change them.

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awesome! i appreciate the feedback. I'll check out the plug in the front and most likely replace at a later time since they are iridium. thanks for the feedback

[TunedRX300]

I found out from http://www.densoiridium.com/faq.php that Denso's power Iridium plugs (0.4mm center electrode) are recommended to be replaced 30K miles. But the one supplied to Lexus/Toyota (no specific mentioning of RX300) has 0.7mm center electrode and platinum tipped ground capable of lasting up to 120K miles.

This puzzles me, don't we need both center and ground electrode to be in good shape for a good lasting plug? If center is made of Iridium but the ground is Platinum, the ground electrode should wear out before the center electrode - making the plug harder to make a spark.

From Denso's FAQ:

Q. What makes Iridium better?

A. Until recently, platinum was considered the best material to use on the top of an electrode because of its durability. However, Iridium is 6 times harder, 8 times stronger, and has a melting point 1200 degrees higher than platinum. Put that into a harsh environment such as an engine piston chamber, and you have a spark plug that can resist wear much better than platinum. Additionally, the DENSO Iridium Power alloy is so durable; it allowed our engineers to produce the world’s smallest center electrode (.4mm) which reduces the voltage requirements, concentrating its sparking power. Also, its smaller size, combined with the tapered U-Groove ground electrode, allows more room for the flame kernel to develop and produce a more efficient combustion.

Q. How long will Iridium Last?

A. Iridium use represents the most significant technological advance in automotive spark plug manufacturing, since platinum was introduced in the early eighties. As vehicle manufacturers produce increasingly complex and efficient automobiles, there is a greater need for long-life plugs that can tolerate leaner fuel mixtures and improved combustion processes. DENSO has responded to this need by developing its Iridium alloy, originally for OE applications. For example, many newer Lexus’ and Toyota models carry an ultra long-life Iridium plug variation (.7mm with platinum tipped ground) that is capable of up to 120,000 miles of service. DENSO Iridium Power plugs, with their .4mm center electrode, have been developed for performance applications. Because gradual wear will “round-off” firing points over time, the concentrated firing power and voltage requirement benefits will be reduced. For this reason, DENSO advises replacement after 30,000 miles.

[RX in NC]

This is important information to have. When replacing your iridium plugs, be sure to obtain the ultra long-life OEM version. Thanks for the details - good stuff.

[monarch]

Do anyone know what is the original spark plug in the RX 300?

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For 30 years every Toyota / Lexus owners manual has told the owner exactly what part# Denso or NGK spark plug to use and to use only those two brands and two part#'s.

[RX in NC]

Due to his inescapable OEM tunnel vision, monarch apparently doesn't realize that not every owner is fortunate enough to receive the original owners manual when they purchase a used vehicle from a third party. Although it certainly ought to transfer with the vehicle, for various reasons it often doesn't. Next time you buy a used vehicle, insist on receiving the appropriate owners manual as part of the deal. For the time being, you may be able to find one cheaply on eBay.

[monarch]

Any Lexus owner can go to http://www.lexus.com/ click on OWNERS, register their vehicle on that site and request Lexus to send you an owners manual at no charge.

Even if you are the third owner of a 1990 model.

Late model Lexus owners who register their vehicles at Lexus.com can also view a .pdf version on their owners manual and Scheduled Maintenance Guide.