DENSO IRIDIUM TT spark plugs anyone tried

Post by **darrylrobert** » 12 Feb 2021, 22:13

Ive ordered a set of Denso Iridium plugs, to replace the stock volvo plugs. Has anyone tried them some really impressive reviews on them..hard to tell from reviews so i have to see for myself. Also i wonder if i keep the stock volvo gap?

Post by **SuperHerman** » 12 Feb 2021, 23:02

I have not tried them, but have considered them for my BMW. In the end I stuck with OEM. The theory and testing looks sound.

I don't like gapping spark plugs with the new metal technology. My fear is the tiny amount of special metals is likely to get damaged in the gapping process. I always check the gap to make sure they are within spec - so far they all have been. So I leave them alone. When I have gapped plugs, closing them down is easy, but opening them up seems to cause the damage. So I don't try to tighten them up if they are within the spec range.

What is the factory delivered gap for the TTs, and what is the Volvo recommended gap? I didn't find any thing specific on their web site on the TTs other than photos of various gap/ignition explosions, but did find Denso general language saying to gap to specific car/model. One would think the plugs would be robust enough to handle the detonation explosions and normal course gapping, but when I have tried gapping iridium plugs I have removed material. Not sure it matters, but I opted to buy another plug.

93SCMax · Post by **93SCMax** » 13 Feb 2021, 05:55

I use Denso Iridiums in my 2007 Lexus GS350. They are good. The original set went for 100k miles. I've got 15k miles on the 2nd set. Denso's were stock from the factory. The car runs perfectly with them.

One thing to watch for, there are so many Denso Iridium counterfeit plugs manufactured in China rather than in Japan. They are cheap and will fail within two years...I had experience with two separate sets. One from Ebay and another from Advance Auto. If you are going to buy Denso Iridiums, buy them from a reputable dealer (they are pricy) and double check the manufacturing codes stamped on the base. They should be identical. I had counterfeits mixed in with some originals from Advance Auto.

...and no, I didn't regap my plugs...too much risk breaking one. The current ones from Japan were gapped correctly.

But frankly, I've only used Volvo (Bosch) plugs in my V70 and have never had an issue. I would not put Denso Irdiums in the Volvo, I'd recommend OEM Volvo spark plugs.

Post by **- Pete -** » 13 Feb 2021, 09:11

I gave the fancy spark plug thing a go a few times. Iridium triple electrode plugs; they were expensive, looked pretty, and didn’t make even a bit of difference. Since FCP doesn’t sell them (and everyone staunchly recommends OEM Bosch/Volvo plugs) I abandoned their use. They certainly are tempting, but overall - not worth it. While using them, though, I didn’t have any misfires or any other maladies.
I’ve stuck with the Bosch/Volvo plugs and change them out at short intervals (30-40k). The theory behind this is you can avoid having an ignition coil failure. Since I’ve adopted the shorter plug change intervals I haven’t had to replace a single ignition coil. If you buy through FCP you really only pay the first time & I don’t mind the labor. Not having to buy ignition coils is a nice bonus.

Post by **cn90** » 13 Feb 2021, 10:45

In terms of Iridium, there was some concern with Denso some ? 10 yrs ago on volvospeed forum.
I might be wrong though.

I have had good luck with NGK brand and am now sticking to NGK Iridium.
I wrote DIY spark plugs in this forum.