Best Spark Plug Replacement for Gen4?

Here is is a Bosch video showing the where the iridium is located on the spark plug. A different design than the Denso.

http://www.youtube.com/watch?v=R5_vtsFuNfk

 

The best advice is to install exactly the same brand and model that came in your Prius. This goes for
almost all new cars today. They are built to different specs. that the older ones were and onlythe very best
is needed to preform up to our expectations.

 

Can Gen 3, Denso SC20-HR11 plugs be used in the Gen 4, instead of Denso FC16-HRC9 ?

 

I'd be saying NOPE.

It is a quite different plug, FC vs SC indicate they're different in shape; plus different heat range, different gap (which on Iridium can't be altered), and the HRC9 indicates a different shaped ground electrode.

DENSO SPARK PLUGS

 

Iridium is a very rare and extremely valuable substance.
I would tend to wait for recommended interval (125k?) to replace (actually I waited to about 135K miles).
I still cannot bring myself to toss out my old plugs.

 

According to the chart below, there are some subtle differences but they appear to be very similar. The on the Gen 3 plugs, SC20=HR11, the S denotes that the electrode is thicker 0.7mm compared to 0.55mm, the 20 indicates the next heat range not sure what is different about the C in HRC on the Gen 4 plugs, it just says shape and the end number is the electrode gap, 11 = 1.1mm on the Gen 3 plugs and 9 = 0.9mm Gen 4.
I was wondering if the differences were radical enough not to use them, e.g. would a 1.1mm gap overload the coils on the Gen 4, would the difference in the shape of the electrode make it possibly foul the pistons etc.

Sp_identification_table_uk-NEW by kithmo posted Feb 24, 2018 at 4:59 PM

 

That got me drooling, here's a link to the pdf:

http://www.globaldenso.com/en/products/aftermarket/plug/catalog/europe/pdf_m/pdfcatalog_eu_mo_all.pdf

 

Expensive experiment if it fails - I'd hate to imagine the co$t of an ignition module etc on a PRIUS.

My reading of it is - there's not much the same. You might bet away with it in a lawn-mower, but a PRIUS (or any modern car).

You could send an email to DENSO and ask, they might respond.

And if they don't work, you've got some expensive plugs you'll have to try to sell.

 

Thanks Alan, I think you're right, it's not worth the risk.
I doubt I'll get to the 100K miles due change anyway, at 3K miles per year its gonna take me another 31 years
Oh well, 1 set of Gen 3/Prius+ plugs to go on Ebay.

 

So has anyone actually gotten enough miles to change them yet? Even here in the middle of 2019, I had to pull hen's teeth at the dealer just to order them, as they're not stocked... And the Bosch fit a 5/8" plug socket, which will NOT fit into the tubes in the head.

I'm still not even sure if the right plugs are on their way, as the part number on the bill is 90919-01265, which by any Google search I do screams Prius C compatibility. This after they matched the part number via VIN.

 

How many miles have you done?

 

I'm at 96,500 as of typing this post, and while I know the plugs are rated for 120,000, I've been doing heavy towing, so I'm thinking my current drop in fuel economy (about 12-15% from baseline while deadheading) is indicating a need for new plugs.

 

did you get to 120k or not yet?
did you change those plugs, mine is 2016 and 105k mi now.i wonder is it easier to relace than the gen 3 or still same issue with wiper assembly and crawel bar needed to be disassembled to get an access to them. Planing to change this coming weekend
i bought those toyota plugs. hopefully im not wrong manual says right p/n is FC16HR-C9 @Mendel Leisk ?

90919-01275
SC16HR11
IRIDIUM

 

@Elektroingenieur has access to the official documentation.

 

Those I think are the revised (slightly hotter) third gen plugs.

They're Denso plugs btw: I don't believe Toyota makes plugs, and not sure if they would assign them a part number. Maybe they do assign them a part number, but they spec them in Owner's Manuals by the manufacturer's designation, and it's simplest to stick with that.

From 2010 Owner's Manual:



From 2016 Owner's Manual:

 

Here is the Toyota spark plug.

Spark Plug - Toyota (90919-01298) | Toyota Parts

 

Which looks to be the Denso plug spec'd in the Owner's Manual, with a Toyota part number assigned.

 

It may be. I am not going to pull mine out to look.

 

All the info is in your Owner's Manual.

Anyway, @amos likely has 3rd gen plugs in hand: I wouldn't gamble that they're compatible.

 

Not in the Maintenance Manual - I looked.