GR Yaris Plugs

Michael Knight

Michael Knight

Totally Hooked
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Stock spec in. This is how they looked after 35tkm

left / passanger side
IMG_5163.webp


center
IMG_5164.webp


right / driver's side
IMG_5165.webp
 
They look ‘gappy’. Just by eye they look like they need a change.
 
Needed to fetch 200mm extension socket in order to get plugs torqued properly.
Thought that they were okeyish by hand tight but they were too loose, less than 10Nm. Torqued now to 20Nm, NGK Spec says 15-20Nm for 12mm plug thread diameter - quite exciting task..

So worth using a torque wrench if changing..

edit - fixed the correct target torque. the plug extension diameter is 14mm but thread is actually 12mm..


Screenshot 2023-06-08 at 11.48.26.png
 
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Could be just placebo but feel that engine runs now smoother. So maybe not a bad idea to replace after 40tkm, depends of course on the application.
 
Michael Knight said:
Could be just placebo but feel that engine runs now smoother. So maybe not a bad idea to replace after 40tkm, depends of course on the application.
Click to expand...

Another one here with placebo, potentially exacerbated by having read your post :)

Changed plugs at even lower mileage than yours, without any other engine-related changes at the same time (not even engine oil) affecting my judgement. Now the car feels to me as if it's running better.

Perhaps a little smoother/quieter (but I might just be influenced by your post). Most importantly, more responsive. As if I had an overdue change of air filter done.

Strange, as even the Toyota maintenance schedule for normal vs severe use doesn't differentiate regarding frequency of spark plug changes, which remain at 100,000 km (60,000 miles).

🤷‍♂️
 
Michael Knight said:
Could be just placebo but feel that engine runs now smoother. So maybe not a bad idea to replace after 40tkm, depends of course on the application.
Click to expand...
Recently replaced mine at 50.000 km (around 2.000 on track) and the difference was night and day especially in low end torque.
I can now cruise at 2k RPM and even gently accelerate, vs 2.5-3k RPM before the change.
IMG_20240124_145659.webp
 
Orion said:
can now cruise at 2k RPM and even gently accelerate, vs 2.5-3k RPM before the change.
Click to expand...

I did mine today at just under 50k KMs. Around town driveability has improved a lot. I also felt that 3k was the normal happy place the engine wants to be at but enjoyed more relaxed driving today.

I wonder why Toyota expect 100k KMs from these plugs?
 
SckSqzBngBlo said:
I did mine today at just under 50k KMs. Around town driveability has improved a lot. I also felt that 3k was the normal happy place the engine wants to be at but enjoyed more relaxed driving today.

I wonder why Toyota expect 100k KMs from these plugs?
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it was more, even 160tkm?
 
Hey Ladies

I am trying to eliminate the occasional hiccup that I am getting once in a blue moon. Usually during hard pulls in the high rev range. Thankfully, mine only happens once a week or so, but I thought what the hell, I am at 60K and already using E85 to push knock value up. I'll use colder plugs to assist anti knocking properties and go back to the factory gap and assist the weak coilpacks we have. Worst case scenario I'll still have the same hiccups but with a warm and fuzzy feeling inside that I pampered the girl, replacing something that could have gone for an other 40,000kms

Either way, I'm hoping I can add to the posts of better performance on this thread. And hey, Toyota gave me 25% discount by forgetting to put in a fourth cylinder. The mob who I bought it from, out of habit sell them in a pack of 4 or individually

Anyway, Bought HKS50003-M40HL (HKS HEAT RANGE 40 / NGK 8 / DENSO 24)

Will report back
 
Just replaced mine with HSK, nicked a few grams of Nyogel 767G from the engineers and applied liberally across the mating surfaces

Funnily my used plugs look exactly the same as the ones posted above. I’m at 60k

Much better starts. Waaaay better

Performance wise. Eh… don’t notice anything different. However I no longer have that hiccup at high revs. That’s a great result. So I’m glad I did this. If it comes back after a few thousand I will be looking at coils


IMG_0655.webp
 
I have been running NGK Ruthenium LKAR8BHX which has a PSPE electrode.
These have a different electrode design verse the OEM plug. The OEM plug has a DFE electrode.
The thing is NGK recommend the PSPE electrode design for turbo charged engines.
The electrode design of the OEM, NGK recommend for NA engines.

Plug Tip.webp
OEM Vs Ruthenium.webp
 
Sekred said:
I have been running NGK Ruthenium LKAR8BHX which has a PSPE electrode.
These have a different electrode design verse the OEM plug. The OEM plug has a DFE electrode.
The thing is NGK recommend the PSPE electrode design for turbo charged engines.
The electrode design of the OEM, NGK recommend for NA engines.

View attachment 26308View attachment 26309
Click to expand...
interesting comment. wonder what has been the logic in engine design - would think they have considered what plug design works best for the engine.
The tip in those special plug looks smaller - easier to create spark but is it that durable as that larger tip? Sorry my blunt and idiotic comments - i am an engineer but not very technical (in all areas.. )
 
I have been using these plugs for around 6 months.
The engine runs really well. Really crisp throttle response. It feels like it starts better too.
With the Motec peak boost is about 23psi and drops to around 19psi at the redline. The engine will bounce off the rev limiter if I am not watching the tach.
I can't notice any drop off in power after 6500rpm. I am really happy with the Motec, its like it is a different vehicle.
I change plugs every 20,000 kms myself.
 
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I will stick to OEM plugs and when Toyota recommends for replacing them, I know it’s a rather large interval but the engine still runs great and they know how to take care of the engine better than anyone in stock form.
 
What is the stock plug heat range?

EDIT: 8 apparently
 
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