Platinum/Iridium spark plugs

I just picked up 8 NGK Laser Iridium plugs, for a 4 cylinder Civic Hybrid (2 per cylinder). They were $17 something per. If they cost 4 times as much and last 4 times as long as a conventional plug, it's a wash financially.

But then you need to consider the labour involved in changing the plugs. 3rd gen Prius is a great example of insane amounts of disassembly required, just to get to the plugs. Just Google Nutsaboutbolt's 1/2 hour plus video on the subject: it requires dozens of bolts being removed, not to mention the wipers and motors. The Civic is better, but not by much: lower windshield trim and a metal cowl behind it need removal.

Then, the Iridium plugs will hold their shape/clearance, pretty much for the life of the plug. OTOH, the conventional plug will gradually get a rounded center post and increased gap, decreasing performance.

 

The correct iridium plugs can be purchased on special for about $7.50. If you use any other ngk copper plug, I would guess the price is around $4.00? I don't see why you would want to mess with it to save only $15.00.

With all the unknowns of whether you'll waste more fuel, car not running properly, etc....not sure it's worth wasting your brain cells to think this through to save $15.00 bucks. Also the potential damage if you happen to strip a thread installing these things multiple times.

 

Why ?

The factors involved with plugs are much different than the discussions about oil and transmission fluid. It is more like tires and brake pads. Do you change them when they are only 1/4 worn out ??
No different with plugs. No reason to throw away 3/4 of their useful life.

AND ......each time you change them, there is a small chance that something will get screwed up
in the process.

And after reading your last post:
Your "cheapy" plugs will have to be changed much more often than they would in an old conventional engine because the ignitions today are higher energy and will erode the soft electrodes more quickly. That is the main reason for the more expensive plugs; longevity is just
a nice side effect.
The part about copper conducting better is a non-factor, even if it is true.

 

Now that the plugs are already installed, you should just leave them. Forget about the antiseize, you won't have them in there long enough. Drive for a while and see if you can get a good 1000 miles in and see your mpg average with the copper plugs.

I don't think I have heard other members do this, but hey, you can be our first test subject. Let us know the results after 1000 miles........

 

If you ever need to get parts for your car, you can get them online at Toyota dealers fairly cheap. I get all my stuff from camelback Toyota in AZ. Their prices are quite a bit lower than MSRP and if you purchase $150, you get free shipping (tax free if you are not in AZ). They sell everything including floor mats (oem for about $75), WS transaxle fluid for under $7.00, I believe the iridium plugs there are about $7.50.....overall great deals.

 

This is what is important about iridium: Voltage Requirements: DENSO Iridium



The last time I had to buy Iridium plugs they were cheapest on eBay.

 

If your time is worth anything to you then I can't see the point of trying to save money by using non iridium plugs and replacing them more frequently.

The overall cost wont be any lower and most people here have found their OEM plugs to still be in good condition at 120,000 miles and even more. I recently changed mine for the first time at 200,000 km and they were still very good.

I paid about $50 for a set of four of denso iridiums here in Australia. If you can get them in the US for $30 all the better, but seriously, whether it's $30 or $50 is not a big deal when you're only doing it every 200,000 km.

It felt weird actually, changing the spark plugs and realizing it's probably the one and only time I'll need to perform that service, even if I keep the car to 400,000 km.

 

Since we are on the topic, what is the recommended Iridium spark plug (brand & part #) for the Gen2?

It appears that Rockauto has Iridium plugs ranging from $4.50 to $7 each. Im just not sure which one is recommended so that I can buy them.

 

There is usually a sticker under the hood that says the model number or in the manual.

 

The OEM plugs were with either Denso or NGK. Most people in the US report Denso as the oem part, but in other regions people report having NGK. They're both probably equivalent.

The part numbers are:

Denso: SK16R11
NGK: IFR 5A11

 

Thanks. Im off to spend some (more) money on the Prius, which will certainly please the better half...lol.

 

It isn't.
I don't think that ANY new car in the past 5 years or so came with "standard" copper core plugs; most models for farther back than that.
A hotter spark helps ensure a fuller burn fewer misfires.
The trade-off is that a hotter spark erodes soft metals quicker.

If you really care, look up "spark eroder".
It's kind of an arc cutter instead of arc welder.

 

I was looking up some information on the Autozone website on the plugs, they have cross referenced a different NGK plug to work with the Gen2 prius. Not sure the difference from the original parts but it's Part BKR5EIX-11 and it's only $6.99

 

I've used Denso Iridium spark plugs on my former '95 Maxima V6 and my wife's former '96 Corolla. In both cases more power was immediately evident and better gas mileage on long road trips was up by 3.2 mpg and 2 mpg respectively. (70 mph average and cruise control whenever possible)

Denso's Iridium plugs give a bigger spark and are now OEM on most Toyota's.

Iridium is so tough that laser welding is necessary.

 

Our previous Civic Hybrid had 2 plugs per cylinder. With each cylinder: one was NGK, one was Nippon Denso. The spec in Owner's Manual called for either one.

 

I changed out the OEM NGK IFR5A11 @110,000mi for CHAMPION 9202 Iridium I had to special order them.
No change in MPG.
The original NGKs looked like they could go another 100,000mi

 

When I got my 2004 Gen II in June 2014 I changed my plugs to Bosch Iridium plugs. They work well, and I have gotten good mileage. 50 MPG +
I may put the Denso's back in for a comparison since the wear was minor on the gap. The price at O'Reilly's was about $7.00 each. I like to keep my purchases local if possible.

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