I put the new NGK iridium plugs into my 93 Corolla yesterday, replacing the plain old $2.50 NGK's that were in there before, and there appears to be a noticeable difference in smoothness and power, in the way the engine runs now.
I'm not sure if it will make any significant MPG difference but it seems nice.
Really good plugs, should last the life of the motor.
"Sarah Houston" ..
Cool. What did the plugs look like when you took the old ones out? Tomes
Is it mostly because the plugs are iridium, or is it mostly because they're new? ;)
In what respect?
They just looked like regular plugs that had been used for about 15 months.
"Sarah Houston" ...
Well, I was wondering if you are seeing improved performance because the old plugs were bad in some way. If they looked like regular plugs (like the new ones and not burnt or oily or some different color), then perhaps the iridium might make a difference (although I did not think it was supposed to on its own). This is what I was getting at. I actually thought that my Sienna felt 'better' when I put them in at the time, but I wonder if it was a self-fulfilling prophesy, where since I was hoping it would happen I perceived it to happen.
As a scientist, I know that one of the pitfalls of analysis is to decide what you will find before one actually looks. Think, then see, then decide, but always see first before deciding. Many scientists that I have dealt with and read about have fit the data to their notions instead of the proper way around. I wondered if I had done that. Your observation that the replacement of the plugs seems to have invoked a noticeable difference in smoothness and power without having 'visibly bad' plugs in there before supports what I believed was my observation too. Hmmm. It is only 2 data points, but it is 2 in that direction. Tomes
Yes, they looked the same as all the regular plugs I've used and changed myself over the years.
No, because I have been having problems, even with the old plugs when I put them in new, with running the inverter for the air cleaner in the back seat. It was drawing enough current with the lights at night, to make the engine run a little rough at idle.
When I put the Iridiums in, that improved noticeably.
Yes, I understand, and agree.
But they even make the claim on the NGK box:
The benefits of NGK IRIDIUM spark plugs :
I looked at the size and surface area of the electrodes of the old $2 plugs, compared to the Iridiums. It appears that the Iridiums present an electrode point surface area that may only be 1/5 of that of the regular plugs. They can do that because they can take the heat better?
They look very much different than regular old plugs on the tip of the electrode.
It must give a really hot intense spark.
"Sarah Houston" ...
What prompted my changeout was I had a misfire code so I changed the plugs and the wires. Been running fine since.
What puzzles me now is what all this has to do with electrical power that you are using. When they boast increased power they are not talking about electrical power, they are talking about moving the car power. Maybe if the engine was stumbling and bumbling enough that the electrical generation mechanism was not spinning fast enough or smoothly enough that might translate into less than optimal electrical power availability, but I am having trouble reconciling this in my little mind. I suppose what we are concluding here is that now with more power from the engine due to these super plugs it is overcoming the additional drag to the electrical system from the inverter/lights. I am glad that this fixed the inverter problem, I am just a bit surprised at this cause and effect. Tomes
If you had a flaky spark from the traditional plugs, I suppose it could help.
I can't tell precisely or anything, but from this first tank of gas, it looks like the Iridium plugs have increased my gas mileage by 2-3 MPG.
I'll take it. :)
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