Has anyone else used them? I've always suspected that these multiple electrode plugs were smoke and mirrors but it was time to change plugs in the Mazda and the Bosch P2s were no more expensive than any other platinum plug (which I have to have due to the waste-spark ignition) so I thought I'd give them a try. My initial impression is that they have added about 200-250 useful RPM to the lower end of the RPM range. The engine can now cruise without lugging at 1750 when before the floor was 2000. This enables me to use 4th gear as low as 30 MPH. Now this could simply be that any new plug is better than the old plugs or it could be that the P2s actually make a difference. I need to run through a couple of tankfuls of fuel to see if there is an increase in mileage.
Bosch Platinum 2 Plugs
- Thread starter StrangeRanger
- Start date
Emerald 74 4X4
Well-known member
I have always heard of problems with Bosch plugs in general. I used to try and use them in my 2 stroke dirt bikes, but they never lasted like an NGK. I have also seen them in a couple automotive applications where the Bosch plugs just do not last as long or are much less reliable, like doing a tune-up on a set of Bosches that looked good with few miles. I stay away from them just because i don't want to spend money on something that I take a chance of failing prematurely. Maybe they dont like the cold? 
EVERY car I've had that either had platinum plugs in it when I bought it, or I had put them in it, ALL had lost the platinum rod or disc that they "weld" to the electrodes. Where did they go? Right into the combustion chamber! I say ALL but I mean "set". When i bought my lumina, it had bosch platinums in it, I was chasing a check engine light and the code said emissions were higher than they should be. Plulled the plugs and 3 of the 6 had the center electrode(platinum wire rod) missing! The gap was like 1/4" then. My dad's ranger had Autolite platinums in it, 4 of the 6 were missing the platinum disc on the ground electrode!
The benefit you are getting is from the exposed arc. There isn't an electrode hiding the arc, and the flame can spread better. Also, the extra electrode give's the spark a "choice", since it travels the path of least resistance, one electrode might have less than the other. It won't go to both at once...
I like E3 plugs. I use them in my mowers and chainsaw, and just put two in my Harley. Noticable difference.
You could also side gap the plugs, or use marine plugs to expose the arc.
The benefit you are getting is from the exposed arc. There isn't an electrode hiding the arc, and the flame can spread better. Also, the extra electrode give's the spark a "choice", since it travels the path of least resistance, one electrode might have less than the other. It won't go to both at once...
I like E3 plugs. I use them in my mowers and chainsaw, and just put two in my Harley. Noticable difference.
You could also side gap the plugs, or use marine plugs to expose the arc.
Mileage has not improved, if anything, I lost about 1 MPG
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