Big Jim
Hard-core CEG'er
There have been numerous posts in the past about Bosch +4 plugs having premature wear on the rear bank of our engines. You can accept the testimony of fellow CEGers or not, it all depends on if you want to learn from others or not.
The issue seems to be that the +4 concept doesn't work well on the reverse polarity of waste fire ignitions. They may work well enough on the normal polarity cylinders, but certainly not better than.
Personally, I don't much care for Bosch as a company. They come across as arrogant. They act like they never make a mistake. They are impossible to deal with over warranty issues. Their "conventional" platinum plug with the ceramic portion of the tip protruding nearly to the tip of the center wire doesn't work well on a lot of engines, serving as a collection point for deposits that lead to plug fouling/shorting.
That being said, I won't let that cloud my mind over the +4 issues. I know it doesn't work on waste fire ignition systems because of what I have found when I have removed them after about 15,000 to 20,000 miles.
The issue seems to be that the +4 concept doesn't work well on the reverse polarity of waste fire ignitions. They may work well enough on the normal polarity cylinders, but certainly not better than.
Personally, I don't much care for Bosch as a company. They come across as arrogant. They act like they never make a mistake. They are impossible to deal with over warranty issues. Their "conventional" platinum plug with the ceramic portion of the tip protruding nearly to the tip of the center wire doesn't work well on a lot of engines, serving as a collection point for deposits that lead to plug fouling/shorting.
That being said, I won't let that cloud my mind over the +4 issues. I know it doesn't work on waste fire ignition systems because of what I have found when I have removed them after about 15,000 to 20,000 miles.