Mike H.

My question is, who has used the bosch +4 spark plugs and what were the results? I need to replace my plugs soon and was wondering if I should get them. TIA
Jim Eagan
83 533i 424,000 miles

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I've run lots of differnt plugs over the years, and the only ones I didn't like were Champions, but that might have been more a function of the particular car than the plugs.

In a well running car with no specific problems (oil burning, etc.), I don't think one plug would make a meaningful performance difference over another. I recently replaced some worn Bosch silver plugs in my B9 Alpina with some 99cent Autolite plugs (59cents after rebate)and the engine has performed flawlessly ever since.

The company that makes "Slpit Fire" plugs is involved in a large fraud suit by the govenment over such claims as we speak.

That said, recip aircraft plugs DO have multiple electrodes (3 or 4), albeit in a slightly different configuration, though there are significant differences in engine design as well.

Whether installing $42 worth of plugs in an engine makes a noticible difference over $3.54 in Autolites I'll leave to someone with a dyno! I know if I were a spark plug manufacturer, I'd rather sell the $42 set!!

Bob