Hi All

My engine runs smoother and feels more power after installing new Bosch spark plugs. It runs so much better. Is it the gap or spark plug brand or both that makes this difference? Now, I can remove my "baby on board" sticker from the rear trunk tailgate. Thank you as always.

New Plug; Bosch Plug with .032" gap
Old Plug; NGK Plug with .030" gap

Copper plugs overtime lose material from the center electrode (cathode) and from the ground L-shaped electrode (cathode). The center electrode can shorten and even maintaining a proper gap as you have on your old NGK plugs, may not properly ignite the compressed fuel / air. Spark temperature, ignition timing at the spark plugs gap, and other conditions effect spark plug performance as they age.

Why you replace copper plugs regular. I use the cupric (copper) Bosch and NGKs, too.

Hi kittysgreyvolvo

Thank you! I will keep that in mind.

Hi,

Were the plugs you pulled old/dirty? If either I would say that is the reason your car was running bad.

Were the ones you pulled NGK copper plugs?

Both NGK and Bosch copper plugs are widely preferred in our cars. I have used both and both seem fine.

The gap spec is .028"-.032" so your old plugs would have been fine in that respect.

Travis

Hi Travis!


"Were the plugs you pulled old/dirty?" 1 year old with 30k miles. Dirty, not really... No photos :(

"Were the ones you pulled NGK copper plugs? " Yes.

My car ran very slow when I put those NGK copper plugs from day one. Now, my car has really good pick up power with Bosch plugs, it's like day and night. I don't get it???


Thank you as always.

Were they torqued to the same value as your new ones? Other than that I don't know.

Travis

Hi Travis

Old plugs were tightened by hand... New plugs are 15ft lbs with tiny amount of anti-seize cream.

I always knew my car was slower than other Volvo...

Thank you as always.

The NGK copper plugs have been reported time and time again to be excellent performers in the B230F. Is it possible something else changed concurrently with the plugs that made it seem as if the Bosch plugs showed an improvement?

Hi Sean

I changed engine oil/filter, air filter and plugs over the weekend. Now, I can merge on the highway with confidence.

As Art mentioned in the past, I took them apart and examined old air filter and old plugs. I should have numbered the plugs and taken some picture for reference...