Semi-Surface Discharge Plug Champion QA55V spark plugs

For a while now I have been using traditional NGK DR7EA plugs. These are great and cheap plugs, but other types of plugs are available as well. Below are some pictures from NGK manual and recommended applications:

 

 

Just for fun, I thought to try out these Semi-surface discharge plugs. These plugs are typically used in high rpm applications and were used in race M3 engines.

Spark plug is Champion QA55V, mainly used in Ducati bikes.Heat range 11, so this is a very cold plug.

Common statement is that these spark plugs are prone to foul and therefore were used after the engine was warmed up with other plugs. Since my car is equipped with Autronic SM4, I can tune the warmup mixture as I like. So, I thought to give it a try. I have been using the plugs for 5 months now and haven’t seen any issues at all, no single fouling incident and engine runs much better.

Verdict: Highly recommended.

 

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