I've been running my ProCharger for over 20K miles now, and up until recently I've always had a good build up of black soot on the exhaust tips. I understand that this means I was running a bit rich. But now I don't notice the soot build up any longer and the only thing I did was swap out my plugs. I was running Autolites and replaced them with NJK's. Would changing the spark plugs affect that at all? I don't have a air/fuel guage so I can't measure it.

Is there a way to measure air/ fuel with an SCT tuner?

 

Anyone? :-)

 

A plug change could possibly affect how completely the air/fuel mixture burns and could result in the reduction of the soot. The only real way to know is put an air/fuel gauge in the car (preferably a wide band). Do you know what the difference in heat range is on the 2 sets of plugs?

 

Thanks for responding. I'll have to check the heat range. The change is very dramatic so I'm very curious as to why.