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Good day everyone!
I’ve owned my 8 for nearly 2 1/2 years now, and have loved every second of it! I just recently changed my oil and thought to check my rear rotor spark plugs while I was at it, and was hoping for some insight as to why they (in my opinion) are excessively blackened. I have 77,800 miles now, and changed them 2 years ago at 63,000 miles along with new BHR global compliant coils and wires. In my opinion they are dirtier than they should be at this point, but was hoping for some insight!
Not really, i don’t drive it that often but when i do its usually highway driving or spirited driving. I was mostly concerned with just how much crud is on the plugs.
Looks like not a lot of heat getting into those plugs, and a very rich mixture when there is some work happening.
Take a drive on the highway in closed loop for 75-100 miles. I am not familiar with the S2 factory tune, but I know on the S1, the real limit to closed loop on the highway is about 3750 rpm. After that it gets rich quickly, and won't help your plug situation.
A lot of guys here run big throttle and redline all day, expecting it to help the engine, but in my view, the best cleaning of both plugs and chamber happens on the highway in closed loop.
Put in in cruise at 73-74 mph for a while and you will actually feel improved response, power, idle, etc. Assuming everything else is in order.
Last edited by kevink0000; Dec 28, 2023 at 03:21 PM.
Same coils and plugs as you after a decent drive. I usually do at least 15 minutes of cruising after a bit of fun. S1 running about 150ml 2T oil per tank of fuel. I was thinking it was running a bit lean.
Did not know it was likely the low RPM was what did the cleaning if the plugs on the way home!
Thank you for this advice, I had forgotten about the closed/open loop system, and usually when I am on the highway I go above 4,000, so next time I am on the highway I will give it a try going a tad slower for a significant distance.
