Spark Plug Question
 

Have any of you changed the plugs yet? What did you use -- Denso? NGK? Other?

I am ready to do mine and want to go with NGK's and thought I'd see who has any experience.

Thanks and have a great day.

NGK DILKAR8A8 is your best bet for a boosted car. Those are the OEM GT-R plug and we have had great success switching to those in our boosted z's. A much more appropriate gap right out of the box.

For a N/A car just stick with the OEM plugs which should be a NGK DILKAR7B11 or Denso FXE24HR-11. The Denso 24 is more like an NGK 8 when it comes to heat range. The hotter plug might make more power on your N/A car but it will put you closer to detonation.

NGK is the way the go for boosted cars using the GT-R plug. If I was going to keep it N/A I would just rock the true OEM Denso FXE24HR-11.

Thanks,
Alex Goodwin
AlexG@motionlabtuning.com

Thank you. :tiphat:

What's the replacement interval for spark plugs under normal driving? I'm at about 40k miles.

The OEM service interval for both "normal" and "severe" driving conditions is 105,000mi. I couldnt IMAGINE running on a single set of plugs that long. When the car is N/A I would recommend pulling and checking the gaps every 30,000-45,000 miles and replacing as necessary. For a boosted car I would plan to REPLACE every 30,000 - 45,000. This will keep you running at peak performance and prevent misfires and detonation from worn plug gaps.

Just my .02

Thanks,
Alex Goodwin
AlexG@motionlabtuning.com

My previous nissan with RB25DET engine has 200,000km on it with original spark plugs and no misfire or detonation. Still running fine.

Wow, thats crazy. I would be interested what those plugs would look like! Have you ever even checked them?

Thanks,
Alex Goodwin
AlexG@motionlabtuning.com

Not sure what type, I think NGK Iridium long life. Its a stock 93 R33 skyline. I have never checked them also. Some lucky person will buy it soon. Hoping the 370z is built just as good.

After having a nice weekend drive roughly 5 cylinders greeted me on a cold start this morning. The car was idling rough, and the fuel smell was very strong. I shut off the engine and started it again with no improvements. It didn't struggle to start, though.

I'm thinking it's the spark plug(s). Would anyone agree?

My '03 Sport Trac has 140K kms or 85K miles with the original plugs. Doesn't miss a beat!

If it's running that poorly it should be throwing a DTC. Use an OBD scanner to find out what the car thinks is wrong.

I didn't see it throw a code, but I've only had it idling for a few minutes early this morning. Probably not enough to trip it just yet.