Just changed my NGK coppers after 20K miles. They were very grey...kinda white, no brown at all. Running lean up top maybe? I was comparing them to the pics in the back of my Haynes and I am a bit worried. I have never been to the dyno so I don't know my exact AF ratio.

Mods:

JWT ECU w/ 7200 rev cut
MEVI
Pathfinder TB
Y-pipe
Intake

 

Sounds lean.

You might try checking your fuel pressure, since your fuel filter could be clogging or fuel pump could be dying/not able to keep the volume you need.

Or maybe JWT gave you a 370cc program? Or you have a post MAF air leak? Just guesses if the fuel pressure checks out.

 

Any signs of"pepper" flakes?

 

mine looked "frosted". The concensus around the local members is detonation or running lean. I'm guessing in my case it was cause the original owner ran regular gasoline

 

I could very well have a small leak after the MAF. I never liked the gasket I made for the PF TB and I don't trust how the couplers are attached to my "bent" style mid-pipe.

Car runs great. No sound of detonation that I can hear or hesistation that I notice.

Talked to my brother who has a sr20det s13 and he said not to be worried, though the color sounded OK. He has his car tuned real well and said that is what his plugs look like.

I wonder what Stephen posted??

 

Well, if you must know.

I posted a doofus remark about maybe you need to use a colder plug. Then I realized that the heat range has nothing to do with whether the engine is running lean, so I deleted before anybody could call me on the carpet about that.

If you are running lean at high rpm, Cartech makes a nifty fmu specifically for NA engines that allows you to increase fuel pressure at more than a 1:1 ratio as you approach zero manifold vacuum.

 

Well, I will be getting to the dyno soon and wanted to do my pulls with a wide band o2. Then I did some reading and found that most wide band o2's that dyno shops use are not accurate. They say that they have to be recalibrated every so often, which most dyno owners don't do and that the load on the car at a dyno is different from the street so an AF ratio on the dyon is different than on the street. So how do I get an accurate reading without my own EGT gauge?

 

Here's what I use:

http://www.innovatemotorsports.com/lm1.php

 

Stephen, have you ever dyno'd with a wide band and gotten vastly different results than your own wide band?

 

I dynoed last October with a wideband sensor up the tailpipe. It showed I was getting about 12.5:1. When I got the LM-1 last January it said pretty much the same thing, with the sensor mounted in the test pipe bung. I go to a reputable shop and they're pretty conscientious about staying calibrated.