Ok for those of you who might or might not know, I have posted before that my car was running extremely lean on 2 dyno pulls that I did, so I went out and purchased a wideband o2 sensor for my car and I have to say it, the dynos were right and wrong.

My car is running extremely lean with headers,intake,greddy rear section exhaust, helix test pipes, at 6k RPM my car is at 13.5:1 compared to a stock 11.8:1 and at 3k RPMS my car cruises at 14.6:1 compared to a 14:1 stock.

The 2 dynos that I tried said that at 6k I was at 14.5:1 & 14:1 so don't trust dynos. But they were still right I am running lean.

Now I am off to phase 2 which is either an AFC or Technosquare.

By the way do you guys think that by putting back my stock air box I would make the car run a little more rich ?

Caribbean Blue 2004 G35c w/Navi
19x8.5 Racing Hart CR's 245/35/19 on Toyo T1-S
19x10 Racing Hart CR's 275/35/19 on Toyo T1-S
TEIN Basic coilovers
Nismo Intake
DC Sport Headers
Greddy Exhaust

 

You might run very slightly richer with the stock airbox, but that is only if the required air is right at the limits of what the stock airbox can supply. I'd say that you have a very free-flowing exhuast setup, and that has much more influence than the intake on A/F.
Seems like you need an ECU mod from Techno or similar, because your mods are probably beyond what the stock ECU can adapt to.

'04 6MT coupe