Well, given the number of mods I have so far, I have started reading and learning about engine management, ECU reflashes, etc. But it is a lot to learn on the side and would like some advice.

Given the mods I have (pop charger, SSV IM, headers, HF cats, pipes...) the first thing I was considering is to monitor A/F. If I understand correctly what I need is a Wideband O2 sensor (2003 car here) and a gauge to install in the car. This will let me monitor, not change.

Is this a good place to start? Or should I be considering some more complex EMS system? I am thinking of getting a reflash, but feel kind of "blind" if I can't monitor before and after the effects of the reflash...

Lets start there I guess.

 

Its really overkill to monitor an n/a engine with a wideband all the time. If you can afford it/want to do it, go for it, but not necessary n/a after tuning.

First thing you want to do is go to a dyno with a wideband O2 sensor. This will give you your cars a/f ratio throughout the rpm band. Then what you need to do is analyze it. You ideally want to be 13:1-13.5:1 n/a. If your over 14:1 that is kinda lean, over 15:1 is very lean. If your 12:1-12.5:1 that is a little rich, but wont damage your motor. 12.5:1-13:1 is also a very decent a/f. Ask 100 people what is the perfect a/f ratio and you will likely get 100 different answers, but for n/a high 12's to mid 13's are where you want to be. You may not even need an ecu reflash to correct the air/fuel ratio, but more than likely you will.

If you do need a reflash you have 2 choices. You can send it to Technosquare, or go to or send it to Altered Atmosphere in Maryland for tuning. At this point you can also raise your rev limit if you want and remove the speed limiter. Once your ecu is flashed I would wait a week, and redyno the car at the same dyno you went to for your baseline dyno with mods.

I was very lean as lean as 15.3:1 a/f. I sent my dyno sheet with a/f and my mods list to Technosquare and I redyno'd 1 week later. I now have a perfect 13:1 a/f and I gained 9whp and 12 ft lbs of TQ. Good luck....

 

For reflashes you want to watch A/F, timing, and the resultant power curves. Its alot easier to lose power with tuning then it is to gain it. A/F is a good gauge to have but if you are not doing some crazy stuff just use the one at the dyno shop.

 

I did go to a dyno and, as expected, am running very lean. 13+ all the way, lots of the time at 14+ reaching 15... But, I had just installed some mods and reset the ECU, so I am not sure about the dyno. I was going to wait a couple of weeks and go back to make sure this is what I have so far.

I am also almost ready to take the plunge into FI. And if I do, I know EMS and some gauges will come with it. So think of this as the begining. Long term investing into the wideband might be a good thing anyway, specialy if I end up FI.

Alberto, that sounds like a good plan for now. Get the new dyno and go reflash with the data I get. Thanks.

 

Agree that a wideband is a must to monitor your A/F no matter you are N/A or F/I.

Apexi SAFC-II works nice with a N/A car. My car was pinging bad with my N/A mods. After a couple of dyno runs and tweaking the SAFC, its runs 13 flat to redline.

If you are planning on going F/I later, just get the emanage for now. It works with N/A and have the ability to keep up with a F/I application.

 

My A/F ratio shows that im at 14 to 4500rpm. so im running lean up to 4500rpm. is this still safe to drive around?? or do i need reflash my ECU ??
please see my thread and my Af ratio dyno graph. thanks

https://my350z.com/forum/showthread....highlight=dyno

 

A good ratio should be ~14.5 at "idle" and as you give gas it should go below 14. At WOT ~ low to mid 13s.

 

+1

and I got an ECU reflash at AAM and couldn't be happier. Put a/f back to a safe place.

 

I am also considering an ECU reflash in a little while for my NA setup. I think Ill wait till I have all the parts purchased then have them all installed and tuned the same day. I am planning on installing long headers (selling my stillen TPs), Cams, upgraded valvetrain, Throttle Body, and Intake Manifold (350EVO), and all the necesary fuel items.

 

I just noticed you are in miami. What do you think is a reputable shop down here? I only know of a handful.

 

I would get a GReddy Ultimate eManage, great product and you can use it when you go F/I. I'd also get the Technosquare L-Spec Reflash (raise rev limiter, throttle plate opens 100% at WOT and remove speed limiter).

 

Reav, no clue on reputable shops. I have never done tuning yet so I can't speak of first hand knowledge. I think one of the shops that comes up the most is Dynamic Turbo in Doral. But I can't testify to their experience with 350Zs. Also Japtrix up in Ft. Worth is gearing up to do tuning and maybe local reflash, but they aren't ready yet and it could be a while.