Wide band readings and air fuel mixture

**cortexx** · 08-17-2011, 10:35 PM

So i was out last night and was logging air fuel mixtures with my newly plumbed innovate gear and a laptop .

My car came with a Essential NERVE ecu tuned in Japan and i wanted to see how close to the bone it was tuned.

I notice that Air fuel ratios average around 14.5 - 15 while pottering around town - around 13-13.5 when under fire and boost starts building finally down to 11 - 11.5 when the hammer is down in 3rd and we are over 5000 rpm under full load .

running a timid .8 bar.

If i look in the reytec instructions on the tomei website their ECU fuel map targets around 10 - 10.5 under full load .

Whats yours look like ?

BTW i'm done doing this in the so called deserted country lanes in my neighborhood last night , i iniated a pull to redline in 3rd without noticing the cruiser behind me and got pulled over by a very irritated cop 5k down the road after i left him standing unintentionally in a dust cloud - long story - might go into it one day - bad judgement on my behalf though ! ended up with a ticket for no front number plate which i was eternally grateful for considering.

**kengeroo** · 08-17-2011, 11:13 PM

are you able to post a map of your AFRs ?

**cortexx** · 08-17-2011, 11:24 PM

I didnt bother saving them , i had graphs that were made with the innovate software with WB afr plotted against rpm , not as good as an actual full trace map but I'll download their other sofware that can create trace map.

**nelsonmxmarc** · 08-18-2011, 12:02 AM

Well in either case, that doesn't sound bad at all..

AFR numbers will vary. Tomei's unit for reading AFR's could have been reading a point high or low; it's very deceptive. My AEM reads high compared to the innovate, and under hard load (9000 rpm) it blows 14.5 because of the amount of air being registered, even though the innovate still sees a clean 11.5-12. Also, the numbers on the site could be real values, vs. values processed on a dyno..

What psi are they plotting these numbers with?

**Skym** · 08-18-2011, 01:21 AM

Sounds normal for a retuned factory engine on pump gas. I wouldn't raise the boost level from 0.8 bar due to it's running a good safe A/F ratio. Some tuners = 11.6:1-12.0:1 under boost, but leaves no room for error (leaking exhaust, intake manifolds, wideband, etc).

Sounds like the AEM needs to be recalibrated (A/F ratio to Lamda settings).

10.0:1-10.5:1 sounds like the rich factory A/F ratio at peak power at higher rpm.

**bobbo** · 08-18-2011, 07:43 AM

At cruise I'm at about 14.5-14.7, squeezing into it goes to about 12.5 and wot is 10.8-11.2.

**cortexx** · 08-18-2011, 10:48 PM

mines a bit on the lean side , actually this kind of makes sence , essential tuned my ecu for 500cc injectors , full exhaust , no cat , 1.2 bar .

I got the car with 440 cc injectors , probably lean because of this , ill install my hks fuel rail , 680cc injectors and fpr and see what it reads on that , ill probably end up installing the pfc at that point because i dont think the essential ecu will account for injectors that large and i can't really retune it anyway .

**GTR-Dad** · 08-18-2011, 11:23 PM

The values you describe are very similar to what I'm running at 17-18 psi - 1.2? bar.
The reason you want to run richer at higher loads is to manage cylinder temps to avoid autoignition and detonation. Fitting an EGT probe to the upstream side of the turbo (you lose waaay to much heat, inconsistently as it varies with backpressure, across the turbo to make any meaninful inference) will let you know if you're running enough fuel. It's a more direct measurement of what you care about. 900C is a reasonable max with 950 as an absolute ceiling.
Dan