Sure.... don't get me wrong people were doing this for a while on CT9A, however doing it with some sort of targeting is definitely ideal.

Don't let that get the zeitronix out of your mind... that will probably keep you in the safe area and allow for the savings you are hoping for.

 

OK, as I understand it:

Zeitronix will make lambda think to be 1 at preset AFR (let´s say 16). This will result in ECU shortening IPW in whole closed loop which will cause LTFT going to negative by 9% (AFR 16 over standard AFR 14,7).

This will lean out open loop driving.

So that I will have to make fuel tables richer by this amount in open loop?

 

Sorry, that last bit was confusing.

Zeitronix will allow a narrowband simulation to be set at whatever AFR you choose. When you set it at 16AFR it will shift the parabolic curve that mirrors the look of a narrowband to 16FR so that below 16AFR will send 1 volt (the circuit can handle 5v) and above it the controller will send 0v. Your ECU will then target 16AFR "thinking" that it is 14.7. This will probably cause your fuel trims to go negative which you can allow to work (but they may max out) or alter your injector / MAF scaling.

Unfortunate side effects are:
-you may have to re-tune your higher load areas
-maf scaling may not be exactly smooth, and you are kind of cheating the system
-idle might be rougher at lean AFR, and its not configurable for an operating range, its a full-time setting (you can run idle in open loop if you'd like, but that goes back to the first problem)

Alternatively (I haven't heard of anyone trying this yet since its a new map to the CZ4A) there is a fuel compensation map that is sometimes called "Unkown Fuel Related Map". This effects the fuel pulse and is how mitsu leans out cars in their updated roms. Tuning the closed loop section of this table with a reduction relative to your simulated narrowband AFR adjustment might just get perfect results without requiring a retune of high load or adjustment to the MAF tables. This table has the same dimensions and axes as the normal fuel maps.

 

I am sorry for last confusion, but I ment the same as you in your last post - that the negative LTFT will require retune in open loop.

Thank you for all the explanation!

 

On the X .. you can shift the closed loop O2 target from 14.7 to anything else .. don't have to get the Zeitronix

what it does is it changes the reference O2 voltage from 0.5v to whatever you want .. so shifting it to 0.4 makes it run leaner in close loop and making it the target trim .. or shifting it to 0.6 to make it run richer (very good for aggressive cammed cars)

 

Care to share the table(s) for this? Is it avail for idle and cruise. As ideally you would want to set cruise loads leaner and idle loads normal Stoich

 

The dash MPG gauge is 100% skewed incorrect when you are on larger then stock injectors and also with different fuel.

Here is a laugh I get sometimes in mine. This is on 1000cc injectors and E85 at hwy cruise:



Actual MPG with math (miles + gallons used) was 21 mpg.

I have a feeling the dash MPG display is off the stock injector scalar but I could be wrong.

 

^Bryan, maybe thats something the ECU pros like you and Tephra can look into. the scaling that is. Woul be cool to adjust depending on injectors etc

 

Sure .. let me get the UDSM model .. for now I only have JDM

 

The scaling is off the IPW versus speed .. so its not off .. update rate is abit slow though ..

If you want better accuracy .. go to settings and select manual .. that will calculate the distance from the Odo versus the fuel burned

I have only 1 complaint .. this manual selection goes off everytime you restart the car ..

 

It's off on mine for sure. I frequently show a reported 25-27mpg on the dash over a constant 150-200 mile hwy stretch when the actual math shows me 17-19mpg.

Yea I have the same complaint with Manual....

 

Aftert swapping in 1500cc injectors my MPG estimator now shows 35-36 MPG where as before it showed 30-31 MPG on the highway. Actual is high 20's in the same situations so the injectors definitely skew the results, not quite double and triple, but they skew them for sure.

 

There is one more piece--the catalytic converter. Its spec'd to run no leaner then 14.7, running leaner then this will fry the cat from what I understand. Not that this is an immediate problem or you can't run lean for a time but its going to cause the cat to become inefficient and at worst melt.. your option is to use something else ( test pipe etc.)

 

Can you post these tables? The JDM ones are perfectly fine. I'll figure the rest out.

 

I am not sure the reference voltage Gunzo is talking about is ONLY used by the front 02, i think its shared.

but none-less I am not sure if modifying that will help anyways, the sensor will still target stoich, but this sort of stuff really is a brain **** for me so I could be wrong!