Desired airflow COS3

[Janke]

How Do you nail down Desired airflow with with COS3 running SD semi closed loop?

[macca33]

Do a cold start RAFIG - Required AirFlow In Gear.

You will need to log these PIDS (at least):-

Absolute Throttle Position,
Engine Coolant Temperature,
Engine RPM,
Idle Airflow Correction AC Off, In gear - either in Neutral for Manual, or in D for Auto transmission,
Ignition timing advance cylinder #1.

Start your logger (open the RAFIG pre-configured table), then run the car on idle, up to operating temperature. The RAFIG will indicate the difference between your current idle airflow and what it determines the engine requires. Then, you add / subtract the log table into the tune table.

I know I've explained it poorly (sorry), but if you do a search around, you'll find a good guide.

cheers

[macca_779]

From there keep in mind on some applications it doesn't give the desired results. I did a car recently with a large cam that I did a RAFIG on but would hang at 1500rpm with zero extra airflow from follower or cracker applied in a non idle condition. To fix it I had to massage the desired air table down. I think why it does it is because at idle the cam is very inefficient but off idle it comes on a bit and that extra base air just keeps it hanging.

[Janke]

The issue I am having is the vehicle dies trying to find an idle after a either a quick gas to break condition or a reverse to drive condition. Im not sure desired airflow is what I need either. Ive added some and removed some.. really doesnt do much. Either way I thought the rafig process used short term fuel trims and long term fuel trims. I thought running semi closed loop I no longer had the short term trims?

[macca33]

Running semi-closed loop SD, you WILL have STFT, if you set EQ1.0 / Lambda1.0 / stoichiometric (for the fuel you are using) in B3647 - as setting the commanded AFR to those respective values will have the STFT's trying to get the fuelling to stoichiometric - well, that is my take on it.

Why don't you try a commanded AFR of EQ1.005, or similar, to command something that won't get the STFT occurring?

Also, what car / mods are you trying to get running - knowledge of that would assist.

It may also be throttle cracker / throttle follower, etc that require adjustment.

cheers.

[macca_779]

The issue I am having is the vehicle dies trying to find an idle after a either a quick gas to break condition or a reverse to drive condition. Im not sure desired airflow is what I need either. Ive added some and removed some.. really doesnt do much. Either way I thought the rafig process used short term fuel trims and long term fuel trims. I thought running semi closed loop I no longer had the short term trims?

RAFIG has nothing to do with fuel. STIT LTIT. short/long term idle trims. It's all air

[Janke]

stupid abbreviations! Once I nail that down what would be the next thing to look for? Throttle cracker and follower had no effect on it either. Honestly could it be fuel related? I am trying to control rather large injectors 80#ers

[Dewglass]

http://forum.efilive.com/showthread.php?4661-Idle-Tuning-Helpful-Info-Inside

Thought I saw a tutorial or sticky on big injectors too somewhere?

[Janke]

When I scale the injectors with the spreadsheet I found here It does not match the data that was sent with the injectors themselves. Anyone have data for the bosch ev14 850cc injectors?

[Dewglass]

When I scale the injectors with the spreadsheet I found here It does not match the data that was sent with the injectors themselves. Anyone have data for the bosch ev14 850cc injectors?

I would stick with the info that came with the injectors. Are the injectors new, or are they used and have been sent for flow testing?

[Janke]

I would stick with the info that came with the injectors. Are the injectors new, or are they used and have been sent for flow testing?

Turns out it was wrong. Called the company I bought them from and they corrected the issue very quickly. Does anyone have a good thread on tuning with fuel trims?

[joecar]

You may want to sanity check the injector flowrate using the spreadsheet here: Calculating-Injector-Flow-rate (http://forum.efilive.com/showthread.php?4821-Calculating-Injector-Flow-rate)

For LTFT tuning try this: A-New-Twist-on-CALC-VE-Table-Computing-the-Entire-VE-Table (http://forum.efilive.com/showthread.php?15236-A-New-Twist-on-CALC-VE-Table-Computing-the-Entire-VE-Table)

[Janke]

I was sanity checking myself and thats why it didnt make sense, the flow rates were WAY off. I didnt know who to believe, now I know the spreadsheet IS accurate. Im trying to get my ve nailed down since im running sd. When I autove I keep over shooting the target. It will go from 1.02 ben to .96 ben I cant get that sweet spot.

[5.7ute]

I was sanity checking myself and thats why it didnt make sense, the flow rates were WAY off. I didnt know who to believe, now I know the spreadsheet IS accurate. Im trying to get my ve nailed down since im running sd. When I autove I keep over shooting the target. It will go from 1.02 ben to .96 ben I cant get that sweet spot.

Are you using an EQ based BEN factor or AFR?
Using AFR can cause swings like you are seeing due to the slight difference in the stoich value reported by the wideband compared to the pcm. You may also need to tighten up your filtering a bit.

[Janke]

Im using eq ratio. What would you suggest for filter settings? Right now only filters I have are the tps and ect set to autove tut.

[5.7ute]

Im using eq ratio. What would you suggest for filter settings? Right now only filters I have are the tps and ect set to autove tut.

There are too many variables to just say "use these settings". I drive a certain way while doing Ve tuning to help my filters work. (for example I lift completely off the throttle when slowing so the tps filter removes decelleration transients) I also view the filtered log file trace to see if any extra filtering is necessary.

[VTuner]

When I scale the injectors with the spreadsheet I found here It does not match the data that was sent with the injectors themselves. Anyone have data for the bosch ev14 850cc injectors?

Which EV14 injector part number? Bosch makes hundreds of EV14s, but I only know of one rated close to 850cc (957cc at 300kpa) and the next smaller one I have listed is 617cc at 300kpa - I have extensively flow tested the 617cc EV14s and they will make close to 873cc at 800 Kpa.