IDC trigger point datalog

[dlheman]

I have Aquamist HFS3v3 installed for my WRX STi 2011, and I've been learning about the HFS3v3 for fine tuning purpose. What I want to know is when exactly did the HFS3v3 begin to inject, and thankfully the green harness has a yellow wire which outputs 0.5v to 4.5v for datalog purpose.

Both Jeff from Howerton Engineering and Richard have been very helpful, and what I understand is the first 0.5v is 'standby', and each 0.5v after represents 1 bar of the gauge flow bar.

So I connect the green harness' yellow wire into my external sensor interface, and enter the following as number conversion:

0.5v = 0%
4.5v = 100%

I keep in mind that my gauge only displays 6 out of 8 bar as I set it that way, which we'll get to that later. For now I just want to know when did the system injects.

I set the treshold trimmer to 1 notch after 9 o'clock which should be around 30%, as any lower I cannot set the failsafe as it always trip. But at this setting I always find the meth flows literally instantly the moment I hammer the throttle - anytime.

So here is the graph:

[dlheman]

Then I just do a dummy analyzing and it looks like the injection starts as low as 13% to 14% of injector duty cycle.



If 0.5v is zero (standby), and every 0.5v increments afterwards represents 1 bar from the gauge, and there are 8 gauge, that means every increases on 0.5v represents 12.5% of WMI flow.

0.5v = 0
1.0v = 12.5% = 1 bar
1.5v = 25.0% = 2 bar
2.0v = 37.5% = 3 bar
2.5v = 50.0% = 4 bar
3.0v = 62.5% = 5 bar
3.5v = 75.0% = 6 bar
4.0v = 87.5% = 7 bar
4.5v = 100.0% = full 8 bar


On the second row of the table title Aquamist flow bar % the number registered is 12.89% which if my calculation is correct means 1 bar, and the corresponded fuel injector duty cycle is 16.98%.

Now the reason of this exercise is I just want to know exactly when to inject, and i find it really interesting it actually injects sooner than I thought (I don't mind it at all to be honest).

But this is just a test and I don't claim this to be accurate, because as shown on the Aquamist flow graph, it flatten itself at around 65% while the fuel injector keeps rising. I think this is because my conversion is for full 8 bars lid up, while I set my gauge to max at 6 bars. So it just some scaling Issue I need to sort out I think.

Perhaps Jeff and/or Richard can chime in as to what voltage to number conversion I should use to properly image the flow of the WMI flow.

[dlheman]

And now this is the data in volt reading.

I simply enter the conversion as below:
0v = 0v
5v = 5v

Again, the first 0.5v is standby so no wmi at that point, and every 0.5v increment afterwards represents 1 bar.

I have dialed in 6 bar maximum on my gauge display, so I want to see 3.5v maximum:



Bingo, the voltage went 3v+.

And I see 1.96 voltage at 19.42% IDC, so that should equal up to 3 bars.

What this then tells me I am injecting very early. Well, earlier than I thought. If all I think is correct, I am injecting below at somewhere below 20% F-IDC, with my TRSH dialed at 1 notch after 9 o'clock.

I do feel I am a bit too ahead of myself and obviously this is just my dummy analysis to quickly see where my WMI is currently is triggered.

[Richard L]

It appeared the upper flow signal has been clipped due to the overflow of the flow table.

I suggest going back to the second flow table and redo the tests. It may not have the good resolution at the low end but it will avoid the clipping. It will not affect you low DC trigger.

It is unfortunate your flow is some where before the two tables.

[dlheman]

You mean de solder the link between 1+2?

Sure, I can do that.

[Richard L]

yes. And recalibrate the SC

Can you log frequency? The white wire has raw signal direct from the sensor. No table is required.

[dlheman]

Yes mate I can connect the white wire into my external sensor interface. Let me hook it up and do a run.

[dlheman]

oops I forgot to change the injector duty cycle to display %.

But anyhow, the max is still 3.2v max, and so this voltage signal is just telling me I cap it at maximum 6 bars. I did tried it at full all out 8 bars and it shoot up to 5v. So it doesn't represent the flow of the wmi, but just the flow bars signal of 0.5v per bar.

Gauge bars displaying 6 bars maximum, flow table 2, 2nd gear pull:


But I supposed what I really want to know is when did the voltage starts to move beyond 0.5v - as this gives me a good idea of when it really starts to inject some jungle juice. And I think this information is good enough.

Oh and by having it on table 2, I have to turn the SC to 2 o'clock. Should I just leave it or solder back links 1 and 2? I don't think it really matters though.

[dlheman]

Hmmm! I noticed the gold pad is gone on number 1. Must'e got lifted when by the solder suction tool.

Does this matter if I solder 1+2?

[Richard L]

You don't need 1 as you are using 2 only + some gain on the SC trimmer.