Ignition angle lower than ignition table

[Christoforos]

Hi guys.

I am running a G4X plug-in ECU on my Subaru WRX V1 and I am missing something on my tuning. I am currently working on increasing performance of the engine by increasing boost pressure, fuel pressure and fuel flow.  Apart form the mechanical modifications, I had to add the next levels of pressure to the fuel and ignition tables. After doing so I confirmed the PCLink to interpolate from the existing values and the values of ignition do not really seem right as it gave values much lower that 10deg BTDC. However I run the car and indeed cuts down somewhere higher that 140kPa where the ignition timing falls little lower than 7,5deg BTDC. 

Then I made a correction to to ignition table by inserting the minimum 7,5deg BTDC which I saw the engine still run well. When I run again I had the same problem and when I see the log file I see that it goes lower than 7,5deg BTDC which I set at the ignition table.

Can you please check the log file and the tuning and advise what am I missing?

 

Thank you in advance.

Christoforos Attas

10.02Subaru WRX initial map.pclx ECU Log 2022-02-5 12;55;44 pm.llgx

[Vaughan]

You haven't logged enough to see it but it looks like MAP Limit will be active (set to 250kPa and advanced mode off so will have a 10kPa lead in and MAP is 244kPa at that point in the log), also ECT ign trim will be trimming ~-0.5deg.

That doesn't explain the weird Ignition table runtime value though but looking at the ECU information it looks like you are a couple major firmware versions behind and have what appears to be a pre-release firmware. I would recommend updating to the newest firmware, I expect this should resolve it.

One other thought would be how confident are you that that log is from when that tune was in the ecu, it looks like an ecu log and you have been playing with your ignition timing so the log could have been recorded when you had an older ignition table setup in the ecu.

[Christoforos]

Thanks Vaughan for the tips.

The rooftop I set for MGP is 1,5bar. So with Advance mode off, shall I set MAP limit to 260kPa?

I will run the update of the firmware soon as well.

The last point you mentioned might be correct as well as I was playing around with tuning. I had another log (similar though) but it was big and I could not upload.

I will follow your recommendations  (please confirm the above question) and I will get back if there is any other issue.

One final question. My car does not have electronic speedo. It is mechanical. I want the ECU to have input of speed as well. What do you recommend to do if I want to keep the mechanical (without changing original speedometer) and provide input to the ECU as well?

 

Thanks in advance!

[Vaughan]

10 minutes ago, Christoforos said:

The rooftop I set for MGP is 1,5bar. So with Advance mode off, shall I set MAP limit to 260kPa?

The MAP Limit value in the table is the value you don't want to reach and so there is  Limit Range setting which specifies how far before the limit value it starts bringing in the cut and limit ignition trim. When Advanced mode is off the Limit Range value it uses for MAP Limit is 10kPa. so If you want it to start cutting at 250kPa with larger cuts the closer it gets to 260kPa then yes 260kPa is the number you want in the table.

15 minutes ago, Christoforos said:

One final question. My car does not have electronic speedo. It is mechanical. I want the ECU to have input of speed as well. What do you recommend to do if I want to keep the mechanical (without changing original speedometer) and provide input to the ECU as well?

As far as I'm aware the GC8 is like a lot of other cars of the same age where it has a mechanical speedo cable from the gearbox to the dash but has hardware inside the speedo gauge that converts the mechanical rotation into a digital pulse of varying frequency which is then sent to the ECU. It looks like that signal is connected to DI4 on your car. If it isn't showing a frequency on DI 4 or a speed in GP Speed 1 or the Driving Wheel Speed runtime then you might need to turn on the pullup in the Digital Inputs->GP Input->GP Speed 1 window

[Christoforos]

From what you explained regarding MAP limit, I understand that with Advance mode OFF there will be larger cuts whereas with the Advance mode ON the cut out will be smoother. That is preferred of course. I did not try it though. Can you advise on default settings for GC8 engine?

For the speedo, I am not sure if it converts the mechanical into digital pulse. I hope it does! Yes, I saw that is DI4. I tried to read also GP Speed 1 and the Driving wheel speed before without any luck. No read. I will try also as per your suggestion to turn on the pullup and provide feedback.

Thanks again for the swift feedback!

[Vaughan]

54 minutes ago, Christoforos said:

From what you explained regarding MAP limit, I understand that with Advance mode OFF there will be larger cuts whereas with the Advance mode ON the cut out will be smoother. That is preferred of course. I did not try it though. Can you advise on default settings for GC8 engine?

Advanced mode off just means it uses default hardcoded values whereas with advanced mode on it will use the user configurable values that become visible when turning on advanced mode. 

With advanced mode off the values it uses are:

• Hard Limit - Off
• Cut Effect - Adaptive
• Limit Ctrl Range - 10kPa
• Hard Limit Activation - 0kPa
• TPS Low - 0%
• End Cut - 100%
• StartCut100 - 60%
• Start Cut Low - 0%
• Cut Decay Time - 400ms
• Limit Ignition Trim - -5.0deg
• Trim Decay Time - 400ms
• Limit Fuel Trim - 0% (not visible when using fuel cuts)

Not turning Advanced mode on won't change the limit in any way unless you also change one or more of the above settings.

Information on what each setting does can be found in the help manual (press F1 or right click and select what's this?)

[Christoforos]

Thanks for the detailed explanation.

While reading the manual I saw that Limit Control Range and Hard Limit Activation is referring to RPM. The PCLink and as you mentioned above, refers to kPa. Please see below:

Limit Control Range Specifies the range that the limiting operates over, the Limit control range operates under the specified limit value. For example, with an RPM limit set to 7000 and a control range of 200, the limit would operate between 6800 and 7000 RPM. A typical RPM Limit Control Range would be 200 RPM.

Hard Limit Activation Specifies how far past the end of the Limit Control Range you can go before the hard limit will apply. A typical value for an RPM Limit would be 200 RPM

Also, the axis of the 3D diagram of the Advanced Limiting Mode are: %Cut, RPM, TP.

Is there a mistake in the manual in regards to RPM?

[Adamw]

RPM limit uses RPM for the limit control range.

MAP limit uses Kpa for the limit control range.

Speed Limit uses Kmh for the limit control range.  

[essb00]

kPa = for MAP limit
RPM = for RPM limit
Same principle applies with the limit control range, hard limit activation, etc.

...but yeah, the help file is generalized for RPM limit so it is kinda confusing if you're setting up MAP limit and not yet familiar how it works.

[Vaughan]

I have added some clarification to the help manual.