Pectel SQ6M: Tuning Documentation




SQ6M: Tuning Strategy... Document Things First

The Cosworth Pectel SQ6M is communicated with and tuned with the PC CalTool 3.6 interface via an Ethernet cable.  You on one end of cable and the SQ6M sitting there waiting for your thousands of keystokes, all intertwined in your strategy for utter domination. In that there are 8800 items in the various CalTool 3.6 drop down menus, your memory and attention span can get a bit taxed, stimulants or no stimulants and, if you are over 28 years old, your mental capacity is shrinking day by day.

For a complete listing of the programmable parameters in CalTool 3.6 we have prepared a 219 page PDF listing these. It can be a bit taxing to remember where things are located in the various categories of drop-down menus, and selecting an item in parameters will jump to that particular section.

It's a good idea to keep a permanent documentation record of where the data is located in the software and what the data is. Unless you are a Cosworth Engineer and work with the software all the time, you won't remember where things are located, much less what you have previously entered, so keeping separate documents provides both a shortcut to and a record of your CalTool 3.6 entries.

Once we had an negative Ignition Adder show up on our SQ6M simulator and we could not locate it even after looking for several days off and on. We finally contacted Cosworth U.K. and a Pectel Engineer suggested we set up a trace for Trq_limit_src and it would point us to where the fixed retard was coming from. Turns out it was an artifact from an older "Dyno Only" SQ6M file and was buried in a gear change category. We found and zeroed out this negative adder. When we first noticed this our simulator did not have a shift activation button so it "thought" it was locked in a shift event. We subsequently added a momentary "shift"button and a ground wire for the shift button and were able to program and see our gear cut programming. The simulator would then only sense a gear change when we pressed the button.

Interuptions, breaks in the process, and life in general,  all intrude to screw up your Dataset and make it easy to both overlook and forget entries.

When you finish your CalTool 3.6 entries and tuning you're going to end up with two files:                 

(1) A CalTool Dataset : That has all the data enries.

(2) A CalTool Workspace: What the computer screen looks like.

Break Down and Document the Important Categories

Unless you are a trained Cosworth Engineer who works on calibrations all the time, the complexity of professional engine control units like the SQ6M can be daunting and it is hard to remember where the data is located within CalTool 3.6 as well as what options are available to implement your strategy. At RB Racing we create 16 separate documents for our data entries to manage our SQ6M Dataset.

For our two-wheeled efforts we create Microsoft Word and Apple Pages Documents and convert these into PDFs for the following 16 categories. We end up with more than one hundred pages of documents for each project.

Note: These are only samples, are specific to one application, and are only for demonstration, not general use.

17 Categories of Data

1. Sensor Data: You must have all the OEM data for all the sensors to include sensor pinouts and connector data. This is mandatory. Within CalTool 3.6 there are certain canned entries for specific sensors, but, by in large, it's up to you. Get and study the sensor datasheets and file this documentation in a digital format.

2. Crank and Cam Sensor Trigger Setup:  For Example a Harley Twin Cam without a cam sensor: Crank Triggering

3. Fuel Maps (4): For these we create four separate Excel Spreadsheets to do the initial calculations. As the Fuel maps can be 50 RPM sites x 25 Load Sites there can be up to 1250 individual entries. These entires break down into divisions of .01 Millisecond which means, including the decimal place, there are potentially 1250 x 5 keystrokes for each fuel map or 6250 per map, not counting the moves to each site.

Example of a 25 x 25 matrix 3 Bar Fuel Map generated in Excel. Resolution 0.01 Millisecond.

For the four CalTool 3.6 fuel maps there is potentially an excess of 25,000 keystrokes if done in a 100% manual manner. It seems a good idea to automate the initial entry if you are going from scratch. Keep these in four separate Excel Spreadsheets so they can be copied and pasted into CalTool 3.6.

Fuel Maps in CalTool 3.6 can have up to 50 RPM sites and 25 Load Sites. In the picture above we have set up a 25 x 25 fuel map for 3 Bar and 6500 RPM operation. A unique feature of CalTool 3.6 is that the RPM axis does not have to be equally spaced i.e. if you need increased resolution in a certain rpm range you can do so. There are four (4) base calibrations in the SQ6M engine controller. The user can switch these "on the fly" with a Cal-Pot rotary switch.

You can edit in either the 3D "Matrix Surface Editor" shown above or on in a 2D "Matrix Editor" table format shown below.

Editing is done in a number of ways, either by direct one cell edit, by the entire map, or selected areas. Math functions are available for editing. Basic resolution is .01 millisecond or .00001 seconds. Any finer gradation than this is meaningless. We generate our four base maps in Excel using predictive equations to save time...If you have four spark maps and four fuel maps and they are maxed out at 50 RPM x 25 Load sites that is up to 40,000 digits and 10,000 decimal points you get to manually enter. We automate the process and use copy and paste from Excel to CalTool 3.6.

 In either format you use the arrow keys to navigate about the map. In the 3D format you use the CTRL Key and the arrow keys to rotate or flip the map.

When in the Matrix Surface Editor mode  (top image) if you "right click" your map, a dialog box will pop up and in "View" you have a number of ways to view your fuel map data. Pictured above is a Wireframe view.

Above is the X Axis Slice. This is very useful, especially in Turbo maps to look for mistakes in manual editing.

Here we are looking at a Single X Slice. Wherever you have left the cursor that X Axis row will be displayed.

4. Spark Maps (4): Keep these in an Excel Spreadsheet so they can be copied and pasted into CalTool 3.6. Note that the resolution is 0.01 Degrees through 20,000 RPM.

5. Fueling During Starting: Parameters and sample data entries

6. Fuel Corrections: Parameters and sample data entries

7. Closed Loop Lambda: Parameters and sample data entries

8. Ignition Corrections: Parameters and sample data entries

9. Idle Entries: Parameters and sample data entries

10. Engine Speed Limiter: Parameters and sample data entries

11. Fly By Wire Settings: Parameters and sample data entries

12. Wastegate Control: Parameters and sample data entries

13. Traction Control: Parameters and sample data entries

14. Cal Pot Strategy: Parameters and sample data entries

15. Knock Sensing: Parameters and sample data entries

16. Water Injection: Parameters and sample data entries

17. Complete wiring harness documentation: Keep complete documentation in programs like Microsoft Excel and Microsoft Visio.

Fuel and Spark Mapping on a Dynamometer

You simply must do ECU calibrations on a dyno. We're two wheeled types so we use a Superflow CycleDyn that can be programmed for specific steps in rpms and loads. Coupling this with the SQ6M's  Data Acquisition greatly simplifies the process. You can do timed sweeps and even write your own road or track program simulations.

In the case of the above fuel and spark maps with 25 divisions of 260 RPM you may do step testing in increments of or multiples of 260 RPM....Say every 520 degrees in eight steps from 2860 RPM to 6500 RPM holding at each step to stabilize the sensor readings: 2860, 3380, 3900, 4420, 4940, 5460, 5980, and 6500 RPM.

These optional $5,900.00 internal "High Pressure Blowers" provide cool airflow to match road speed 1:1 up to 200 mph. The CycleDyn is calibrated at Superflow at the time of manufacture to measure and account for this additional drag.

Fuel Map Editing in CalTool 3.6

The dyno tuning process is simple with the SQ6M: You first must turn Closed Loop Lambda off.

1. Set up a Trace Window with the following,  selected from Exploring Channels / Matching Channels





Scroll down the list to:

The entries will show up in the trace window and will be scrolling during the dyno run.

2. Do a Dyno pull and then press the "Pause" icon at the top of the screen.

3. Move the cursor over the traces and go to the corresponding points on the fuel map where the cursor is in the center of a cell.

4. Multiply the cell value by the  Inj_m_lambda value. For example if the cursor is in the middle of the 4680 RPM and the 0.96 Bar cell, Inj_m_lambda reads 0.92, i.e. richer than the target,  then multiply the cell value by 0.92.

5. If lnj_m_lambda values are leaner than or equal to the target i.e. greater than or equal to 1.0 then you might want to add a bit more fuel than the multiplier. Separate banks or cylinders need to be even, otherwise you may want to use individual trims to even things out. Monitor LAM1 and LAM2.

Ignition Maping

Dynamometer time. There really is no better way. The SQ6M can be set up with a four position rotary Cal_Pot which allows you to select 4 separate fuel maps on the fly or on the dyno. You don't edit your timing in real time while running.

Optimizing horsepower and Torque v. your ignition timing has to be evaluated on the dynamometer.

In addition you can datalog your knock sensor inputs to isolate areas where fuel or ignition inputs should be edited.

Track or Real World the Application

You can't do it all on a dynamometer because you don't race, ride, or set records on a dynamometer. The SQ6M has 4 Mb of logging memory at up to 2000 samples per second. You set the sample rates and setup traces to analyze your data after your run at Bonneville or on your local driving loop.

The defacto standard for data analysis is Pi Toolbox. In conjunction with Pectel ECU Offload Tool you can analyze your vehicle's operation just like the formula1 data engineers do.

Above: Bryan Stock "Flyin Bryan" of Brother Speed has just completed a 200 MPH record run at Bonneville. Time for a beer. Maybe time to look at the data.