Here it is, as I promised... My megasquirt stuff...

Megasquirt and Megasquirt-N-Spark fuel and ignition maps.

I have upgraded to the new Megasquirt-Extra code. There will be pictures, schematics and explanations here eventually. Hopefully enough information so that anyone can use megasquirt instead of looking for a genuine 20v ECU when doing a 4agze or 20-valve engine swap. Information can be found st the website of the creators of the Extra code, James Murray and Philip Ringwood. I can't thank them enough for their hard work. http://www.jsm-net.demon.co.uk

Hi, this will be my megasquirt-n-spark page. but for now, here are the pictures.. I'll explain when I have time or E-mail me Twincharger@hotmail.com

This is a 1987 Toyota Corolla, model AE86. It has a 1600cc, twincam, 4 valve per cylinder, fuel injected, supercharged, turbocharged, intercooled engine. Kinda complicated...

I searched for a Toyota 4AGZE ECU, but never found one, so I put the car together using a stock 4AGE ECU, Supra Airflow meter, 4AGZE 360cc fuel injectors and a MSD 6 BTM to retard spark. I did have to re-calibrate the AFM to make the setup work. Unfortunately the setup was AFM based, instead of MAP based, and with the twincharging setup on the car, the ECU could not tell the difference between 'low rpm with high boost' or 'high rpm with no boost'. Both would flow the same amount of air, and both could happen with very small throttle angles. The timing requirements of these conditions are very different. 'low rpm with high boost' wants a retarded spark to keep from detonating, and 'high rpm with no boost' wants lots of advance to keep efficiency up. So the Throttle position sensor was not a very good indicator of engine load. Most times I could make more power at half throttle than full throttle. I knew that I needed a standalone engine management system. At the time, I could not afford to buy one, so I built a Megasquirt kit. Now there is a version of software for megasquirt that allows the same board to control fuel and spark. Megasquirt-N-spark.
This is the stock Corolla ECU, located by the passenger's feet (left-hand drive).

This is the inside of the Toyota ECU.

Since you supply your own enclosure for the Megasquirt kit, why not use the original Toyota enclosure... That way you know it will fit back into the car, and it would look sort of like it belongs there. Plus you won't have to cut the connectors off of the wiring harness and splice each wire to the megasquirt. Here is the Megasquirt board in a Toyota enclosure. Click it for a bigger view.


My thought was to use the Megasquirt-equipped ECU as a 'universal' Toyota replacement, like I could move it from car to car at will... But that didn't work because the Toyota's throttle position sensor works backwards compared to the rest of the EFI world. Idle is 5 volts, floored goes to zero. The sensor needs to be re-wired to go from 0 to 5.



Here is the almost-finished unit. Notice stock Toyota wiring harness connectors, hose for MAP sensor, 37-pin megasquirt connector, and serial port for programming. Click it for a big one.



It's fully installed now and runs pretty well. I have only begun to tune the spark and fuel maps. All settings are set to the safe side until I get time to tune some more. I will post my final fuel and spark maps here if anyone needs them.

Here are my Megasquirt settings...

I'm using 3.3 ohm peak/hold injectors with the stock toyota resistor pack. All 4 injectors are on 1 megasquirt output. My O2 sensor is narrowband and getting old.

CONSTANTS

Req Fuel 14.0 injection control 1 Squirt, Simultaneous
Inj open 1.0ms Batt = 0.1 ms/v 4-stroke, 4 cylinder
PWM current limit 30% PWM time=15.0ms Multiport, 4 injectors
Fast idle - used for spark Engine Stroke = 4 stroke
Control speed-density MAP type 250KPA, Even-fire
O2 sensor - NarrowBand, Barometer Disabled


With multiport fuel injection there is little chance for fuel to drop out of the mixture and sit at the bottom of the manifold compared to a throttle-body setup, so very little warmup enrichment is needed. Plus in AZ, the car is over 100 degrees when I go to start it, so I can get away with almost no warmup enrichment. My TPS signal was a bit noisy, so I disabled the slowest accel bin. That cleared up the symptoms. The EGO step of 1% is a huge change when you have 450cc injectors on a 1600cc engine. I can't use it at idle. My o2 sensor rarely puts out over .7 volts, so I decreased the trigger voltage to something I could hit. Maybe I should replace the sensor? Naaaahhh.

ENRICHMENTS

Cranking -40 = 12.0 170 = 4.0 Priming = 2.0 afterstart = 10% cycles = 10
Warmup enrichment bins 101,101,101,101,101,101,101,101,101,101
TPS trigger .59 Accel duration .5 Acc bins .1 , 1.0, 1.0, 2.0
cold accel enrich 0, cold accel enrich 0, Decel fuel cut 80%
EGO Active temp 175, events/step 33, EGO step 1.0 (wish it would go lower)
EGO limit 30%, EGO active above 1200 RPM, EGO volts .397


This map is a little rough around the edges, but it's okay in the range for normal driving. It's a good base map for less than 10psi of boost. This map passed a required IM-240 smog test.

FUEL MAP FOR 1600cc 4AGZE WITH 360cc (stock) injectors.

MAP
20 79 55 40 29 25 32 34 34
30 95 79 59 44 34 38 41 50
75 83 71 61 54 54 55 58 63
100 74 84 84 73 70 72 72 76
125 82 85 90 89 77 82 83 94
150 94 92 95 94 89 93 102 113
175 100 100 99 108 101 107 114 124
200 100 100 100 116 117 128 125 142
RPM 500 1000 1500 2500 3800 5300 6500 8000


FUEL MAP FOR 1600cc 4AGZE WITH 450cc (RX7 non-turbo saturated) injectors. This map is a good starting point for low to medium boost. I was mapping to about 10 psi of turbo boost, then I experienced turbo problems. A foreign object entered the turbo and ended my testing. Oh well, it will be back, bigger and better soon.

MAP
20 78 66 54 23 20 26 27 27
30 78 68 57 51 49 30 33 40
75 76 67 59 56 55 54 46 50
100 59 67 67 60 70 66 62 61
125 66 68 72 67 70 67 69 70
150 75 74 76 75 79 73 73 76
175 80 80 79 86 81 83 82 86
200 80 80 80 93 94 102 100 100
RPM 500 1000 1500 2500 3800 5300 6500 8000


The ReqFuel value for this table was calculated by assuming that it was a 3000cc engine, instead of 1600cc. This keeps the VE values down much lower than the previous map, even though these injectors are only 25% larger than the 360cc injectors. If you use this map, you may want to fiddle with the ReqFuel value before adjusting individual cells.

Megasquirt-N-spark Ignition settings.

Trigger Angle 52
Crank timing - Time based
Crank angle 10 - needs changed!
Hold ignition 2
Ignition output - Noninverted


Ignition Map

MAP
25 8 8.5 12.5 10 10 14 27 28
30 9 17 10.5 17 15 25 38 40
50 30.5 33 28.5 28 24.5 27 34 34
80 32 31 33 30 31 31 31 36
100 25.5 28 27 25 25 29 30 32.5
125 24 26 26 26 27 30 32 33.5
150 20 23 23 24 29 30 32.5 35
200 10 10 10 22 27 27 27 30
RPM 1000 1500 2000 2500 3000 4000 5000 7000
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