Finally, here is an update on my progress with the new ignition system.
INITIAL EXPERIENCE WITH THE 123 SM TUNEPLUS IGNITION
INSTALLATION
The installation was straightforward. Initially, I set it up on the bench using a small 12 volt battery but without the coil. Establishing a Bluetooth Connection went smoothly and I was able to read the curves that were already programmed from the factory. I was also able to observe the internal LED that is used to set the distributor at close to the firing point. I used a permanent marker to draw a line under the number 1 HT lead connection. Because I had been running a dual ignition, the HT lead connections positions change on the single ignition cap, so I had to work out an orientation of the distributor so that the HT leads would reach their connections, number 1 was in a position that I could view the marking line to line up the rotor and the wires coming out of the distributor and the pressure connection would be convenient. A diagram of the envisaged layout was drawn. I also found that the rotor on the 123 includes a 5 kilohm resistance just like the original SEV rotor.
I rotated the engine so that number 1 was at the PMH mark on the compression stroke and pulled out the existing distributor. I installed the 123 and rotated it to line up the rotor to suit the LED and at the start of the HT lead mark, tightened it down lightly and put the distributor cap on and fitted the HT leads. I then installed the new coil that came with the distributor and connected up the wires to the injection, coil, power, earth and tacho. Then I tried for a start. There were a couple of cylinders that fired initially but then nothing. I think the SM was objecting to the new kit. So I then fitted new BP5ES spark plugs and new Bougicord HT leads and the engine started immediately and ran quite smoothly. I used my timing light to rotate the distributor so it was firing on PMH at low idle and zero advance and tighten down the distributor clamp.
I had been doing some thinking about how I would manage the vacuum retard system with the 123. They do have a method to use the pressure sensor to provide a vacuum retard, but I decided to just use the lower end of the engine speed advance curve to simulate the vacuum retard and leave the vacuum sensor for use as a traditional vacuum advance. In the first stage, I decided to not implement a vacuum advance but I did connect the manifold to the sensor so I could monitor manifold pressure on the mobile phone app. So my first engine speed advance curve matched pretty closely the factory settings from an IE SM engine which incidentally have quite a bit less advance than those on the carby engines.
With this curve, the engine felt strong to about 2500 rpm but I had lost the top end whoosh effect above 3000 rpm. Further testing also showed that the engine still had the effect of increasing torque as I released the throttle from WOT at around 3000 rpm. I started to further reduce the advance at the medium to high rev range. I have been battling unusual high levels of rainfall and thunder storms. Also the SM lives in the most luxurious car accommodation I have, my 2 car shed in the backyard and the need to drive over the (wet) back lawn to get to the cement driveway. As a result, the SM has only been getting a couple of solo drives each week, and the results of some trials have felt great initially and then not so good on the next drive. The high amount of traffic has also made it difficult to really compare one curve with another. I think another factor is that the amount of advance an engine required changes as the engine warms up and fuel mixtures lean out. I have been juggling a lot of inputs, the strobe timing setting of 22o @ 2000 rpm for this engine, some discrepancies in the factory advance data for this model of engine and the inference that the engine has been running over advanced over the last 5 years. Dyno tuning has not been easy to access.
After many iterations and experiments, I arrived at this advance curve today which as you can see is about 3 degrees retarded on the factory curve. This curve has had two drives today, one with just engine speed advance and then with vacuum advance progressively added from 0 degrees at 0.85 to 10 degrees at 0.65 Bar and lower manifold pressures above 1300 rpm.
The engine seemed to be a lot less touchy to throttle changes with the vacuum advance added but seemed to retain the same torque characteristic at large throttle openings. The other huge benefit is that the engine seems to be running a lot cooler – less than half way up the white section on the temperature gauge today.
Cheers, Ken
INITIAL EXPERIENCE WITH THE 123 SM TUNEPLUS IGNITION
INSTALLATION
The installation was straightforward. Initially, I set it up on the bench using a small 12 volt battery but without the coil. Establishing a Bluetooth Connection went smoothly and I was able to read the curves that were already programmed from the factory. I was also able to observe the internal LED that is used to set the distributor at close to the firing point. I used a permanent marker to draw a line under the number 1 HT lead connection. Because I had been running a dual ignition, the HT lead connections positions change on the single ignition cap, so I had to work out an orientation of the distributor so that the HT leads would reach their connections, number 1 was in a position that I could view the marking line to line up the rotor and the wires coming out of the distributor and the pressure connection would be convenient. A diagram of the envisaged layout was drawn. I also found that the rotor on the 123 includes a 5 kilohm resistance just like the original SEV rotor.
I rotated the engine so that number 1 was at the PMH mark on the compression stroke and pulled out the existing distributor. I installed the 123 and rotated it to line up the rotor to suit the LED and at the start of the HT lead mark, tightened it down lightly and put the distributor cap on and fitted the HT leads. I then installed the new coil that came with the distributor and connected up the wires to the injection, coil, power, earth and tacho. Then I tried for a start. There were a couple of cylinders that fired initially but then nothing. I think the SM was objecting to the new kit. So I then fitted new BP5ES spark plugs and new Bougicord HT leads and the engine started immediately and ran quite smoothly. I used my timing light to rotate the distributor so it was firing on PMH at low idle and zero advance and tighten down the distributor clamp.
I had been doing some thinking about how I would manage the vacuum retard system with the 123. They do have a method to use the pressure sensor to provide a vacuum retard, but I decided to just use the lower end of the engine speed advance curve to simulate the vacuum retard and leave the vacuum sensor for use as a traditional vacuum advance. In the first stage, I decided to not implement a vacuum advance but I did connect the manifold to the sensor so I could monitor manifold pressure on the mobile phone app. So my first engine speed advance curve matched pretty closely the factory settings from an IE SM engine which incidentally have quite a bit less advance than those on the carby engines.
RPM | Advance (degrees) | Comment |
500 | 0 | 123 Fixed RPM Setting |
1000 | 0 | |
1100 | 9 | 1000 to 1100 Simulates Vacuum Retard |
2400 | 26 | First Knee in Curve |
4000 | 28 | Maximum Advance |
8000 | 28 | 123 Fixed RPM Setting |
With this curve, the engine felt strong to about 2500 rpm but I had lost the top end whoosh effect above 3000 rpm. Further testing also showed that the engine still had the effect of increasing torque as I released the throttle from WOT at around 3000 rpm. I started to further reduce the advance at the medium to high rev range. I have been battling unusual high levels of rainfall and thunder storms. Also the SM lives in the most luxurious car accommodation I have, my 2 car shed in the backyard and the need to drive over the (wet) back lawn to get to the cement driveway. As a result, the SM has only been getting a couple of solo drives each week, and the results of some trials have felt great initially and then not so good on the next drive. The high amount of traffic has also made it difficult to really compare one curve with another. I think another factor is that the amount of advance an engine required changes as the engine warms up and fuel mixtures lean out. I have been juggling a lot of inputs, the strobe timing setting of 22o @ 2000 rpm for this engine, some discrepancies in the factory advance data for this model of engine and the inference that the engine has been running over advanced over the last 5 years. Dyno tuning has not been easy to access.
After many iterations and experiments, I arrived at this advance curve today which as you can see is about 3 degrees retarded on the factory curve. This curve has had two drives today, one with just engine speed advance and then with vacuum advance progressively added from 0 degrees at 0.85 to 10 degrees at 0.65 Bar and lower manifold pressures above 1300 rpm.
RPM | Advance (degrees) | Comment |
500 | 0 | 123 Fixed RPM Setting |
1000 | 0 | |
1100 | 9 | 1000 to 1100 Simulates Vacuum Retard |
2400 | 23 | First Knee in Curve |
4000 | 25 | Second Knee in Advance Curve |
8000 | 27 | 123 Fixed RPM Setting |
The engine seemed to be a lot less touchy to throttle changes with the vacuum advance added but seemed to retain the same torque characteristic at large throttle openings. The other huge benefit is that the engine seems to be running a lot cooler – less than half way up the white section on the temperature gauge today.
Cheers, Ken
.... The answer is obvious you know .... You obviously desperately need a 2nd hoist 
