Q for someone who is all over Dakota Digital SG1-5e

From Australia so metric measurements



After receiving advice here I have purchased SGI-5E Universal Signal Interface Unit. The Instructions over abut 7 pages present as a little complex and I am unsure of the correct settings for the "output side" of the unit to my Volvo 240 electronic speedometer and I don't want to burn out either the Dakota unit or my speedometer unit.

Vehicle Information
Ford 5.0, C4 Transmission, Salisbury Differential - speed sensing comes from transmission - not diff as in std Volvo.
Diff Ration (t-shaft turns 2.7 times per wheel revolution 2.78
Ford C$ Top Gear Ratio 1.1
Tyre Circumference (mm) 1930
Tyre Revolutions per Kilometer 518
Ford Speedo Sensor Pulses per rotation of transmission output 8

Volvo Electronic Speedometer Information
Volvo Speedometer is marked on the face as a K24964 - It think this means that over a distance of 1 kilometre the speedometer reads 24964 pulses - but I am assuming this from what I have read.

I am unsure of which of the various options in the Dakota Digital instructions (there are seven different methods) to correctly wire from the unit to the wring into the speedometer unit.

I would appreciate any advice.

Gear ratio shouldn't matter if you are measuring at the trans output.

518 revolutions per km * 2.78 driveshaft revolutions per tire revolution * 8 pulses per driveshaft revolutions = 11,520.3 pulses per km from the Ford sensor.

So you need to multiply by approximately 2x. Reading the manual, this seems to correspond with Application 2. Output 2 is marked as a DC signal, which is what the 240 speedometer expects. Calibration ratio will be 2.16, 2.17 or thereabouts.

Disclaimer: I don't own a SGI-5E so can't test this myself.

I note in "Advanced Setup" it specifies that it has low and high voltage signal options, but doesn't say what those voltages are. I would try the low voltage first just in case. Suspect "high voltage" is 12V but wouldn't take any chances.

Pull-up setting shouldn't cause any damage if it's incorrect. Try toggling it if things aren't working. It just adds a little extra load to the circuit to bring up the voltage towards 12V, in case it's too low to register.

I'm really leaning toward one of these to 'fix' my Ford 8.8's sensor readings.

I was pondering taking out every 2.25 teeth (every two teeth, every 4th tooth take out a 'leap' tooth as well) to go from 108 down to 48, but I sort of think a digital processor like this might work better.

Thanks Indeed

Khrrck, thank you for taking the time to look at this situation and to have taken the "thought time" to consider the options I was faced with. Fantastic information because you have given me a starting point to work from and some things to consider,

Khrrck said:

Gear ratio shouldn't matter if you are measuring at the trans output.

518 revolutions per km * 2.78 driveshaft revolutions per tire revolution * 8 pulses per driveshaft revolutions = 11,520.3 pulses per km from the Ford sensor.

So you need to multiply by approximately 2x. Reading the manual, this seems to correspond with Application 2. Output 2 is marked as a DC signal, which is what the 240 speedometer expects. Calibration ratio will be 2.16, 2.17 or thereabouts.

Disclaimer: I don't own a SGI-5E so can't test this myself.

I note in "Advanced Setup" it specifies that it has low and high voltage signal options, but doesn't say what those voltages are. I would try the low voltage first just in case. Suspect "high voltage" is 12V but wouldn't take any chances.

Pull-up setting shouldn't cause any damage if it's incorrect. Try toggling it if things aren't working. It just adds a little extra load to the circuit to bring up the voltage towards 12V, in case it's too low to register.

Click to expand...

You want to drive the Volvo 240 speedo with an AC signal (it originally comes from a VR sensor, which is an AC signal). Looks like it's the "OUT1" pin on the Dakota box.

See: http://cleanflametrap.com/speedo.html

It works, Thanks all

I suppose it was a bit of confidence thing -fear of stuffing the speedo with electricity and fear of stuffing the Dakota Box with electricity.

Tried on output 1 nothing happening, went back to the shed and changed to Output 2 and away it went. Had calibrated in the shed using the info posted here, and it feels about right, but it is night time, I was holding the steering wheel in place and it was starting to get cold. I know it works though. It turned out to be real easy.

Much thanks to you all and at this stage I can suggest this is a good solution to the problem.

Glad to hear everything is working well! So to summarize, you set it to Application 2, used Output 2, didn't touch the advanced settings and calibrated to ~2.17?

bobxyz said:

You want to drive the Volvo 240 speedo with an AC signal (it originally comes from a VR sensor, which is an AC signal). Looks like it's the "OUT1" pin on the Dakota box.

See: http://cleanflametrap.com/speedo.html

Click to expand...

The stock sensor is a Hall sensor fed with DC 12V and outputting a DC square wave signal - that's why the Output 2 (DC) setting worked.

Edit: Might be wrong about that, the cleanflametrap pictures do indeed show it working when fed a sine wave signal. Interesting. Perhaps the ABS speedometer is different?

I know Dakota Digital says 'don't try to feed an ABS system with this', but I've heard of it working. And I'm going to try. I'd like to keep ABS working on my car if at all possible.

JohnMc said:

I know Dakota Digital says 'don't try to feed an ABS system with this', but I've heard of it working. And I'm going to try. I'd like to keep ABS working on my car if at all possible.

Click to expand...

Likely liability reasons...big deal if the speedo is off due to user error, but if it causes adverse issues with the ABS...thats a big deal

Khrrck, Yes your description worked in the order you said, I stewed over it and used option 1 first, but that didnt work. You nailed it. I am grateful.

I will now put everything back together and fine tune it. I have to see if I can work out getting my Tacho sorted, have a 6 cylinder one and a 4 - just a bit of fiddling.

The instructions that came with the Dakota made the process a little daunting as there were so many options.

Khrrck said:

Glad to hear everything is working well! So to summarize, you set it to Application 2, used Output 2, didn't touch the advanced settings and calibrated to ~2.17?



The stock sensor is a Hall sensor fed with DC 12V and outputting a DC square wave signal - that's why the Output 2 (DC) setting worked.

Edit: Might be wrong about that, the cleanflametrap pictures do indeed show it working when fed a sine wave signal. Interesting. Perhaps the ABS speedometer is different?

Click to expand...

some problems occured

Yes those are the settings I used and 2.16


Well I got to put it all back together over the weekend - I connected the tacho (4cyl one) while I had the cluster out - it worked at double rpm of course - thought I would just try a 6 cyl one I had. I dont know why but whilst I was trying that my fuel gauge and temperature gauge stopped working. Checked the net and then went back and made sure all the screws holding the cluster together were tight, didnt work. Bit annoyed but anyway I went for a drive to test the cluster - drove down my driveway which is 700 metres long and noticed the odometer was reading about 900 by the time I got to the end. When I stopped at the road I noticed the handbrake lights and some of the others flicker as it would if it was going to stall, but it wasnt stalling. Went for a drive and notice that I was running showing a speed at 60kps on my GPS as about 80kph - did a couple of checks and noted the speed didnt want to go over 80kph (50mph) and the needle had a fair bit of flicker at a constant speed - went home to the shed, went to restart and it sounded and felt like a flat battery. Going to get some professional help I think. Really annoyed with the fuel/temp gauge situation.
Did wonder later if the Hall sensor is sending 10 pulses instead of 8 - it could be one option

Will provide an update later.

Khrrck said:

Glad to hear everything is working well! So to summarize, you set it to Application 2, used Output 2, didn't touch the advanced settings and calibrated to ~2.17?



The stock sensor is a Hall sensor fed with DC 12V and outputting a DC square wave signal - that's why the Output 2 (DC) setting worked.

Edit: Might be wrong about that, the cleanflametrap pictures do indeed show it working when fed a sine wave signal. Interesting. Perhaps the ABS speedometer is different?

Click to expand...

Well after the last attempt a faulty voltage regulator on the speedometer cluster was identified as a problem with the fuel and temperature gauges. That is sorted. Whilst the cluster was out I obtained a Dakota Digital Tach converter and that worked perfectly. The speedometer conversion unit however still has an odd problem. Calibrated it roughly in the shed first time around, took it for a drive and calibrated it manually had to decrease it down to 1.67 or something and it is working perfectly against GPS up to 80kph then the needle flicks about. At 100kph on the GPS the unit the speedometer will sit steadily at 70kph, once you bring the road speed back down to 80 or lower it is steady and perfect.

I have had a look about on the net and cant find a solution to this. Many people report erratic reading and needle flicker and that seems to be related to wiring interference, I would have expected that if I had an issue with interference it would be right through the speed range.

I have noticed that my earlier calculations on were incorrect the vehicle is doing about 2500rpm at 100kph (GPS reading) I had miscalculated something there and that would explain the original setting of 2.17 needing to be reduced to 1.67.

Any clues anyone?

Although I think Derek has this sorted -- I had a Ford 5.0L in mine for a good long time; VDO/OEM Volvo 6 cylinder tach. There is a potentiometer on the tach that allows adjustment - and there is enough 'range' in the 6 cylinder tach to accommodate the V8 signal. So using the 6 cylinder tach you can get a good tach reading from the proper side of the coil on a V8 without any interface provided you adjust the pot.