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Location:
Sydney
Registered:
May 2004
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Club Member
Location:
sydney
Registered:
May 2002
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Re: Engine conversion - hooking up tacho?
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Sun, 23 May 2004 00:40
 
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the EMS should have a tacho output, pull the gauge cluster out and find the circuit for "signal in" on the tacho and wire the ems output to that point.
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Location:
Montrose, VIC
Registered:
May 2002
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Re: Engine conversion - hooking up tacho?
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Sun, 23 May 2004 03:39
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If you can, by all means do use the factory tacho. However, you may find that it doesn't actually want to trigger from the output on the EMS, in which case there's a couple of fairly easy ways around it. Are you using an SR20 with a dizzy, or individual coils? If you have a dizzy/one coil, then do the obvious and connect the tacho straight to the coil - side. If you're using 4 coils however, then you'll need to take the - side of each coil, connect them all together, and use a diode between each one to stop them shorting. If it's running waste spark (2 channel) ignition, you only need to connect the coil on cylinders 1 + 2 in this way. If you need a diagram to show you how to connect it, let me know. Total cost would be under $5 including heatshrink, diodes, wire, etc. If you don't quite understand, I can probably dig you up a simple diagram showing you how to connect it together.
The other way, if you're a little more electronically minded, would be to build a small amplifier to connect to the tacho output of the EMS, and boost the size of the signal. A suitable circuit is published in Silicon Chip, I THINK it's July '99, as a side note to the CD ignition project.
Whatever happens, you don't NEED an aftermarket tacho despite what people will tell you!
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Location:
Rosanna, Melb
Registered:
June 2002
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Re: Engine conversion - hooking up tacho?
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Sun, 23 May 2004 15:39
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I made up a small circuit that took the tach output of the ECU and made it right to go straight into the old style tach. Let me know your email and I will send a drawing of it. About 5 bits, including a gutted relay.
Does the job, but a little sluggish.
Hen
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Registered:
February 2004
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Re: Engine conversion - hooking up tacho?
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Sun, 23 May 2004 18:41
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Your other option is to do what my mate did and buy a Sixworks tacho booster. Cost him $48 (I think) and worked perfectly throughout the rev range. Was small too; half the size of a box of matches.
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Location:
Sydney
Registered:
May 2004
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Re: Engine conversion - hooking up tacho?
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Sun, 23 May 2004 21:33
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Thanks guys for the feedback
mrshin to answer your qn i'm not using a dizzy. I've got individual coils. I only just got a manual for the ems and the software. The tacho does actually move when I turn on the car so something is connected to it. I'll have to look further into it tho. The software for the ems does have some settings i think regarding the tacho output. I might play around with those.
Let me have another look at it all next wkend.
Cheers.
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