GeoffB
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| posted on 16/4/05 at 10:01 AM |
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REVS OUTPUT.?
I WILL BE USING A 97 BLADE ENGINE,WILL THE REVS OUTPUT ON THE CDI UNIT CONNECT STARIGHT TO A SPA COMBINED REVS AND SPEEDO UNIT..IT SAYS YOU JUST
CONNECT IT STRAIGHT UP AND IT HAS A DIGITAL FILTER TO COPE WITH IT
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tks
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| posted on 16/4/05 at 01:32 PM |
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digital filter??
well in fact it will use a transistor to make square waves...
i think the cable of the cdi units is the same singal as from a coil..
that's how you also can measure RPM
TKS
The above comments are always meant to be from the above persons perspective.
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ChrisGamlin
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| posted on 16/4/05 at 05:40 PM |
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As TKS said, you could always use a feed off of one of the coilpacks if it doesnt work or you get interference. If you dont want the hassle of finding
out, Id say just plump for the coil trigger straight off.
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tks
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| posted on 17/4/05 at 10:25 PM |
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to go somewhat deeper
and then they are several ways to know rpm...
As you use the coil line (the pickup placed after the coil resistance!!!)
You then can measure how many times the line = 0 per time fraction....(pulse frequency)
but you also could messure how long it has the 12volts on it (pulse with)
pulse with is the fastest way of measureing and also the best.
to do this use a Microcontroller and a transistor (for example BC547C) and 2 10KOhms res (1/4 W)
Feed the Transistor on the Base with the singal including the res) then hook the trans up to give 5volts on emit pin then the other 10Kres conected to
0, the micro pin goes in between..
then program the chip with the measureing prog and you are done..
You could easyly make a Data Logger...
TKS
The above comments are always meant to be from the above persons perspective.
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GeoffB
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| posted on 18/4/05 at 01:03 PM |
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SO IT WORKS STRAIGHT OFF THE CDI OUTPUT ,AND DOESNT NEED ANY INPUT FROM ANY SPEED SENSORS..?
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ChrisGamlin
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| posted on 18/4/05 at 01:07 PM |
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Revs will work from the CDI output, but its not going to be able to work out the car's speed just from revs so you'll need to put a speedo
sensor on the prop or something. Unfortunately the 97 engine doesnt have a built-in speed sensor in the gearbox like the 98/99 engines otherwise you
could have used that 
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chrisf
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| posted on 18/4/05 at 01:21 PM |
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quote:
...a built-in speed sensor in the gearbox like the 98/99 engines
Is that what the wired bit is on top of the gearbox? The previous owner cut the wire on mine. I'd been meaning to ask the group what that
was.
--Chris
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ChrisGamlin
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| posted on 18/4/05 at 01:41 PM |
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It sits on top of the gearbox with two little bolts holding it in. If you post up a pic I'll confirm we're thinking of the same thing 
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GeoffB
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| posted on 18/4/05 at 03:02 PM |
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THE STRANGE THING ABOUT MY 97 ENGINE THAT IT HAS THE CASTING IN THE GEARBOX FOR THE SPEEDO PICK UP SO THEY WERE THINKING ABOUT IT,OR DOES ANYBODY
KNOW IF ITS BACKWARD COMPATIBLE
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ChrisGamlin
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| posted on 18/4/05 at 03:07 PM |
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I have a feeling that the casting has always been there right from the 92/93 engines. I think all it does is pick up pulses off the gearbox teeth so I
imagine if you could drill it out and fit the sensor then it might work, will be a right pain in the arse to do without seperating the engine casing
though, you wouldnt want any swarf laying escaping in there!
Chris
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