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

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

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.

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

SO IT WORKS STRAIGHT OFF THE CDI OUTPUT ,AND DOESNT NEED ANY INPUT FROM ANY SPEED SENSORS..?

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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...a built-in speed sensor in the gearbox like the 98/99 engines

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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

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

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