JustGav Posted February 11, 2005 Share Posted February 11, 2005 Very technical question here.... How is the signal presented to the rev counter and speedo units... Is it a voltage based system or a pulse based system.... Thanks Gavan Link to comment Share on other sites More sharing options...
SimonB Posted February 11, 2005 Share Posted February 11, 2005 Both are pulsed. There's a thread in the members section where wsb2 was asking recently, but basically AFAIK you get 6 pulses per engine revolution for RPM and 4000 per mile on the speedo. Link to comment Share on other sites More sharing options...
JustGav Posted February 11, 2005 Author Share Posted February 11, 2005 So I'm right in assuming at 180mph you get 720 000 per second? and at 8000 rpm you get 48 000 per second? Gav Link to comment Share on other sites More sharing options...
SimonB Posted February 11, 2005 Share Posted February 11, 2005 No, you get 6 pulses per rev, so at 8000rpm you will get 48000 per MINUTE. Or 800 per second. Same for speed, 180mph you will get 720000 per HOUR, or 200 per second. Link to comment Share on other sites More sharing options...
JustGav Posted February 11, 2005 Author Share Posted February 11, 2005 Sorry ignore me, been a long day at work... Just putting my electronic engineering head on now.... So my thinking is the following...... 8000rpm will generate 800Hz signal 180mph will generate 200Hz signal Seeesh... I'm so used to megahertz and gigahertz freqs I hope my IC's can run that low Gav Link to comment Share on other sites More sharing options...
SimonB Posted February 11, 2005 Share Posted February 11, 2005 That's what I believe, I've not actually confirmed it though . I know that you have to tell my Apexi RSM and various other gizmos how many cylinders the car has or you get the wrong RPM displayed, so it makes sense. You also have to give the speed signal type, which is 4P - I'm fairly sure that is 4000 per mile as that seems to be a Toyota standard. Link to comment Share on other sites More sharing options...
JustGav Posted February 11, 2005 Author Share Posted February 11, 2005 Damn....nobody got a freq counter handy to confirm these thoughts.... Link to comment Share on other sites More sharing options...
JustGav Posted February 11, 2005 Author Share Posted February 11, 2005 Well.. Iv'e done all the calculations using those figures... lets hope like hell they are accurate or else I'll have to change a 1p resistor *grin* Link to comment Share on other sites More sharing options...
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