What is the signal Frequency from the stock speedo?

[s-10]

So, after hours, correction, weeks of searching i still cannot find this one bit of information. I would like to know what the frequency (in pulses per mile, preferably) is leaving the toyota speedometer, on the pink (i think it's pink) wire that goes to the ECM. The short of it is that I'm using an electronic speedometer that's running off the ABS/Skid Control sensor in the top of the transmission. I occasionally will get a stall situation when I slow down to take a corner off the highway. A quick bit of Background info; I stuffed my 7M into a 96 Chevy s10, so I didn't need the ABS sensor on the tranny to run the ABS. My VDO speedometer works perfectly, and is always accurate because of it's reprogrammability.

And another related question, what is the revolutions per mile from the Tranny to the speedo cable? It is not in use currently, but was considering a marlin/driftmotion/jagsthatrun 4 or 2 pulse sensor to plug in there and using it for the Chevy ABS/Cruise Control (which wants a 4000 pulse per mile signal)

And just in case anyone is wondering, the ABS sensor in a W58 trans puts out roughly 126,000 pulses per mile with a 26.6 in tire on a 4.10 axle. Just so that's out there.

Thank you in advance for helping.
-3stan

 

[jetjock]

It's four pulses per revolution of the speedo cable if that's any help. You should be able to figure it from that.

 

[s-10]

that does help, but leads to the second question, what is the revolutions per mile of the speedo cable?

 

[jetjock]

As you pointed out it's going to depend on several factors. Why not simply measure it? Any frequency or universal counter will work.

 

[tjzyx]

My speedo has 1026rev=1Mile printed on it. I believe all the speedometers are the same. What you are getting now would be dependent on how your current gearing and tire size compare to the car the trans came from.

 

[s-10]

Good Point. Thanks for helping, jetjock. It sounds like a 4 pulse is the way to go.

 

[jetjock]

You're welcome. Fwiw you can buy a cheap battery powered counter for around $20 and get a real number. For freq alone any decent DMM will do. I have better instruments but if I was in a bind that's what I'd have done. Metrology always beats head scratching for weeks

 

[s-10]

Metrology always beats head scratching for weeks

lol at weeks.... it's been 13 months and 25000 miles since I completed the swap, the whole time, no abs or cruise. this question has been on my mind off and on the entire time.

tjzyx, the engine and trans came from an 88 supra (naturally aspirated, so a w58 trans), it's installed in the 96 s10 in my sig pic, which has 4.10 rear gears, and from what i understand, 4.30 is common for NA supras, so it should be fairly close. I'd have to do some math, and look up stock tire sizes on a supra, but i think that it should come close enough to 4000 pulses per mile for my purposes. Hopefully the Chevy ABS computer works without the matching ECM to help it, but, Jags That Run can answer that question.

 

[Jeff Lange]

637 revs = 1 km
1026 revs = 1 mile
4 pulses per rev

It was basically all covered already in the thread, but there you go.

Jeff

 

[te72]

Stock tire size on the Mk3 Supra is a 225/50/16, so ~631.4mm = ~24.86" height. Nice swap by the way, I like it...

And "Jags that run"? Sad what that seems to imply.