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speed sensor..
Posted: Tue Jul 10, 2012 8:09 pm
by Goldspeed
hi.. wondering if you can help me out.. i was wondering if i could pick up my speed from the gearbox speed sensor or anywhere else off my car without purchasing a speed sensor.. (celica gt4)
Posted: Thu Jul 12, 2012 4:51 pm
by osborni
Most speed sensors in OEM applications are variable reluctance sensors. The signal is pretty dirty and you need a converter box to get them into square wave - which he DL1 can understand.
It's less hassle to mount your own hall effect sensor. I've mounted mine through the brake baking plates to pick up a bolt on the back side of the front bearing flange. Iirc the celica is front drive,, so not sure how that would work.
Posted: Fri Jul 13, 2012 12:55 pm
by 924RACR
...and then you bring this in as a freq input, correct?
I'm interested, as I have a speed sensor on my drive sprocket from the factory ('08 Suzuki GSXR), would love to log that without burning up another analog input channel - already maxed out!
Posted: Fri Jul 13, 2012 4:35 pm
by osborni
Yes, one of the frequency inputs. Needs to be enabled via the config tool.
Just make sure it's a hall sensor, not a variable reluctance sensor. Multi tooth wheels on abs rings or cranks are normally VR sensors. You could just put a smallish bolt through the drive sprocket. Or pick up bolt heads on the brake rotor.
FYI - i'm running into a saturation problem at ~100 mph or so. My M8 bolt head isn't big enough. The head passes before it can activate the hall sensor (cherry, not a R-T sensor) Need to machine a bigger target for the sensors to pick up reliably above 100 or so.
Posted: Mon Jul 23, 2012 2:31 pm
by 924RACR
osborni wrote:FYI - i'm running into a saturation problem at ~100 mph or so. My M8 bolt head isn't big enough. The head passes before it can activate the hall sensor (cherry, not a R-T sensor) Need to machine a bigger target for the sensors to pick up reliably above 100 or so.
Ack, that sucks. How many pulses per rev, only the one bolt correct?
Posted: Mon Jul 23, 2012 5:30 pm
by osborni
Your mileage may vary....
One bolt. I have the sensor less than 1mm to the bolt head - need a little clearance in there.
Bolt head just isn't big enough - or not enough magnetic variation relative to the face of the bearing. (as I write this....) might make sense to space the bolt head out a bit more to get more delta Gauss... dunno - speculating.
I was going to machine a little steel block though.... simple enough.