my LT1 PCM needs a VSS input (GM spec is 4k pulses per mile). the Audi transaxle i'm using does not have a speed sensor output, AFAIK. So i need to generate (or hijack / split) a signal and convert it to the type of signal that the PCM wants. because i'm using the C4 front and rear corners, i will have four wheel speed signals i could use -- fronts are undriven and rears are driven. my google-fu has returned zero hits for anyone doing this. so i ask the hive: anyone done this before? could a GPS unit provide an output that could be used as the source? etc . any help will be greatly appreciated.
I've used a Dakota Digital SGI-5 to convert speedometer signals before, do you know the PPM of the wheel speed sensors?
There are GPS units for just such an occasion.
I added a mechanical VSS to the speedo output on my gearbox, so that my ECU can determine what gear I am in compared to the wheel speed sensors...
see if jagsthatrun.com has anything that you can steal ideas from. Or find a way to mount the c4 vss and reluctor on an output of the audi box?
the googles tell me the wheel speed tone rings have 47 teeth, which maths out to a little over 37k ppm for a 275/40R17, or about 10.3 Hz/mph
RossD
MegaDork
6/12/19 5:20 p.m.
File off all but 4.7 teeth.
Kind of kidding
AngryCorvair said:
the googles tell me the wheel speed tone rings have 47 teeth, which maths out to a little over 37k ppm for a 275/40R17, or about 10.3 Hz/mph
Theoretically, an arduino like thing can take pulse inputs and drive pulse outputs. Since you are basically doing a 10-1 lowering of frequency, doing that kind of output should be pretty easy. Easy if you know how to actually program one of those things.
What about magnets glued to the driveshaft with a hall effect sensor like the rostra cruise control setup?
RossD
MegaDork
6/12/19 6:48 p.m.
http://www.ti.com/lit/pdf/snas555
Figure 29 and 28 and then try to tune it to get the speed right.
AngryCorvair said:
my LT1 PCM needs a VSS input (GM spec is 4k pulses per mile). the Audi transaxle i'm using does not have a speed sensor output, AFAIK. So i need to generate (or hijack / split) a signal and convert it to the type of signal that the PCM wants. because i'm using the C4 front and rear corners, i will have four wheel speed signals i could use -- fronts are undriven and rears are driven. my google-fu has returned zero hits for anyone doing this. so i ask the hive: anyone done this before? could a GPS unit provide an output that could be used as the source? etc . any help will be greatly appreciated.
Which Audi transaxle is that?
If you are using an 016, I am pretty sure that you can convert an 01E to cable by using an 016 drive flange (or something), so you may be able to go the other way, converting an 016 to digital by using early 01E (ur-S4/S6) parts.
alfadriver said:
AngryCorvair said:
the googles tell me the wheel speed tone rings have 47 teeth, which maths out to a little over 37k ppm for a 275/40R17, or about 10.3 Hz/mph
Theoretically, an arduino like thing can take pulse inputs and drive pulse outputs. Since you are basically doing a 10-1 lowering of frequency, doing that kind of output should be pretty easy. Easy if you know how to actually program one of those things.
Yeah, a friend of mine built an arduino to convert the tach output of an LS1 computer to the 13 on/13 off output that the dodge body computer needed to see to make the tach work. I'd imagine it'd be just as easy to do, and it cost him less than $20.. Want me to get you in touch, Angry? He'd be happy to help. He's a complete Arduino n00b, this was his first project with it.
In reply to WonkoTheSane :
I appreciate the offer, but I’ve got a guy figuring it out for me as we speak.
In reply to RossD :
Very cool, thanks for that info!
In reply to Dusterbd13-michael :
I was hoping to use a non-driven wheel but 5 magnets on a halfshaft would do what I need.
