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Explorer 8.8 VSS to 240 Speedo

I've had an 8.8 in my '91 240 for years now. Cut/grinded the teeth off of the 8.8 wheel to get to 12 and then spliced in the 8.8 sensor. Little bouncy up to 20 and then solid.
 
I've had an 8.8 in my '91 240 for years now. Cut/grinded the teeth off of the 8.8 wheel to get to 12 and then spliced in the 8.8 sensor. Little bouncy up to 20 and then solid.

Thats exactly what I did but mine is bouncy in a lot of places up to about 50. Did you just barely grind away the teeth or knock down the ring farther.
 
Thats exactly what I did but mine is bouncy in a lot of places up to about 50. Did you just barely grind away the teeth or knock down the ring farther.

I used an angle grinder with cutoff then grinding wheel to make it as smooth as possible and equal to the troughs in between the remaining teeth. I'm guessing the imprecision of the angle grinder is why my speedo bounces.
 
There was a discussion about this on the facebook group, and I know John (Giffins Performance) had drawn up 48 and 12 tooth wheels for the 8.8, he sent me the drawings. I don't know if he cut any prototypes yet. If you have an 8.8 in a car already, it's worth sending him a message about testing one.
 
I want it for abs. the dash speedo working is nice too, but I mainly want it for the abs.

Expensive is relative

Three rings to fit the stock 240 axle under the parking brake was ~US$300 including shipping from the UK.

They needed measurements accurate to a couple of thousandths, as you heat the ring to get it on. Might be easier / cheaper since what you're doing has almost certainly been done before, and our job was 100% custom.

Reluctorrings.com
 
After putting a Honda Civic manual transmission in my Insight, I notice the speedo was 10% off, so I used an Arduino Uno to correct my speedo since there are no correct count speedo gear available.

VSS goes to Arduino Uno, do the calculation, then output the modified signal (5V) to the ECU/Cluster/EPS/climate control.


Works pretty good and I don't see why someone can't get it work for the explorer VSS to the 240 speedo.
 
You could always remove the resistor on the volvo electric speedo & solder in a pot - can move the speedo how you like then.
Dave Bartons site has full info - so easy even I could do it. Just don't use the cheap chinese variable resistors - they're too variable in their variableness.
 
I used an angle grinder with cutoff then grinding wheel to make it as smooth as possible and equal to the troughs in between the remaining teeth. I'm guessing the imprecision of the angle grinder is why my speedo bounces.

That's exactly what I did too. Mine bounces a round a lot. I'm wondering if I have it wired wrong or something. Going to dig into more once it's up and running again.

There was a discussion about this on the facebook group, and I know John (Giffins Performance) had drawn up 48 and 12 tooth wheels for the 8.8, he sent me the drawings. I don't know if he cut any prototypes yet. If you have an 8.8 in a car already, it's worth sending him a message about testing one.

I'm gonna shoot him a message. That's not a terrible idea.
 
I looked briefly at the DRAC and I don't think it has enough range to convert from a 8.8 VSS to 240 ABS/Speedo.

The 240 ABS and Speedo expects a 48-tooth ring off the axle. A 205/60R15 tire gets 817 rev/mile. Multiply this by 48 and you get 39216 pulses per mile. The number on the face of the 240 speedo is the calibrated PPM, e.g. 39200.

If I understand correctly, the 8.8 is normally a 40-tooth sensor off of the driveshaft. With a 3.73 diff, and the same tire as above, this results in 817 * 3.73 * 40 = 121896 PPM, or roughly a 3x higher rate than what the 240 ABS/speedo needs.

The DRAC is a PLL based frequency converter. From the "input ratio" charts, it can rescale with a frequency multiplier of 0.5 to 2.0, based on the jumper settings. This isn't enough range -- the 240 speedo would need an "input ratio" of 3.0. This is off the charts of the available jumper settings.
 
Seems to me the solution is already in here on page 2. Cut a new reluctor ring or modify the one in the axle, and use the ford abs sensor. Several members reported success.
 
I looked briefly at the DRAC and I don't think it has enough range to convert from a 8.8 VSS to 240 ABS/Speedo.

The 240 ABS and Speedo expects a 48-tooth ring off the axle. A 205/60R15 tire gets 817 rev/mile. Multiply this by 48 and you get 39216 pulses per mile. The number on the face of the 240 speedo is the calibrated PPM, e.g. 39200.

If I understand correctly, the 8.8 is normally a 40-tooth sensor off of the driveshaft. With a 3.73 diff, and the same tire as above, this results in 817 * 3.73 * 40 = 121896 PPM, or roughly a 3x higher rate than what the 240 ABS/speedo needs.

The DRAC is a PLL based frequency converter. From the "input ratio" charts, it can rescale with a frequency multiplier of 0.5 to 2.0, based on the jumper settings. This isn't enough range -- the 240 speedo would need an "input ratio" of 3.0. This is off the charts of the available jumper settings.
I usually see a sensor above and behind the pinion flange, but reading the tone ring next to the ring gear. Usually 108 teeth.
(on explorers)
 
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Seems to me the solution is already in here on page 2. Cut a new reluctor ring or modify the one in the axle, and use the ford abs sensor. Several members reported success.

I read that it was bouncy. I would imagine that would cause the ABS unit some issues.
 
Likely because of unevenly spaced teeth, 130/48 means you cut off every 2.7 tooth on the wheel. Obviously not gonna work well. Best to fab a new wheel with 48 evenly spaced teeth.

Could also cut a wheel that bolts onto the driveshaft flange. You'd have to divide 48/ the gear ratio to get the correct teeth, and make a bracket to hold the volvo speed sensor.

I'm just throwing out ideas I've had recently to get the speedometer working in my welded diff car thats missing the tone wheel. I was gonna try to run it off a front ABS sensor but obviously your ABS would have to be decommissioned, mine already has been.
 
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