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Explorer 8.8 VSS to 240 Speedo

The gear ratio doesn't matter. The sensor reads the rotations of the diff carrier/axles directly. Gearing only matters when you're 'upstream'. At the diff, all the gearing is already done.

What really matters is how many triggers per rotation. If you can get the same number as the Volvo axle uses, you're good.
True. That said:
If I am not mistaking, the original gear ratio in my car was 3.31:1. I have an automatic wagon if that helps.
3.73:1

Cut teeth if possible until there is 12
Yep. Even if one space ends up a little different, it will work.
 
The needle doesn't react quickly enough to register a change in speed based on tooth gaps being a little uneven as the diff turns all the way around. You know, don't leave all the remaining teeth in one spot, spread them around as evenly as possible, and rely on the latency of the needle to handle the remaining slight 'theoretical' unevenness.

Or just leave the oily metal bits alone and use the Dakota unit. That actually sounds like a nice alternative.
 
I wonder if the stock ABS system would be happier with the removed teeth or the dakota signals? Might not matter either way, the ABS shouldn't react so quickly as to false on a very slightly uneven tooth placement.
 
Just remember, I don't think this will keep your trip/odometer in check. They will continue to be off by the % that you deviated from the original resistor value. If you want the trip/odometer AND speedo to be dead on you need to fabricate a new ring like Lord_Athlon said. I have also read about cutting the ring off of a Volvo diff and welding it onto the ford 8.8" unit and then slightly adjusting with a pot. Let me see if I can find that.

This isn't about a ford unit but you may be able to do something like this.
http://www.davebarton.com/volvorearends.html

Some more info about the tone ring and peoples fixes
http://forums.turbobricks.com/showthread.php?t=204882
http://forums.turbobricks.com/showthread.php?t=280512

Here is a 108 tooth tone ring for the ford 8.8" axle. You could cut the teeth again like Lord_Athlon said to bring you down to an even 12
http://www.yukongear.com/ProductDetails.aspx?ProdID=1889

If they work on the input from the speed sensor in the diff then all you have to do is condition the signal before it is interpreted by the speedo/odo cluster.
 
The speedometer is controlled by a ITT UAF2115 chip. This chip is used in many cars of the same era, including the 7/900 series.
There is a calibration resistor in the cluster that will alter the speed shown by the meter. The trip/mileage counter calibration is not affected by this resistor.

That was the statement I went off of. I think the signal come into the speedo and then is split up between the odo/trip and the speedo. The resistor being adjusted is on the speedo side of things, the UAF2115 chip side of things.

That's how I understand it, but you are absolutely right if you can intercept/change that signal before it hits the cluster then everything would work perfect, the cluster wouldn't know any different
 
Lots of good ideas here. I have no clue of which route is best for me, but like everything else I've done I'm sure I'll figure something out.
 
There are more than plenty teeth to grind off to get the count you need. Had to do this with my electronic speedo. The tone ring in the exploder 8.8 gives too many pulses per mile for most aftermarket speedos.
 
Do all 240's have an electronic speedo ? My plans to put an 85 240 turbo motor and tranny in a 122 meet another wrinkle cause the cluster from a 140GT I've planned to use is cable driven. It was accurate in a 220 wagon with a 4.56 rear.
The new tranny is, I believe an M47 , no switch on the shifter but a 5 speed diagram. Is there possibly a speedo gear on the tail shaft? Haven't brought it home yet, just the 122.
I'm new, guys, should I have asked this in a new thread?
Jack
 
Gonna bump this up. Im at the point where Im doing the 8.8 swap and have a question.

8.8 explorer sensor. Does the polarity matter when connecting it to the Volvo 240 wiring? Ive already modified my tone ring down to 12 teeth and just need the driveshaft modified and then its time to drive the car again.
 
curious how that modified tone ring work out for you? I'm about to do a 8.8 swap on my 92 and want to keep the abs.
 
I'm not sure yet. Speedo worked just fine on the Volvo tone ring but the modified ring only read accurate and smooth from 70mph to about 110mph. Below that and it reads about 5mph high and bounces around a lot. Above 110mph and it just kind of hangs and doesn't climb any more.

Not sure if my speedo is having an issue or if I need to modify the tone ring more or change sensor. It's a weird result honestly and I didn't expect it.

In this video you can see the needle hovering around 110 or so even though I was doing 140 at the end of the pass.
<iframe width="560" height="315" src="https://www.youtube.com/embed/Hag9OvwUt4c" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
 
I don't think so after a little google searching.

I'm wondering if the sensor output is being weird even though its a 12 "window" setup like the factory Volvo speedo is used to seeing. One thing I can think of is that the material I removed wasn't enough and the sensor is picking up the mass of the ring a little and throwing it off.
 
There was a similar thread not all that long ago where someone linked to a site that makes custom tone rings.

Other than that, there are stock 49 and 50 tooth rings, but they fit different flavors of the 8.8.

I actually ended up buying the 8.8 axle volvowagoon was talking about in the original post, I still want to put that in the 245 at some point and keep ABS working properly, as well as speedo/odo.
 
It was me posting about tone rings. They're expensive, you don't want to go there.

Use the Dakota unit, or if you are really cheap, you can almost certainly convince a GM DRAC module to do what you want.

Keeping ABS will be harder, but still doable - the challenge will be getting the signal out of the converter to look enough like the signal from the pickup so that the ABS unit is happy with it. The DRAC is more likely to help there, but you'll still be doing some fiddling with resistors.
 
I want it for abs. the dash speedo working is nice too, but I mainly want it for the abs.

Expensive is relative
 
I think I'd figured out a pretty even pattern of grinding teeth out of the 130 tooth ring to arrive at 48 teeth.
 
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