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#1 |
Board Member
Join Date: Jul 2012
Location: India na
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![]() I'm sure that there aren't many if any people on here who have thought about this, but I'm determined to keep the factory gauges in my '89 240. I think the speedometer is going to be the biggest pain in that though.
If I am not mistaking, the original gear ratio in my car was 3.31:1. I have an automatic wagon if that helps. The new Ford unit I'm guessing is a 3.73:1 because the VSS only comes on the differential if the Explorer is 2WD. A rough estimate by look spinning the rotor once and counting the pinion rotations indicate closer to this than the 3.27:1 ratio from a 5-speed. Weren't there 240s with factory 3.73s? If so, does anybody know what speedometer was used with it and if it was electric? Of course, there are other factors. I don't know how the Ford sensor operates other than that it's a VR. I haven't counted the reluctor wheel teeth or measured distance between wheel/sensor on either of the rear ends yet to see, but I'm hoping somebody knows enough to say "yeah it's easy" or "not worth your time" before popping the new dif cover off again. I know that I didn't offer a lot of solid information, but I was mostly hoping to find somebody who has been through this already. Otherwise, I will attempt to be a pioneer! Thanks everybody.
__________________
1986 Buick Grand National 2002 Camaro V6 M5 +turbo 1989 245DL - Girlfriend's car IG: @v6buick |
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#2 |
Ronald Culberbone III
Join Date: Feb 2010
Location: Portland, OR
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![]() Dakota Digital offers an electric speedometer adapter/controller/signal manipulator thingie. Sounds like it's what you want to use.
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#3 |
Board Member
Join Date: Jul 2012
Location: India na
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![]() That looks nifty! Dakota digital is a pretty trusted brand too. I will have to read into it a little more.
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#4 |
PV Abuser
![]() Join Date: May 2004
Location: St. Louis
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![]() 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.
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'63 PV Rat Rod '93 245 16VT Classic #1141 |
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#5 |
Ronald Culberbone III
Join Date: Feb 2010
Location: Portland, OR
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![]() ^ Before you buy anything, pull the cover on the Ford diff and count the teeth. I seem to remember them being 40+ teeth.
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#6 |
Board Member
Join Date: Jul 2012
Location: India na
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![]() Ahh yeah... brain fart. The ring gear is going to spin at the same speed regardless of ratio. I didn't bring wheel size into play though. My new ones will be bigger and there is no use going through too much trouble for a wrong signal. The Dakota Digital universal signal interface is probably my best bet if I want to do it right.
How many teeth are there on the Volvo? |
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#7 |
Ronald Culberbone III
Join Date: Feb 2010
Location: Portland, OR
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![]() 12, what ever ABS is (24 or 48?), and I think another one. Definitely significantly less than what the Ford 8.8 used (at least the truck ones that I have been into).
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#8 |
Board Member
Join Date: Jul 2012
Location: India na
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![]() I found 49 and 50 tooth wheels on Summit. I guess that's the job for the signal interface. I'm reading the manual for that controller you talked about, and it seems like a really helpful piece!
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#9 |
Ronald Culberbone III
Join Date: Feb 2010
Location: Portland, OR
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![]() You could also just get a GPS speedometer. That might fit into a gauge cluster, maybe.
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#10 |
They see me trollin'
Join Date: Dec 2008
Location: Cold Lake, AB
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![]() The factory explorer ABS tone ring is 130 teeth.
__________________
'88 245 - 2JZGTE VVTi | MS3X ECU, MS2 TCU | GT3582R-HTA | Staged simultaneous dual fuel | 590whp 580ftlbs 1968 Furd Rustang fastberk | 2JZGTE VVTi | MS3X ECU | PT6776S | 4L80e Microsquirt TCU Sloppy Transbrake | 3.73 8.8" rear end 1981 Piper Cherokee Archer II | All stock |
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#11 |
Turbo LS ****poster
Join Date: Jan 2013
Location: Kenly, NC
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![]() If you can get the speedo to read the signal coming from the diff, even if it's WAY off you could just replace the resistor that calibrates the speedo with a pot and adjust as needed. I have a 0-100 ohm installed and it is enough to wildly change the speedometer calibration.
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#12 |
Board Member
Join Date: Jul 2012
Location: India na
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![]() I want a factory gauge as well as the bezzel.
A pot could working too. Which resistor is it? Do you have a pic? |
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#13 |
Chuckie Blows
Join Date: May 2003
Location: Hillary's Emails
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![]() Cut teeth if possible until there is 12
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#14 |
Board Member
Join Date: Jul 2012
Location: India na
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![]() lol maybe if 130, 50, 49 or whatever it is was divisible by 12 that would work. Otherwise, the needle will bounce, and that would annoy the **** out of me.
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#15 |
Chuckie Blows
Join Date: May 2003
Location: Hillary's Emails
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![]() Then fabricate a new ring.
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#16 |
Turbo LS ****poster
Join Date: Jan 2013
Location: Kenly, NC
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![]() http://forums.turbobricks.com/showthread.php?t=239021
https://www.brickboard.com/RWD/volvo...eedometer.html Is there I got my info to swap out the resistor for a pot. You could also temp install the pot and tweek it until your speedo is dead on with a GPS or something and then remove the pot at it's current setting and replace it with an equal value resistor. I don't think you need to mess with the ring at all if you can bring the speedo into calibration by adjusting the value of the resistor. Photos here also of how somebody ran the wires for the pot. http://forums.turbobricks.com/showpo...7&postcount=23 Last edited by Andrewhans; 01-19-2015 at 11:11 PM.. |
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#17 |
Board Member
Join Date: Jul 2012
Location: India na
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![]() Good links! Thanks. This will make one part of my build easier.
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#18 |
Turbo LS ****poster
Join Date: Jan 2013
Location: Kenly, NC
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![]() 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/ProductDeta...px?ProdID=1889 Last edited by Andrewhans; 01-19-2015 at 11:47 PM.. |
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#19 |
Board Member
Join Date: Jul 2009
Location: Chicago, IL
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![]() I have the dakota unit in my 940. works pretty well. My car had ABS so 48 teeth was OEM.
__________________
1993 Volvo 940 Turbo - B230FT + 16V - M90 - MS3x - HE351CW - Methanol injection - Ford 8.8 1980 Volvo 242 GT - B5254T - M90 - MS3x - HE351CW - 17Z - E85 |
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#20 |
Board Member
Join Date: Jul 2012
Location: India na
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![]() Ahh well that changes everything. I want the odometer to work too. I should have remembered that those two work semi independently. I guess I will look into tone ring mods.
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#21 | ||
The MP
Join Date: May 2003
Location: 38° 27' N 75° 29' W
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![]() Quote:
Quote:
Yep. Even if one space ends up a little different, it will work. |
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#22 |
PV Abuser
![]() Join Date: May 2004
Location: St. Louis
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![]() 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. |
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#23 |
What, me worry?
![]() Join Date: May 2003
Location: Acworth, Ga. USA
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![]() http://www.dakotadigital.com/index.c...roduct_id=126/
Thats the Dakota item- decodes input and outputs to your speedo. Its adjustable- use gps speedo app On your phone and adjust until it matches
__________________
I coulda had a V8! |
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#24 |
PV Abuser
![]() Join Date: May 2004
Location: St. Louis
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![]() 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.
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#25 | |
Bad for Babies
Join Date: Feb 2006
Location: USA
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![]() Quote:
__________________
RIP BADVLVO 3/1/1980-10/10/2015 Died at age 35 93 245 m47 300k miles, one owner, zero compression |
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