Abbott Ratio Adapter Question
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Joined: Dec 2004
Posts: 66
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From: Kansas City Missouri
Abbott Ratio Adapter Question
Hello Everyone,
I am in the process of installing the Abbott ratio adapter in my 91 with auto. Have the Helms manual but it is not real clear if the purple or yellow wire from VSS is input or output. Anyone know which is which? Also, where is the best place to pick up an ignition on hot wire. I am thinking about putting the box in the compartment behind drivers seat where the ABS system is located for easy access but have concerns about using the wires for power and ground because I do not want to take a chance messing up ABS. Thinking of running hot from dash to compartment but which would be the best/easiest. Any help would be appreciated.
I am in the process of installing the Abbott ratio adapter in my 91 with auto. Have the Helms manual but it is not real clear if the purple or yellow wire from VSS is input or output. Anyone know which is which? Also, where is the best place to pick up an ignition on hot wire. I am thinking about putting the box in the compartment behind drivers seat where the ABS system is located for easy access but have concerns about using the wires for power and ground because I do not want to take a chance messing up ABS. Thinking of running hot from dash to compartment but which would be the best/easiest. Any help would be appreciated.
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Joined: Dec 2004
Posts: 66
Likes: 0
From: Kansas City Missouri
Originally Posted by bogus
What is an Abbott adaptor?
Check the C4 Audio FAQ over in Audio.
Check the C4 Audio FAQ over in Audio.
It is an electronic ratio adapter for the speedo. It is used to correct speedo when changing rear end gears.
Drifting
Joined: Jun 2001
Posts: 1,704
Likes: 459
From: Mass Mass
I installed one on my 1988 automatic when I went from a 2.59 to a 3.54.
This is what worked for me
Two wires going to the VSS at the rear of the trans, purple and yellow. Cut/splice into the yellow wire near the trans.
White wire, from box to the VSS/trans side of the cut yellow wire.
Blue wire, from the box to the ECM/car side of the cut yellow wire.
Switch settings ratio, if you haven't changed the old vss & speedo gears, is your old ratio divided by the new rear ratio.
Example 2.59/3.54 = .732
I mounted mine behind the passenger side dash/crash panel.
Drilled small hole in the floor near the shifter and ran the wires up under the dash.
But I had already replaced the dash pad with a guage panel, so it was easy to get behind it and hook up 12volts.
Hope that helps
This is what worked for me
Two wires going to the VSS at the rear of the trans, purple and yellow. Cut/splice into the yellow wire near the trans.
White wire, from box to the VSS/trans side of the cut yellow wire.
Blue wire, from the box to the ECM/car side of the cut yellow wire.
Switch settings ratio, if you haven't changed the old vss & speedo gears, is your old ratio divided by the new rear ratio.
Example 2.59/3.54 = .732
I mounted mine behind the passenger side dash/crash panel.
Drilled small hole in the floor near the shifter and ran the wires up under the dash.
But I had already replaced the dash pad with a guage panel, so it was easy to get behind it and hook up 12volts.
Hope that helps
Thread Starter
Advanced
Joined: Dec 2004
Posts: 66
Likes: 0
From: Kansas City Missouri
Thanks for the info everyone. Tapped into yellow wire at VSS on tranny. Ran wires through rubber boot with cable from tranny to shifter than ran to console and compartment behind dash on passenger side. Tapped a red and black wire there for power. Just got back from test drive and everything seems to be working fine. Actually seems to have a little more punch.
Drifting
Joined: Oct 2004
Posts: 1,976
Likes: 0
From: Patchogue NY
Congrats on your install. A little more punch? I experienced a significant difference when I went from 2:59 to 3:54 gears. But, then again, you have to first break them in before you "really" blast the gears off the line, right?
Joe B.
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