Originally posted by SCooke
My '99 Ram has 35x12. 50 16. 5 BFG AT's on it and my speedo is therefore slow by almost 10% @ 60mph. Does anyone have the Abbott module installed in their Ram? How do you like it & does it completely get rid of the speedo error? Was it easy to install? Will it make the trip computer more accurate?
Thanks!
I have one on my '98 and it has worked flawlessly since I put good connectors on it. The Abbott box can be set to correct from 2. 5x to 0. 33x. You could correct tires from about 12" to about 90" (assuming stock tires are 30" diameter).
By design, it corrects the signal from the RWAL sensor to the CAB. With a slight modification, it will correct the signal from the CAB to the PCM, which is quite useful for vehicles with four-wheel antilock brakes.
A slight drawback is that it needs good, solid connectors and connections. My original problem was that the speedo would not operate under about 5MPH; this would interfere with the ABS at low speeds. Turns out the connectors I had crimped on were too large; the crimps didn't squeeze the wire tightly enough. When I switched to the proper size (pink, 22-18 ga. ), the problem vanished and the Abbott has worked flawlessly since.
I set mine by driving 100 miles as indicated by highway yard sticks, and dividing that by the elapsed miles on the odo. Then I lowered it by 1. 5%. Why? Because the tires change 3% in diameter from full tread to no tread. Hey! I'm *not* anal; just thorough.
As to the speedo, you'll likely find that, if your odo is dead on, your speed will likely be off. Mine can read 60, and radar will show me as 63 or so. As long as the odo is accurate, I can live with the off speedo. I believe federal law allows speedos to be off by up to 10% or so, maybe more, so I don't worry too much about driving slightly fast.
Installation of the Abbott box was fairly easy. You need a fused +12V power source; I tied mine in with the Add-A-Fuse I installed under the dash for my combo gauge and radar detector. You need a ground; there's one under the hood right near the CAB. You need to cut a wire on a CAB connector to 'splice' the Abbott box into the circuit. I used double-sided foam tape to attach the Abbott box to the top of the under-hood power distribution box; alternatively, you might have room to slip the box between the PDC and the fender.
Go for it!
Fest3er
(Gaaaaaaaaaaasp! ... Sorry. Forgot I could gab so much without inhaling. )
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