un-normal VSS question

[doc76251]

So I was thinking........ dangerous concept I know

Has anyone ever considered putting in a different VSS for larger size wheels n' tires. Say one off an Exploder with 255's into a Ranger w/ 225's to see if it would calibrate the speedo?

Cheers

Doc

 

[4x4junkie]

Not sure if I understand the question...

The VSS sensor in the axle is the same part no matter if it came from a strip-model 4-cyl truck with a 7.5" & P195 tires, or a 4WD 4.0L Ranger having a 8.8" and P265 tires. The speedo calibration is done through the PCM.

 

[doc76251]

That I guess would be the answer. The VSS has no effect over the speedometer other than it sends info to the PCM where it gets translated. I just had a thought that by swapping out the VSS (equivalent to the old school gear swap) you could change your Speedo' calibration w/o doing the whole PCM change thing which costs $$$$$ at the stealership

Cheers,

Doc

 

[yyc_tbird_sc]

There are two kind of Vehicle Speed Sensors. One is gear driven in either the transmission or transfer case. It was a plastic toothed gear on it. This gear can be changed. I can't remember, but I think there is about 7 or 8 different toothed gears available. These will get you close, but most likely it won't put your speedometer right back on like reprogramming will.

The other version uses a hall effect sensor. Essentially a magnet and a sensor, with a toothed wheel passing in close proximity to it. This kind of sensor is found the in the rear diff on the carrier. Unfortunately there is only one version of this out there and it won't matter if you swap it out for another from a different vehicle.

If you don't want to reprogram the computer, there are different boxes that tweak the signal from the VSS to account for larger tires or different gears.

 

[hondaxr650]

That I guess would be the answer. The VSS has no effect over the speedometer other than it sends info to the PCM where it gets translated. I just had a thought that by swapping out the VSS (equivalent to the old school gear swap) you could change your Speedo' calibration w/o doing the whole PCM change thing which costs $$$$$ at the stealership

Cheers,

Doc

Reprogramming for a different tire size isn't a big deal. A dealer should charge you at most 1 hour labor to do it and it doesn't take anywhere near that long. No parts involved, just changing the revolutions per mile in the module. Probably a whole lot cheaper than some aftermarket module to let you do it yourself. I know a lot of you guys have had bad experiences at shady dealerships but we're not all bad.

 

[bobbywalter]

depending on setup you can mod the psom yourself as well. i have done some fullsize trucks, but i dont remember the exact details. the new tuners make it all cake