Speedometer calibration after 4.11 swap
 

I've got my 4.11 trans and rear differential swapped into my 1992 SVX. Everything works great, but I've found that my speedometer now reads about 10% faster than my actual speed. Has anyone come up with a solution to this problem. I'm not so concerned about the inacurate reading on the speedo, but I don't like the idea of clocking up 1.10 mile on the odometer for every mile I drive! If any of you SVX geniuses has come up with a fix for this, I'd appreciate hearing about it.
Thanks A Lot
Steve

Besides changing the rims.
 

I believe the fix is to swap out the speed sensor from the SVX box into the 4.11 box.

Harvey. ;)

Thanks Harvey, but I did use the SVX speed sensor when I did the swap.
Steve

We discussed this a while ago. A number of us have come to realize the SVX is usually 4mph slower than the speedo. Kinda goes along with the pessimistic gas gauge.

Pessimistic gas guage. It down right lies. Drove on empty for 20 miles and still had 7 gallons left.

You mean there's no way to calibrate the speedo properly? It would suck to have to run taller tires to offset the gearing change... You'd lose any benefits the shorter gear set would provide in acceleration, etc.

Well you could reposition the speedo needle using a GPS to calibrate your speed. I believe Lwin/Seraph does this with every SVX he goes through.

The problem with re-positioning the needle is that my speedo is about 10% off. The inacuracy is not linear with increased speed. So the difference between indicated speed and actual speed increases the faster you drive. For example 70 mph indicated = 63 mph actual or 7 mph off, 90 mph indicated = 81 mph actual or 9 mph off. If I were to simply re-position the needle, the speedo would only be truly accurate at one speed.

I think I've heard of an electronic box that can be wired in with your speed sensor that will allow corrections. Has anyone else heard of such a thing?

Steve

Yes that is correct. The difference is a percentage and moving the needle won't be perfect but it will be a little more accurate. I do not know of anyone here using an electronic device to calibrate their speedometer yet.

Check out this link: http://www.terf.com/SpeedChangerPage.htm

There are others out there as well. Some don't work with AWD or ABS. This company has experience with Subarus and hasn't had any problems.

Are our speed sensors 2-wire or 3-wire?

You can also do a google search for "electronic speedometer calibration" or "electronic speedometer recalibrator"

.

Ours are 3 wire

^^^ a.k.a. 'Hall Effect'.

I am also having the same exact problem with my speedo after my 4.44 swap, but i didn't get an exact or approximate remedy to correct it.

I would be more than happy if someone comes up with something to correct this.

-Pavan.

Could someone explain how this error could happen by a swap?

My understanding of the speedo setup is that a gear is driven from the right side axle, which in turn does some magnetic signaling that gets decoded and sent on to the speedometer.

My point is the speedo, since it's driven by axle revolutions, should register exactly the same (good or bad) before & after, regardless of the ratio installed.

So, which automotive class do I need to take over again?