Speedometer calibration after 4.11 swap

[lee]

Originally Posted by pavanbabut

Guys, come on, some one help us what we can do to rectify this. We are not saying that the speedo off is due to transmission faults or someother. Just we don't know what's causing this. Give us your ideas on what we can do. As far as we can say-

1) There is no mismatch of tire sizes and they are all of stock size and are same as they are on old tranny.
2) Stock speed sensor is installed

we are trying to say tht the only ones that are been changed are the tranny and the rear end. Hope now you can get what we are trying to say.

-Pavan.

the problem with answering this (I predict) is there won't be a single answer. I can tell you that most every day I pass one (sometimes 2, even 3 on rare occasions) of those unmanned radar trailers on the side of the road (the police around here really like them, every little town up & down Highway A1A uses them). I presume they show you your speed in the hope you will slow down (pretty rare to see traffic flow at/below the limit during the morning rush). Anyway, I saw exactly zero difference in speedo readings at any given indicated speed from before, to after the swap going from OEM SVX transaxle to 4.111 using a '98 Imprezza transaxle (and matching 4.111 from a '97 Legacy).

[blacknite]

i did notice a 10 mile difference between what my speedometer read and what the radar said (with the 5 speed 4.11). after i put the knew rims a get an empty gas at about 240 miles and before it was at around 340. so what ever it is i really don't think is accurate...

[svxfiles]

I have driven 12 different SVXi that have either 4.44s or 4.11s, and some of them are exactly right on, some are very close.
It seems to me it would have to be the sensor in the bell housing, or the speedometer itself.
Since it is so much easier to trade out the sensor, I would try that first.
Pavan, pm me your mailing address and I will send a sensor for you to try.
Please send me your old one.
When you install the new sensor, make sure it seats properly.
Or stop by at the shop and I'll install it. Tom

[pavanbabut]

Originally Posted by svxfiles

I have driven 12 different SVXi that have either 4.44s or 4.11s, and some of them are exactly right on, some are very close.
It seems to me it would have to be the sensor in the bell housing, or the speedometer itself.
Since it is so much easier to trade out the sensor, I would try that first.
Pavan, pm me your mailing address and I will send a sensor for you to try.
Please send me your old one.
When you install the new sensor, make sure it seats properly.
Or stop by at the shop and I'll install it. Tom

Thanks Tom for your reply. Please dont misunderstand me, we are just trying to know why this is happening. At present my car is not with me, but I tested it many times while I drove it and even talk about this many times with Mark too. As soon as i ship my car to my place, I will let you know. At present I am using Mark's sensor. I think stopping by your shop will not happen again as I moved to west coast

-Pavan

[benebob]

[QUOTE=svxfiles]Since all the transmissions I have looked at were WV and MD transmissions, there is NO UNIFORMITY TO THE TEETH!!!

QUOTE]

HEE HAW!!!

[Chiketkd]

Originally Posted by benebob

HEE HAW!!!

Nice one Ben!

-Chike

[svxfiles]

Here is a picture of the inside of the front differential.
You can see the green plastic gear on the right side.

There are moore pictures i my locker.
http://www.subaru-svx.net/photos/use...svxfiles|30258

[oab_au]

Originally Posted by svxfiles

Since all the transmissions I have looked at were WV and MD transmissions, there is NO UNIFORMITY TO THE TEETH!!!

OK, that was fun....

As long as the teeth were of the same #, and they drove each other, the angle is not important.
However, the HAL effect speedometer sensor COULD be affected by the distance when seated. I do not know this for certain, but it "sounds logical"
Harvey, can the third wire be a shielding wire if it does not surrond the two pulse carring wires?

As the Euro version does not have the speed sensor in the front diff, it is driven by the parking gear in the box, I am only guessing. It is showen in my book as a sheild.

Which model has a Hall effect pick-up?. Hall and magnetic pick-ups are not compatable. The Hall gives a 0 to 5Volt square wave sig. The magnetic gives a zero crossing sine wave.

Harvey.

[drivfour]

I bought a 96 legacy 4eat to put in theee svx. The speed drives at the rh axle are different one is square one drive is a slot- so it does not appear I can put the 3 wire svx into the 96 legacy housing. Any ideas?
thanks

[AJ4U2]

Originally Posted by lee

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?

The speed sensor is doing what it is surpose to do,need to slow down the speed sensor< it is messuring the speed of the alxe that is turning, say the svx was turing 50 times and now it is turning 60 times because of the smaller gears, so you will have to change the speedo gears, say4:11 has 40 splines and the svx has 60 that means the speed sensor is counting revolotion per alxe, it is not the sensor it is the speedo gears itself, because the axle is turning faster,your right it is decoding the signal but it is for the 4:11 not the 3:54, The samller the gear the faster it turns, the speed sensor is desisgn to work with the 3:54,not the 4:11, I have not got into this yet since i am still in the process but somehow it has all got to match from one tranny to the other, The speedo gears are spline with more or less and the speed sensor has got to signal it has 4:11 or 4:44, you might have to change the gears on the axle shaft to match the speed sensor, If i am not mistaken the speedo on the axle has 41 spline while the sensor has 10 and the stock has 35 while the sensor has 10 so big difference in ratio, don't know if speedo gears are interchaneable or not, You can take to the speedo shop where they calabrate them buy moving the spring on the dial behind the speedometer they either tighten it up or back, it just like the old time clocks when they were fast you move the spring tension one way or the other about 60 bucks here in NC, best way to go, Just some thoughts on this, it does fix the mileage to
I might be all wrong on the SVX but i know on GM you have to match all the speedo gears to be correct, you got to change the speedo gears in the trans and the sensor gears to be correct, when you change out 3:55 to 4:10

[pavanbabut]

Hi all,
Any updates on this issue??

I am having a doubt, even if we adjust the needle to exact position (say while crusing at 60mph using GPS as reference), the total miles reading will still have wrong miles on it (I mean more miles than it actual had on it), right??

thanks,
-Pavan.