4.44 Swap done, now speed issue?

[kis86]

I just got my car back...outback 4.44 now in it. The thing is, my speedo seems to be quite a lot off..5mph at 40mph, and 10mph at 70mph!

Any idea why I don't get it...

[Trevor]

Originally Posted by kis86

I just got my car back...outback 4.44 now in it. The thing is, my speedo seems to be quite a lot off..5mph at 40mph, and 10mph at 70mph!

Any idea why I don't get it...

I do, but I will leave it to others to explain gear ratios and where sensing for the speedo is located.

[svxfiles]

Originally Posted by kis86

I just got my car back...outback 4.44 now in it. The thing is, my speedo seems to be quite a lot off..5mph at 40mph, and 10mph at 70mph!

Any idea why I don't get it...

Did you install an automatic trans?
If so, then the THREE wire speedometer sensor is located on the front right side of the trans, just behind the bell housing.
You have to sue the SVX three wire sensor.
They can be a bugger to install.
Is it all the way in?
Do you have another SVX speed sensor to try?
Tom
I just Re-read your post.
The speed sensor ONLY READS THE AXLE ROTATIONS!
So the gear ratios have NOTHING to do with the MPH readings.
If it is off now, it was either off before, went bad during the swap, or you never noticed it.

[kis86]

Is it possible that they left the outback speed sensor in, and that would make a difference? I didn't know it could even be used...the speedo does work, as does cruise etc and no cel on or anything.

[svxfiles]

Originally Posted by kis86

Is it possible that they left the outback speed sensor in, and that would make a difference? I didn't know it could even be used...the speedo does work, as does cruise etc and no cel on or anything.

The Outback sensor has TWO wires, so unless they re-engineered it they HAD to use the three wire sensor.

[Michael Blue]

Having the exact same issue, did you ever get this resolved?

Thanks!

[kis86]

No, I didn't. The speedo continues to work, but is consistantly off. I'm not sure what else to look at, so I guess I'll just get used to it

You've had the same issue after a 4.44 swap?

[Michael Blue]

Yup. It reads 30 at 25 and more than 80 at 70. I was told before the swap that'd be about 2-3 off, and the person who did it "used my dash clock and the mile markers on the road" to confirm it ("redneck radar", imho) although the local mobile radar stations disagree.

If there's a fix, I'm all ears.

[kis86]

Exactly the same as mine...is it possible others on the forum didn't notice the difference maybe? From researching on the net it seems the speedometer should be off after a gear ratio change. ANyone else care to give us some input...pretty please?

[kwren]

I think our SVX speedometers were off about 8-10% the day they were born!
In both of my SVXs they are with no modifications.

[Hocrest]

Since the SS reads the rotations of the axle, I think it has less to do with the gear ratio and more to do with the tire size on the vehicle that the "new" tranny came from.

Have you also checked your odometers? Find a stretch of highway at least 10 miles, but longer is better. Reset your trip odometer as you pass a mile marker, make as few lane changes as possible and do not get off at any exits. Then read the odometer when you pass mile marker +/-10. If you travel 10 actual miles and your car indicates 10.2, your indicated mileage/speed is 2% high.

Anything up to 5% is pretty standard.

[kis86]

haha anything's possible for sure...in mine i instantly noticed it had changed after the swap because I got on the interstate and was going wayyy slower than other cars when the speedo was at 80 mph, which isn't normal...at least here

Hmm...an interesting though Hocrest with the wheel size thing. The tranny came from a 98 outback. I wonder what tire size they have? Could you explain this idea a little more?

[crazyhorse]

From www.cars101.com
Outback tire size for 1998 was 205-75R/15
In other words the tires were considerably smaller in diameter than the OE 225-50VR/16 tires on the SVX.
Bigger tires causes an error in the speedo calibration in the negative. smaller tires cause an error to the positive.
If you go to a 40 series tire you'd be back closer to accurate on your speedo. Unfortunately I think both the looks & ride would degrade to a point that would make this not entirely practical.

[svxfiles]

Originally Posted by crazyhorse

From www.cars101.com
Outback tire size for 1998 was 205-75R/15
In other words the tires were considerably smaller in diameter than the OE 225-50VR/16 tires on the SVX.
Bigger tires causes an error in the speedo calibration in the negative. smaller tires cause an error to the positive.
If you go to a 40 series tire you'd be back closer to accurate on your speedo. Unfortunately I think both the looks & ride would degrade to a point that would make this not entirely practical.

I believe you guys have hit on something.
Reguarding tire size.
The 1996-1999 Legacy Outbacks came with 205/70/15 tires that (when new)are 26.30" tall.
The 1992-1996 SVX came with 225/50/16" tires that (when new) are 24.86" tall.
With the shorter tires an Outback (or SVX with Outback transmission) should read 105.5 mph when the car is traveling at an actual 100.
This, in todays world is pretty darn accurate.
I believe that some people are getting different readings because of speedometer inaccuracies, and a variance in ACTUAL tire sizes.
I have measured two different brand, brand new, 225/50/16s and had a 1.5" differance in circumferance!

However Subaru installed 215/55/16s at 25.31" tall on the 1997s, USING THE SAME SPEEDOMETER SENSOR!
This taller tire would read 98.2 when the car was actually traveling 100.
So Subaru allowed a 1.8% variance in their production cars.
More later,
Tom

[SSSVX]

Good info, OT.

Just wonder how accurate for the spdo from a manual swap?