Speed Cal .... or not?

SeventyMach1 · Nov 16, 2005

Well, as I've stated before .... my speedo is way off. The car had a lower gear installed when I got it. (previous owner said they were 3.73's) It reads like 45 mph when I'm actually going around 65-70 mph. I have yet to use the "turn wheel-watch drive shaft" method to see what they are .... but I'll get to that here soon.

I don't know much about this stuff .... so my question is .... if I find out what gear it has + known tire size .... can I just get a Speed Cal to fix the problem? Or do I have to get a new gear for the speedo or tranny? I just want it to work properly.

95COBRA241 · Nov 16, 2005

I'm curious myself as to whether or not the speed-cal works for our year cars? I've heard yes and no.

Thta's weird that yor car reads slower than actual with higher numerical gears. Usually its the other way around like 70 when you're really going 62.

95BlackTan50 · Nov 16, 2005

I've got a speedcal in mine and it works fine.

It is strange that the MPH is reading lower than your actual speed. It should be the other way around since the VSS is turning faster than it used to with the lower gears. Maybe someone already changed the speedo gears?

FlyBy763 · Nov 16, 2005

I have the SpeedCal. It has worked great for me so far, speedo seems to be dead nuts. Worth it if you have the money.

SorsCode · Nov 16, 2005

get the speedcal

final5-0 · Nov 16, 2005

Well

There always has to be one who don't go with the crowd I guess, lol.

I just did the 23 tooth gear thing and never looked back.

It reads a couple fast when cruising around the city streets and about 3 to 4 fast at highway speeds.

Don't bother me in the least little bit.

Been doin it that way since 1997 with no probs of any kind.

Grady

CManT1914 · Nov 16, 2005

Speedcals do work, I didn't know this either until a few weeks ago.

I also say it's strange that your speedo is reading slower than you're going.

FWIW, I'm with Grady on this one. I just did the mechanical gear in the tranny, and it's dead on at 70 with my slightly bigger tires. Stock sized tires it will read maybe 3mph faster at 70. In town it's minimal.

HoofnIt · Nov 16, 2005

Dallas Mustang's website says the SpeedCal will work for 94-04. The driven gear in the tranny mechanically turns the speedo gear which mates to the Vehicle Speed Sensor which is electronic. There are multiple electrical wires that connect to the VSS.

SeventyMach1 · Nov 16, 2005

Yeah I called them today. (their website said "for 96-98" & "for 94-98") I called them to confirm that it will work on our cars. They said it will & they run for $99. I guess I'll be getting one ... but one more question ....

Does it matter what driven gear I have in the tranny or whatever? Will the Speed Cal work right as long as I have the correct rear end gear ratio & tire size?

95WhiteVenom · Nov 16, 2005

humm thats something to look into mine reads 5mph slower than im really going. I may have to invest in one of those things.

HoofnIt · Nov 16, 2005

As far as the speedcal you need to know what your rear gear ratio is and the ratio your speedo gear is for. For example if my speedo gear is for 2.73 and I switched to 4.10s then I will use the speedo gear (2.73) to look up the first binary code. The second binary code will correspond to the new gear ratio (4.10). Did this make any sense? So, SeventyMach1 you will need to find out what speedo gear you have ie. how many teeth, as well as your rear end ratio. I hope this helps.

krahkin · Nov 17, 2005

Another vote for SpeedCal here. Installed and never regretted it. The only thing I did different was I wired the power to a switch on my ashtray panel. I hate things staying 'on' all the time.

xkuntrycowboyx · Nov 17, 2005

Those of you saying that it's weird that it reads lower than actual....
Im having the same problem. I bought the car with the speedo off, they'd changed to aftermarket wheels.
Mine reads 47 when im at actual 55mph.

was wondering how to fix this myself, and WHERE are the gears that need changed?

xkuntrycowboyx · Nov 17, 2005

HOOFIN... As far as the speedcal you need to know what your rear gear ratio is and the ratio your speedo gear is for. For example if my speedo gear is for 2.73 and I switched to 4.10s then I will use the speedo gear (2.73) to look up the first binary code. The second binary code will correspond to the new gear ratio (4.10). Did this make any sense? So, SeventyMach1 you will need to find out what speedo gear you have ie. how many teeth, as well as your rear end ratio. I hope this helps.

i don't understand... could you help me out

I now have 3.55's in the rear, and 17in. wheels, could u try to figure it up for me, thanks! i'd appriciate it.
@d@m

krahkin · Nov 17, 2005

Go here and see the calculator: http://dallasmustang.com/page/speedcal.calc.php

final5-0 · Nov 17, 2005

xkuntrycowboyx said:
i don't understand... could you help me out

I now have 3.55's in the rear, and 17in. wheels, could u try to figure it up for me, thanks! i'd appriciate it.
@d@m

It really is about tire diameter and not so much about 16 or 17 inch wheels.

Look at the link krahkin gave you and here is another one for you which I would bet is similar.

http://www.allfordmustangs.com/Detailed/608.shtml

Grady

88GT460 · Jan 27, 2006

I just got my speedcal from dallasmustang for $89.99 plus shipping. cheaper than the website

Speed Cal .... or not?

SeventyMach1

Keep it lubed .... keep it straight .... and keep

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