SPEEDO Calibration Shop?

[drivingslow]

Well, it is a laugher...

Just redid the DRIVESHAFT and now was caught speeding.

Sure, I knew my speedo wasn't telling the truth, as it is an old DYNA rear end, and the speedo is often 8 to 10 to 15 miles off.

Question, anyone in the NJ - NY Arena, know of a good spot to have the calibration service done?

I was going to do it myself with a kit, but the local fine LAW Enforcement would like a receipt from PRO-SHOP.

Figures, when I get her running very kindly, they spoil the fun.

Just doing their job I suppose.

Would appreciate the tip, closest place that still does the 'OLD SChool' calibration is 4 Hours away.

[70cstjr]

i dont know how to answer your question i just wanted to say how ironic that your screen name is drivingslow maybe we should put in a change of name for u
but i think the dealers can do fix the speedo for u...or i thought they used too

[cdowns]

i've always found local tranny shops either did it or could refer me to the right person who does the work

[piecesparts]

I cannot believe that you could do the speedo work and go to them and let them clock it to prove the MPH is right. A receipt is NOT always easy to get. The cops in my area would accept that, if the speedo shop is not around

All you need to do is change the drive or driven gears in the tranny output and then have the speedo checked on a highway using a stopwatch and a calculator. I usually carry those around in my console---it has gotten me out of a ticket in the past. My MPH chart was better than the one the HIPO was carrying. Any auto or tranny shop can do it. Start with you gear ratio, go to the tranny output ratio and use tire size to calculate the MPH that you want. Use the GM parts manual and find the right gear ratio numbers for your tranny---you may have to change the gear adapter as you make your changes.

Just remember 60 MPH X 60 seconds = 3600 and then just divide your seconds into that 3600 to calculate the MPH from there. It is easy. EXAMPLE: a 51 second mile = 70.5 MPH

[drivingslow]

Originally Posted by 70cstjr

i dont know how to answer your question i just wanted to say how ironic that your screen name is drivingslow maybe we should put in a change of name for u
but i think the dealers can do fix the speedo for u...or i thought they used too

hehehehe...

i thought the same and was waiting to here it from someone.

the thing is, the C10 has never run this fine ever, and it was fast to begin with...

it is amusing, as i was joking about making it run as it used to, so i would be still 'drivingslow'.

thanks for the insight.

all the shops around i have checked, use the new computer code to set speedos.

found one in PA, and might take a trip.

the local finest, were eager to see me get it corrected.

it was one amusing conversation, by the way.

"Officer, Thank you, I know, I am sorry..."

[drivingslow]

Originally Posted by cdowns

i've always found local tranny shops either did it or could refer me to the right person who does the work

I have called all around, and most say they gave up that service long ago on a twenty - near thirty year old.

but I have one closer, within range, just looking for some more tips.

thanks...

[drivingslow]

Originally Posted by piecesparts

I cannot believe that you could do the speedo work and go to them and let them clock it to prove the MPH is right. A receipt is NOT always easy to get. The cops in my area would accept that, if the speedo shop is not around

All you need to do is change the drive or driven gears in the tranny output and then have the speedo checked on a highway using a stopwatch and a calculator. I usually carry those around in my console---it has gotten me out of a ticket in the past. My MPH chart was better than the one the HIPO was carrying. Any auto or tranny shop can do it. Start with you gear ratio, go to the tranny output ratio and use tire size to calculate the MPH that you want. Use the GM parts manual and find the right gear ratio numbers for your tranny---you may have to change the gear adapter as you make your changes.

Just remember 60 MPH X 60 seconds = 3600 and then just divide your seconds into that 3600 to calculate the MPH from there. It is easy. EXAMPLE: a 51 second mile = 70.5 MPH

HEY, thanks for the suggestion, I will call the Local Law Enforcement to see if they would except your fine idea.

THANK YOU.

[71Rat]

where in nj are you from? my buddy has a inspection facility and he let me run on it to set mine, my old shop had one and we did it for a few guys also... also some speed shops have chassis dynos and could help ya out.

i know a few places that should be able to help you out in northern nj (morris county)

[70c10]

The easiest way to figure your speed I found out from fellow board member 70GMCer was to use a GPS unit. As you drive it will tell you your rate of speed. I checked my dad's truck recently and it's off by 15 mph!. If you are not going to change the plastic gears yourself, at least you can let the trans shop know how much it's off.