Author Topic: My speedo needs recalibration!!! (Read 5991 times)

achtungE30 · « **on:** January 25, 2007, 10:54:06 AM »

I am fairly certain my speedo is off by 8-10mph once i pass the 55-60mph threshold...i know this because at an indicated 80mph, i am constantly tailgated and passed by angry drivers in newer cars. At that speed indicated, my seat of the pants tells me im i70-75.

I once approached a toll plaza at 50mph and it indicated 42mph.

I will have my cluster out soon to fix the odometer gear, while its out, is there any way to recalibrate the speedo while im at it? I've read years ago that e36s had a similar problem to which some dealer techs just bent the speedo needle a few deg backwards and it fixed the problem, although im not too sure i want to try this if someone has a better explanation.

EDIT, im back on 14" basketweaves.

Gunni · « **Reply #1 on:** January 25, 2007, 11:48:29 AM »

You can remove the needle and put it back a little higher,
then you should be within specs,
I had to do that to one fuel gauge so the amber light came on when it hit the red zone,

achtungE30 · « **Reply #2 on:** January 25, 2007, 01:28:16 PM »

well dont i need to do the reverse of that since my mph now is reading higher than it actually is?

how do i do that if its pinned at 0 now and resting at the needle stops?

Gunni · « **Reply #3 on:** January 25, 2007, 03:10:11 PM »

I forgot about the needle stop, maybe you should try finding a speedometer calibrator

Wizard · « **Reply #4 on:** January 25, 2007, 03:15:24 PM »

Have heard of this problem a lot with our cars....every one blames it on tire size (BULL)...Mine is running about 10% higher also....Still haven't found a solution....I have an extra 4.10 -- I may try to switch over the speedo sensor and see if that may work. I do not see any calibration screw on the back of the actual speedometer...

kowalski · « **Reply #5 on:** January 25, 2007, 03:20:12 PM »

http://www.miata.net/garage/tirecalc.html

stock tires are 195/65/14.

and yes it is because of tire size, most people arn't running stock tires, and this is why their speedo is off. My tires are 205/40/17 and that is why mine reads faster then i'm doing.

Wizard · « **Reply #6 on:** January 25, 2007, 03:47:41 PM »

Canada=kilometers.......You guys are always off...J/K

I run 195/65/14's so I should only be off 3.2% but mine is way higher....10% according to radar...

silverblades181 · « **Reply #7 on:** January 25, 2007, 06:09:03 PM »

From experience, all my E30s (4) speedos were optimistic by 5-10%. Must be in the algorithm bmw used to calculate the oscillations in the speed sensor in the diff.

johna · « **Reply #8 on:** January 27, 2007, 05:48:15 PM »

You can buy a device that alters the electronic signal from the differential such as this one... http://www.jaycar.com.au/productView.asp?ID=KC5435

BrandC · « **Reply #9 on:** January 27, 2007, 09:57:37 PM »

I constantly had gauge cluster problems on my VW MK3 VR6 (VDO). Then I found out about these guys:

http://www.tacomaspeedometer.com/index.htm

I sent out the cluster on my own dime, and it was $65 shipped after that to have my entire cluster recalibrated. Ask for a guy named Eddie.

sheepdog · « **Reply #10 on:** January 29, 2007, 02:00:37 PM »

Find someone with a gps, that is how I did it.

195/60-r14's will be off by 10%
At 55 on the speedo you are doing 50, at 66 you are doing 60, 77 equals 70, etc..

4000rpm is almost exactly 80mph.

Moving the needle only works if it is is off by the same amount all the time. Most are of by a ratio/percentage, in which case only a recalibration will help. Best just to know how far off it is.

Alpine003 · « **Reply #11 on:** January 29, 2007, 02:16:54 PM »

Quote from: sheepdog;18395

Find someone with a gps, that is how I did it.

You can also go through school zone or construction areas that have the radar setup to clock your speed and display it on the sign "Your speed limit is: "

Obviously, do not whizz by when school is in session or construction workers are present. :p

sheepdog · « **Reply #12 on:** January 30, 2007, 10:04:59 PM »

Quote from: Alpine003;18397

You can also go through school zone or construction areas that have the radar setup to clock your speed and display it on the sign "Your speed limit is: "

Obviously, do not whizz by when school is in session or construction workers are present. :p

Not as good, you have few speeds to get a good reading, you have to take your eyes off the road and focus on the sign and your speed. You also may see the speed of the car next to you.

Alpine003 · « **Reply #13 on:** January 31, 2007, 11:10:14 AM »

Quote from: sheepdog;18514

Not as good, you have few speeds to get a good reading, you have to take your eyes off the road and focus on the sign and your speed. You also may see the speed of the car next to you.

It worked for me. I can actually see the instrument cluster and sign at the same time. Holding steady throttle is no big deal for me. I know some hardcore "city" people that never take long highway trips and are unable to hold a steady speed though...

///Motorsport · « **Reply #14 on:** February 01, 2007, 03:08:06 PM »

I have same issues, running Azenis on weaves.
However, Seeing that I am 5 mph off at 25 in a 25 radar screen zone doesnt help me much. I'm worried about how off my speedo is up aorund highway speeds.

Just gonna cruise next to a friend while on the cell phone...

Author Topic: My speedo needs recalibration!!! (Read 5991 times)

///Motorsport