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View Full Version : Need the K-Value for 400E speedo with 2.65 diff ratio



Rouven036
01-30-2015, 09:32 AM
Hey guys need your help, I want to send my AMG 300km/h speedo to vdo for refurbishment (drive gears) and to adjust it to the 2.65 diff ratio. For this I need the speedometer k-value of a 400e with 2.65 diff ratio.

Tanks and regards Rouven

samiam44
01-31-2015, 06:47 PM
K=2.65/2.24

M

gsxr
01-31-2015, 06:56 PM
I think me means the calibration number. For the 500E that is K=9086. I do not know the 400E Euro number, sorry, Rouven...

https://www.500eboard.com/forums/images/imported/2015/01/182.jpg

Rouven036
02-01-2015, 07:35 AM
Hi Dave, yes this is what I m looking for...

Rouven036
07-09-2015, 07:14 AM
In the meantime I've figured out the required K-Value and the speedo is off to VDO for refurbishment. If you ever want do this you must calculate it as follows: 1000 (meters or 1600meters for mph/h) : dynamic Tire circumference (standard 036 wheels 225/55 r16) is 1,994(m)=501.5 (wheel revolutions per km) * 2.65 (wanted diff ratio) =1328.99 * 4 (segments on the speedo pulse wheel inside the tranny) = 5316 pulses per km = wanted k value

Christian_K
07-09-2015, 08:34 AM
In the meantime I've figured out the required K-Value and the speedo is off to VDO for refurbishment. If you ever want do this you must calculate it as follows: 1000 (meters or 1600meters for mph/h) : dynamic Tire circumference (standard 036 wheels 225/55 r16) is 1,994(m)=501.5 (wheel revolutions per km) * 2.65 (wanted diff ratio) =1328.99 * 4 (segments on the speedo pulse wheel inside the tranny) = 5316 pulses per km = wanted k value

Thanks. But if i put a 300kmh in it, it will read it wrong anyways as stock its 260kmh in europe. How to adjust the K Value? Can only VDO do this? Because i also think about putting in the 300KmH speedo-plate that one US guy offers on Ebay.


Regarding the E420 Diff+Speedo combo: Does the .034 has the same tires as the 500E or the same circumference? Because i have a 2.65 Diff and fitting Instrument Cluster here from a Donor E420, so that would mean if i put the Diff and IC in my 500E, it would still read a bit off?

gsxr
07-09-2015, 09:47 AM
Thanks. But if i put a 300kmh in it, it will read it wrong anyways as stock its 260kmh in europe. How to adjust the K Value? Can only VDO do this? Because i also think about putting in the 300KmH speedo-plate that one US guy offers on Ebay.
I don't know how, but yes the speedo can be adjusted to a 190mph or 300kph faceplate. A VDO repair shop modified my speedo to work correctly with a 190mph faceplate. Both the speedometer and odometer read correctly. Internal modifications were required, cost was around $150 USD, and this was probably 10 years ago.



Regarding the E420 Diff+Speedo combo: Does the .034 has the same tires as the 500E or the same circumference? Because i have a 2.65 Diff and fitting Instrument Cluster here from a Donor E420, so that would mean if i put the Diff and IC in my 500E, it would still read a bit off?
400E uses same tires as all other 124's, smaller than the 500E. So yes, if you put a 500E diff+speedo in a 400E, it will be off around 3% unless you also change tire size.


:pc1:

Rouven036
07-09-2015, 03:15 PM
Absolutely correct Dave, the speedo (no matter if electronic driven like in 124 v8 models or mechanical as in the smaller versions) have a setting depending of gear ratio, differential ratio and Tire size. Of course you have (should) send your speedo for recalibration if you change the dial unkessyou are an show tuner ;-)
The adaptation is done by changing of drive gears on the mechanical ones and by modifying the frequency counter (quartz?) on the electronic versions.

@Christian, I send my stuff always to VDO Gleichauf. They can make new dials in absolute original layout.

gsxr
07-09-2015, 03:26 PM
BTW... looks like K=7428 for USA/Japan spec 124.034 with 2.24 gears. Pics attached.

Christian_K
07-11-2015, 06:28 PM
Wow Rouven. So what is the price for a 300KMH Dial? I really want one in the near future :-)

Rouven036
07-12-2015, 02:01 AM
There is an original AMG 300km/h dial currently offered on German ebay. The seller asks as little as 600 euros for it. As said, the dial alone is just something for show posers... VDO charges me for the overhaul of the odometer drive and adjustment of the K-Value 350 euros. I had done with them the tachometer (rpm gauge) of my Evo before, there they made a new dial and adjusted the electronics for a higher rpm range. It cost me also something near to 350 euros.