Hello everyone, my mercedes W123 2003 1978 94hp automatic has the final ratio 1:3,92.
driving at 100 km/h the engine rauns around 3400 rpm.
I want to change the final ratio using one of those final ratio:

- 3.69 from All 240D
-3.46 from All 300 non-turbo
- 3.07 from 300 turbo to 1984
- 2.88 from 300 turbo 85
- 3.69 from All 230 and 250

The car is driven 90% on highway and I don't know exactly witch one could be right for my mercedes.
Any suggestion please?

The lower the number, the more your acceleration suffers. I guess you already know this, right?
You'll save on fuel though.

__________________

1976 280C
SLOWER DRIVERS KEEP TO THE RIGHT.
DRIVE RIGHT PASS LEFT

Hello Tomas, yes i know this. The only problem is: do you think is not too low to install a 3,07?
Actually when you drive around 100 km/h it seems to drive at 140/150km/h. I would like to make a longer ration to drive around 2800 Rpm when i run at 100km/h.

dm:

Although you have indicated the type of use, terrain is important; where are you?

Your transmission likely starts in second gear (of four); manually selecting first would allow use of a 3.07 in an area devoid of hills. Otherwise opt for a 3.46 or 3.69.

Hello Frank, thanks for the reply. Oh yes, I believe your suggestion is fully correct. Probably is better to install 3,46 to prevent problems starting in 1st.

You might consider fitting the back wheels with taller tires--you should be able to reduce the effective ratio by 8% or so



Tim Kraakevik
kraakevik@voyager.net

Don't forget to change the speedo.

Hi Sterschuppe. How I should change the speedo? Shall I have to swap it with a new one or ther's a chance to trim it?

Thanks

No, it is impossible to trimmed it.
You need another with corresponding K ratio.
Optimal way to resolve this problem is to buy diff and speedo from the same vehicle.

Fantastic. Thanks a lot