6.9 Transmission Upgrade

[Oversize]

The Aussie 560 uses a 2.47 final drive which is another reason why it's slower 0-100 than a Euro one.

[Styria]

SEL 69L (David Rollason) had a 450 differential fitted to his 6.9 that he sold some while back. He did this on the advice of a friend of his, and obviously I did have opportunities to drive his car. To be perfectly frank, I really couldn't tell all that much difference despite that fact that David DID think it made his a more satisfying, and faster car, to drive. Personally, I still think that Gleaming Beauty had the legs on his car.

It is feasible that a 6.3 box could be used behind the 6.9 engine, but even though it is a four speeder, if one would utilize first gear, you would just about rip out the diff/rear axle arrangement - a very, very costly option on 6.3s and accompanied by heaps of work. This weakness in the 6.3 drivetrain is probably one of the reasons why the 6.3 needs special, loving and tender care. Plus, the box has two looped bands one of which is prone to let go, and another expensive repair option is on its way. I don't know - I think I'll stick to what I've got for the time being. Regards Styria

[c107]

Originally Posted by Styria

SEL 69L (David Rollason) had a 450 differential fitted to his 6.9 that he sold some while back. He did this on the advice of a friend of his, and obviously I did have opportunities to drive his car. To be perfectly frank, I really couldn't tell all that much difference despite that fact that David DID think it made his a more satisfying, and faster car, to drive. Personally, I still think that Gleaming Beauty had the legs on his car.

Was his car an aussie delivery? if I recall right, your GB is a high comp motor, so I could easily see a high comp motor being about the same as an aussie car with a 450 rear end???

[Styria]

Hi Bryce, yes it is. I have always found ever so much, or perhaps so little, of a difference between the high and low compression engines. Seat of the pants and ears demonstrate an aural difference, as well as an ability for the high compression engine to "want to go on with it". Maybe I am barking up the wrong tree, but there just seems to be that little bit of a difference. Regards Styria

[Oversize]

My people are telling me the Benz 5sp is far too hard with programming the controller the main hurdle. Currently looking at a GM 6L90E 6sp trans which is normally mated to the HSV LSA engine so it should be able to take the torque of the M100.

[Oversize]

[Oversize]

FYI here’s the Benz box and ratios that were considered:

[c107]

Have you seen these transmission controllers?

Apparently folks are using them to adapt modern Mercedes transmissions ns to the m117.

http://mbturbo.com/new-722-6-gearbox-in-you-old-car/

http://soundgermanautomotive.com/pcs/

Not specific to the m100 but could be of interest.

[Oversize]

Seems more questions than answers & PCS was mention by the people I’ve consulted. Apparently they supply OEM with little after sales support. Calibration, mapping & tuning are the big issues here. Unless you’re an expert or have very deep pockets it’s not the way forward.

It does make some sense if the bolt patterns are the same but the M100 is a different animal.

Things have progressed so far with modern transmissions integrating with engine ECUs to do things like reduce power on gear changes to protect various components. The NAG1 is not plug n play and may never be so cause it’s an older trans with little R&D interest. The 6L80E & 90E mapping is nearly done so full control is more likely.

Another hurdle may be the speedo drive & im hoping a later unit can be adapted.