6.9 Transmission Upgrade

[Oversize]

If you had the choice of any transmission to sit behind an M100, what would it be and why? How many gears would be ideal? Top Gear mentioned that some of the 8 speeders were no good, as the transmissions couldn't decide on a gear!

I know this has been mentioned in other threads, but I thought I'd dedicate a specific one to the issue. I don't think a manual would suit the saloon nature of the W116, so are there any advances on the GM TH700?? I know my AU four speeder is nice, but I doubt it'd handle the NM and there's obvious issues with the control module etc...

 

[motec 6.9]

Hi Mark i have a adaptor to fit a Turbo700 behind my 6.9 but the cost of upgrading the th700 to handle the torque is prohibative. If you look on ebay the current v12 biturbo 5 speed can be bought for about $2000 us it is rated to 1000nm no other trans is .So i have been asking about adapting 1 behind a m-100 will need stand alone control computer .

 

[Oversize]

I think that 8 speeder I was talking about was in the Lexus ISF and according to TG it sounded like errrrr, ahhhhh, errrrrrr, ahhhhh, errrrrr!!! I think the cost of the TH700 conversion is prohibitive, simply based on the cost of the adapter from Big Boys!!

Motec (or anyone else), do you know what the original 6.9 trans is rated to?

 

[Michel]

What does an E55 or C63 use?
Surely one of those would have enough strength to take the torque...

 

[motec 6.9]

Hi Michel the trans in the e55 is the same as the S65 S600 biturbo. It is rated to 1000nm the 7speed is not fitted to these cars becauce it cannot handle that level of torque. http://en.wikipedia.org/wiki/5G-Tronic I hope this helps i was looking this morning on ebay they sell for about $2500 US from wreckers in the US. PS Mark & Michel it is also fitted to 300c but lower spec version

 

[Michel]

Hi Michel the trans in the e55 is the same as the S65 S600 biturbo. It is rated to 1000nm the 7speed is not fitted to these cars becauce it cannot handle that level of torque. http://en.wikipedia.org/wiki/5G-Tronic I hope this helps i was looking this morning on ebay they sell for about $2500 US from wreckers in the US. PS Mark & Michel it is also fitted to 300c but lower spec version

One needs to find the right mechanic (lateral thinker) who can adapt it and then affix a computer to the wiring and make it work reliably!
I feel 5 speeds should be a HUGE leap in performance in a stock 6.9

 

[Tony66_au]

Gents something to keep in mind when thinking of adapting late model Benz trannys is the anti theft features of the donor cars, I can state from experience that anyone wanting to use all or part of the driveline of a 300C Series I, II or III will need ALL of it including engine management, ABS module etc and it all has to work as intended and all be from the same Vehicle or it wont work.

And if you do manage to get it running then it will be in limp home mode. (Tranny locked in 3rd with only Reverse and neutral as options.)

And as this technology came straight from Mercedes Benz I cant see it being any different when sourced from an E55 or similar.

I know of 2 very skilled people, who have played with these parts with the aim of using them to upgrade old cars who have gone down a different path because they couldn't get it to work.

Id also suggest that the only way to get a trans to work in such a situation would be to manualise the tranny so the shifts are made via shifter but it would still be a dodgy enterprise.

Definitely look into the security aspects of the car control system.

 

[Oversize]

I'd say it's the transmission that was put into this '54 Buick (from a G55), but then again, so was everything else! Just have a look at the looms that were transferred over!!!

http://www.radrides.com/proj.htm

The security features would be incorported in the ECU/s for the transmission and if they're removed and a stand-alone ECU installed, it should work; in theory! The big question is where to source such a computer?? And how much...

 

[motec 6.9]

Hi Tony there is a Valiant over here in Perth with SRT8 drive train .It was at recent hod rod show at Berswood . I spoke with the owner using Haltech engine computer with PCS powertrain computer. http://www.powertraincontrolsolutions.com/transcontrol.php i hope this helps they list 722 mercedes trans in there list or you could go with http://www.fuelairspark.com/Products/details/controller/benefits.asp they list chrysler and KHM use's there efi on his supercharged W100

 

[Tony66_au]

I'd say it's the transmission that was put into this '54 Buick (from a G55), but then again, so was everything else! Just have a look at the looms that were transferred over!!!

http://www.radrides.com/proj.htm

The security features would be incorported in the ECU/s for the transmission and if they're removed and a stand-alone ECU installed, it should work; in theory! The big question is where to source such a computer?? And how much...

The issue Mark was that the system checks for a Vin encoded into each item and the ABS computer is the key.

You will get the engine going but without a lot of the features that made the 300C such a fun car to drive including the shut down of one bank of cylinders in light traffic etc.

Hi Tony there is a Valiant over here in Perth with SRT8 drive train .It was at recent hod rod show at Berswood . I spoke with the owner using Haltech engine computer with PCS powertrain computer. http://www.powertraincontrolsolutions.com/transcontrol.php i hope this helps they list 722 mercedes trans in there list or you could go with http://www.fuelairspark.com/Products/details/controller/benefits.asp they list chrysler and KHM use's there efi on his supercharged W100

The someone has finally developed a system for this combo as it couldnt be done a few years ago although id have figured Haltech would be the people to do it.

Previous efforts involved using an aftermarket EFI system and playing with the transmission with much gnashing of teeth and swearing.

The other way to do it is to buy a V8 Mopar crate engine, big block or otherwise which comes without fuel system and add your own which you can do right up to the V10 used in Dodge Ram trucks and Vipers (or whatever they call them today.)

 

[Michel]

Hmmmmm...

T700 is sounding more and more interesting!

 

[motec 6.9]

Hi Michel did you click on pcs 750 for transcomputer i believe haltech are working on 1 as well. as for the cost of trans there was more than 1 on ebay in US . Knowing what i have been quoted for th700 to handle torque i have been told to use 4le80 trans cost goes up quickly

 

[Michel]

Hi Michel did you click on pcs 750 for transcomputer i believe haltech are working on 1 as well. as for the cost of trans there was more than 1 on ebay in US . Knowing what i have been quoted for th700 to handle torque i have been told to use 4le80 trans cost goes up quickly

I have a T700 behind my 454-powered 62 Chev wagon.
That big block produces some serious torque, trust me.

In my opinion, unless you are planjing to modify it, the 6.9 can be easily handled by the T700

 

[Tony66_au]

Agreed Michel, But not all TH700's are created equal and the US early units with minimal electronic Servo mech is the unit to use.

The Aussie units are ok but the US sourced units are better and far more adaptable.

I believe that the 50's Rolls Royces used GM sourced 4 speed autos and I believe they are an excellent unit.

 

[SEL_69L]

Is there a 4 or 5 speed American auto transmission from the muscle car era?

Auto transmissions from this period do not have electronic control, and therefore should be more adaptable to the 6.9.

I know of another alternative currently installed in an American muscle car:
-three speed auto with manually operated lockup on all three ratios.

 

[motec 6.9]

Hi Mark & Michel here are the prices for a 722 trans from v12biturbo http://www.ebay.com.au/itm/MERCEDES...270269709?pt=DE_Autoteile&hash=item518dbc290d and http://www.ebay.com.au/itm/00-06-ME...r_Truck_Parts_Accessories&hash=item4ce92f4c1e i hope this helps

 

[Michel]

Is there a 4 or 5 speed American auto transmission from the muscle car era?
Auto transmissions from this period do not have electronic control, and therefore should be more adaptable to the 6.9.
I know of another alternative currently installed in an American muscle car:
-three speed auto with manually operated lockup on all three ratios.

The TurboHydro 400 (T400) by GM and the Torqueflite 727 (T727) by Chrysler are bullet proof boxes.
However, they are only 3 speed...

 

[Michel]

Agreed Michel, But not all TH700's are created equal and the US early units with minimal electronic Servo mech is the unit to use.

The Aussie units are ok but the US sourced units are better and far more adaptable.

I believe that the 50's Rolls Royces used GM sourced 4 speed autos and I believe they are an excellent unit.

My T700 was out of a VN V8 with cable shift.

The 4speed auto in the Rolls Royce is an old GM design (from the fifties) that was fitted to the Cloud series I, II & III as well as Bentleys' SI, SII and SIII.

 

[Tony66_au]

Well then you have a US sourced Turbo700 Michel as i believe that pre VP they had US units with a chev V8 pattern?

Re the T400? 2 pumps and more internals make them a bit hard on engine HP and ive found that the T350's are far simpler and harder wearing.

 

[Michel]

Well then you have a US sourced Turbo700 Michel as i believe that pre VP they had US units with a chev V8 pattern?

Re the T400? 2 pumps and more internals make them a bit hard on engine HP and ive found that the T350's are far simpler and harder wearing.

We (in the Chevy fraternity) tend to use T350 as a straight replacement and upgrade from a 2speed Powerglide because of the simplicity of the exchange.
Same size and same spline!
T400 were in demand when you had serious horsepower to deal with.