I'm contemplating a merger of three cars into one... - Page 2 - PeachParts Mercedes-Benz Forum

babymog · #16 04-07-2016, 07:57 AM

The 190D 2.5turbo was never made for North America in a 5-speed, not sure it was anywhere. It was only built MY 1987.

At the time, Mercedes felt (as did Audi) that the turbo engines had so much turbo lag that it would not be civilized mated to a manual transmission so they only built them with automatics.

The automatic with its torque converter in the '87 190D 2.5turbo would easily spin the tires in the wet (annoyingly easily at times), and really could have used LSD. A tame ALDA setting will help but the sub-2000rpm boost rush tends to make it a bit squirrelly in the wet. With a clutch, I would think that it would reward the technique of rolling on the power as you release the clutch to keep the engine out of the full-boost range until fully engaged. With the 2.65:1 it should be fine, it is a torquey little beast. Even though a turbo engine, with a rich ALDA it is also a 2.5L diesel in a car that at 2800lbs weighs less than a modern Jetta.

Stretch · #17 04-07-2016, 10:30 AM

Quote:

Originally Posted by babymog

The 190D 2.5turbo was never made for North America in a 5-speed, not sure it was anywhere. It was only built MY 1987.

At the time, Mercedes felt (as did Audi) that the turbo engines had so much turbo lag that it would not be civilized mated to a manual transmission so they only built them with automatics.

The automatic with its torque converter in the '87 190D 2.5turbo would easily spin the tires in the wet (annoyingly easily at times), and really could have used LSD. A tame ALDA setting will help but the sub-2000rpm boost rush tends to make it a bit squirrelly in the wet. With a clutch, I would think that it would reward the technique of rolling on the power as you release the clutch to keep the engine out of the full-boost range until fully engaged. With the 2.65:1 it should be fine, it is a torquey little beast. Even though a turbo engine, with a rich ALDA it is also a 2.5L diesel in a car that at 2800lbs weighs less than a modern Jetta.

Quote:

Originally Posted by t walgamuth

That jump in ratios does not seem out of line to me. Getting the car moving with a torque converter is much easier than with the clutch.

The 346 was used in the 123 300D na. It'll make a sweet ratio for taking off with the stick. I'd prolly go with the 307 though.

According to this data the 5 speed non turbo OM602 had the 3.64 final drive whilst the automatic version (of the NON turbo) was 3.07

W201-190D25-2-Getriebe/en

The turbo OM602 specs are here =>

W201-190D25T-2-Getriebe/en

5 speed has 3.46

Automatic 2.65

Crazy

vstech · #18 04-07-2016, 11:10 AM

Quote:

Originally Posted by Stretch

That's a crazy jump for the 2.5 turbo diesel between 5 speed manual and automatic - perhaps that needs to be checked?

I'm interested in finding out which differential needs the shorter axle lengths as the bigger differentials seem to keep themselves in better shape and don't whine so quickly as the small bodied ones...

Hmm... I was unaware the manual trans ever sold on the turbo diesel...

babymog · #19 04-07-2016, 11:21 AM

Apparently it was, in Germany/western Europe, but never in North America.

However, it appears that the final gearing is nearly the same (3.46:1 x .75:1 overdrive = 2.6:1), which would be disappointing to not have a higher ratio for highway travel, I always felt that my 190Dt needed another gear, ... I'd go with the 2.65:1 and see how you like it. Again, if you live in an area where you need to start on a hill regularly, and/or travel with a heavy load, I can see the need for lower gearing. For most people however, the taller gears would be a benefit. Maybe a 3.07:1 would make a happy medium if you have one around.

Another way to look at it is: how do you like the performance of your 5-speed now? Can you see driving it with only 75% of the torque at launch? If so, you are looking at the 2.65:1. Would you give up this launch (until boost) for taller highway gears?

Stretch · #20 04-07-2016, 02:15 PM

Quote:

Originally Posted by vstech

Hmm... I was unaware the manual trans ever sold on the turbo diesel...

See post #17 my good man - follow the links

t walgamuth · #21 04-07-2016, 04:29 PM

I have a 2.88 and instrument cluster for the 123 chassis that I'd sell reasonably.

vstech · #22 04-07-2016, 10:35 PM

Quote:

Originally Posted by t walgamuth

I have a 2.88 and instrument cluster for the 123 chassis that I'd sell reasonably.

Is this posted for me? It won't fit a w201... and I've got two for those anyway...

t walgamuth · #23 04-07-2016, 11:11 PM

Whomever.

mannys9130 · #24 04-08-2016, 01:22 AM

I would tend to agree that an auto would be OK with the listed gearing because the torque converter multiplies torque at take off.

I can't really decide in my mind what a 2.5 turbo would drive like, but I know my 1st gear is so short that I can't get more than 10-15 feet without needing to shift. It would be nicer to have a little bit more time, but with the AC on take offs are difficult.

Stretch · #25 04-08-2016, 05:04 AM

Quote:

Originally Posted by mannys9130

I would tend to agree that an auto would be OK with the listed gearing because the torque converter multiplies torque at take off.

I can't really decide in my mind what a 2.5 turbo would drive like, but I know my 1st gear is so short that I can't get more than 10-15 feet without needing to shift. It would be nicer to have a little bit more time, but with the AC on take offs are difficult.

I have a 2.0 litre M102 and a 3.46 differential with a 717.412 five speed and first gear gets used all the time. It is good for about 30 kph with out making the engine scream.

Stretch · #26 04-08-2016, 05:05 AM

I'd still like to know about the larger case differentials for the W201 if any one has information about that...

vstech · #27 04-08-2016, 08:52 AM

Quote:

Originally Posted by mannys9130

I would tend to agree that an auto would be OK with the listed gearing because the torque converter multiplies torque at take off.

I can't really decide in my mind what a 2.5 turbo would drive like, but I know my 1st gear is so short that I can't get more than 10-15 feet without needing to shift. It would be nicer to have a little bit more time, but with the AC on take offs are difficult.

judging by my 2.5 turbo and my na 5 Speed, I can get around 20MPG in first, with its 3.46 diff.
The 3.07 from the gasser diff should significantly bump that over 25, and drop my 75 mph cruise speed rpms below 2500...

No major hill starts around here. Turbo power acceleration is far more needed...

mannys9130 · #28 04-08-2016, 12:37 PM

Mercedes manual transmissions | Mercedes-Benz turbo

This lists the gear ratios for various transmissions. Should also be useful here.

The 717.410 is what the 190D 2.2 came with. 1st is 4.23:1 on the .410 trans. I use it, because otherwise it would require a lot of clutch slipping for a 2nd gear start. Downshifting into 1st isn't possible unless you're at a crawling speed like in a parking lot. It's a granny gear.

w123fanman · #29 04-08-2016, 03:23 PM

I rode in a 190D turbo 5 speed. Car was completely worn out but it was fairly quick. No clue on what transmission they used or what diff. My dad liked the car but it was in too rough shape to warrant buying.