I guess it depends on the kind of driving you want to do and what your priorities are. Did you want really good off-the-line acceleration? Punchy overtaking? Hypermiling in 5th gear? Given you've got a bit of extra power/torque to play with in that 2.5 turbo, you've probably got a reasonable margin of error and the consequences of getting the wrong ratios will be a lot less severe than if you had a 190D 2.2.

I'd be tempted to try the 190E 2.3 manual box and taller final drive ratio, given the extra grunt your motor has. As I've said elsewhere, the standard 5 speed box is a bit of a truck-like thing to drive and would probably better suit someone wanting really relaxed highway cruising than someone wanting to charge up mountain roads working up and down through the gears.

Then again, perhaps the safest bet is to just look at whatever Mercedes built the 5 speed manual 190D 2.5 turbo with and just go with whatever box/axle ratios are closest to that; it's probably going to be the best all-round compromise.

Straight up, it's a sweetheart of a car and an absolute JOY to drive but, like many others, I can't help but think a 5 speed would just be the icing on the cake.

Before you commit yourself, I just hope you've taken a Benz 190 with the standard 5 speed box for a drive so you know what to expect.

 

Before you commit yourself, I just hope you've taken a Benz 190 with the standard 5 speed box for a drive so you know what to expect.

I've driven quite a few stick benz's including a 190E and a Euro 4 cyl 4 spd diesel w124 wagon so I know exactly what you're warning of! Thanks for the heads up

 

Thanx John,
Ideally I'd like a set up close to the stock euro 5 speed 190DT's, as I'm sure they represent the best overall balance for the car ... but if I had the choice, I wouldn't mind something that trades some highway mileage for a quicker jump off the line and more passing punch then the stock ratios offer.

It sounds like the 2.2 trans with a taller rear ratio then the stock 3.42 might just be that option if I've read your recommendation correctly. Would the 3.27 then represent enough of a difference? Or would you need an even taller ratio to balance the stronger 2.5 turbo engine with the low 1st gear ratio of the 2.2?

 

It sounds like the 2.2 trans with a taller rear ratio then the stock 3.42 might just be that option if I've read your recommendation correctly.

Oh I wouldn't dignify my relatively uninformed idle speculation by calling it a recommendation. ;-) There's so much information we don't have (such as knowing the power/torque curves of the respective engines to try and think about what's going to be available at the rear wheels for a given speed in a given gear). It could even be that the 190D transmission has other differences like less robust bearings that mean it isn't up to the stresses that would be imposed by your 2.5 DT. I really don't know.

My only recommendations were that it's probably better to declare what your reason for the swap is (which you've now done; you want punchier acceleration and don't mind higher revving at cruising speeds) and that you'd driven a manual Merc (which you've done) before making any assumptions that it'd improve the driving experience and then starting to modify your perfectly good car. Now others more informed than me can assist you.

 

Sorry I cannot help with your project , but I wanted to add a bit of my experience , in case it applies to your car.

I replaced the auto in my w115 300D with a manual trans (4spd from about the same yr 250) and now have a really NASTY harmonic that is totally uncomfortable in the car at normal road speeds.
In hindsight, it appears that MB match balanced the 300D rotating assy , including the flywheel or flex plate , depending on options , and I have yet to satisfactorily sort this issue out , mean while the car is pretty much undriveable.

I hope this is not an issue for your car.

Regards

ps, I did not have any of this bother with the manual trans swap on my w115 240D.

 

Basically you want to multiply the gear ratios with final drive ratio to come up with axle ratio:

ex. axle ratio for 190D 2.2 with 3.42 rear end
I: 14.47 II: 8.07 III: 5.1 IV: 3.42 V: 2.87

whichever trans + final drive combination, you should stay very close to 2.5D Turbo 5 spd factory axle ratios.

A quick look it appears that
The 190E 2.3 trans
3.91, 2.17, 1.37, 1.00, 0.78
3.27 final drive
or 190D 2.2 final drive
come pretty close to 2.5D 5 spd axle ratios

A tall final drive like 3.07 was probably intended for german high-speed autobahns and would be pretty useless for north american freeways.

As far as LSD, its main benefit is to let the car exit high speed corners with max horsepower without wheel-spin. the 190D 2.5 doesn't have the chassis or suspension setup to let you do high speed cornering, so I think LSD would be a pretty useless thing on a diesel sedan.

 

Thanks for the replies Wink
Been head scratching all weekend but I think I've finally nailed down what set up I'm going to go for.
I'm going to put in the transmission and flywheel from the '84 2.2 190D, upgrade the clutch and match it with a 2.3-16V LSD differential.

I compared all the realistic combos of manual transmissions and rears and the 3.27 (16V) and 3.42 (2.2 190D) diffs both compare well to the stock euro 190DT ratios when matched with either 2.2/2.5 diesel or 2.3 gasser 5 speeds. A 2.3 8V transmission with a 190D 2.2 rear yields almost the identical ratios as the euro 190DT stick but the other options all look like they'll work well and are only off by a hair.

I decided not to go for the "closest to stock" option and I think the old 190D trans (with the benefit of the heavier diesel flywheel) with a 16V rear would be just the ticket for my 190DT. The limited slip 16V 3.27 diff fits the 190DT without having to swap the diff flanges/axles and the 2.2 trans gears are lower than the euro/gasser gears but since the 3.27 is a bit taller then the euro 3.46 rear, it balances the combined ratios out very well and overall it is almost identical to the stock 190DT 5 speed.

The only MINOR differences (less the 5mph) end up being a lower first gear to start with, slightly lower 2nd and even slighter/identical 3rd, a slightly taller 1:1 4th and a lower final 5th. Again, slight differences from the stock ratios, but in my mind, lower early gears to zip, a 4th and 5th that work perfectly for the highway AND a limited slip differential works out to be the ideal combo. I've pulled together the combined ratios and speed of a few of the w201 transmission / differential combos and please feel more then free to comment on any of my logic,info or ideas about any of this! Wink

190DT Stock Euro 5 Speed
Gears:3.86, 2.18, 1.38, 1.00, 0.75
Rear:3.46
Combined Ratios (gear X rear) and Speed at 3500RPMS
1st: 13.36, 19.0 MPH @ 3500
2nd: 7.54, 33.7 MPH
3rd: 4.77, 53.2 MPH
4th: 3.46, 73.5 MPH
5th: 2.60, 97.9 MPH

190D 2.2 Trans + 16V Diff
Gears: 4.23, 2.36, 1.49, 1.00, 0.84
Rear: 3.27 LSD (early)
Combined Ratio/Speed:
1st: 13.83, 18.4 MPH @ 3500
2nd: 7.76, 32.9 MPH
3rd: 4.87, 52.1 MPH
4th: 3.27, 77.7 MPH
5th: 2.75, 92.5 MPH

190E 8V Trans + 190D 2.2 Diff
Gears: 3.91, 2.17, 1.37, 1.00, 0.78
Rear: 3.42
Combined/Speed:
1st: 13.37, 19.0 MPH @ 3500
2nd: 7.42, 34.2 MPH "
3rd: 4.68, 54.2 MPH "
4th: 3.42, 74.3 MPH "
5th: 2.77, 91.7 MPH "

 

Hope it all goes well and looking forward to hearing how it all turns out.

 

You seem to be getting way ahead of yourself ...

190D 2.2 Trans + 16V Diff
Gears: 4.23, 2.36, 1.49, 1.00, 0.84
Rear: 3.27 LSD (early)
Combined Ratio/Speed:
1st: 13.83, 18.4 MPH @ 3500
2nd: 7.76, 32.9 MPH
3rd: 4.87, 52.1 MPH
4th: 3.27, 77.7 MPH
5th: 2.75, 92.5 MPH

Based on my observations, 190D 2.2 trans + 3.2 diff will do about 73 mph in 5th at 3500 RPM - not 92.5 mph

your speed numbers are off by some 30% for all (gears + rear-end) combinations.

 

Hmmm, not sure where I made the mistake. I tried 2 different gear calculators and both came up with the same results for 185/65/15 tires @ 3500rpm. What calculator did you use? Can you post the numbers you'd get? The speeds may be off, but the ratios still have the same subtle differences which shouldn't vary much off of what the Euro stock car would actually do on the road.

 

That's based on actual observation is a real car.

Seems like there is a further 25% reduction in the system (either in transmission output or final drive) that is not accounted for in the MB published data.

If you divided your speed numbers by 1.25 you'd arrive at actual real world numbers.

my guess is MB differentials have a fixed 1.25 reduction on top of the stated diff ratio.

 

Ok, considering a bias, here are the revised Speeds (/1.25) at 3500RPM (MPH and KMPH)

190DT Stock Euro 5 Speed

1st: 15.2 MPH / 24.5 KMPH
2nd: 27.0 / 43.5
3rd: 42.6 / 68.6
4th: 58.8 / 94.6
5th: 78.3 / 126.0

190D 2.2 Trans + 16V Diff

1st: 14.7 / 23.7
2nd: 26.3 / 42.3
3rd: 41.7 / 67.1
4th: 62.2 / 100.0
5th: 73.9 / 118.9

190E 8V Trans + 190D 2.2 Diff

1st: 15.2 / 24.5
2nd: 27.4 / 44.1
3rd: 43.4 / 69.8
4th: 59.4 / 95.6
5th: 73.4 /118.1

 

Hang on, where did this 1.25 multiplier come from?

My 190E 1.8 with 3.46:1 final drive (same ratio fitted to the stock 2.5DT with 5 speed) screams away at roughly 2900rpm at 100km/h in fourth gear (1:1) according to its reasonably accurate speedometer. So at 3500rpm, it'd be sitting on an indicated 120km/h (75MPH), which is within 1.5MPH of your original calculations in this post for the stock 2.5DT in fourth gear (1:1).

 

My (US) 2.2D with 3.27 diff in 5th (0.84 ratio) @ 3500 RPM does 73 mph.

the only explanation can be the difference between north american and european final drive ratios.

With US speed limit of 60mph in the 1980's, I suspect MB geared the US diffs for lower top speed in favor of better acceleration - perhaps that's the reason for 1.25 multiplier ?

 

Yes, the U.S. gear ratios were clearly setup for a 55MPH speed limit.

In your calculations, you MUST include tire rotations per mile. It is not a constant, but a variable. The 1984 2.2L 190D is 880 revolutions per mile. This makes 60MPH a convenient baseline for comparison.

190D Stock, 4th gear = 880RPMi x 3.42diff x 1.00gear = 3010RPM
This is also my real world experience. And everything properly flows from that.
3010 x 0.84 (5th gear) = 2528RPM at 60MPH
2528RPM x 1.33 = 3370RPM at 80MPH in 5th.

185/65R15 = 850 RPMi.

To set gear ratio, you must know your torque and power curves. Since torque provides acceleration, and power holds speed (like going up a montain pass), you want to center your gear ratios around the peaks, for your priority.

Since both power and torque are more strained at higher speed, you want to set your upper gears at a closer ratio.

 

Theres a guy selling a 2.5 turbo 300d with a manual transmission on 190rev.
http://190rev.net/forums/showthread.php?t=40625

 

So considering everything, it look like the 2.3 trans with stock diff will give the best combination of top speed and gear spreads for the 2.5DT.

The 190E 2.3
3.91, 2.17, 1.37, 1.00, 0.78
3.27 final drive

w/ 1.25 Reduction (N American specs)

185/65/15 tire

Speeds @3500 RPM
I: 16 mph
II: 28.8 mph
III: 45.6 mph
IV: 62.4 mph
V: 80 mph

I would stay away from the 2.2D trans since it is geared too high for the smaller (non-turbo) diesel engine.

 

w/ 1.25 Reduction (N American specs)

Sorry, I still don't buy the idea of this unwritten 1.25 reduction for North American cars. Where does this 1.25:1 reduction gear reside? (In the transmission housing? in the differential?) Why would Mercedes Benz literature not explicitly state it? Why publish gear and final drive ratios if they're going to be out by 25%? Why not just say the car has a 4.08:1 final drive rather than a 3.27:1 final drive?

Note that vishvamata seems to be able to tally his RPM/MPH relationship for his 2.2D without the 1.25 multiplier.

Also, note lomtevas's recent photograph of his (North American) 190E 2.3 clocking 180000 miles. He's ticking over at around 2600rpm at 60MPH/96km/h, not 3500. I reasonably certain this car is automatic (so no overdrive 5th gear to reduce those revs), but someone please correct me if I'm wrong.

If your car is showing much higher revs, it could be that it's been fitted with a non-standard final drive ratio. Or your tachometer could just be wacky and reading high. (Hopefully not your speedometer reading low, or else you've been driving at 75MPH when you thought you're doing 60! Any speeding tickets recently?)

 

Its not like these transmissions are all over the place ripe for the picking. If you find a 5 speed manual that bolts up of any kind, USE IT. You can deal with gearing later by swapping out the diff. A number of different ratios are available from W201 or W124.

 

Hi guys and thanks for chompin' on this discussion!

I suppose I'm open to the idea that Mercedes somehow did alter the US/NA ratios by 1.25, but I must say I'm skeptical and agree with all of the points John H raised.

It's definitely enough of a difference to sway me from my original 190D 2.2 trans choice if it were indeed true and hopefully there are some people around that can add some more solid info and put the question to rest ... and give me the go ahead on which slippery 5 spd to grab before they're both gone!

From vishvamata's calculations, a 190D 2.2 trans with a 3.27 diff running 185/65 15's would give:
850RPMi X 3.27 X 1:00 = 2779.5 RPMs @ 60mph in 4th
and
2779.5 X 0.84 X 1.33 = 3105.3 RPMs @ 80mph in 5th
2779.5 X 0.84 X 1.22 = 2853.6 RPMS @ 73mph in 5th (differing quite a bit from NMBMBZ's 3500RPM)

An auto 190dt should give 850RPMi X 2.65 X 1:00 = 2252.5 RPMs @ 60 in 4th and
2252.5 X 1.33 = 2995.8 RPMs @ 80mph in 4th

If the tach on my auto worked, I'd verify those last numbers and hopefully someone else can ... but it seems to me that all of those ranges seem very realistic. In my reading about 5 speed 190DT swaps, I also do recall someone wanting to use a 16V trans with the 1:1 non-OD 5th with their stock 2.65 diff since their automatic lulled along at 80-95mph with it's 1:1 4th. A 0.84 5th with a 3.27 has an overall ratio of 2.74 compared to the autos 2.65. That's US car to US car. If the auto can cruise comfortably low at fast highway /80-95mph speeds and the 0.84/3.27 combo is only 0.09 higher in overall final ratio, it's hard to believe the car would be pushing 3500 RPM at lower (73MPH) speeds IMO.

 

John H -
Looking at your posted picture, assuming it is a US spec car in the top gear (regardless of manual or auto), it shows 60mph at 2,600 RPM, which means at 3500 RPM it would do 80 mph - not 94 mph ! (3,500/2,600 x 60 = 80)

I suspect it is a 190e 2.3 5-speed car, which based on my posted numbers would indeed do 80 mph at 3,500 RPM, w/ 1.25 US bias !


Don't know about Australia. No american spec manual 84-93 190e (regardless of type) does 94mph at 3500 RPM.

I re-measured the 190D in 5th at 3.5k RPM today, it showed 74mph +/- speedo error


The 1.25 is an empirical number, could be 1.23 - 1.27 but it is not 1.0, only mercedes detailed country specs could give the exact number.

 

I re-measured the 190D in 5th at 3.5k RPM today, it showed 74mph +/- speedo error.

But, what is your tire RPMi? Just look it up at specs on TireRack.com. If one knows all 3 values, then it is straight multiplication = no mystery at all!

Beyond that, the only factors to consider are the spread between gears, and the best final drive ratio for bottom and top gear based on maximum torque and BHP points. This tends to drive the decision between a Getrag and an MB MT5.

Getrag intervals:
1st / 2nd = 62%
2nd / 3rd = 42%
3rd / 4th = 41%
4th / 5th = 26%

G717.411 intervals:
1st / 2nd = 69%
2nd / 3rd = 63%
3rd / 4th = 42%
4th / 5th = 28%

 

Yes. My 8v is an automatic.

I get a kick out of its fuel economy on the highway and its longevity. It seems both characteristics are directly attributable to how low the rpm's are for a given speed thanks to the differential gearing.

 

How many poor innocent zebrano trees were killed to make your car interior lomtevas?

 

MB EPS shows exploded views for the entire drivetrain. For an MT5 there is no "magical" multiplier gear. I have never looked at the AT4, since I chose a reliable MT5.

See this chart:
Rear Axle Ratios

If there is a 1.25 difference, then the differential is 1.25 different from the assumed ratio. MB EPS gives the ACTUAL ratios for both pinion and ring gears. On a 190D-2.5T, the rear axle ratio difference between MT5 / AT4 is 1.31.

Also, don't get caught up in an overdrive concept. Unless you have a 1:1 differential, your wheels are ALWAYS rotating slower than your crankshaft.

It really is as simple as the math shows. MB is too efficient to add an intermediate hi/lo 1.25 transfer case, like you would find on a 4WD offroad vehicle. Have you ever heard anybody ask, "Hey, what is this extra box attached to the driveshaft?"

However, I would LOVE multiple gears in the diff, kind of like a bicycle can shift gears at both ends.

For example, I have larger rear wheels & tires, and enjoy a 6.6% reduction in RPM at a given TRUE speed (not speedometer display) at 822RPMi. It is just like changing my diff from 3.42 to 3.19. This yields greater fuel efficiency. And yes, I added a magical 1.07 gear to my drivetrain.

 

Been reading and have found a thread on peachparts that lends some insight.

Jetmugg states:

"I had another 190D 2.5T that I put a gasser 5-speed in with the 2.65. It was VERY sluggish off the line. A subsequent owner put a 2.88 in it, and said it was much better.

With my current 2.5T and diesel spec 5-speed, with the 3.07 rearend, there is still a big step from 1st to 2nd, but it's much better than with the 2.65. I think the main issue is the ratios in the diesel spec tranny. 1st is lower, but I believe that 2nd is the same in the diesel boxes.

The gasser transmissions may be a little more "close range" in terms of the spread between 1st and 2nd. They also have a slightly "taller" 5th gear compared to the diesel spec trannies.

Anyway, 2500 rpm gives me right at 70mph in 5th gear with this combo and 225/50/16 tires.""


When I calculate his setup with 225/50/16's, I get 2518RPMS at 70MPH. This should put the "phantom" gearing debate to rest but it still leaves me in limbo ... diesel setup w 3.27? gas setup w 3.27? Or scrap the 3.27 idea and go for a different ratio?

My 190DT with the 2.2 trans (0.84) and the 3.27 rear would rev at 2724 RPM @ 70 MPH, 2918RPM @ 75 MPH and 3113RPM @ 80 MPH. Is this too high for the highway?

My 190DT with the 2.3 8V (0.78 5th) and the 3.27 rear would rev at 2529RPM @ 70 MPH, 2719RPM @ 75 MPH and 2891RPM @ 80 MPH. Hands down better then the diesel setup on the highway but how much of a difference would this represent? Would the lower diesel first gear be any asset if highway driving was compromised?

'Gotta bite the bullet on the tranny and finally decide if the 3.27 is it's mate. Hopefully this all helps with a group consensus and I can have some confidence in the final call

 

Observe in the above chart to which I provided a link, that for the 190D 2.5T with the MT5, the stock rear axle is 3.46, with 850 RPMi tires. That gives you 2941 RPM at 60MPH in 4th.

I suggest using that as your reference point, with a 4th gear 1:1. From that, simply decide whether you want higher RPM for more responsive performance, or lower RPM for better fuel efficiency.

I would like to offer further suggestons, but I do not know what the torque and power curves of the 2.5T feel like.