I was just pointing it out in case FI missed that part. I drove my stepdad's around today and looking at the speedometer and thinking 75mph in third made me giggle.

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http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

I've had three 240Ds. My first - an '82 automatic - was especially noisy, almost deafening, at highway speeds. My second - an '81 stickshift version - was much better, but still kind-of loud when revved-up.
My latest is fairly quiet and smooth on the road - perhaps because it has a much more solid body and/or tighter engine than my first two.

Anyway, has anyone installed the 3.07 rear-end gear from a NA 300D in a 240D, and can report the results?

Happy Motoring, Mark

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DrDKW

the N/A 300D uses a 3.46, not a 3.07 the turbo had the 3.07...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

My bad. I meant the 3:46 ratio used in the NA 300D.
(or my 5-speed Euro TD) That would seem to me a better choice for the 240D, than a 3.07, at least for a hilly area.

Happy Motoring, Mark

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DrDKW

Thanks for all the comments!
Forced, wow, I had no idea the rpm would be that low at 50 in 3rd! I obviously don't have a tach but it just sounds really wound out there. It definitely makes a difference when I hold it in 3rd longer, I'll probably make it a habit.
I think the 3.46 would be an improvement (albeit small) over the 3.69 in highway driveability. My 3.07 might have been a bit of a large step but there was no middle ground. I would have like the option of something in the 3.2-3.3 range. However, after a bit of a learning curve and some driving habit changes, I like the 3.07.
And, I'm happy to report that I made a 420 mile round trip today (averaged 65-70) and the fuel mileage was 28.8. I know, one tank doth not a conclusion make but it's enough better than the usual 25 that even if there's an error, I still feel that an improvement has been made. It's an absolute joy on level ground, a dream on trailing throttle but a bit of a drag on uphill runs especially if you begin the grade at under 65.
Valve adjustment later this week. Hopefully it will unlock some more of that pavement rippling power.

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1983 M-B 240D-Gone too.
1976 M-B 300D-Departed.

"Good" is the worst enemy of "Great".

Getting the fuel pressure up to 19 pounds would help somewhat as well if you are using diesel fuel. It may take a 617s fuel pump to get enough pressure to still have return valve overflow at 19 pounds operational pressure.

Even with the original rear end the majority of owners want the most power possible from the 616 engine.

I was interested enough to mess about with a spread sheet to see the effect of three final drive ratios with different sized tyres at a range of engine revs.

The numbers I've come up with are in the attached pdf file. I think they are good - only watch out! The final speeds do not take into account any flex in the side wall of the tyre, power of the engine, or other losses so they are a bit optimistic - as a guess take off about 10% of the values listed for a more realistic guesstimate!

Attached Files

Estimated wheel speeds with different final drive ratios.pdf (22.3 KB, 211 views)

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Army, thanks for sharing! That's going to be helpful since I am about to need new tires and given my recent change I sure don't want to get anything to make the ratio higher.
Barry, I assume you're talking about the lift pump. I see where the part numbers are different on the 616 and the 617. Is there that much difference between the two as far as output pressure? Is it a direct replacement? I had removed the relief valve spring and stretched it to the length recommended on the forum (I think you were a heavy contributor to that thread) some time ago. I don't have a pressure reading on my lift pump discharge though so it's hard to quantify the results. I had considered adding an electric pump back by the tank to push fuel to the lift pump. I have read about others that did this with good results.
And you're not kidding about most owners wanting the most out of the 240D. They are not powerhouses to start with and any incremental change (for better or worse) is very noticeable.
Thanks again.

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1983 M-B 240D-Gone too.
1976 M-B 300D-Departed.

"Good" is the worst enemy of "Great".

My latest stickshift 240D is the peppiest of the three I've owned. So it would probably handle a swap to a 3.46 rear-end. Don't know if I would want to go as far as a 3.07. I'm running 195-70R14 Michelin X tires, and on my last 200-mile trip the odometer error was under 1% - checked against highway mile-markers (don't have GPS).

Happy Motoring, Mark

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DrDKW

If you're interested in fuel pressure get in touch with funola - he's even selling adjustable pressure relief valves:-

http://www.peachparts.com/shopforum/showthread.php?t=285308&highlight=adjustable+funola&page=2

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

the spring from a 617 turbo lift pump will fit in the 616 lift pump. this is good for up to about 30psi. 616 lift pump is good for about 15 psi. I set my relief spring about 21 under load

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1977 240D turbo

Takes a 30 mm socket to change the lift pump spring. no need to take the lift pump off, it can be done in place.

I must say I have no idea how much if any it will help a stock IP. If you have adjusted the IP for more power, then more fuel pressure will give even a little more power.

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1977 240D turbo

47dodge I haven't made any adjustments to my injector pump. Don't really know how or what to do. Long ago I made sure I was getting full travel with the linkage and I've adjusted the VCV for good shifting.
I wouldn't mind changing the lift pump spring. Are they available separately?
I need to get the right speedo head to go with the FD and definitely need to adjust the valves. So far it's a good thing though.
Thanks!

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1983 M-B 240D-Gone too.
1976 M-B 300D-Departed.

"Good" is the worst enemy of "Great".

You might consider switching from 75 to 70 series tires.
With all your modifications so far, what changes have you noticed in your fuel mileage?

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DrDKW

Mark I am thinking of doing just that. I'll need tires in the next few months.
As far as fuel mileage, I have filled twice since the change and one was only a top off after 100 miles. It was just over 26 mpg but the long trip (over 400 miles driving 65-70) was 28.8. Average so far this winter has been in the 25 range. I fill up about every 5 days so I'll keep track and post anything noteworthy.

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1983 M-B 240D-Gone too.
1976 M-B 300D-Departed.

"Good" is the worst enemy of "Great".