240D Slow on Highway - Page 5 - PeachParts Mercedes-Benz Forum

katja · #61 09-29-2009, 12:01 AM

Where did you find a W115 240D with a 5-speed automatic? Even a 5-speed manual would be aftermarket.

240D's and even 220D's should be OK on the highway, that is, if it's a relatively flat highway...they can keep up with traffic as long as they have momentum!

My stock 240D with 4-speed manual does pretty well at 70 but it's revving pretty high at 75 and I haven't tried to go over 80...I'd rather make the engine last another 250,000, and I want to avoid the embarrassment of getting a speeding ticket in a 240D.

I have no trouble keeping up with traffic, UNLESS someone slows down in front of me drastically, forcing me to slow way down, and then speed way up in a short duration. Then I feel like I'm a road hazard until I get back into the torque curve.

The other problem with the 240D is on hills. On a long steep grade I have trouble maintaining speed and can simply forget about having ANY acceleration possibility. People would understand this if my 240D had 18 wheels and was towing a huge trailer, but other drivers seem to think I'm just a slow-driving moron that doesn't know the accelerator from the brake and so they tailgate me. Or maybe they just like the smell of the biodiesel!

pixelsblack009 · #62 09-29-2009, 04:40 AM

I would invest in some S3 polarized oil for the engine and may be transmission becouse of its unique lublicating capabilities (oil on oil insted of metal on metal) this should reduce friction and heat, well atleast most of it becouse we all know fricion will generate atleast some heat especially at such high speeds.

pixelsblack009 · #63 09-29-2009, 04:41 AM

http://www.youtube.com/watch?v=DAmDhhC5MVc&NR=1

Watch this video

pixelsblack009 · #64 09-29-2009, 05:47 AM

Quote:

Originally Posted by katja

Where did you find a W115 240D with a 5-speed automatic? Even a 5-speed manual would be aftermarket.

240D's and even 220D's should be OK on the highway, that is, if it's a relatively flat highway...they can keep up with traffic as long as they have momentum!

My stock 240D with 4-speed manual does pretty well at 70 but it's revving pretty high at 75 and I haven't tried to go over 80...I'd rather make the engine last another 250,000, and I want to avoid the embarrassment of getting a speeding ticket in a 240D.

I have no trouble keeping up with traffic, UNLESS someone slows down in front of me drastically, forcing me to slow way down, and then speed way up in a short duration. Then I feel like I'm a road hazard until I get back into the torque curve.

The other problem with the 240D is on hills. On a long steep grade I have trouble maintaining speed and can simply forget about having ANY acceleration possibility. People would understand this if my 240D had 18 wheels and was towing a huge trailer, but other drivers seem to think I'm just a slow-driving moron that doesn't know the accelerator from the brake and so they tailgate me. Or maybe they just like the smell of the biodiesel!

First I think its rediculus to think that W115 did not come with a 5 speed automatic too, loooooool and usualy comes with a kick down switch
like mine which is activated via electronic solonoid, I myself have no trouble on hills maybe you car has some problems with it to make you just assume that all W115's are like this, my dad and I have seen many other W115's with 5 speed automatic transmission this gear box had come original with the car I know this because this was my dad's forth car (I dont mean he owns 4 cars) and its not second hand Its an Australian model, by the way and this is included in the service manual too, you might want to check your injectors IP timing valve clearance or any air restrictions in the intake manifold or the tubing that goes from it to the back of the IP also there is a lever on the IP that regulates the correct fuel with air mixture which may cause the car to be sort of low on torque and try's to stall, I have never encountered any of the problems you say specially that you have trouble with hills

JEBalles · #65 09-29-2009, 03:37 PM

Quote:

Originally Posted by pixelsblack009

First I think its rediculus to think that W115 did not come with a 5 speed automatic too, loooooool and usualy comes with a kick down switch
like mine which is activated via electronic solonoid, I myself have no trouble on hills maybe you car has some problems with it to make you just assume that all W115's are like this, my dad and I have seen many other W115's with 5 speed automatic transmission this gear box had come original with the car I know this because this was my dad's forth car (I dont mean he owns 4 cars) and its not second hand Its an Australian model, by the way and this is included in the service manual too, you might want to check your injectors IP timing valve clearance or any air restrictions in the intake manifold or the tubing that goes from it to the back of the IP also there is a lever on the IP that regulates the correct fuel with air mixture which may cause the car to be sort of low on torque and try's to stall, I have never encountered any of the problems you say specially that you have trouble with hills

Well, I'm not sure what kind of hills are in Sri Lanka. Maybe the 115 is lighter than the 123? Even then though, it couldn't be much lighter. What are the speed limits there? I can sustain speeds of 45 Mph on hills.

pixelsblack009 · #66 10-03-2009, 12:08 PM

It would do around 50-60 on hills but thats in KMH a W123 would definetly be better no doubt, what I'm saying is W115 are'nt that bad

there is this little nut on the back of the IP next to the vacume line that goes into the manifold, I find that a few turns may be 3 no more, will give you a better torque I think it controls the fuel presure acceleration is good to but not as good as the W123

if your traveling at a constant speed and try to accelerate just a little you will get some wheel screech when it accelerates

PS : no idear of speed limits none I guess

Codifex Maximus · #67 10-10-2009, 01:16 AM

I remember when I first got my 81 240D. I thought something was wrong with it - it didn't want to go any faster than 70MPH and whined loudly.

That was until I talked with my MB mechanic. He told me they were designed at a time when 55MPH was the speed limit. The car is not designed for speed but for comfort.

Reminded me of my 60 VW beetle with 36bhp. Ok on the flats but slows down on the grades. Best to get a good 5-10MPH head start on that hill.

How feasible is an aftermarket turbo on a 240D? My mechanic said it's probably not a good idea. Just get an already turbocharged car - which I did. The turbo really makes a difference when it kicks in.

Codifex
1981 240D SkyBlue
1983 300DTurbo w/sunroof

JEBalles · #68 10-10-2009, 06:49 AM

Quote:

Originally Posted by Codifex Maximus

I remember when I first got my 81 240D. I thought something was wrong with it - it didn't want to go any faster than 70MPH and whined loudly.

That was until I talked with my MB mechanic. He told me they were designed at a time when 55MPH was the speed limit. The car is not designed for speed but for comfort.

Reminded me of my 60 VW beetle with 36bhp. Ok on the flats but slows down on the grades. Best to get a good 5-10MPH head start on that hill.

How feasible is an aftermarket turbo on a 240D? My mechanic said it's probably not a good idea. Just get an already turbocharged car - which I did. The turbo really makes a difference when it kicks in.

Codifex
1981 240D SkyBlue
1983 300DTurbo w/sunroof

If you search the archives for "240D Turbo" you get plenty of results. From what I gathered (I've thought about it myself) is that it can be done, but takes lots of modifications and will shorten the life of the engine unless there are appropriate interior modifications. It's supposed to be easier just to get a 617 turbo and swap it in.