From: owner-diesel-benz-digest-at-digest.net (diesel-benz-digest) To: diesel-benz-digest-at-digest.net Subject: diesel-benz-digest V1 #754 Reply-To: diesel-benz-at-digest.net Sender: owner-diesel-benz-digest-at-digest.net Errors-To: owner-diesel-benz-digest-at-digest.net Precedence: bulk diesel-benz-digest Monday, April 29 2002 Volume 01 : Number 754 Forum for Discussion of Diesel Mercedes Benz Automobiles Derick Amburgey Digest Coordinator Contents: Re: Diesel? Re: W123 - 240D RPM question Re: W123 - 240D RPM question Re: W123 - 240D RPM question Re: Diesel? W123 vs. w116 RE: W123 - 240D RPM question Re: W123 - 240D RPM question Diesel Benz Digest Home Page: http://www.digest.net/diesel-benz/ Send submissions to diesel-benz-digest-at-digest.net Send administrative requests to diesel-benz-digest-request-at-digest.net To unsubscribe, include the word unsubscribe by itself in the body of the message, unless you are sending the request from a different address than the one that appears on the list. Include the word help in a message to stag-digest-request to get a list of other majordomo commands. ---------------------------------------------------------------------- Date: Thu, 25 Apr 2002 15:54:03 -0700 (PDT) From: john Subject: Re: Diesel? well, the ML series isn't sold in the states with one... unimog and gwagens are a bit out of my price range... :) I've got a friend that got rid of his Full Size Jeep for a UNIMOG. Not exactly a daily driver type of vehicle... :) To the question about whether we needed a 4x4... you haven't seen my driveway... ;) john On Thu, 25 Apr 2002, Renaud OLGIATI wrote: >-->On Thursday 25 April 2002 12:24, my mailbox was honoured by a missive from >-->john: >-->> only two problems (mainly) with a Mercedes Diesel, >-->> they don't come in 4x4 >--> >-->I'm sure they do. >--> >-->Never heard of the Unimog ? >--> >-->Ron, on the banks of the aParaguay River. >-->-- >--> Do not meddle in the affairs of wizards, >--> for you are crunchy and tasty with ketchup. >--> --- http://personales.conexion.com.py/~rolgiati --- >--> ---- - ------------------------------------------------------------------------- ** john-at-wagoneers.com via PINE on Linux ** (plain text please!) ** http://wagoneers.com ** ** http://freegift.net ** Snohomish, Washington USA - where Jeeps don't rust, they mold. ...and remember, leaving life without Jesus just isn't recommended... - ------------------------------------------------------------------------- ------------------------------ Date: Fri, 26 Apr 2002 10:57:07 +0200 From: Nepppi Subject: Re: W123 - 240D RPM question Hi Jim, a manual available in Germany says 3275 RPM at 100 km/h in fourth gear. This means about 2900 rpm at 55 mph and 3700 rpm at 70 mph. Depending on your tires it might be more or less, if you have an automatic tranny the engines usually make a few rpm's more. Hope this helps, Thorsten At 09:36 25.04.02 -0500, you wrote: >Folks, > > Does anyone know how many RPM's my engine should >be turning at 55mph and at 70mph?? My car doesn't have >a tach so I can't tell. > >Thanks, > >Jim/ > >'83 240D ------------------------------ Date: Fri, 26 Apr 2002 08:14:03 -0500 From: Jim & Barb Hoffman Subject: Re: W123 - 240D RPM question Thanks Thorsten! This is what I suspected. Here's an observation I made on a trip this past week. I put about 900 miles on my little 240D in two days. It ran beautifully. BUT... I noticed that my fuel mileage dropped off dramatically. It went from about 27-29mpg to 23mpg on the highway. Now normally with a gas engine you get better fuel mileage performance at HWY cruising. But I also know that numerous diesel experts have told me that the optimum efficiency of a diesel engine is around 2200rpm. After that your fuel mileage will drop off exponentially NOT linearly. My experience on this trip would support that claim. Now I'm wondering if since this car was made for the American market in the 80's, if it weren't optimized for 55mph since that was the speed limit nation wide at that time. 2900 rpm is still a bit higher that 2200 but a heck of a lot closer that 3275! I'm thinking about changing the gearing to get me closer to 2200. I know someone asked about gearing a few weeks ago and Alec pointed out that that would hurt acceleration in a car that already has problems with acceleration but I'm more interested in efficiency ;) Any thoughts?!?! Jim/ '83 240D Nepppi wrote: > Hi Jim, > > a manual available in Germany says 3275 RPM at 100 km/h in fourth gear. > This means about 2900 rpm at 55 mph and 3700 rpm at 70 mph. Depending on > your tires it might be more or less, if you have an automatic tranny the > engines usually make a few rpm's more. > > Hope this helps, > > Thorsten ------------------------------ Date: Fri, 26 Apr 2002 10:21:33 -0700 From: "Dan J." Subject: Re: W123 - 240D RPM question >But I also know that numerous diesel experts have >told me that the optimum efficiency of a diesel engine is around 2200rpm. >After that your fuel mileage will drop off exponentially NOT linearly. >My experience on this trip would support that claim. >Any thoughts?!?! > >Jim/ This would depend on the engine and it's application. A car made for Europe or japan, or even a car made back in the '70's when the USA speed limit was 55 MPH would be different than one made today, with speed limits here reaching as high as 75 (AZ). My '79 MBZ300D will cruise the highway at 70, but it would much rather go 55 or 60. My BIG truck engine, a '98 Freightliner with a 14 liter Cummins heavy duty set at 425 HP runs best at either 1200 RPM (Peak torque), or 1500 RPM (Peak HP), and with the 10 speed tranny, it runs 55 at 1350, and 70 at 1550. IOW, it all depends on what the vehicle was designed to do, and how the running gear was selected for that job. Diesel Dan, your "moving at a high rate of fuel consumption" man in Washougal, WA ------------------------------ Date: Fri, 26 Apr 2002 10:13:30 -0700 From: "Dan J." Subject: Re: Diesel? At 03:54 PM 4/25/2002 -0700, John wrote: >To the question about whether we needed a 4x4... you haven't seen >my driveway... ;) > >john He _needs_ a 4 wheel drive. Besides, without 4x4, he couldn't do his annual run up the snow covered hillside just to prove he's a man with a manly vehicle. ;-) Diesel "You're gonna drive that thing up that hill every year?" man from gray but bee-oo-T-full Washougal, WA http://dieseldan.net ------------------------------ Date: Fri, 26 Apr 2002 14:54:04 -0600 From: "JC Jones" Subject: W123 vs. w116 Does anybody know if the front door power window regulators are compatible between the w123 and a w116? JC Jones http://www.jtruck.net http://www.wagoneer.net 1979 Jeep J-10 "Max" 1984 Grand Wagoneer "Eeyore" 1978 MB 300D "Fritz" 1986 Jeep XJ Cherokee "Junior" * * * * * =================== "They that can give up * * * * =================== essential liberty to * * * * * =================== obtain a little ============================= temporary safety ============================= deserve neither ============================= liberty nor safety." ============================= -Benjamin Franklin ------------------------------ Date: Fri, 26 Apr 2002 17:57:15 -0500 From: "Black, Waylon" Subject: RE: W123 - 240D RPM question See if I can remember this right. This is for my 300 SD(3.07 - I found that 123 300Ds use a 3.46) Assume 1.1 drive (I am told my 4 speed auto is not an OD but has a lower 1st gear - bummer) Assume axle ratio(or overall ratio) = 3.07 or 3.46 Assume tire diameter - 24 inches Assume 2200 rpm RPM x 60 X (Tire diameter X 3.14) divided by 63360(inches per mile) 3.07 So 2200(rpm) x 60 divided by 3.07 x 75.36(24" x3.14) divided by 63360 = 51.14 mph for the 300 SD or 45.37 for the 300 D Best mileage at about 51 mph for the 300 SD or 45.37 for the 300 D - let's not get run over. LOL Increase Tire diameter to 28"(87.92) - 59.66 for the SD or 52.938 for the 300 D - better but still too slow. For an OD trans multiply your axle ratio by the top gear for overall ratio. Your mph will actually be less with the auto, due to slippage. This is get you some close numbers. Not sure of how your MB would look with 28-30" tires. ;) Waylon Dallas, Texas -----Original Message----- From: Dan J. [mailto:dieseldanotr-at-earthlink.net] Sent: Friday, April 26, 2002 12:22 PM To: Diesel-benz-at-digest.net Subject: Re: W123 - 240D RPM question >But I also know that numerous diesel experts have >told me that the optimum efficiency of a diesel engine is around 2200rpm. >After that your fuel mileage will drop off exponentially NOT linearly. >My experience on this trip would support that claim. >Any thoughts?!?! > >Jim/ This would depend on the engine and it's application. A car made for Europe or japan, or even a car made back in the '70's when the USA speed limit was 55 MPH would be different than one made today, with speed limits here reaching as high as 75 (AZ). My '79 MBZ300D will cruise the highway at 70, but it would much rather go 55 or 60. My BIG truck engine, a '98 Freightliner with a 14 liter Cummins heavy duty set at 425 HP runs best at either 1200 RPM (Peak torque), or 1500 RPM (Peak HP), and with the 10 speed tranny, it runs 55 at 1350, and 70 at 1550. IOW, it all depends on what the vehicle was designed to do, and how the running gear was selected for that job. Diesel Dan, your "moving at a high rate of fuel consumption" man in Washougal, WA ------------------------------ Date: Mon, 29 Apr 2002 09:22:15 +0200 From: Nepppi Subject: Re: W123 - 240D RPM question Hi Jim, the manual also says that the old diesel engines have a maximum torque at 2400 rpm. So that is what you want to have at highway speed for best economy. Does your 240D have an automatic transmission? If it does than I would try the rear axle of the 300turbos. They have a ratio of 3.07 compared to your 3.69 and with that axle your car would have 2400 rpm's at 55 mph. Depending on the area you live (rather flat or in the Rockies?) this would surely work. I own a 200D W123 (yeah, unreached 60 hps ;-)) which had a factory 3.92 rear axle. First I put a 3.58 rear axle in it and didn't notice any considerable difference at all. It was a bit more difficult to get the thing moving since you have to be more careful with the clutch. But the accelaration didn't change noticably and the fuel economy didn't change, either. And here is why. Since the engine runs at about 300 rpm's less on the autobahn I am driving faster than I did before. No wonder that the fuel economy was the same. Later I fitted a five gear standard transmission. In fifth gear the engine runs at 2400 rpm's at about 55 mph. The fuel economy improved slightly, but not too impressive since I am again driving faster than without the fifth gear. And believe me, whatever overall transmission ratio you have, you will automatically drive faster than before and won't notice an improvement in fuel economy. But here is what really gelped a lot concerning fuel economy. Remove the fixed engine fan and change to en electrical one. This saved 5 mpg. With the standard fan I got 31 mpg, after removing it I get 36 mpg. Maybe you should simply try it. You can remove the fan blade with 4 srews. Be sure to put 4 other screws in so you won't loose the pulley. If you try this on the highway and don't have any traffic jam it will work as the first test. I am driving my car like this for half a year now and haven't noticed any problems. But one has to fit an electrical fan for the summer or when using the ac because otherwise the enige get too hot. Bye, Thorsten At 08:14 26.04.02 -0500, you wrote: >Thanks Thorsten! > > This is what I suspected. Here's an observation I made on a trip this >past week. I put about 900 miles on my little 240D in two days. It >ran beautifully. BUT... I noticed that my fuel mileage dropped off >dramatically. It went from about 27-29mpg to 23mpg on the highway. >Now normally with a gas engine you get better fuel mileage performance >at HWY cruising. But I also know that numerous diesel experts have >told me that the optimum efficiency of a diesel engine is around 2200rpm. >After that your fuel mileage will drop off exponentially NOT linearly. >My experience on this trip would support that claim. > > Now I'm wondering if since this car was made for the American >market in the 80's, if it weren't optimized for 55mph since that was >the speed limit nation wide at that time. 2900 rpm is still a bit higher >that 2200 but a heck of a lot closer that 3275! > > I'm thinking about changing the gearing to get me closer to 2200. >I know someone asked about gearing a few weeks ago and Alec >pointed out that that would hurt acceleration in a car that already >has problems with acceleration but I'm more interested in efficiency ;) > >Any thoughts?!?! > >Jim/ > >'83 240D > >Nepppi wrote: > > > Hi Jim, > > > > a manual available in Germany says 3275 RPM at 100 km/h in fourth gear. > > This means about 2900 rpm at 55 mph and 3700 rpm at 70 mph. Depending on > > your tires it might be more or less, if you have an automatic tranny the > > engines usually make a few rpm's more. > > > > Hope this helps, > > > > Thorsten ------------------------------ End of diesel-benz-digest V1 #754 *********************************