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#16
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Should be around 2677rpm or so at 70mph with a 2.88:1 axle (25.3" tire on mine). That's where I cruise on the freeways always around here. Gotta remember we don't have lock up torque converters so that can and does vary from what the stock instrumentation reads. Perhaps there's a few percent of error within them like others?
With the 2.47:1 shows appx 2296rpm at 70mph with the same variables as previous. There looks to be about 62rwhp at 2300rpm and around 75rwhp at 2700rpm. I still have a dyno chart I found on here from a 300D where the torque is pretty flat from 2000-2600 then tapers probably 20rwtq from 2600-3000rpm.
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I'm not a doctor, but I'll have a look. '85 300SD 245k '87 300SDL 251k '90 300SEL 326k Six others from BMW, GM, and Ford. Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG] |
#17
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20 year old tachs can't be trusted, they just give you a general idea of what rpm the engine is running.
Still 603's like to rev I don't think lower rpms would make them to happy.
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1999 SL500 1969 280SE 2023 Ram 1500 2007 Tiara 3200 |
#18
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Quote:
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Proud owner of .... 1971 280SE W108 1979 300SD W116 1983 300D W123 1975 Ironhead Sportster chopper 1987 GMC 3/4 ton 4X4 Diesel 1989 Honda Civic (Heavily modified) --------------------- Section 609 MVAC Certified --------------------- "He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche |
#19
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So 300SDLs do 70mph at 3,000rpm? Wow... must be a lot more quiet on the highways than the 617s. 300SDs do 65mph at 3,000rpm. That has to be one aspect of this car I hate, truly hate. The highway noise. Lately, I've been playing book CDs and listening to some music during long trips in the 300SD and those make it impossible for me to even hear the noise of the engine, but when I decide to turn off all sorts of music for some peace, I wish I never sold my Toyota Avalon. Oh well.
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1999 Mercedes-Benz S600, 103K miles - garage queen 1988 Mercedes-Benz 560SEL, 89K miles - daily driver 2007 Hyundai Sonata Limited, 31K - daily driver |
#20
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What tire height did you use? I used 25.3 which is off my 205/70R14
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I'm not a doctor, but I'll have a look. '85 300SD 245k '87 300SDL 251k '90 300SEL 326k Six others from BMW, GM, and Ford. Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG] |
#21
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26.62 inches, from a 225/60R16 tire.
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1999 Mercedes-Benz S600, 103K miles - garage queen 1988 Mercedes-Benz 560SEL, 89K miles - daily driver 2007 Hyundai Sonata Limited, 31K - daily driver |
#22
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Thanks for the links Whunter. You're always there when needed.
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1999 Mercedes-Benz S600, 103K miles - garage queen 1988 Mercedes-Benz 560SEL, 89K miles - daily driver 2007 Hyundai Sonata Limited, 31K - daily driver |
#23
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My stock tire is a 205/65/15.
It runs just below 3k at 70 maybe 2,900. My car is very quite on the highway for a diesel MB at least, the sunroof makes more wind noise then the engine does. (I need to fix that)
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1999 SL500 1969 280SE 2023 Ram 1500 2007 Tiara 3200 |
#24
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I've often wondered if my SD has LSD. On the rare occasion I get the rear tires to spin(wet pavement, gravel, ect), it seems they both do.
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past MB rides: '68 220D '68 220D(another one) '67 230 '84 SD Current rides: '06 Lexus RX330 '93 Ford F-250 '96 Corvette '99 Polaris 700 RMK sled 2011 Polaris Assault '86 Yamaha TT350(good 'ol thumper) |
#25
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I'm sick of .sig files |
#26
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Just like you don't think so (meaning you don't factually know so), I think that those factors affect rpm. But I don't know this for a fact, I'm just going off seeing my car doing 65mph at around 3,200 rpm when it is extremely windy on the highway instead of the usual 3,000 rpm. Maybe someone who knows the facts can chime in here.
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1999 Mercedes-Benz S600, 103K miles - garage queen 1988 Mercedes-Benz 560SEL, 89K miles - daily driver 2007 Hyundai Sonata Limited, 31K - daily driver |
#27
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Our 83 does 70mph at about 2900rpm according to the tach.....I think mine is probably a little higher. I love the sound on the freeway! Hearing the engine purring along is music to this addict's ears. In the fall I will be commuting a lot (probably 2-3 times a month) between the very top of MI, Sault Ste Marie, to GR a lot....305ish miles each way.....my SD is gonna love it.
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-diesel is not just a fuel, its a way of life- '15 GLK250 Bluetec 118k - mine - (OC-123,800) '17 Metris(VITO!) - 37k - wifes (OC-41k) '09 Sprinter 3500 Winnebago View - 62k (OC - 67k) '13 ML350 Bluetec - 95k - dad's (OC-98k) '01 SL500 - 103k(km) - dad's (OC-110,000km) '16 E400 4matic Sedan - 148k - Brothers (OC-155k) |
#28
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Resistance = RPM is higher for lower speed.
I drove in Hurricane Hugo's 135 mph wind, engine full throttle screaming, and looked down to see max speed was eighteen too twenty mph...
Hurricane Hugo Sept. 10-25, 1989 Max. winds: 160 mph. SUSTAINED WINDS: 135 mph PRESSURE: 934 Mb./27.58 inches. STORM - SURGE: 16 - 20 feet above Mean Tide. http://www.geocities.com/hurricanene/hurricanehugo.htm http://www.wunderground.com/hurricane/hugo1.asp http://www.clemson.edu/special/hugo/ http://www.hurricaneville.com/hugo.html http://www1.ncdc.noaa.gov/pub/data/images/hurricane_hugo_1989_goes_ir_3.gif http://www1.ncdc.noaa.gov/pub/data/images/hurricane-hugo-radar-chs.gif http://www1.ncdc.noaa.gov/pub/data/images/hurricane-hugo-ir2.gif http://www1.ncdc.noaa.gov/pub/data/images/hurr-hugo-19890921-n11rgb.jpg http://www1.ncdc.noaa.gov/pub/data/images/hurricane_hugo_1989_goes_ir_1.gif http://rsd.gsfc.nasa.gov/rsd/images/HugoPersp.html |
#29
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Now, the variable that is not mentioned is the automatic transmission and the torque converter. Once you add the torque converter, you don't have a rigid coupling between the engine and the drive wheels. So, when the engine turns 2187 rpm, the vehicle cannot go 70 mph anymore because there is some "slip" in the torque converter. This slip can be as little as zero, if the vehicle is going slightly downhill and the vehicle needs just a touch of power from the engine to maintain the vehicle speed. The slip can be as much as 1300 rpm (estimated) if you stand on the brakes and mash your right foot on the floor. The engine is turning at 1300 rpm but the wheels are stopped! Most of the time, M/B with their high stall torque converters will be slipping about 300 rpm on level ground at 60-70 mph. So, if you want to maintain 70 mph in an automatic with 2.47 gears and 225/60/16 tires, you will need to have an engine speed of somewhere around 2487 rpm. You will need more than this rpm to go uphill and you will need less than this rpm to go downhill. This is why you see different tach speeds for the same vehicle speed. Hope this makes some sense. Last edited by Brian Carlton; 02-18-2005 at 09:53 AM. Reason: more thoughts |
#30
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Dont tires also "grow" at high speeds ? futher throwing off the speed ratio calculations...
(though I would agree if it were a negligable amount) -John
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2009 Kia Sedona 2009 Honda Odyssey EX-L 12006 Jetta Pumpe Duse (insert Mercedes here) Husband, Father, sometimes friend =) |
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