What should be the normal rpm at 60 mph? - MBWorld.org Forums

Go Back  MBWorld.org Forums > Technical & Vehicle Assistance Forums > Mercedes Tech Talk
What should be the normal rpm at 60 mph? > What should be the normal rpm at 60 mph?
Notices
Mercedes Tech Talk Discuss general technical questions and issues about your Mercedes-Benz. Moderated by a certified MB Tech.
Sponsored by:
Sponsored by:

What should be the normal rpm at 60 mph?

Reply

 
 
Old 02-03-2006, 05:53 PM
  #1
Newbie
Thread Starter
 
Join Date: Feb 2006
Posts: 10
Thanks: 0
Thanked 0 Times in 0 Posts
What should be the normal rpm at 60 mph?

Driving my wife's all original 1989 300SE inline 6/gas at 60 mph I noticed the rpms at a little over 3000. This rpm seems high to me when I would expect the transmission to be in overdrive. The automatic transmission seems to shift properly. The local MBZ mechanics are unable to answer this question after test drivng it. Does anyone out there have a clue?
lvduke is offline  
Reply With Quote
Old 02-04-2006, 01:05 PM
  #2
Member
 
Join Date: Nov 2005
Location: Palm Beach County, Fl.
Posts: 106
Thanks: 0
Thanked 1 Time in 1 Post
W163 ML500 w/Kleeman headers, 3.09 gears, 1995 W124 Cab, heated seats, S600 style grill, FOR SALE
Originally Posted by lvduke
Driving my wife's all original 1989 300SE inline 6/gas at 60 mph I noticed the rpms at a little over 3000. This rpm seems high to me when I would expect the transmission to be in overdrive. The automatic transmission seems to shift properly. The local MBZ mechanics are unable to answer this question after test drivng it. Does anyone out there have a clue?
From memory, my friends old 89 TE turned similar rpms. The car is geared a little stiff IMHO because the motor does not have a ton of power. So to make up for it, MB uses gearing. If you can tell me the real diff ratio (prob around 3.07), the tranny ratios and the tire size, I can post for you, or email to you, the speed in gear at various rpms.
Regards,
Jerry
gsfent is offline  
Reply With Quote
Old 02-04-2006, 01:57 PM
  #3
MBWorld Fanatic!
 
Join Date: Sep 2005
Location: Albuquerque
Posts: 4,965
Thanked 6 Times in 6 Posts
'07 GL320CDI
It's normal and there's no overdrive.

Our '88 300E with same engine turns 3500 at 75 mph

Our '06 E320CDI turns 2200 at 75 mph and will accelerate from that faster than the W124.
lkchris is offline  
Reply With Quote
Old 02-06-2006, 01:25 PM
  #4
Newbie
Thread Starter
 
Join Date: Feb 2006
Posts: 10
Thanks: 0
Thanked 0 Times in 0 Posts
Thanks for the input.

I tried to locate the information requested but did not have much luck. I did find that it's a 124 chassis, the automataic transmission is a 4 speed, the rear axle ratio is 3.07:1, and the trans starts out in 2nd gear if not floored - apparantly this feature was an fuel conservation measure implemented for the 1989 model.

I test drove it to again check out the shifting steps: with easy starts - presumably in 2nd gear - I felt 2 shifts suggesting that it went from 3rd to 4th gear. But when I floored it to engage 1st gear, I also only felt 2 shifts, suggesting that it stopped shifting when it reached 3rd gear. All driving done on flat streets - no inclines.

Any further thought/comments would be appreciated!
lvduke is offline  
Reply With Quote
Old 02-06-2006, 04:01 PM
  #5
MBWorld Fanatic!
 
Join Date: Sep 2005
Location: Albuquerque
Posts: 4,965
Thanked 6 Times in 6 Posts
'07 GL320CDI
Not really "implemented for 1989" as all previous W124s (USA) featured 2nd-gear start.

1st in these cars is a bit of a stump puller anyway, as all European cars must pass the "pull a house trailer away from a stop up a hill" test mandated in Switzerland.

You know, it takes a certain amount of power to do a given amount of work and it takes a given amount of fuel to produce that power.

A 180-cu in engine like your W124 is going to have to rev higher than some 350-cu in American iron to accomplish the same thing. If you made it 180 vs 360 it would take exactly twice the revs to accomplish this ... theoretically, that is, as cam lift and timing would have to be identical, etc. Of course the American car is likely to be heavier and perhaps not as aerodynamic as the W124, too, but perhaps you get the idea.

Had your W124 been turbo- or supercharged, the system might cram 350 cu in of air into 180 cu in space and fuel flow increased to match and then perhaps your W124 could turn lower revs. That's the way it works with our turbodiesel E320CDI (plus the fact diesel fuel contains more power per unit than gasoline).

The idea is ... don't expect things to be the same with a Mercedes as you may be used to having owned other cars.

Last edited by lkchris; 02-06-2006 at 04:04 PM.
lkchris is offline  
Reply With Quote
Old 02-11-2006, 03:22 PM
  #6
Newbie
Thread Starter
 
Join Date: Feb 2006
Posts: 10
Thanks: 0
Thanked 0 Times in 0 Posts
Points well taken. Thanks for the input. You are absolutely correct about Mercedes not being like any other car. A fact I continue to learn more each day.

I must conclude that 3000 rpm at 60 mph is normal for this car.

Peculiar that my Mercedes mechanics didn't have a clue. Time for new mechanics!
lvduke is offline  
Reply With Quote
Old 02-15-2006, 05:21 PM
  #7
Almost a Member!
 
Join Date: Jan 2006
Posts: 25
Thanks: 0
Thanked 0 Times in 0 Posts
its all good

my 91 300 e is exactly the same
3000 at 60 i have a 2.6 really hard to tell when it shifts
to smooth butt my car has hit its redline with no problem
just do your maintence and you will have no worries
j.wilhite is offline  
Reply With Quote
 
 
 

Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
ManchesterMan
C Class (W205)
25
12-21-2016 07:00 PM
pmgiarrizzo
W219
20
09-19-2015 12:25 PM
kthanxbye
C63 AMG (W204)
2
09-08-2015 07:07 PM
ELLAV8
S-Class (W220)
3
09-06-2015 04:09 PM
jakc
C Class (W205)
9
09-04-2015 11:50 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Search this Thread
Rate This Thread
Rate This Thread:
You have already rated this thread Rating: Thread Rating: 0 votes,  average.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 06:12 AM.


Copyright 2001-2012 InternetBrands, Inc. / MBWorld.org. All Rights Reserved. We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: