W115 220D Top Speed - Mercedes-Benz Forum

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 20 (permalink) Old 10-03-2016, 11:02 AM Thread Starter
BenzWorld Member
 
Winegarden's Avatar
 
Date registered: Jul 2016
Vehicle: 1972 220 D (Red)
Location: Europe
Posts: 85
Mentioned: 0 Post(s)
Quoted: 11 Post(s)
(Thread Starter)
W115 220D Top Speed

Hey guys,

according to the official technical data, the top speed of the 220D W115 is 135 km/h (or 84 mph), but does anyone know at how many rpm this top speed takes place?

Thanks!
Winegarden is offline  
Sponsored Links
Advertisement
 
post #2 of 20 (permalink) Old 10-03-2016, 11:50 AM
BenzWorld Veteran
 
Date registered: Aug 2009
Vehicle: '72 250C, '74 280C, '85 500SEL, '81 300CD.
Location: Tucson, Az.
Posts: 700
Mentioned: 3 Post(s)
Quoted: 60 Post(s)
Too many variables to make a calculation. Tire size, axle ratio, clutch slippage, etc.

Maximum rated RPM's are 5200.
Mike D is online now  
post #3 of 20 (permalink) Old 10-03-2016, 12:37 PM Thread Starter
BenzWorld Member
 
Winegarden's Avatar
 
Date registered: Jul 2016
Vehicle: 1972 220 D (Red)
Location: Europe
Posts: 85
Mentioned: 0 Post(s)
Quoted: 11 Post(s)
(Thread Starter)
Quote:
Originally Posted by Mike D View Post
Too many variables to make a calculation. Tire size, axle ratio, clutch slippage, etc.

Maximum rated RPM's are 5200.
Well, let's say with everything stock. Stock tires, stock axle ratio
There must be some kind of info, like 135 km/h @ x rpm.

I'm asking because I'm wondering if I'll be at 5000 rpms when driving around 130 kmh, or if I'll be able to drive more relaxed at 2500 rpms.

Actually, what I'd need to know, is the speed of the car in 4th gear at around 2500 rpms.
Winegarden is offline  
 
post #4 of 20 (permalink) Old 10-03-2016, 01:23 PM
BenzWorld Member
 
TZ_280SEL's Avatar
 
Date registered: Feb 2010
Vehicle: 1972 280SEL daily driver. 904 Dark Blue with cognac interior. euro 4.5 engine
Location: Williamsburg, VA
Posts: 322
Mentioned: 3 Post(s)
Quoted: 39 Post(s)
It all depends on your tires/rear end ratio, but I'll make some assumptions for you.

Assume you had original bias ply 14" tires with an 82 aspect ratio, the tire would have an OD of 25.3" so a rolling distance of 79.5"/revolution or 6.62'/revolution.

Your quoted top speed is 83.89mph which is 7382 ft/min.

traveling 7382 feet in a minute with a rolling diameter of 6.62' gives you a rear wheel speed of 1114.5 rev/min.

The stated final drive ratio on the internet for your car is 3.92:1 which means the engine is turning 4369 rev/min (which is coincidentally close to max torque for your engine).

Now, what size tires do you actually have?
rumb and Winegarden like this.
TZ_280SEL is offline  
post #5 of 20 (permalink) Old 10-03-2016, 01:25 PM
BenzWorld Member
 
TZ_280SEL's Avatar
 
Date registered: Feb 2010
Vehicle: 1972 280SEL daily driver. 904 Dark Blue with cognac interior. euro 4.5 engine
Location: Williamsburg, VA
Posts: 322
Mentioned: 3 Post(s)
Quoted: 39 Post(s)
BTW, at 2500 rpm, using the data above, you are traveling 48mph
Winegarden likes this.
TZ_280SEL is offline  
post #6 of 20 (permalink) Old 10-04-2016, 02:37 AM Thread Starter
BenzWorld Member
 
Winegarden's Avatar
 
Date registered: Jul 2016
Vehicle: 1972 220 D (Red)
Location: Europe
Posts: 85
Mentioned: 0 Post(s)
Quoted: 11 Post(s)
(Thread Starter)
Quote:
Originally Posted by TZ_280SEL View Post
It all depends on your tires/rear end ratio, but I'll make some assumptions for you.

Assume you had original bias ply 14" tires with an 82 aspect ratio, the tire would have an OD of 25.3" so a rolling distance of 79.5"/revolution or 6.62'/revolution.

Your quoted top speed is 83.89mph which is 7382 ft/min.

traveling 7382 feet in a minute with a rolling diameter of 6.62' gives you a rear wheel speed of 1114.5 rev/min.

The stated final drive ratio on the internet for your car is 3.92:1 which means the engine is turning 4369 rev/min (which is coincidentally close to max torque for your engine).

Now, what size tires do you actually have?
Stock tires**apparently 175 SR 14. When the engine is running 4369 rev/min, is that at 135 km/h / 83.89 mp/h in fourth gear then? It would make sense at least. So I won't be able to drive at that speed without ruining the engine. Some cars can drive at their top speed all while being at a reasonable 2500 rev/min, so I was wondering if it's the same on the 220D. I'm wondering why they put this as the top speed of the car, anyone driving at that speed with the engine revving so high would probably ruin it. Then again, my grandmother said she always drove the Mercedes full speed at 140 km/h (probably 135 but it says 140 on the speedometer).

What would happen if I mounted bigger wheels, like the 15" wheels that you find on the W115 ambulance and wagons for example? The rolling distance would be bigger and the car would be slightly faster, no?

Quote:
Originally Posted by TZ_280SEL View Post
BTW, at 2500 rpm, using the data above, you are traveling 48mph
In 4th gear you mean?
Winegarden is offline  
post #7 of 20 (permalink) Old 10-04-2016, 06:02 AM
w108,107 Parts Hoarder
 
Fonzi's Avatar
 
Date registered: Jun 2010
Vehicle: 4Keep:450slc5.0cab 280sl5sp 280se4.5 500seAMG 2sell:500sl92 380se83 300se86 350sl4sp 75slc MorInSig
Location: Philadelphia Area
Posts: 19,273
Mentioned: 29 Post(s)
Quoted: 1717 Post(s)
Lifetime Premium Member
Garage
Quote:
Originally Posted by Winegarden View Post



What would happen if I mounted bigger wheels, like the 15" wheels that you find on the W115 ambulance and wagons for example? The rolling distance would be bigger and the car would be slightly faster, no?




I think your question is about tire diameter, not really wheel size. Normally as the wheel size increases for a car, you reduce the tire sidewall. For example, the diameters of all these tire sizes I use on r107 chassis cars have about the same stock rolling diameter:
205/70/14, 205/65/15, 205/55/16 and 225/50/16 (or maybe a slightly taller 205/60/16 and 225/55/16).

The speedometer is probably calibrated for a stock diameter tire size. When your tires are new, you might go slightly faster than your speedometer says, and when your tires are old and bald, you might go slightly slower than the speedometer reads.

The larger tires may give you "longer legs" and a little more highway speed as long as you can get there. The acceleration may be slower though as you are effectively reducing the gear ratio. You could obtain a more dramatic affect by changing the rear differential to a lower ratio. Lower differential ratios will make acceleration a little slower but give you lower highway RPMs, but also probably less passing power.

If your car is still capable of hitting the top speed, it's probably running well and you should probably leave it as is and enjoy it. That's my opinion.
lea007 and Winegarden like this.

.

My signature:
Click for list of my 34 MB since 2010. If, you want 70's-80's Mercedes tuner wheels, let me know.
Fonzi is offline  
post #8 of 20 (permalink) Old 10-04-2016, 06:20 AM
BenzWorld Member
 
TZ_280SEL's Avatar
 
Date registered: Feb 2010
Vehicle: 1972 280SEL daily driver. 904 Dark Blue with cognac interior. euro 4.5 engine
Location: Williamsburg, VA
Posts: 322
Mentioned: 3 Post(s)
Quoted: 39 Post(s)
As Fonzi said, changing your tire size isn't going to make a huge difference. For example, if you went with a 15" wheel and ran 205/70/15 radials, you only increase tire diameter by 4% so now at the stated top speed, you are turning 4203 RPM. Yes, this all assumes 4th gear, a 3.92 rear end, no slippage in clutch etc....

What you do gain is more tire on the road. going to a 205 width from the stock bias (which I think were 175) you gain 17% more road contact area. I happen to like more tire on the road. I run 205/75/14 on my W108 chassis. That is about 3% larger diameter than your stock tire.

Anything you do to reduce engine speed is going to drop the rpm below the 4200RPM (max torque) which may actually reduce your top speed as that little engine will run out of power.
Winegarden likes this.
TZ_280SEL is offline  
post #9 of 20 (permalink) Old 10-04-2016, 06:29 AM Thread Starter
BenzWorld Member
 
Winegarden's Avatar
 
Date registered: Jul 2016
Vehicle: 1972 220 D (Red)
Location: Europe
Posts: 85
Mentioned: 0 Post(s)
Quoted: 11 Post(s)
(Thread Starter)
Thanks for explaining guys! I will most likely leave the car in stock condition. I will be driving mainly in the city with it, so I won't reach high speeds anyway and acceleration is more crucial even if it's just a minimal difference on this slow car

Larger tires would mean I'd have to get larger wheels, and in that case I would want to get Mercedes wheels from that time. I really like them. I would most likely have to get them from the W108 or another chassis that had larger tires. I know that you don't see the look of the wheel when the hubcap is on, and that I could get just any wheels, but I still want Merc wheels

At some point I was thinking of getting the 15" wheels for the W115 because they look more proportional with the rest of the car. If the car will be slower at accelerating I won't do it (even if it's just minimal). And in combination with the white-wall-tires, the car looks more proportional anyway, even with 14s:





So yeah, most likely leaving everything stock.
Winegarden is offline  
post #10 of 20 (permalink) Old 10-04-2016, 06:30 AM Thread Starter
BenzWorld Member
 
Winegarden's Avatar
 
Date registered: Jul 2016
Vehicle: 1972 220 D (Red)
Location: Europe
Posts: 85
Mentioned: 0 Post(s)
Quoted: 11 Post(s)
(Thread Starter)
Don't know what images don't work, and no edit button (??).
Winegarden is offline  
Sponsored Links
Advertisement
 
Reply

  Mercedes-Benz Forum > General Mercedes-Benz Forums > Vintage Mercedes-Benz

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Mercedes-Benz Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











  • Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
     
    Thread Tools
    Show Printable Version Show Printable Version
    Email this Page Email this Page
    Display Modes
    Linear Mode Linear Mode



    Posting Rules  
    You may post new threads
    You may 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 On
    Pingbacks are On
    Refbacks are On

     

    Title goes here

    close
    video goes here
    description goes here. Read Full Story
    For the best viewing experience please update your browser to Google Chrome