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  #16  
Old 09-18-2007, 01:43 PM
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Neither shock is going to greatly affect ride quality. Your ride is harsh because of your springs.







Quote:
Originally Posted by RBYCC View Post
For optimum handling the rear of the vehicle should be slightly higher then the front to allow weight transfer which assists handling both in acceleration and cornering !
If the rear of the vehicle is higher, you're raising the center of gravity, causing jacking. Also, weight transfer occurs in any accelerating, decelerating or cornering. The amount of weight transfer would be changed by raising the center of gravity, but not for the better in cornering or decelerating. For RWD, the only benefit is in straight line acceleration.

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  #17  
Old 09-18-2007, 02:44 PM
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KONI adjustable!
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  #18  
Old 09-18-2007, 06:34 PM
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Quote:
Originally Posted by tankdriver View Post
If the rear of the vehicle is higher, you're raising the center of gravity, causing jacking. Also, weight transfer occurs in any accelerating, decelerating or cornering. The amount of weight transfer would be changed by raising the center of gravity, but not for the better in cornering or decelerating. For RWD, the only benefit is in straight line acceleration.
I will stand by my statement of a slightly higher rear ride height on a front engine rear wheel drive based on real world road racing experience.

I'm open, site me your personal examples of how you've set up cars for road race use....

Willing to learn !!!

You could have schooled the design team at Ferrari when they did the 612

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  #19  
Old 09-18-2007, 07:35 PM
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Quote:
Originally Posted by RBYCC View Post
I will stand by my statement of a slightly higher rear ride height on a front engine rear wheel drive based on real world road racing experience.
How does it help?
I'm also willing to learn.

Have you read Fred Puhn's How to Make Your Car Handle?
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Last edited by tankdriver; 09-18-2007 at 07:45 PM.
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  #20  
Old 09-19-2007, 08:50 AM
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Quote:
Originally Posted by tankdriver View Post
How does it help?
I'm also willing to learn.

Have you read Fred Puhn's How to Make Your Car Handle?
I think I read it when it came out in the mid seventies....

If you have it then see what he writes about "roll center"
Front lower then the rear?

Suspensions are very complex and components must be well matched to achieve balance, especially with struts in the front.

Tires are a much more important suspension component then most realize.
Why...because they present an infinitly variable component to the equation.
Under acceleration they respond to what they see, power, road surface, etc.
Cornering there is the slip angle to consider.

Also spring rates....higher in the front produce less weight transfer when braking and limit the amount of understeer they induce.

Too low of a vehicle with too stiff spring rates will result in a slower and erratically performing car as it induces roll.

If you look at most vehicles that are designed for high speed handling you will always see a slightly higher rear ride height as I indicated in the picture of the Ferrari.
I'm addressing front engine rear wheel drive cars that have a front to rear weight bias.

Use an example of a slight rear/front ride height bias with heavier front spring rates.

Brake as you enter a corner and weight shifts to the front, but the heavier front springs do not allow front end dip or a substantial increase in understeer.
As you accelerate into the corner the weight moves to the rear, leveling the car, and affording better traction allowing the vehicle to operate under hopefully optimum understeer.

Look even how a vehicle sits side to side...not always even.
Race cars have the ability to adjust suspension at every wheel based on track conditions.

Trying to be simplistic, but lower, stiffer is not always better.

I stand by my opening statement that the choice of HD's or Sports with a lowering spring is up to the owner.
Tires are more important then you realize.
Ride height should not be excessive as also camber settings

I'm running a modified 300CE, primarily street use that accelerates to 60MPH in the low 5 second range.
Not bad for a M103-12V that weighs 3700lbs.

I have no problem with the HD's, but that was my choice !!!

Last edited by RBYCC; 09-19-2007 at 08:57 AM.
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  #21  
Old 09-19-2007, 09:34 AM
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Quote:
Originally Posted by RBYCC View Post
I think I read it when it came out in the mid seventies....

If you have it then see what he writes about "roll center"
Front lower then the rear?

I don't have it with me, I'll have to refer back later.

Quote:
Suspensions are very complex and components must be well matched to achieve balance, especially with struts in the front.

The 300E doesn't have Mac struts.

Quote:
Tires are a much more important suspension component then most realize.
Quote:
Why...because they present an infinitly variable component to the equation.
Under acceleration they respond to what they see, power, road surface, etc.
Cornering there is the slip angle to consider.

Yeah, tires are the single most important part of the suspension.

Quote:
Also spring rates....higher in the front produce less weight transfer when braking and limit the amount of understeer they induce.

Spring rates do not affect the amount of weight transfer.


Quote:
Use an example of a slight rear/front ride height bias with heavier front spring rates.
Quote:

Brake as you enter a corner and weight shifts to the front, but the heavier front springs do not allow front end dip or a substantial increase in understeer.
As you accelerate into the corner the weight moves to the rear, leveling the car, and affording better traction allowing the vehicle to operate under hopefully optimum understeer.

Having the rear higher than the front raises the CG v. having them the same height. Naturally, the engineers decide to have the CG at a certain point. Raising the rear is different from designing the rear to be higher. The reason the rear may be designed higher than the front is, with a RWD car, the drive wheels get more of the weight transferred to them during acceleration. In your example, you have the weight transferring front to back. In a corner, it also transfers side to side. You are loading - at turn in, the outside front - and in the corner, both outside tires. In a corner, there will be more weight transfer to the outside front with a higher CG v. a lower one, and more weight transfer to the outside rear mid corner.

You're right that it's complicated, which is why I commented on the seemingly simplistic statement of yours. Rake is not always best.

Quote:
I stand by my opening statement that the choice of HD's or Sports with a lowering spring is up to the owner.

Certainly it's up to the owner, but his ride quality is due mainly to his springs. A less stiff shock may help a bit, but it will also wear out faster.
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  #22  
Old 09-19-2007, 11:26 AM
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Quote:
Originally Posted by tankdriver View Post
I don't have it with me, I'll have to refer back later.

The 300E doesn't have Mac struts.
I didn't say "Mac struts"....the W124 has a "compact damper strut front suspension"


You're the expert.....

What do I know....you're showing me how much I failed to learn in many years of SVRA with a Aston Martin DB Vantage.

Need to do the cones in a parking lot to learn how to drive...who needs Lime Rock !!!

Guess it was just a design faux pas that the W124's as delivered by the factory had a slight rear to front rake....

Got nothing to prove, I know I've gone fast for forty years and the reasons why !!

How fast have you gone or is it all theory ????

I'm out on this subject....

Last edited by RBYCC; 09-19-2007 at 11:55 AM.
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  #23  
Old 09-19-2007, 04:07 PM
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Quote:
Originally Posted by RBYCC View Post
I didn't say "Mac struts"....the W124 has a "compact damper strut front suspension"


You're the expert.....

What do I know....you're showing me how much I failed to learn in many years of SVRA with a Aston Martin DB Vantage.

Need to do the cones in a parking lot to learn how to drive...who needs Lime Rock !!!

Guess it was just a design faux pas that the W124's as delivered by the factory had a slight rear to front rake....

Got nothing to prove, I know I've gone fast for forty years and the reasons why !!

How fast have you gone or is it all theory ????

I'm out on this subject....
The thing about information is that it doesn't require reaching a certain speed to get it.
If it makes you feel better, I have spent some time at Summit Point in WV.

As far as I'm aware, the only suspension that uses a strut is the McPherson strut suspension (aka Chapman for the rear), and the definition of a strut would be a suspension component that attaches at the top directly to the chassis, eiliminating the upper control arm. It consists of the mounting hardware, a shock absorber, and a spring perch welded to the shock body.
Do you (or anyone else) have a diagram of the 300E suspension? I'm curious as to how a strut is incorporated.
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  #24  
Old 09-19-2007, 05:44 PM
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Quote:
Originally Posted by tankdriver View Post
The thing about information is that it doesn't require reaching a certain speed to get it.
Information acquisition is simple, but the ability to comprehend and convert to real world application is lost on many !

Quote:
If makes you feel better, I have spent some time at Summit Point in WV.

So how was the view from the stands?
You remind me of the saying: "Those that can....do, those that can't...talk about it"


Quote:
As far as I'm aware, the only suspension that uses a strut is the McPherson strut suspension (aka Chapman for the rear),
Perhaps you weren't in school that day ????

Quote:
and the definition of a strut would be a suspension component that attaches at the top directly to the chassis, eiliminating the upper control arm. It consists of the mounting hardware, a shock absorber, and a spring perch welded to the shock body.
Do you (or anyone else) have a diagram of the 300E suspension? I'm curious as to how a strut is incorporated.

I couldn't resist responding..

You've been quoting chapter and verse on performance suspension set ups and being rather technical at that !!!

Meanwhile you don't know zip about the twenty + year old suspension design on the very vehicle you drive.

Now where is that upper control arm ???

Let's not even attempt to understand the rear suspension....

Don't knock over too many pylons in the parking lot with your fine tuned suspension.




THE LOGIC OF DAMPER STRUT FRONT SUSPENSION

A COMPACT DAMPER STRUT FRONT SUSPENSION contributes to aerodynamic efficiency by permitting a low hoodline. The design achieves advantages in ride comfort over MacPherson strut suspensions by separating the spring and the gas-pressurized damper strut, thereby allowing optimum placement of these components. Negative-offset geometry contributes to the straight-line tracking of the 190/300 Class automobiles.

Last edited by RBYCC; 09-19-2007 at 05:52 PM.
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  #25  
Old 09-19-2007, 08:44 PM
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Quote:
Originally Posted by RBYCC View Post
Information acquisition is simple, but the ability to comprehend and convert to real world application is lost on many !
You seem to think stiffer springs affect the amount of weight transfer. I guess if you've applied information to the real world, you don't need to abide by the laws of physics.


Quote:
Meanwhile you don't know zip about the twenty + year old suspension design on the very vehicle you drive.

I don't drive a 300E. Nor would I buy a vehicle with that kind of suspension setup. Keep jumping to conclusions though, you're good at it.

Quote:
THE LOGIC OF DAMPER STRUT FRONT SUSPENSION

A COMPACT DAMPER STRUT FRONT SUSPENSION contributes to aerodynamic efficiency by permitting a low hoodline. The design achieves advantages in ride comfort over MacPherson strut suspensions by separating the spring and the gas-pressurized damper strut, thereby allowing optimum placement of these components. Negative-offset geometry contributes to the straight-line tracking of the 190/300 Class automobiles.
Thanks for the diagram, no thanks for the attitude.
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  #26  
Old 09-19-2007, 11:51 PM
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Originally Posted by tankdriver View Post
You seem to think stiffer springs affect the amount of weight transfer. I guess if you've applied information to the real world, you don't need to abide by the laws of physics.
Let me "cut and paste" like you are so good at doing....
Obviously the more you post, the less knowledge you show....
The theory conforms to all laws of physics....
Try to be logical....

Spring Rates

The Spring Rate controls the transfer of weight of the car. During braking and acceleration the weight of the car shifts forward and backward. Softer front springs aid in shifting the weight to the front, thereby reducing understeer. Softer rear springs allow the weight to transfer to the rear, consequently reducing oversteer. Alternatively, to induce understeer or oversteer, do the opposite and stiffen the corresponding spring rates. Keep in mind that spring rates that are too soft produce a car that is not as responsive as one with a stiffer spring rate. So, you have to find a compromise.


Quote:
I don't drive a 300E. Nor would I buy a vehicle with that kind of suspension setup. Keep jumping to conclusions though, you're good at it.

Thanks for the diagram, no thanks for the attitude.
Attitude ????

You're the one who chimes in as the suspension expert on W124's and you're not even familiar with the design geometry.

You wouldn't own a W124 ...prefer the antiquated suspension design of a W123 diesel wagon ???
Talk about nose bleed performance....

Only conclusion that I come to is that you're long on reading, short on real life experience.

Don't be so critical of one who has experience on the particular vehicle in question when you have none...
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  #27  
Old 09-20-2007, 12:58 AM
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Quote:
Originally Posted by RBYCC View Post
...Only conclusion that I come to is that you're long on reading, short on real life experience...
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  #28  
Old 09-20-2007, 02:59 AM
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Quote:
Originally Posted by RBYCC View Post

Only conclusion that I come to is that you're long on reading, short on real life experience.
hehehe

And i dont know why he is arguing about the W124 suspension when he drives an old diesel wagon with a very outdated, clunky, and wobbly suspension in the W123.....especially the wagon!
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  #29  
Old 09-20-2007, 11:17 AM
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Quote:
Originally Posted by RBYCC View Post
Let me "cut and paste" like you are so good at doing....
Obviously the more you post, the less knowledge you show....
The theory conforms to all laws of physics....
Try to be logical....

Spring Rates

The Spring Rate controls the transfer of weight of the car. During braking and acceleration the weight of the car shifts forward and backward. Softer front springs aid in shifting the weight to the front, thereby reducing understeer. Softer rear springs allow the weight to transfer to the rear, consequently reducing oversteer. Alternatively, to induce understeer or oversteer, do the opposite and stiffen the corresponding spring rates. Keep in mind that spring rates that are too soft produce a car that is not as responsive as one with a stiffer spring rate. So, you have to find a compromise.
Your own quote, mind you. "Controls the transfer of weight". "Softer springs aid in shifting the weight...". The amount of weight transfer is unchanged by spring rate. The opposite of what you said here:
Quote:
Originally Posted by RBYCC View Post
Also spring rates....higher in the front produce less weight transfer when braking and limit the amount of understeer they induce.


You can't change the amount of weight transfer (with spring rate), only affect where it goes. Missing from your quote is the effect on the rate of transfer. Also, softer spring rates in the front contribute to understeer, not the opposite.

CG height is one way to change the amount of weight transfer. Changing the track width is another.


Quote:
Attitude ????
Quote:

You're the one who chimes in as the suspension expert on W124's and you're not even familiar with the design geometry.
Expert? I said raising the rear ride height raises the CG (which it does). You didn't even dispute that, you just smugly dismissed me because what I say is less important than where I've been.

Quote:
You wouldn't own a W124 ...prefer the antiquated suspension design of a W123 diesel wagon ???
Talk about nose bleed performance....
Nice to see you can keep jumping to conclusions so well. I have another car.

Quote:
Only conclusion that I come to is that you're long on reading, short on real life experience.
I've got ~5 years at autocross, and took a few HPDEs. I apparently haven't acheived the level of of real life application that allows me to not bother with physics and to mock others without addressing their actual points, but I'm not going on track in my car without a roll cage, which is not in the budget any time soon. Since this is the internet, I could've easily made up years of experience with Aston Martins or Porsches or Ferraris. I don't know how that would've affected the information I potsed.

Quote:
Don't be so critical of one who has experience on the particular vehicle in question when you have none...
Please quote where I was critical. I made a comment based on one of your quotes (which was general, not specific to the 300E). You're the one who was derisive.
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Last edited by tankdriver; 09-20-2007 at 11:27 AM. Reason: spelling
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  #30  
Old 09-20-2007, 11:30 AM
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Quote:
Originally Posted by greasybenz View Post

hehehe

And i dont know why he is arguing about the W124 suspension when he drives an old diesel wagon with a very outdated, clunky, and wobbly suspension in the W123.....especially the wagon!

I admit I have "attitude" toward this poster

But why ???

Because I value the importance of information exchange on forums.

I have utter disdain for "disinformation" usually posted by graduates of "Google U " with in depth cut and paste "Wikepedia" knowledge.

Nothing worse then someone commenting with what appears to be undisputed facts on something that they have zero real world expeirence with.

The OP wanted comments on a 300E W124.
I own a 1988 300CE, purchased new in may of 1988.
Lived with it and its anomalies for almost twenty years.
Recently did a TurboTechnics twin turbo install.
Did the full suspension at the same time to handle 5.0 liter V8 torque in a six cylinder chassis.

Too many believe that you must use a sport shock/strut with a lowering spring...you really don't.
Choice is up to the buyer based on how and where they drive.
Personal choice was HD's based on that they are extremely compatible with H&R lowering springs.
Much empirical data from installs on Porsches.

If I didn't increase the power, I had no reason to lower the car.
The stock shocks and springs still worked well with the M103-12V

It works for me, will not see shortened life on the shocks/struts and pushing a whole lot more power then a stock M103/M104 and even more then a 500E

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