Top 3-5 cost efficient ways to decrease body roll? - Page 4 - PeachParts Mercedes-Benz Forum

English Bulldog · #46 01-13-2011, 12:28 AM

A. Keep the Bilstein Comforts

B. Buy a new set of HDs front
B. Keep the rear Comforts

C. Buy 4 new HDs
C. Toss the Comforts.

DeliveryValve · #47 01-13-2011, 12:49 AM

Quote:

Originally Posted by English Bulldog

racers and mechanics agree?

A. How much for TD springs front and back with new bushings?

B. How much for TD springs front with new bushings?
B. How much for the Vogtland rears? new bushings?

A or B good ideas if I cut them.

The typical front turbo TD spring is the same as the typical Turbo D spring. The rear TD spring is going to be shorter.

.

t walgamuth · #48 01-13-2011, 05:43 AM

[QUOTE=leathermang;2634896]Cutting off spring will not make the spring stiffer.

I disagree with this. Hey I could be wrong but everybody else says cutting off some of the spring will make what is left stiffer in its compressive state. It is true it reduces wheel travel and will change the steering geometry a little, but the car is designed to operate with up to about 1200# load so operating correctly with different ride heights is part of the reality of suspension design if you are working with springs and passive dampers.

Now if you have adustable air bags and the necessary controls you can keep the ride height constant but we are not talking about that.

t walgamuth · #49 01-13-2011, 05:55 AM

Having autocrossed my 84 500sec and my 84 euro 280e I can tell you that even though a benz rolls a lot in a corner, it will still corner pretty well. In autocross the time it takes for the springs to compress and expand is considerable compared to really quick cars but you have to start turning further away from the cone to give it time to compress. Once the springs are compressed the car will corner pretty decently.

Stiffening everything, springs, sways and shocks will give quicker response between turning left and right as especially in a slalom.

In my 99 MIata I was running the last two years in CS which allows anything you want in a shock as long as you keep the stock holes in the chassis and anything you want on the front sway but you have to keep stock springs. You also must keep the stock sized wheels but any tire you can cram on there is allowed.

I was running a very large front bar and As allowed the stock rear bar. The problem at the limit, especially as the Hoosier slicks wore was understeer. To balance the car I had to stiffen the rear shocks.

The ES Miatas running the same tires I was running in
CS had huge lean angles but were quicker than my car. They leaned so much you would swear they were going to go on over. You can see quite a bit of the bottom of the car (it seems like) when they go through a tight corner and the slicks are hot and sticky.

My point being that for street use, all talk about handling is pretty academic. What folks are really doing when changing all this on a street car is changing how the car LOOKS, and the impact on actual handling is pretty much minimal.

Also if you want to make it feel quicker put on a smaller steering wheel. This will make it feel quicker on the steering and the difference is dramatic. I have not done this with any of my benzes but did it with my 74 Saab 99.

moon161 · #50 01-13-2011, 09:04 AM

Quote:

Originally Posted by leathermang

Cutting off spring will not make the spring stiffer. It will only lower and give the suspension there less travel distance.
If you want stiffer proper springs you should buy new ones with ' a larger wire size' as MB refers to the various stiffness options.
There are posts I think where I posted the chart from the FSM on this subject.

Cutting a spring will not change the torsional stiffness of the wire. Counterintuitively, however, it will change the load/deflection relationship of the spring as a whole, making it stiffer (less spring deflection for a given load). Some head scratching and free body diagrams are involved, but it's neat when the light comes on about this.

#51 01-13-2011, 09:19 AM

Quote:

Originally Posted by t walgamuth

My point being that for street use, all talk about handling is pretty academic. What folks are really doing when changing all this on a street car is changing how the car LOOKS, and the impact on actual handling is pretty much minimal.

Also if you want to make it feel quicker put on a smaller steering wheel. This will make it feel quicker on the steering and the difference is dramatic. I have not done this with any of my benzes but did it with my 74 Saab 99.

The problem is that these mods will look very silly on a W123. He will end up with a 125HP sedan that "looks fast" to a 12 year old.

I had a 350mm Momo steering wheel on a 914, it was quick but it took some muscle to turn.

English Bulldog · #52 01-13-2011, 11:25 AM

Quote:

Originally Posted by Craig

The problem is that these mods will look very silly on a W123. He will end up with a 125HP sedan that "looks fast" to a 12 year old.

I had a 350mm Momo steering wheel on a 914, it was quick but it took some muscle to turn.

__________________
'82 300D (563K)
'83 240D (250K)
'04 E500 4matic (69K)
'83 BMW R80/ST (36K)

I came out of a coffee shop and walking thru a parking lot, when i happened upon what seemed to be an immigrant busboy behind the restaurant with a 1970ish corolla. Upon the front panel above the front wheel, he had sprayed painted the words TOYOTA with a stencil. It looked like he did not have enough paint because you could see the color of the car through the painted logo and the edges were not sharp. Obviously spray paint over a paper stencil.

moon161 · #53 01-13-2011, 12:10 PM

You can get clamps for your springs to drop your car by a coil or 3, try it on for size w/o cutting your springs. Bit of work to wrench them down, it is. Make sure no that no brake or fuel lines are in the way of the clamps or suspension.

If you choose to drop it, you'll probably need to have it aligned. Camber and front wheel toe will couple w/ suspension travel. IIRC, Porsche started putting roll steer into the rear wheels to tame the way the rear end breaks loose, read about it ~1995 or 7.

leathermang · #54 01-13-2011, 12:26 PM

[QUOTE=t walgamuth;2635038]

Quote:

Originally Posted by leathermang

Cutting off spring will not make the spring stiffer.

I disagree with this. Hey I could be wrong but everybody else says cutting off some of the spring will make what is left stiffer in its compressive state. ......

You don't take MY WORD on this ? What is this forum coming to ?
Your butt is telling you one thing... me something different...

I am not a spring expert... but for this thread lets assume that I AM.

A coiled spring with regular matching coils ( meaning the same size and existing directly above each other ) .. .like most automotive coiled springs...have a variable rate of springing... starting in the free state uncompressed state determined by the type of metal, the wire size, the heat treating method , etc. and it goes from that starting point to ZERO.... NO SPRINGing at ' fully compressed'.... so there is a curve in the spring rate which nearing compressed increases very fast.

In other words.... this is a dynamic system and what your butt is feeling is the result of the suspension GETTING to that increased resistance section of the curve FASTER... thus making the spring feel stiffer...
when in fact all the result is from the reduced travel available due to shortening.

But the metal in the spring is not stiffer due to cutting them shorter.

I enjoy talking about these finite physics things... but I totally agree with Tom on the big picture... these cars are not going to do what some who have experienced firm rides in smaller cars might think is only a suspension ' fix' needed...

At the same time... if your car has old springs, old tires, old shocks , old bushings, old antisway bar..... and you are entering corners too fast and braking into them....as compared to slowing properly before hand and accelerating out of them... then there are some things which you can do to bring it back to nice MB ride and cornering you deserve.... or most of you deserve.. LOL

dalek · #55 01-13-2011, 12:36 PM

You do know Bilstein HDs can be revalved to your specs, right?

Any benefits to putting a strut brace?

leathermang · #56 01-13-2011, 12:43 PM

Quote:

Originally Posted by dalek

You do know Bilstein HDs can be revalved to your specs, right?

Any benefits to putting a strut brace?

Ah,, nomenclature moment..
what do you mean by ' strut brace' ?
It may already have what you are envisioning...

whunter · #57 01-13-2011, 01:26 PM

Quote:

Originally Posted by English Bulldog

1. $
2. $
3. $
4. $
5. $

Just completed a 300CD for the exact same issue a few days ago.

Typically on the W123 chassis:
I assume most of the roll is in the rear.

#1. New heavy duty shocks.
#2. New differential mount.
#3. New sway bar links.
#4. New springs + shims.
#5. New front sway bar end bushings = on the end of the bar at the upper control arms.