Custom W123 Rear Anti Roll Bar - PeachParts Mercedes-Benz Forum

OM616 · #1 03-06-2010, 08:31 PM

My 84, 300D handles terribly. If I get behind the power curve in a turn, it is a delicate negotiation to keep it pointed where I want to go. I converted it to a 4-speed and the front being high isn't helping anything. I am sure it needs a 4 wheel alignment, but the body roll is incredible. I had to check to make sure there was a rear sway bar there and that the links were hooked up.

I am use to driving my 240D, which handles like a track car compared to this 300D.

I am going to drop the front and make a stronger sway bar for the rear. I am thinking a .875 OD, .188 / .250 wall, tube. May use 4130, not sure yet.

The heat treating shop charges by the pound with a 60Lb min charge, so I could heat treat a couple bars for the same cost as one.

I have taken a quick look under the back, looked pretty straight forward. I want to but wider tires all the way around, so I may have to do something different at the ends for the bend to keep it tight to the chassis.

I have the front up in the air now doing the brakes. I made some spring jacks for a customers 240D race car and I think I will make another set for mine.

Anyway, if the rear bar turns out well, is there any one interested in the others I may have treated? I am sure my 240D guy is going to get one, so there may be one or two left. Probably going to cost around 275.00 ea. That would include new mounting brackets with urethane bushings and an adapter plate to bolt the larger brackets to the chassis using the stock bolts, (no drilling).

vstech · #2 03-06-2010, 08:39 PM

i would think improving the front sway bar would make more improvement.
that heavy front anchor of a motor, has to be attributing to the sway...

t walgamuth · #3 03-06-2010, 11:02 PM

Putting a huge rear sway will make the rear end break loose first. Oversteer. I would only increase the rear if I could also increase the front bar.

Are your shocks good?

OM616 · #4 03-06-2010, 11:14 PM

Shocks are not new, but not shot either. It drives the CG is way high. The ride height is much higher than my 240D.

Yes, the front bar is wimpy for the weight, but it is a pain to get at. I want to drop the front and use stiffer springs. I may even retro fit some in cab adjustable shocks.

I can deal with the back end wanting to come around, in fact, prefer that to the front pushing.

Just had a thought, Perhaps an additional bar for the front that goes under the car? May be under the front of the engine? I will have to look tomorrow.

t walgamuth · #5 03-07-2010, 07:14 AM

I actually bought a bar from a 107 in order to add it to the front but could not find a place to mount it.

What you want is a neutral car. Having the rear or front break loose drastically before the other will not be fun.

If your front is riding a lot higher than the rear something is wrong on one end or the other.

If you really want to autocross a 123 you might consider looking at the one I have for sale. It's really quick and cheap compared to what you will spend to set up your car. I used to beat mustangs in ESP with it regularly.

vstech · #6 03-07-2010, 10:32 AM

there is not a lot of places on the control arm to mount additional antisway. I bet something could be welded to the lower control arm like they do to nova's but I don't see a lot of room there for the needed pivot...
if T couldn't find anyplace, there is no place for it...

OM616 · #7 03-07-2010, 04:54 PM

The 4-speed manual trans is probably 1/3 the weight of the automatic and it is shorter so the trans weight is more forward. It now sits like 4X4 AMC.

I looked at the front and there is room, (IMO), for a bar in front of the control arms. The mounts would have to be bolted through the tubular frame, and space the bar down some. To connect the bar to the lower control arm, I can see putting a longer bolt in the strut rod bolt and using it to hold the sway bar busing on the bottom of the arm, or when I make new spring pads, have a provision for the bar designed into them.

The bar ends would have to extend out to the control arm at the same angle as the strut rod so the tire will be able to turn to its lock without contacting it.

The bar will have to be designed and made for this application without question. I have never done a duel sway bar application before. I am wondering how much "new bar" is needed to tighten the front up?

T Walgamuth, sounds like you have a fun car. I have driven my customers 240D at three different tracks, and every time people are surprised how well it does. It could definitely benefit from stiffer bars both front and back. Changing the springs and lowering it turned it into a totally different car.

I took my 300D on a coarse and it really challenged my driving skills. I have raced from dirt track to open wheel cars, and dragsters. It took everything I had to keep any kind of reasonable time, and I ate a few cones during the process. After that I was nerves driving it home

Eric · #8 03-07-2010, 08:23 PM

theres always the 21mm wagon front bar and the NLA 15mm rear bar.

OM616 · #9 03-13-2010, 11:00 PM

I have gotten some requests to make some 18mm or 19mm rear sway bars. Is there any consensus as to which size would be best for non-competition cars?

I read that MB offered a 15mm one, I could make some of those if the demand is there.

I haven't put much thought as to what dia rod to use for the "booster bar" for the front. It probably will not take much.

JHZR2 · #10 03-13-2010, 11:17 PM

While I think that the idea is neat, and hope that you do experiment, driving around with an imperfect set of bushings, mounts, shocks/springs and suspension hardware is a major issue. You would be setting up a project and throwing parts at an issue which may not be related.

I'd start by renewing the car and getting the alignment done. This should take care of some issues right away. Then you can experiment and fix from a decent baseline.

Good luck!

turbobenz · #11 03-14-2010, 03:37 AM

my 300SD used to have terrible body roll. Put on new shocks and it basicaly fixed it but lowering it also reduced the body roll alot. Ive also replaced all suspension items sans a few bushings in the rear

t walgamuth · #12 03-14-2010, 08:11 AM

Quote:

Originally Posted by JHZR2

While I think that the idea is neat, and hope that you do experiment, driving around with an imperfect set of bushings, mounts, shocks/springs and suspension hardware is a major issue. You would be setting up a project and throwing parts at an issue which may not be related.

I'd start by renewing the car and getting the alignment done. This should take care of some issues right away. Then you can experiment and fix from a decent baseline.

Good luck!

This is good advice.

t walgamuth · #13 03-14-2010, 08:15 AM

Quote:

Originally Posted by OM616

The 4-speed manual trans is probably 1/3 the weight of the automatic and it is shorter so the trans weight is more forward. It now sits like 4X4 AMC.

I looked at the front and there is room, (IMO), for a bar in front of the control arms. The mounts would have to be bolted through the tubular frame, and space the bar down some. To connect the bar to the lower control arm, I can see putting a longer bolt in the strut rod bolt and using it to hold the sway bar busing on the bottom of the arm, or when I make new spring pads, have a provision for the bar designed into them.

The bar ends would have to extend out to the control arm at the same angle as the strut rod so the tire will be able to turn to its lock without contacting it.

The bar will have to be designed and made for this application without question. I have never done a duel sway bar application before. I am wondering how much "new bar" is needed to tighten the front up?

T Walgamuth, sounds like you have a fun car. I have driven my customers 240D at three different tracks, and every time people are surprised how well it does. It could definitely benefit from stiffer bars both front and back. Changing the springs and lowering it turned it into a totally different car.

I took my 300D on a coarse and it really challenged my driving skills. I have raced from dirt track to open wheel cars, and dragsters. It took everything I had to keep any kind of reasonable time, and I ate a few cones during the process. After that I was nerves driving it home

I did have a lot of fun with it. It will lay two nice strips of rubber on launch using the 225 hoosiers. People always got a big kick out of it. Now even though its been two seasons since I drove it occasionally the subject of it comes up and people always smile and say they enjoyed how fast it was for such a big car. (Actually 123s aren't all that big...or heavy).

One guy referred to it as the bagdad taxi. I actually looked for a taxi sign on the internet to put on the roof once.

The 110 euro is a very sweet, powerful motor.

OM616 · #14 03-14-2010, 05:36 PM

Bagdad taxi, I like that, it puts a different twist on the Road Warrior theme.

Putting my car aside, I have orders to make 2 rear bars for the W123 chassis, in the 18mm-19mm, (.750 inch) range.

It is much more efficient to make all the parts at once verses setting up each time for one here and there.

If there is anyone that has been looking for a rear sway bar for a 123, speak up now or forever hold your piece. MB stopped making a bigger bar for 123s, (my understanding), so this is your chance to get one while it is actually hot.

These would be heat treated and everything, with new urethane bushings / brackets, and an adaptor plate to allow the larger bushings to bolt to the chassis. I am also contemplating making the link attachment locations adjustable.

Makes no difference to me if I make 3 or 10, I just thought I would be nice and offer to share.

t walgamuth · #15 03-14-2010, 09:49 PM

Quote:

Originally Posted by OM616

Bagdad taxi, I like that, it puts a different twist on the Road Warrior theme.

Putting my car aside, I have orders to make 2 rear bars for the W123 chassis, in the 18mm-19mm, (.750 inch) range.

It is much more efficient to make all the parts at once verses setting up each time for one here and there.

If there is anyone that has been looking for a rear sway bar for a 123, speak up now or forever hold your piece. MB stopped making a bigger bar for 123s, (my understanding), so this is your chance to get one while it is actually hot.

These would be heat treated and everything, with new urethane bushings / brackets, and an adaptor plate to allow the larger bushings to bolt to the chassis. I am also contemplating making the link attachment locations adjustable.

Makes no difference to me if I make 3 or 10, I just thought I would be nice and offer to share.

I'd have interest if you can make a bigger front bar too.