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Suspension arms made from steinless steel

7K views 54 replies 20 participants last post by  davormar 
#1 ·
After a good deal of time (and money) finally i am sharing with you one of the projects that I've finally finished.
MarInox® suspension arms are made for Alfa Romeo 147/156/GT/GTA standard and sport suspension.
Suspension arm assembly was tested and certified by University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture in Laboratory of Experimental Mechanics, Croatia.
MarInox® suspension arms with reinforced bushes are made of extremely high quality rust free Inox® steinless steel.
All parts are manufactured and assembled by highly qualified and skilled labor certified by third party.
Rear suspension arms are made of seamless profile, whilst front suspension arms are made without it.

Later I will put more material about the test .
 

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#2 ·
It looks great.....great update for a trackday car.......
However you must consider that if side impact occurs, entire alloy subframe will be damaged.....
Had serious sideways hit on sidewalk recently, both arms damaged, but that's all......
Anyway it looks great, and there will be improved stability on the rear.
 
#3 ·
Looks good. What's the weight difference?
 
#8 ·
My experience with these rear arms is that there is many ways to do stiffen of make-it-looks-better arms....but IF you need to push a bush into the arm, no matter PU or aftermarket rubber bushes, bigger washers must be used to prevent the arm to slip away when load occurs.....when i put a PU on mines i even put a weld on it to prevent failure.....and it survive 2 years trackdays with slick tyres.....now i used same arms on my everyday car......
 

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#10 ·
1) It really stiffens the rear end, but would not know does the alloy sub frame brake. Someone wants to test it? :D

2) The weight difference is approximately 15 percent lighter than the original.
I'll check the exact difference in weights.

3) Yes the rubber is bonded, a pair has a stainless steel cylinder in the middle of the rubber. It is made of high quality Dunlop rubber and vulcanizing a special technique to adhere to stainless steel

4) Yes, it will outlive the car itself

5) They are machine made specifically for this use.

6) This is for the original arms. Doesn't apply for my suspension arms

7) The rear end is more stiffer(doesn't knock), the car handles better, life span is 3x longer than the original(bushes), it will never rust(stainless steel). The originals are not made from steel, but from vulgaris Iron. That's the whole point, if you get a chance try to bend the old Iron suspension arm, you will probably succeed. You absolutely can't bend my suspension arm with your legs and arms (if you bench press 300 pounds, then maybe :D)
 
#11 ·
Suspension arm assembly was tested and certified by University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture in Laboratory of Experimental Mechanics, Croatia.
A special camera that is used to record material stress.:D
 

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#16 ·
Who said it's for sale? Is it, Davormar?
 
#19 ·
Aah, okay then :thumbs:
 
#21 ·
This report presents the results of the mechanical properties of the arms. All three types of arms are subjected to static tensile tests. Each experiment was repeated on three samples that means nine experiments are conducted. After the results confirmed the higher stiffness of newly constructed arm.

Suspension arm with the additional material is further subjected to dynamic testing. Parameters and a description of tests are given to each individual test.

Static test results show that the arm, Marinox - with additional material shows superior properties in terms of breaking force and in terms of stiffness relative to the construction of a new AR - without additional materials also in relation to the original AR arm.

Dynamic testing was conducted only on the suspension arm Marinox - with additional material, which showed the best mechanical properties in static tests. The arm withstood 5.000000 cycles after which the test is stopped. After test there is no visible damage on the Marinox arm.
Alfa Rome Test 1.avi - YouTube
Alfa Romeo Test 4 Strain overlay camera right1.avi - YouTube
Alfa Romeo Test 3 Source deformed camera right.avi - YouTube
Alfa Romeo Test 2.avi - YouTube
 

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#24 ·
Hello davormar. The arms look great. What gauge and diameter of tubing are they made from? I was wondering how far you could go with making them lighter without compromising strength. It's the weld that fails anyway on the tests and in use that's always going to be the week point.

I always think it's a bit strange when people are worrying about this type of upgrade being too strong in the event of a side impact and twisting the chassis etc. I'm pretty sure that every insurance company out there would write off any car involved in a side impact of that nature regardless of what extra damage the arms may or may not cause. If you get hit there that hard it's gonna hurt and gonna cost
 
#25 ·
in a side impact (wheel hitting kerb) these arms would be put under compression, not tension....
Under hard cornering, the outside arms would also be under compression, not tension...

Why were the arms tested under tension, as I cant think of any situation where these arms would be under a high tension load.
 
#27 ·
not really, look again at the fixing points for the bars.

the weight of the car will cause the body to lower, causing the distance between the fixing points for the bars to get smaller.

My point is, the bars wont be under the kind of tension stress's that the stainless ones have been tested too......

I would like to see how the stainless ones compare to the standard bars under compression loads.
 
#29 ·
The rear arms are under some tension when the car is static, how much exactly I'm not sure, but the tension in the bar is what stops the hub from pushing further out as weight is placed on the axle. The rear arms link the rear subframe to the rear hubs. On hard cornering the outer arm will be under compression instead though.
 
#31 ·
The rear arms are under some tension when the car is static, how much exactly I'm not sure, but the tension in the bar is what stops the hub from pushing further out as weight is placed on the axle..=
At this point, the bars would be under compression. The Friction between the tyre and road surface would resist the action of the hub being pushed outwards. Next time you jack up the rear of the car to change the wheel, for example, as you are lowering the car back onto the ground, watch the sidewall of the tyre, you will see it deform slightly. The hub is try to move outwards, but the friction provided by the contact patch of the tyre will counteract this motion and put the pars under compression.
 
#32 ·
I've pushed a car with no rear arms before (on gravel), the hubs were dragged outwards by the motion of the car going forward, which was being limited by the trailing arm. We had to keep pushing them back into the arches as it was making it really tough to push. It seems in that situation the missing rear arms would have been under tension to hold the wheels in place. Thats my experience of it anyway although I'm sure the arms are under both tension & compression at points in their life so should be tested for both.
 
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