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Discussion Starter #761 (Edited by Moderator)
Excellent. We did minor design adjustments and beefed up some sections, so we gained a bit of weight, but also almost doubled the initial design rigidity and still noticeable lighter than OEM rear arms. I should get the arms I was physically testing, back from stress analyse in next few days. If all good, we are ready to make the first batch of GMS performance rear arms.
 

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Excellent. We did minor design adjustments and beefed up some sections, so we gained a bit of weight, but also almost doubled the initial design rigidity and still noticeable lighter than OEM rear arms. I should get the arms I was physically testing, back from stress analyse in next few days. If all good, we are ready to make the first batch of GMS performance rear arms.
Good, just in time to ship out with the OCC's, perhaps?
;)
 

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Discussion Starter #763
It could be. 🏁

We were discussing what a shame it is, to cover the beautiful hand welds and rainbow patterns with wrap on exhaust and it got me thinking...

...these are some decent welds on pretty special CroMo tube material (obtained from Pipistrel, the famous lightweight aircraft manufacturer from Slovenia) too, and then powder coating them in to incognito black to cover the work of art is a shame, isn't it. Perhaps we should leave it raw. 🤩

GMS - GALEMOTORSPORT - 4C PARTS PROMO PICTURE 1.jpg GMS - GALEMOTORSPORT - 4C PARTS PROMO PICTURE 2.jpg GMS - GALEMOTORSPORT - 4C PARTS PROMO PICTURE 3.jpg
 

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You are doing some awesome R&D work. Thank you!
What grade Chromium-molybdenum alloy steel are you using? Uniform wall thickness throughout?
I Guess there is no immediate need for powedercoating, and it'll keep the price lower. It'll still corrode, but should be good for the lifetime of the balljoints anyways. Hell, it should be good for the lifetime of the car.
 

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Living in Belgium, where they use salt on the roads in winter, I’d prefer coated. I’ll look at the R&D pictures when I want to see the excellent work!
 

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It could be. 🏁

We were discussing what a shame it is, to cover the beautiful hand welds and rainbow patterns with wrap on exhaust and it got me thinking...

...these are some decent welds on pretty special CroMo tube material (obtained from Pipistrel, the famous lightweight aircraft manufacturer from Slovenia) too, and then powder coating them in to incognito black to cover the work of art is a shame, isn't it. Perhaps we should leave it raw. 🤩

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Oh... YES.
You have a customer here when that's ready. Please, I'll be patient, make sure these are perfect and test, test, test when you debut! I will 10/10 buy the whole ChroMo suspension replacement, as my time with off roaders has me loving the material, and is perfect for a daily anything. 💪
 

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It could be. 🏁

We were discussing what a shame it is, to cover the beautiful hand welds and rainbow patterns with wrap on exhaust and it got me thinking...

...these are some decent welds on pretty special CroMo tube material (obtained from Pipistrel, the famous lightweight aircraft manufacturer from Slovenia) too, and then powder coating them in to incognito black to cover the work of art is a shame, isn't it. Perhaps we should leave it raw. 🤩

View attachment 108696 View attachment 108697 View attachment 108698
Once we install them in the engine bay I dont think it matters much visually whether they are wrapped or not.
 

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My intuition is telling me that the oem control arms are too thin to sustain the stress on the rear wheels, but I really don't have any idea what forces they encounter (their value).
For sure, if you test the new developed control arms on a bench they will be considerably stronger than the OEM ones, but my question is: Are the OEM ones strong enough for our cars, or yours are strong enough ...? How can you test them?

1) One option would be to mount a GO PRO camera on the rear fender above the wheel and film in slow motion what happens during cornering --> Maybe (maybe not) we can visually determine if there are any TOE changes in the rear wheels --> For sure they go up and down but left-right are harder to determine.
2) Another option: we can calculate the stress based on the car deceleration forces when braking and the length of the arms.
3) Another option: bench testing ... but this would not be that relevant --> It will only say that one control arm is stronger than the other.

I'm very interested in these control arms but I would like to know what would be the improvement after installing them. Maybe they have no real advantage for those who use street tires because the forces are much lower than with semi slick or full slick tires. I use semi-slicks and probably i will go with full slick tires.

Any thoughts on how will you test them?
 

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IMO, OEM control arms are most likely adequate for the OEM tires. Once you go to wider and stickier tires, that's when the question of stronger control arms becomes relevant. Regardless, most of the flex comes from the bushings.
The only way to judge flex on control arms properly is to attach strain gauges to them and datalog during the track day. Again, my guess is that they are plenty strong for the forces that oem tires exert.
 

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Discussion Starter #770 (Edited)
Today we had a final testing of the last revision of GMS performance rear arms and a few other mods.

I have to admit, I do love 4C and it is the craziest car I ever had, but sometimes it just feels unfinished, like a prototype. So many shortcuts and underdevelopment can be found. But that's good, it means it can be improved. OEM rear arms are definitely one of the things that can be improved and we did it. The increased rigidity definitely can be felt, coming out of corners, or especially coming out of drift or oversteer. It is about the same change in the handling feeling like it was switching from rubber bushings to uniballs, but a bit less noticeable as the flex in OEM arms is not as nearly as bad as it is the flex in stock rubber bushings. For stock tires, the stock rear arms are adequate as the grip from the stock tires will not surpass the rigidity of stock rear arms. The grip or more precisely the lateral force generated by semislick or slick tires is superseding the rigidity of stock rear arms and they start to flex. Every flex in control arms transfers to dynamic alignment change which is something we definitely don't want. It is similar story like rubber bushings vs. uniballs. It even got me thinking, that perhaps the rear stock arms were not very rigid and Alfa Romeo decided to use soft rubber bushings to prevent deflection of rear arms, but that's just guessing. More science down below.

Objective facts and what have we achieved compared to OEM arms:
  • Zero flex on any tire compound (testing on the bench showed, that the flex on stock arms is becoming noticeable at about 900kg of lateral force and increasing steadily and at about 2100kg the stock rear arms pass the point of damage and stay misshaped. The issue is the material mechanical properties (strength, ductility, resilience). So what that means in the world of motorsport? Example: If 4C with driver weights 1000kg and it does 1G of lateral force and car has 40/60 FR weight distribution, and hits the curb with inner wheels pushing them in the air, providing zero grip at the moment on them and all the force is being transferred to the outer wheels, the outer front tire will carry 400kg and outer rear tire will carry 600kg. A rare case, but it can be done. So if you are running stock tires, then no need to worry, you won't overstress the stock rear arms as you will understeer or oversteer before reaching 1g with two wheels of the ground or in other words, put more than 900kg of lateral force on rear OEM arms. If your run semislick or slick tires and pushing hard, there is a chance that your are flexing rear arms and experiencing dynamic toe change leading to imprecise handling and feedback. There is also a lot of flex coming from rear arm toe links once the rear OEM arm starts to flex, but until the rear arms don't flex, the toe links are OK. In the real world scenario, on 1000kg car, you would need 1.5g forces and both inner wheels in the air to generate 600kg lateral force on front arms and 900kg of lateral force on rear arms to get the flex in OEM rear arms. Getting steady 1.5g is just not gonna happen unless you are running full slicks and track has cambered corners, but running semislicks, and heavily cambered track or sliding through the corner and hitting the curb the peak G-forces are way over. You are not gonna break or bend OEM rear arms easily, but they do flex at relatively low lateral forces (900kg), so that means dynamic toe changes, which upsets the handling and feedback in a similair way the rubber bushings do when they flex.
  • Roughly 600g lighter weight due to use of better material CroMo (aviation grade)
  • Reduced unsprung weight (better performance)
  • Superior rigidity (whichever sticky tires you run, the dynamic toe change just won't happen)
  • Superior precision with very, tight tolerances (the uniball hole diameters are all round and exact, so once worn out, you can easily press in the new GMS uniballs, but that just won't happen any time soon)
  • Superior handling due to higher rigidity and zero flex (better feedback from the steering wheel, easier to drive on the limit)
  • Superior hand welds welded by certified TIG welder, the same guy that is welding GMS 3" Modular exhaust system components for us (craftsmanship)
  • Superior finish (will be available in raw + polished + clear coated finish or incognito black electrophoretic coating) (looks, durability and rust free)
  • Availability (we'll have a set of these always on stock, so don't worry, 30-90 days of waiting times on OEM rear arms are over)
Now off to material fatigue and weld control analyze again, which is expected to pass easily as the previous versions did too, and then, we are finally good to go publicly.

Some "light" testing today captured on a phone. I'm not too much in to the videos lately as I am focusing on development of parts, so sorry about that.

 

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Discussion Starter #772 (Edited)
I fixed some data from yesterday post I messed up, sorry.

We used 3D scanner to get the stock rear arm mounting points and then did CAD drawing, which was followed by 3D printing and once fitment and clearance issues due to bigger rear arm tube diameter were fixed, we welded the GMS performance rear arms. After a few improvements and tests, we built a "jig" that serves us for welding every GMS performance rear arm. The tubes are laser cut, placed in to the jig and welded with TIG.

1x OEM and 1x GMS rear arm were sacrificed to test the limits. Both arms were mounted to a test bench in exact same position as the rear arms are mounted on a car (like in a previous page where I provided CAD drawing). The forces were then applied from 3 angles to test the deformation on acceleration (force from rear towards front), deceleration (force from front towards rear) and cornering (lateral force from outside of the car towards the inside of the car). For the force, we used a 35t hydraulic press and that's it. No noticeable flex was noticed on acceleration and deceleration forces but on lateral forces, as mentioned before, the flex was becoming noticeable at 900kg, exponentially progressing all the way to roughly 2100kg where the OEM arms bent to the point of no return and remained bent. Anything below this limit, the OEM arms just flex and return to default shape, so no big deal if you don't mind a bit of wiggly, waggly tail. :D
 

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Well, eventually they probably stop returning to original shape if you repeat the experiment (on bench or on track) enough times. Whether that is once more than you tested, or 10,000 times more, who knows.

Any measurements or graph of the deflection at different forces?
Any pictures of the process?
 

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So, @GMS , it’s about 4 months until Christmas...

I know that you’ve been working on a number of performance parts for our cars, and we are grateful. But you teased us with an idea a while back that I think you should run with. It would make the perfect gift for the 4C owner IMO. A lightweight, waterproof container perfectly fitted for the trunk.

I have a Sterilite plastic container that fits in reasonably well, with my OEM tool kit and helmet outside of it. Its main advantages are that it is cheap, and watertight. But it would be nice to have one container that could hold everything, make the most of every cubic centimetre of space, and keep everything safe from the elements when you pull it all out at the track, or picnic, or home from the shops, or travelling (if you are a masochist). Maybe with a half tray or partition inside. Just throwing some ideas at you.

FYI, there are at least two different shapes/sizes of factory tool kit for the 4C, so creating a shape that leaves the tools in the trunk, although perhaps a good idea, will preclude some owners being able to use it. My LE has a container for the compressor and a separate one for funnels and tools. The SE has these all packaged in a single case like a small, thick laptop bag. I’m assuming that the coupe and spider have identical trunk tubs. But Spider owners have that roof thing to contend with.

Just a thought! ;)
 

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Discussion Starter #775 (Edited)
More than enough of opened project until Christmas. The trunk idea is cool, but not my priority, as I'll be tracking without one in 2021. It is heavy and blocks the heat dissipation in the engine bay.

I still need fo finish GMS adjustable swaybars. This project is killing me. I spent so much time, energy and money on developement and still not finished.

Lots of opened projects, so got to be selective not to wander too far with the ideas.
 

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More than enough of opened project until Christmas. The trunk idea is cool, but not my priority, as I'll be tracking without one in 2021. It is heavy and blocks the heat dissipation in the engine bay.

I still need fo finish GMS adjustable swaybars. This project is killing me. I spent so much time, energy and money on developement and still not finished.

Lots of opened projects, so got to be selective not to wander too far with the ideas.
Oh well. I guess it's socks and underwear for me again this Christmas!

:D
 

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Discussion Starter #777
Enjoying the holidays in the local lands. 😍


 

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Discussion Starter #779 (Edited)
Special news my dear 4C family. o_O

After 10.5 years of daily job, where I started in a car wash, moved to car sales assistant and last 5.5 years worked as a car sales manager, I am changing my career path. I felt stuck an miserable with my job and I really had a hard time going to the job for the past 2 years. I tried pretty much everything to change that. Sports, change of approach to the work, psychiatrist, even used to take anti depression pills for about a year, but it didn't work out. My personal ideas and beliefs, have started to differ from my employer to the point, that I decided to make a change. 2 months ago I felt so down, that I wrote a resignation letter, without having any back up plan. I just said it to myself, "f*** it, I'm not doing this anymore, it's now or never". In resignation letter I wrote that I'm grateful for all the opportunities and experiences that I have achieved through this career and that I am willing to stay and help as long as the company needs me to. The CEO was shocked, although I was telling him for at least a year or so that I don't see my self selling cars until retirement, which was pretty much an obvious note that I'm thinking of quitting. Past two months it was somewhat OK on the job, I had a constant appointments with CEO meanwhile and we kind of, found an agreement to continue, confirmed it on Monday 31/08/2020, but on Tuesday 01/09/2020, I was called to an office and I was given a sack. Surprise! I was actually offered to work for payment, without being officially signed for the job and I didn't agree. I had to return the keys, code cards and other company possessions and signed, to work here until 01/10/2020 and transfer my unfinished business to co-worker who is now taking my position of a car sales manager.

Next day, 02/09/2020 Tuesday morning, I went to the automotive engineering company I work with for some of my GMS projects and asked for a job. We had 1h brief conversation and we made a deal. Today 05/09/2020 I had another discussion with my future employer to discuss the job details. I start my new job on 01/10/2020 as the "we don't even know the position yet", where I'll be responsible for development of suspension and chassis parts for performance automotive and aeromotive program. The paycheck will be 1/2 of the one I used to have as a car sales manager, but the future is pretty much unwritten and in my hands, so I'll do my best to rock. It is scary, I am afraid, but I needed the change so much that I'm, glad I was actually forced to make a change. I can't wait my new career path. The future CEO knows about GMS and it is fully supporting it, so the GMS project goes on and you can expect even more serious upgrades in the future as I'll have much better inside support and tech available as an "insider".

Thank you all for your support, orders and even some personal discussion I had with some of you, which helped me to move on. You are the best, my 4C family. 🥰
 

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Special news my dear 4C family. o_O

After 10.5 years of daily job, where I started in a car wash, moved to car sales assistant and last 5.5 years worked as a car sales manager, I am changing my career path. I felt stuck an miserable with my job and I really had a hard time going to the job for the past 2 years. I tried pretty much everything to change that. Sports, change of approach to the work, psychiatrist, even used to take anti depression pills for about a year, but it didn't work out. My personal ideas and beliefs, have started to differ from my employer to the point, that I decided to make a change. 2 months ago I felt so down, that I wrote a resignation letter, without having any back up plan. I just said it to myself, "f*** it, I'm not doing this anymore, it's now or never". In resignation letter I wrote that I'm grateful for all the opportunities and experiences that I have achieved through this career and that I am willing to stay and help as long as the company needs me to. The CEO was shocked, although I was telling him for at least a year or so that I don't see my self selling cars until retirement, which was pretty much an obvious note that I'm thinking of quitting. Past two months it was somewhat OK on the job, I had a constant appointments with CEO meanwhile and we kind of, found an agreement to continue, confirmed it on Monday 31/08/2020, but on Tuesday 01/09/2020, I was called to an office and I was given a sack. Surprise! I was actually offered to work for payment, without being officially signed for the job and I didn't agree. I had to return the keys, code cards and other company possessions and signed, to work here until 01/10/2020 and transfer my unfinished business to co-worker who is now taking my position of a car sales manager.

Next day, 02/09/2020 Tuesday morning, I went to the automotive engineering company I work with for some of my GMS projects and asked for a job. We had 1h brief conversation and we made a deal. Today 05/09/2020 I had another discussion with my future employer to discuss the job details. I start my new job on 01/10/2020 as the "we don't even know the position yet", where I'll be responsible for development of suspension and chassis parts for performance automotive and aeromotive program. The paycheck will be 1/2 of the one I used to have as a car sales manager, but the future is pretty much unwritten and in my hands, so I'll do my best to rock. It is scary, I am afraid, but I needed the change so much that I'm, glad I was actually forced to make a change. I can't wait my new career path. The future CEO knows about GMS and it is fully supporting it, so the GMS project goes on and you can expect even more serious upgrades in the future as I'll have much better inside support and tech available as an "insider".

Thank you all for your support, orders and even some personal discussion I had with some of you, which helped me to move on. You are the best, my 4C family. 🥰
Congratulations, Rudi. As much for seeing the dead end and getting out with your pride and sanity, as for the new job. This new position will be what you make it, and that is exciting. Change, for some like me, is not easy. But sometimes it provides the kick in the backside that you need in order to reconnect with what is important - your family, your creativity, and yourself!

Best of luck with the new direction. We’re rooting for you!
 
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