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2G Tubular adjustable suspension parts for the entire chassis. Tubular subframes

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EC17PSE

Freelancer
5,867
3,448
Nov 1, 2008
London, UK, Europe
So its been a while and I thought I would make a proper thread on this.

My plan has been to make adjustable upper wishbones for the front and rear for some time now, my later plan is to also make all the arms including the front lower compression arm!!! Thats a big task but for now the uppers, I have had plans and drawings for about a year but didnt like the design i thought out so they was scrapped, NOW i had now decided on a design i think is better and the best option in terms of ease of adjusting and strength. So much so that I have now comitted and have all the parts i need to actually mock up a jig soon and build these.

Starting with the fronts then i will sort the rears out as the rear is a bit easier as i dont have to add another spherical for the knuckle/top joint so is a bit easier to design.

I wish i knew how to put all this onto a system to show in 3D modeling but im not very good with that stuff so drawings might have to make do.

The tube i am going to be using is CDS (no seams) 25mm x 2mm wall! I had considered 1.5mm wall but just thought it might be on the risky side of things so 2mm will be stong enough.

All the rod ends and sphericals are teflon injected race series bearings from a motorsport company here in the UK! No crap cheap bearings here. I opted for a spherical outer bearing as I feel for now this to be the better option but I have considered the coleman racings balljoint and that is still a possibility but not just yet. Yes it may look cleaner but and I might make a set up and check them out after ive used these for a while but for now I will stick with my design and see how it pans out.

All bolt hardware is going to be 12.9 grade zinc socket cap bolts for high strength.

All locking hardware, jam nuts and lower metal locking nuts (no nylocs) are all stainless steel for long life, the metal locking nut for the lower is self locking and can be reused several times from what I have read online so worth the extra cost.

If you all have any questions please ask or any feedback and thoughts i will gladly try and explain as best as I can. I plan to have the jig made and my sets made up by the end of july or sooner.

Pictures are just of the parts i got in today. I will add my drawings and pictures sometime soon
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Thanks guys. I still have to machine up some custom spacers/tapered inserts to seat nicely into the stock mounting locations in the strut tower area, this is to centralize them like oem and keep them from moving around.

I will post up some drawings i have tomorrow. There rough sketches right now but i will need to get some proper 1mm x 1mm graph paper and draw them to size. Ive just not had time to go buy some yet.
 
Right i got a few more pics of workings out and a sheet of drawings, the rest are at work which i forgot to bring home. I will add those to the next update.

The threaded part is what is spare and the spacer that will be above the rod end is going to put the inner joints at stock height. Now this is where it might be on some use but they can be made smaller or bigger to make the inner points raise up or down so that means the arms can be adjusted height wise. Not sure if this will be of any real benefits though. From what ive read online it might be of some use in some situations on here i am not sure.
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Sorry i did not reply yesterday, it never showed me a notification on a reply.

Its going slow at the moment. Works got super busy and im using most of my breaks to look at projects i got on the go (too many) haha i am getting close to having the jig machined and holes located for different lengths but i still got to finish up the measurments first before it can be done.
 
Instead of trying to fabb a control arm from scratch , have you considered starting with a control arm from Speedway motors or a racing distributor ? They have all kinds of control arms to chose from. At lease for the uppers.
Rick
 
Instead of trying to fabb a control arm from scratch , have you considered starting with a control arm from Speedway motors or a racing distributor ? They have all kinds of control arms to chose from. At lease for the uppers.
Rick
If they already had something close to ours i am sure i would not be here right now trying to make one! But why start with something thats not even related to our cars? Its backwards as you would have to modify it anyway im pretty sure of it. Please feel free to list up any you found but i have searched and found nothing i can just bolt up without major modifcation! So thats why i am here and making these from scratch means i can add every aspect of control from caster/camber in 1 arm.
 
Sorry I will keep my suggesting to myself in the future. If you get a chance check out my profile and photos
Rick
Sorry if you felt like i didnt want your opinion its not what i ment by my reply. I just ment as in if there was something out there i would not be here now. If you want to link me to any you think is useabe then please do! Ive spend countless days even a good few months over a course of a year or 2 looking at arms or similer and nothing i found would be of use without modifying them heavily which makes zero sense when its just as much work making my own from scratch!

I see you pics in your profile! Assuming they are from other cars? Or from similer cars just modified?

Dont take my reply badly ok and all comments are welcome but i dont see the logic in taking something to make it semi work rather then starting fresh for it to 100% work as designed to do.
 
Another reason to start from scratch is because i want to incorperate as i said caster/camber but i also will be making them adjustable on the roll centers a bit so all 3 things is alot to ask from anything else unless its designed from scratch! Hope you now see why im doing this now
 
Sorry if you felt like i didnt want your opinion its not what i ment by my reply. I just ment as in if there was something out there i would not be here now. If you want to link me to any you think is useabe then please do! Ive spend countless days even a good few months over a course of a year or 2 looking at arms or similer and nothing i found would be of use without modifying them heavily which makes zero sense when its just as much work making my own from scratch!

I see you pics in your profile! Assuming they are from other cars? Or from similer cars just modified?

Dont take my reply badly ok and all comments are welcome but i dont see the logic in taking something to make it semi work rather then starting fresh for it to 100% work as designed to do.
All those modds are done on my car in my machine shop at my house.
http://www.speedwaymotors.com/Shop/Oval-Track-Suspension-Control-Arms/15.html
Here are some control arms that might fit your needs
Rick
 
Great idea. I did something similar on my Miata. Wanted a wider from track without rediculous low offset wheels and made each side 1.5" wider

Good idea
 
Another reason to start from scratch is because i want to incorperate as i said caster/camber but i also will be making them adjustable on the roll centers a bit so all 3 things is alot to ask from anything else unless its designed from scratch! Hope you now see why im doing this now

If you don't know about them already check out http://www.aa-mfg.com. They've saved my bacon on numerous occations and made several difficult projects cheaper and easier.

Cheers!
 
Little update!

I got the chance to measure all points on the suspension on sunday, measured all the pivot points and the lengths for it all and now its going to be input into the system for a model of it and it should hopefully show us a rendering and gives me close estimates on lengths of parts aswell. Slowly moving forward and dedicating more time to the car and the projects now so should hopefully move along abit quicker now.

The tool is from work and its made for measuring chassis and points and locations. Its pretty easy to use and it helped alot rather then using a tape measure.

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Out of curiosity why does it look like your tires are on backwards? If those are what I think they are they're also mounted reverse to how assymetric should be. Looked strange to me.
 
Out of curiosity why does it look like your tires are on backwards? If those are what I think they are they're also mounted reverse to how assymetric should be. Looked strange to me.
Haha no they are vredestein ultrac sessantas. They are an amazing road tire and grips amazingly well in all weather. I used to run the GD3S eagle F1's but they are no match for vreds now as they are still pretty much leaders here for tires! They even out sell their new tread pattern and folks still come back to the sessanta's.
 
This is pretty cool, look forward to see more...

Hu? Did I miss something Pauly is a wise man?
Oh no he thought i was running some tires backwards haha
 
Right its about time for an update. Sorry its been a while, ive not had a great deal of time for much playing around lately and its only recently ive managed to make time to mess around with this and other things im doing.

This is the final step now as the next stage is building the jig to spec.then building a set and testing

All the standoffs and adjustable bushes are all machined up now, and everything is perfect fitment and awaiting the next step.also all rod ends and hardware has been bought.

Few changes ive made mainly to the spherical rod end and upper knuckle bolt hole area, firstly ive gone from a m12 fine thread to a 5/8 UNF rod end! Reason being is not for strength as the m12 would have been more then capable for the upper arm, strength wise and such, its for adjustability and it gave me an extra 9mm or shaft length for adjustment and more area to work with. 32mm vs 41mm length with the jam nut being nearly 10mm it helps gain some extra shaft length, and as you can see there is still aload of room for the end and not bind on the OEM mounting plate.

My next revision is not 100% yet but its the knuckle mounting plate,
ive scrapped the idea i wanted to run with in favor of a slightly lighter option haha its not even worth weighing the difference really but less overall material volume i guess is better suited and a redesign of it. Im now going to use 4mm thick steel and not 5mm because it needs a small amount of crush on the bush to take any play of left/right out of it as the oem does plus both my bushes are minimally different so it will take that up just fine and is 1mm thicker the the Galant upper mounting bracket aswell,
its also easier to make how i want to do the lets call it a cage/upper mounting point around the upper knuckle bush, but no drawing of that as its kind of fresh in my head and not on paper just yet.

The bushes in the Galant arms and rod going through it are only there for the reasons of datum points! I want to measure the angles, lengths and cross check the heights aswell so i know what i can and cannot adjust or modify when making the jig,

I may revert back to a different sized rod end depending what I get as results from the suspension geo testing and the amount of adjustment aswell, it may not need so much but I shall see.

Thanks and thats it for now and I will get back on here once i have some more progress, hopefully a set welded and made next time.

Bobby

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another step forward!

But before I start the update Ive been busy for other reason but still relating to this but in a whole different ball game! I recently contacted a suspension builder here in the UK and he talked me through alot of things I've over looked or not given enough thought about and he has been in the field for over 30 years or so. This guy was amazing so a big thanks to Patric at Quantum Racing Suspension.

Another amazing bit of news is I got a hold of a guy which used to work at lo-la race cars (sorry had to split it as it just made a LOLa face)before the company went into Administration a few years back and I've asked if I can go to the suspension/wind tunnel facility one day and watch when the 7 post suspension rig is being used so I can understand more in depth the suspension systems and what alterations are made and to which effect! this is great news to me and I am really looking forward to this!!! alot of learning though but I hope it can go to good use!

RIGHT to the update.....

I've now played with the setup enough to now warrant a new inner bracket to be made and adjust the pick up point so it raises the inner pivot and it also adjusts roll center but let me explain myself in some detail more

when I measured the stock upper arm I found the inner pivot point to the outer pivot point had a difference of 3/4" pointing up so the outer was raised meaning it has a pretty high roll center to start off with.
when you lower the car let say 1.5" the roll center now alters to and it now has a low roll center because the outer pivot has now risen 1.5" but the inner point is still the same! but its not gone alot lower but with this the lower arm is now more level (ish) so to help raise the side effect of this, the upper arm is risen to lenghthen the reaction point so the reaction point is now further away which make the roll center that bit more lower in the end. I will list below the differences between high/low roll centers.

So based on this finding if its lowered 1.5" you can raise the inner pivot higher 1.5" to keep the same upper difference between inner and outer pivots but the lower levels out some and this in effect makes the car have a much lower roll center which is good! it was already good but this is much better and again the list of the HIGH/LOW Roll centers will be below to explain why its much better to go lower.

So today I've drawn out a template and on monday will cut it out and make an exact plate with holes and bending to see if my working out are ok and if it all checks out I will go ahead and make some more for the other 3 mounts. once this is done Im onto the final step and finishing up my jig to mock them up on but since this now make the arms shorter I did not want to make the jig to then have to take it apart again so thats why I held off on making the full jig until I worked all this out.

Another reason you do not want much of an angle on the arm is something I've still not quite got upto speed on yet but its the effect of camber gain due to the arm is past its swing range! if its pointing up its going to gain alot more camber sooner which is bad so having a more level upper arm will keep this in check but the down side is the lower has not had any adjustments yet so the possibility of it getting neg camber is an issue but its so small as the arm is not at the super bad angle the upper arm is at. but this is something I will need to address once I know more about what effects the upper arms have.

It may not read across like a great idea to go lower but the main benefits are all pointing to go lower as thats what a 2G lacks on the rear, its good already but if I can make the rear gain more grip then the car can carry more speeds out the corner and the rest is obvious.

.
Here is the list of high/low roll centers and a small explanation as to why its best to go lower ( this info I have taken from a site online )

* To give a lower roll center, make the suspension arms flatter (more horizontal).
* To give a higher roll center, make the suspension arms more angled. Upper arms would have more of an upward angle where they meet the wheels; lower arms would have more a downward angle where they meet the wheels.

LOWER rear roll center
* More on-throttle grip
* Less grip under braking
* Use to avoid traction rolling at corner entry (increases rear grip)
* Use under low traction conditions
* Increases traction, reduces rear tire wear

HIGHER rear roll center
* Less on-throttle steering
* Car is more responsive
* Use in high grip conditions to avoid traction rolling
* Use on tracks with quick direction changes (chicanes)

by letting the car roll more, a lower roll center lets the suspension generate more traction than a high roll center.

  • Focus on tuning roll center only after you’ve already chose the best possible tires for the track.
  • To change just the roll center, adjust the inner hingepin location; adjusting the camber link affects the camber gain (how the camber of the wheel changes throughout the suspension travel) as well as the roll center.
  • Don’t forget all the variables that affect roll center, especially ride height, camber link location, and camber gain. When testing different changes, keep a notebook of your results.
  • In general, if the rear end is sliding around corners, try changing to a lower rear roll center. If the rear has a lot of grip and is pushing through the corners, try raising the rear roll center. The same can apply to the front end—if you need more front grip then lower the front roll center

Please keep in mind im still fairly new to this and its a whole new game to me but im pretty much on this everyday or so and its not easy by no means, I am trying my best to learn this but its not going to come fast or easy so my knowledge is still limited but im headed in the right direction

Thank you
 
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I feel a need to comment on this with regards to what you were thinking about Roll Center. Andrew Brilliant has gone through quite a bit of effort on his Time Attack car to get the Roll Center back up to where it should be. He even went so far as to have the lower front subframe modified to raise the lower suspension pick up points. I know that he stated after that modification that the car felt so much better that he actually made the entire front end a bit softer (ie lower spring rates/softer shock valving) to rebalance the car. Just a thought.
 
I feel a need to comment on this with regards to what you were thinking about Roll Center. Andrew Brilliant has gone through quite a bit of effort on his Time Attack car to get the Roll Center back up to where it should be. He even went so far as to have the lower front subframe modified to raise the lower suspension pick up points. I know that he stated after that modification that the car felt so much better that he actually made the entire front end a bit softer (ie lower spring rates/softer shock valving) to rebalance the car. Just a thought.
I agree Andrew is very good and raising the front is good but the upper still needs adjusting to take full effect, if the cars lowered the reaction point on the front of a DSM is pretty much infinite so it has no roll center to chart out. Raising it at the lower arm does give a high roll center which is great for turn in and fast changes but why have that if the rear cannot follow as fast with the front? The whole reason to alter the rear is to get the rear to follow as fast as the front but with the increase in rear grip without adjusting the rear the RC is high and is not in its optimum range.

If you look at the arms when its been lowerd wether it be 1.5" or 2" how flat the lower arms are or pointing up they seem to do, thats the bad side of it. Adjusting the upper arm at least nets you some play to alter the roll center its not the full best option but its a start, the idea is to keep them in a more straight line then pointing down or up, but if you was to wa t one or the other then ideally pointing down would be a much better option but we cannot physically achieve this so close to level will be more then fine or slightly raised will be good.

Also remember this is something im going to be adjusting alot throughout and the whole suspension system will be made to be adjusted or raise/lower of arms etc etc, and every effect has to be taken into account per car so im baseing all my info from my car and my ride height and it will be adjusted per my setup and I may have to re make brackets and adjust the centers but i would like to look into a multi bracket where you have 3/4 locations on it in 1/2" sections to make arm angles much easier but ive not got far enough along yet to consider this and if its possible with the adjustment ranges I'ge got written down,
 
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