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Uniball rear suspension on 1303
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cheeselover
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PostPosted: Tue Apr 17, 2012 12:04 pm    Post subject: Uniball rear suspension on 1303 Reply with quote

Hi, has anyone out there got any experience with uniball rear suspension? I am thinking of removing the torsion bars and converting to a setup of the type offered by Red 9 in the UK

http://www.red9design.com/type1.htm

Or from MBT
http://www.mbt-engineering.com/beetle.html

I know that there are some others out there and so far every kit is unique in its own way, the ones from USA seem to be more for off roading rather than street use

I would be interested to know from people who have tried this conversion what spring rate they used, how the car rides, what ride height they had as spring length now becomes a factor.
There are a lot of different things to consider that will affect how well this conversion would work and it would be nice to hear from someone who has tried this.
I was thinking of converting to Porsche rear arms at the same time to get disc brakes but not sure if there are mounts on the arms that the coilovers fit onto.
Any information would be greatly appreciated
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owdlvr
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PostPosted: Wed Apr 18, 2012 11:13 am    Post subject: Re: Uniball rear suspension on 1303 Reply with quote

cheeselover wrote:
Hi, has anyone out there got any experience with uniball rear suspension? I am thinking of removing the torsion bars and converting to a setup of the type offered by Red 9 in the UK

http://www.red9design.com/type1.htm

Or from MBT
http://www.mbt-engineering.com/beetle.html

I know that there are some others out there and so far every kit is unique in its own way, the ones from USA seem to be more for off roading rather than street use

I would be interested to know from people who have tried this conversion what spring rate they used, how the car rides, what ride height they had as spring length now becomes a factor.
There are a lot of different things to consider that will affect how well this conversion would work and it would be nice to hear from someone who has tried this.
I was thinking of converting to Porsche rear arms at the same time to get disc brakes but not sure if there are mounts on the arms that the coilovers fit onto.
Any information would be greatly appreciated


Having just completed a uni-ball conversion on my 1302, I'm quite qualified to answer your questions and will be happy to help. The thing is, you need to provide some more information before we get into it. The honest truth is that after doing this, eliminating the torsion bars and going to coil-overs was more headache then perhaps it was worth.

1) To get started, it would really help to understand why you want to eliminate the torsion bars and what benefits you think you'll gain from doing so. List 'em all.

2) What will the car be used for?

3) What other modifications to the car have you done, or plan on doing? (again, list 'em all).

Once you've provided feedback and answers to those questions, I'll be happy to post up the answers I had for those same questions, how I did the Torsion Bar delete, issues I came across and some feedback as to why I wouldn't likely do it a second time around.

-Dave
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1971 1302s - Salzburg Tribute the #RallyBug
1958 Beetle
1975 Beetle
1973 Super Beetle
1993 C3500 with Cummins swap
1967 MGB
1963 MG Midget
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cheeselover
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PostPosted: Thu Apr 19, 2012 11:29 am    Post subject: Reply with quote

hi,
Thanks for the interest, Here we go...
Reasons for converting to coilovers:
1. Car sagging on one side so i was thinking new torsion bars, bushes etc and my practice is to look at upgrades before replacing with stock items
2. I like the idea of something i can adjust / fine tune as the car develops
3. I am heading towards a track day car rather than the usual beetle motorsport of drag racing
4. I like it low but it is a bit impractical so coilovers would give easier ride height adjustment
Was thinking of adjustable spring plates but never had any experience of them, have had experience of coilovers/rose jointed suspension on my previous cars (nonVW) so feel more comfortable using them
The car is a low use second car that is totally solid, i have owned it for 23 years and it is a well maintained street car with a german look

The car is running Porsche cup1 7.5 x 17 wheels, height adjustable home made coiloves on front 2.25 dia springs to clear wheels. 5 stud discs so wheels bolt on direct, poly bushed with castor adjusted to restore lost steering feel as car is quite low. New steering box, damper, rod ends etc. Rear currently on drums with adaptors to get 5 stud. Am looking to upgrade to rear discs as part of development of rear suspension. Was thinking of 944 rear arms/disc assy.

Currently stock engine fitted while supercharged 1641 being built

Information seems to be a bit thin regarding spring rates, suspension travel and ride height.
Thanks for any help offered!
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owdlvr
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PostPosted: Thu Apr 19, 2012 4:41 pm    Post subject: Reply with quote

Thank you for posting clear and well thought out answers. My reply is going to be long and detailed, but I think by the end you'll find it to be relevant and quite helpful.

So that you have an understanding of where I'm coming from, here is how I answered those same questions for my build:

Quote:
1) To get started, it would really help to understand why you want to eliminate the torsion bars and what benefits you think you'll gain from doing so. List 'em all.


My main reason for eliminating the torsion bars was height-adjustability, corner-weighting and spring rate adjustment. All of which becomes important because of the next question:

Quote:
2) What will the car be used for?

The car is primarily a race car, which will be daily driven. Let me be clear that this is not a daily driver which will be raced. If a question comes up between a or b, and b is better for racing…I will sacrifice the driving experience on a daily basis. Car will be used for Rally, RallyX, IceX, Track and AutoX

3) What other modifications to the car have you done, or plan on doing? (again, list 'em all).

1776cc, Porsche 901 5 speed, dry sump oiling and the list goes on.

…so Having got that far, here’s what I’ve done to my car:

- Eliminated the coil-overs with my own custom mix of bits
- QA1 DS-402 Coil over shocks
- Custom Lower Mounts
- Racing CV Boots
- Limit Straps

Eliminating the Torsion bars, strictly for ride-height adjustment, really isn’t worth the trouble and hassle (in my opinion). For the majority of users, despite how much they say think they’re going to be adjusting their ride height…they don’t. They set it once, low, and then typically come up with excuses about why they can’t be bothered to raise it up or change it. “oh, I was going to adjust the height but it’s just one day at this track so I figured it wasn’t worth it”. Etc. etc. Switching from gravel rally, to track, to ice racing in my build is very clearly going to require different ride heights. Indexing torsions twice a year (winter height, summer height) is reasonable…three or four times a year is too much.

It has also been my experience, even with dedicated “race” cars, that most users don’t actually take the time to fully dial in and adjust their setups on an event by event basis, or on a weather by weather basis. In rally a lot of people run the same spring and damper setup regardless of the event or time of year. I see a lot of track users go from track to track with the same spring and damper setup. If a person doesn’t take the time to change the spring rate on the car…why bother with the trouble to make that feature possible?

Okay, that ends my rant on people who make crazy modifications and never use them Razz

My first comment on your links is specifically towards the pivot point. The RedUK units mount both the plate and rod end in single-shear. There is a significant load going through that rod end pivot bolt, and through the four mounting bolts. Single shear is a mistake, and I wouldn’t let those near my car. Incidentally, I started with a set of plates that were single shear, and did all the work necessary to make them mount in double-shear. The final step (which I haven’t yet completed) is to machine a u-shaped spacer of aluminum to link each of the four mounting bolts are joined together (spreading any single load to the set).

Image may have been reduced in size. Click image to view fullscreen.


With the second set that you’ve linked to, they are in double shear, so I don’t anticipate any issues there.

Please note that neither set will allow your factory limit points for upwards or droop travel to function. This is quite important as you’ll need to figure out how to stop the suspension from moving before the shock extends all the way. Having the shock limit the droop will void your warranty instantly.

Mounting any coil-over shock into the rear shock mounts is almost impossible. You have to cut away a LOT of material, and then drill a hole in the upper portion above the factory lower mounting hole. This hole is now on a round mounting surface, offset from square. Unless you fabricate little adapter bits to make it all sqare up, it’s neither safe nor strong. Simply stacking washers (like I’ve seen photos of) is downright scary. Using both the upper and lower factory mounts will also cause the shock to bind at the top of it’s travel, which isn’t ideal.
Image may have been reduced in size. Click image to view fullscreen.



My solution was to cut off the lower shock mounts completely, and weld in a custom set, made by a buddy at a local rally shop. The mounting bolt is now square (and strong) and we were able to reposition the bottom of the shock for smooth travel across the whole range. Pictured below without spring for clarity
Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.


In that photo above, you can see the Motorsport racing CV boots I sourced at $30/ea. Without them, the CV boot would hit the spring at anything above full-droop. Obviously that’s not going to work! Guys who built systems using coil-overs that allow for 2.25” i.d. springs apparently didn’t have this issue, but with a 2.5” i.d. spring like I’m using there isn’t a hope of using the factory CV boots.

Once that was all said and done, I had to deal with limiting the suspension droop. I eventually used 12”: limiting straps which are connected to the top shock mount and then manipulated into what was going to be my rear sway bar mounts.

None of the above talks about the hours spent addressing the upper shock mounts (shocks don’t just bolt up), the spring rates and all the time spent trying different options for clearance.

Now that it’s all bolted together, I’ve discovered I can’t quite get the travel I had hoped for with the QA1’s, so I’m going to end up swapping them out this summer for a set of Fox Racing shocks which have a slightly shorter body so allow for more travel in any given “fully extended” length.

Spring Rates
There was quite a bit of discussion on the German Look forum about spring rates and what the coil equivalent to the Torsion bars should be. The discussion focused on straight-rates, instead of progressive (like a Torsion bar is) as the math to get that far is questionable enough without adding in the progressive factor! By memory, which isn’t very good, it was determined that about 250 should be similar to a stock setup and 300 a “performance-street” option.

For my first set of springs I bought a set of 350’s. 300’s weren’t available and I was worried 250 would be too soft. Well, good thing I didn’t go 250 as the 350’s dropped through ¾ of my travel when I lowered the car!. This was without engine, doors, oil system or glass! True, if I cranked up the dampening on my QA1’s it wouldn’t blow through the travel, but that just meant I had locked out the shocks.

I was always taught to find a spring rate that holds the car to your desired ride height with little preload, then begin to adjust the dampening from there. Once a semi-close setup is found, begin adjusting spring rates and then dampening for desired handling. Lastly, add in sway bars to correct errors that can’t be fixed through springs and dampening.

To be fair, I never cranked the preload with the 350’s to see if I could get it to sit right. I did, however, test out a friend’s 550s. The 550’s would hold up the finished car to my desired ride height with little or no preload. The dampening on my QA1’s has been adjusted 3-clicks in, which was the softest setting that didn’t keep the rear end bouncing on the “bounce test”. So that has been my starting point.

On the front I’m running stock KYB gas struts and the ‘Red 2” lowering springs’ found almost anywhere. It’s a relatively stock, soft, front setup. But I needed a starting point from which I could learn the effects of rear spring choice as it relates to the front end. As you have no doubt found, there is little to know real-world advice or experience online for spring rates!

With this soft front end, my 550’s out back, and running 165 tires I can provide the following feedback:
- Ride comfort is streetable, though a ‘touch’ stiff in the back.
- Bump compliance on rough roads is not good out back, needs a softer spring.
- On dry pavement the back end squirms early…I’d call it “3/4 limit” and you feel it squirm.

The above info told me that this was going to be a handful in the wet. Once it rained I discovered that it’s not quite a handful…it’s a widow-maker. If the car starts to slide in the wet, and you lift…you spin. Been there done that, on a city street when I wasn’t planning it. I have driven a Porsche 930, the car most famous for this type of widow-maker handling…and I would rate my current setup as about 9/10ths as scary. The car either needs more tire out back (205’s are my guess) , or a softer progressive spring. I would estimate a 450 to 600 progressive spring in a 9” rate would be about right…but I haven’t tested it.

At the same token, one of the guys on the GL forums is shocked to hear I’m running 550s, as he finds 300’s out back to be more then enough and even a little tail-happy. I doubt by car would even be off the bump-stops on 300’s…but his is a very real world example that it should work. We haven’t each weighed our cars, but given the modifications I can’t see how I’m that much drastically heavier then he is.

My next step will be to put a set of 450 straight-weight springs in it, test those and that should give me the benchmark needed to choose a final “street-performance” rate. From there I will build my front coil-over struts and start upping the front spring rate to find a comfortable and well-handling match to the rears. Once I do, I will finally have a base-setup for front and rear “street-performance” that I find acceptable. Adapting to gravel rally, ice rally or track from that stage should be relatively easy.

I anticipate buying 4 sets of rear springs and 4 sets of front springs to simply arrive at the first set-up. There will be 1-2 full sets of springs for each setup I work out after that fact. What is acceptable on my roads, to my driving style has very little to do with yours. If we’re talking true race-cars here, where we are dialing in for that “perfect feel” (not just “close”) then you too will need to invest in a whack-load of springs. My car/setup will help you get close on your first go…but you have to dial it in from there.

Sorry this is so long, but can you see why I don’t think “the average” person should bother with rear-coil overs? I’m not suggesting you’re one of them…just be sure you know what you’re getting into!

-Dave
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1971 1302s - Salzburg Tribute the #RallyBug
1958 Beetle
1975 Beetle
1973 Super Beetle
1993 C3500 with Cummins swap
1967 MGB
1963 MG Midget
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cheeselover
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PostPosted: Fri Apr 20, 2012 11:56 am    Post subject: Reply with quote

Hi Dave,
Thank you very much for the time you have taken to provide the information. I am not a great 'joiner' of clubs or forums as there are too many armchair experts but it is obvious that you are not one of them and clearly know a lot about this modification!
It would seem to me that you use your car a lot harder than i ever will, my car is part of me and i will never drive it as hard in competition as you must be doing but i am not afraid of spending on it to get what i want, hence the idea to convert to coilovers.
What i have taken most from your information is that the companies offering this conversion perhaps do not know much about what they are selling as you seem to have had to re-engineer the mounts which are a pretty fundamental part of the whole thing!
Regarding your comments on the quality of the uniball joint itself (or as i have always called them rose joints) I did have my doubts on the strength of some of the ones i have seen and decided that if i were to go ahead i would buy the best that i think are the MBT option but after reading your post and the issue of controlling the droop of the arm which i must admit i hadn't thought much about i think that this will probably not be the modification for me!!
I don't mind trial and error, problem solving and development of a car. This is what i love about the hobby, but i do not want to pay a lot of money and then do the development on behalf of the company selling me the kit!
Thank you, i think you have helped me make up my mind.

Good luck with your motorsport
Ian
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owdlvr
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PostPosted: Fri Apr 20, 2012 12:03 pm    Post subject: Reply with quote

Thanks Ian,

And glad to help. I think you understood what I was trying to do perfectly. The modifications do have lots of benefits, but there will be a tonne of garage-space-engineering to get it all dialed and perfect!

Good luck with your build.

-Dave
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1971 1302s - Salzburg Tribute the #RallyBug
1958 Beetle
1975 Beetle
1973 Super Beetle
1993 C3500 with Cummins swap
1967 MGB
1963 MG Midget
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PostPosted: Fri Apr 20, 2012 12:27 pm    Post subject: Reply with quote

owdlvr wrote:
I was always taught to find a spring rate that holds the car to your desired ride height with little preload, then begin to adjust the dampening from there. Once a semi-close setup is found, begin adjusting spring rates and then dampening for desired handling. Lastly, add in sway bars to correct errors that can’t be fixed through springs and dampening.

To be fair, I never cranked the preload with the 350’s to see if I could get it to sit right. I did, however, test out a friend’s 550s. The 550’s would hold up the finished car to my desired ride height with little or no preload. The dampening on my QA1’s has been adjusted 3-clicks in, which was the softest setting that didn’t keep the rear end bouncing on the “bounce test”. So that has been my starting point.


Then you were taught wrong. Choosing your spring rate to give you a specific ride height would only be applicable if you couldn't adjust the spring perch height or spring length. Choose your spring rates to give you the control you want, then adjust the ride height to where it needs to be. The QA1 coilover is not separately adjustable for ride height and preload so you can only adjust the spring perch height to get the ride height right. The amount of preload has no effect on the spring rate.
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cheeselover
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PostPosted: Fri Apr 20, 2012 12:59 pm    Post subject: Reply with quote

Hi again Dave,
Sorry, forgot to mention, well thought out part regarding the spring rate, you are being realistic regarding the quantity of spring sets to arrive at a reasonable base point. My last car with coilovers (converted from hydragas spheres) took ages, eventually i ended up throwing away the caculations and instead working from the length, wire diameter and compression of a known set of springs. Whatever way you do it is not a quick job.
The other thing i forgot to mention is nice work on the welding and mounts! I love a neat weld and attention to detail in the areas that do not get seen to me is an indication of the quality with the rest of the build.

Ian
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PostPosted: Thu Apr 23, 2020 7:21 am    Post subject: Re: Uniball rear suspension on 1303 Reply with quote

In reading all of this, I'm kind of seeing that if I ran coilovers, in mostly the stock position, to get the same amount of travel, I'm looking at a coilover that would have about 6" of useable travel and a spring of 400-500 pounds? Just trying to find out what spring rate would roughly equal what the torsion bars put out.
Jeff
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