rear coil-overs

[lightning bug]

Now that I may need to eliminate my torsion bars for my 915 install, I may be in the market for rear coilovers. Who makes 'em? Preferrably in North America. I checked out KAW....... just too far to ship ($$$$). I'm looking for ride height adjustability and a stiffer spring. I'll consider using Porsche parts too. Maybe there's a swap from a 944 or something. I'm going to research custom builds too. Any help is greatly appreciated. THANKS!!!!!!!!!!

[Alex]

Ask Oliver in his forum.

He should be able to get them for you from Remmele.
Do not forget that you save 16%. All German prices included taxes you do not have to pay and shipping is not that bad.

Alex

[lightning bug]

Cool! Thanks Alex!!

[kdanie]

Summit, Jegs and Speedway all sell coil overs here in the U.S. Speedway has the best selection, including racing valving and adjustability or just the simple coil overs used on streetrods.

I like the idea of supporting the businesses that support and frequent our forums but I also believe in looking at all options.

ken

[Alex]

you have to make sure that the spring rates will match with the car. With a bug that is kind of hard. Can not use 944 stuff since it does not have that much weight in the front.

You are right to look at all the options but make sure it will work before you buy.

Alex

[kit]

http://www.eagleperformance.com/NewFiles/Coil-overKit.html
if going coilover rear you might need these
kit

[kit]

Oh well that didn't work
try this link
http://www.eagleperformance.com/NewFiles/Coil-overKit.html
kit

[GUTTERS]

right i am considering using coil over units which are hieght and dampening adjustable. i will remove the torsion bars and as i am using 944 spring plate and torsion bar end caps which are wider than vw units i think there will be enough support for the spring plate/ trailing arm. the question is how long do the coil overs need to be on full length and what spring pound rate should i use, the car is running a t4, type1 gearbox, no interior apart from front seats. any help would be good then i can order the units.

[lightning bug]

I was told in a n e-mail by a company I'm researching to measure between the mounts. AVO is the company. I noticed Ricola is using these on his speedster. They have some really cool products. Spring rates I'm still researching also. I'm not sure if you just match the rate with the torsion bar rate or what. I'll keep you posted.

[factman]

wow i didn't even know ther was a conversion kit for this. thanks guy. i know you cant use the torsion bar spring rates because the leverage ratios would be way differnt from the coil over where it is set further up on the trailing arm where as the torsion bar is at the pivot of the trailing arm. thanks again guys.

[RonRyon]

I don't understand why you would need the conversion kit. Why can't you just remove the torsion bars? It seems to me that the spring plates (without the torsion bars installed) are sufficently supported and with aftermarket bushings the setup would be as good are better than the convsersion kit. Am I missing something here?

Also, you'd think that there would be someone out there that has converted to coil-overs who could give us a report on how well they worked and what spring rates worked best. I'm converting the front of my Speedster replica to coil-over and may do the same to the rear.

[ricola]

http://www.ricola.co.uk/left_susp_complete2.JPG
Here's mine!
I used AVOs which are 10" compressed, 15" extended length, from memory. Springs are 300lb, mainly due to the extra weight and power of the Impreza turbo engine. With softer springs the rear squatted way too much!
There is a site somewhere on the web which has a table with a direct corrolation between torsion bar diameter and spring rate at the coil-over...

Hope this helps!

Rich

[lightning bug]

Thanks Rich!! What diameter spring are you using? If I remember correctly, you went with the DA-2000 20+ point adjustables right? Nice shock. These are one of my candidates. What did you use for the spring plate/ torsion bar cap? Thanks again!!

[chigger]

Though I wasn't looking for them, both the Koni and Bilstein sites had coil over shocks. Look under the hot rod headings. They had different length shocks and different springs so you could get together a combination you could use. The stock car sites have lots of infor on springs and spring rates as most of them sell the parts.
I hope you are going to save the trailing arms and flex plates it would make things easier. A buggy with a mid engine uses custom arms which might be affordable.

[ricola]

Forgot about the spring diameter! You have to used the 1.9" springs, the 2.25" won't fit. You will have to space the top mount out slightly and use spacers at the lower bush to centraliswe the damper in the trailing arm bracket.
I'm sure Koni/Bilstein would have what you want but at a price! The big advantage with the AVOs is that almost all of the damper body is threaded for spring seat adjustment (I have 6" of adjustment!) so when you are startign from an unknown you will be able to get to where you want with less experimentation with spring lengths/rates...

Rich
PS The only problem with the rear suspension I have is that I have an early pan converted to IRS so the shock towers are thicker and on really bad bumps the trailing arm can hit the tower. The plan is to pocket the trailing arms, I don't want to clearance the shock towers as I have heard of these braking if you do!

[lightning bug]

Again I thank you Rich. Those are I.D. values, correct? I assume the larger spring will interfere with the tire? Or the trailing arm? Thanks!!

[ricola]

Yes, coil-overs come in two standard diameters which are basically the Id of the springs they use, 1.9" and 2.25".

Any bigger than the 1.9" and there won't be enough clearance to the trailing arm...

rich

[lightning bug]

I see. Thanks for the info!!! Hopefully I'll come up with something soon. I have a shell and a room full of parts, including my engine. Once I get these shocks squared away, I'll be cruising. Thanks again!!

[lightning bug]

........... another question. Did you use anything like the Eagle product to transfer the weight to the torsion housing? Thanks!!

[SprintStar]

Originally posted by ricola
http://www.ricola.co.uk/left_susp_complete2.JPG
Here's mine!
I used AVOs which are 10" compressed, 15" extended length, from memory. Springs are 300lb, mainly due to the extra weight and power of the Impreza turbo engine. With softer springs the rear squatted way too much!
There is a site somewhere on the web which has a table with a direct corrolation between torsion bar diameter and spring rate at the coil-over...

Hope this helps!

Rich

Hello Rich,

Why is there a need to conver to coilovers for the rear?

I kinda want to do so myself so I'm looking for reasons. So far, I've thought that :

Cooler look. :)
Easier adjustment of height.

Please add on to the list. Thanks!

Alvin.

[ricola]

OK:
I used cut down 944 spring plate end cover things that were cut down to the minimum. Using the 944 spring plate which has a much bigger bushing than stock but replaced this with a performance item. (I can't remember the details, it's on my web site)

The first reason I did it was that I couldn't fit the longer IRS bars in without removing the body as I didn't have time to do this! I also plan to cut through the torsion housing at some point in the future. Ease of adjustment, better dampers and not knowing exactly what rates I wanted before a first go were the other reasons

Rich

[SprintStar]

Originally posted by ricola
OK:
I used cut down 944 spring plate end cover things that were cut down to the minimum. Using the 944 spring plate which has a much bigger bushing than stock but replaced this with a performance item. (I can't remember the details, it's on my web site)

The first reason I did it was that I couldn't fit the longer IRS bars in without removing the body as I didn't have time to do this! I also plan to cut through the torsion housing at some point in the future. Ease of adjustment, better dampers and not knowing exactly what rates I wanted before a first go were the other reasons

Rich

Anyone anything to add? What advantages are there to a coilover rear?

Sprint.

[lightning bug]

Easier and safer adjustability than torsion bars for one. I'm going coilover b/c I'm going to notch my torsion tube to fit my 915 trans. so I'll lose my torsion bars. And the adjustability. Also if you want to uprate springs, change $100 pair of springs rather than $200 pair of torsion bars. If you ever decide to change spring rates, you have a larger variety of coil spring rates to choose from than torsion bar rates. Coil springs are pretty much standard sizes from company to company. Torsion bars are more limited in availability.

[SprintStar]

Originally posted by lightning bug
Easier and safer adjustability than torsion bars for one. I'm going coilover b/c I'm going to notch my torsion tube to fit my 915 trans. so I'll lose my torsion bars. And the adjustability. Also if you want to uprate springs, change $100 pair of springs rather than $200 pair of torsion bars. If you ever decide to change spring rates, you have a larger variety of coil spring rates to choose from than torsion bar rates. Coil springs are pretty much standard sizes from company to company. Torsion bars are more limited in availability.

Makes sense... Anything we can do to reinforce the mounting points? Looks a tad fragile to me....

Sprint.

[jv911]

Check with John Connelly at Aircooled.net he has coil overs that will work with the stock VW mounts. Again, there are a number of different rated springs that you can play with. I'm my be using them once I install my 915 tranny into my VW based speedster. The other option is to let the selector rod run below the tube & leave the stock suspension alone (see the install in the "Performance VW" book)

[ricola]

Jeff,
Your 'other option' doesn't really work as the 915 is longer than the 901 or stock VW trans. Pushed as far forward as it will go, even clearancing the nose cone and torsion bar housing, the engine would sit further back than standard...

Rich

[SprintStar]

Originally posted by ricola
Jeff,
Your 'other option' doesn't really work as the 915 is longer than the 901 or stock VW trans. Pushed as far forward as it will go, even clearancing the nose cone and torsion bar housing, the engine would sit further back than standard...

Rich

Hmm... Wil that affect handling? Considering that German Lookers have some much more weight behind due to the heavier Type 4 AL case and now the tranny too.... :(

[jv911]

The 901 & 915 tranny are almost identical in length. However, the 915 is heavier and a bit more bulky than the 901 - I'm trying both to compare. The VW trannies are a couple of inches shorter, plus the selector rod is on top of the nose instead of the bottom. I'll most likely go with the 901 to save some weight

[alt+f4]

Rise from the dead!!!



Ok SO ive found this post to be most informative so far in regards to a rear coil over setup.

I Want to know if there has been any progress or problem solving with a coil over set up. What are some component models and specs?

[petevw]

I'll bring it back too.....

Was working on mine this weekend and ran into a few problems.

Couldn't lower the rear lower more because the spring hits the trailing arm. So i pulled the bolts to see if i can space it out some more and found the threads to be damaged. Could be wrong bolt or stripped thread. :(

What is the thread inside the 944 AL trailing arms?

I was thinking of spacing out the coilover further out another 1inch. Could a longer bolt be a problem. Would it flex or break?

pics:

http://i2.photobucket.com/albums/y8/petevw/split/split071.jpg~original

http://i2.photobucket.com/albums/y8/petevw/split/split075.jpg~original

[alt+f4]

What brand and model are those Pete? How much further out you think you need to space it?


Also......Tell me about your sway bar setup!!!!!! Looks interesting!

[Bug@5speed(US)]

Ditto on the setup, very nice from what you have shown us.

What spring rates are you running in the front and rear, what type of compression/rebound settings are on those struts and are they adjustable..

Laslty I believe the rear 944 utilize 14mm bolts while most coilovers are 1/2 bolts.. At least that is what I have come across during my reading of rear coilovers..

Maybe something like this will help, http://www.paragon-products.com/product_p/re_mc7000.htm

I have seen something else that is similiar on some 944 site, because some racer, had the same situation, just can't remembe right now.. and my computer at works history gets wiped everyday..
Alex

[petevw]

I bought this bug as a project from Alex that had to let it go a few years ago. Most of the car came in boxes. The parts that were on the car are either hand tightened, or missing some of its fastners. So i'm going over everything.

From what i know they are 944T AL arms with Bilstein/Eibach coilovers and Remmele Uniball springplates. I don't know the details of the springrates. The bolt is pretty tight in the eyelet of the bottom mount. No play. I'll make sure its a 14mm hole and 14mm bolt. It was bolted so the "ball" inside the eyelet couldn't rotate/twist because of the spacer and bolt/washer that's around it. So i'll make some spacers with a small outer diameter and install them on the sides, then the bolt and spacer. This should allow the bottom mount to move freely.

This bottom bolt goes in about 1inch inside the arm before hitting a thread. The threads on the bolt that i pulled are terrible. Looks like it was fastened without everything lined up, and loaded, so it's crossthreaded.

Is the thread in the 944AL arm M14 x 1.5? M14 x 1.75? or is it something else? I will have to get new bolts and run a tap through them, and hope they are ok.

I took it apart to see if i can space the bottom of the coilover further away from the arm. If i don't, then i can't adjust the coilover lower as the springs and perch interfere with the arm. Not allowing it to be unscrewed lower. There is no motor in the car, and i don't think it will drop 4inches with the engine it to bring it to a decent ride height without looking like a 4x4. Figure i need to come out another inch so the arm doesn't touch the coilover.

The rear swaybar doesn't look right to me as i see nowhere that the ends can mount to. I believe Alex had said the swaybar was a modified 928 bar. Some guy on the net made it. I have no details on it. I was thinking of cutting it out and installing a generic Bugpack IRS bar as i have in my super.

[alt+f4]

If you take some pics of the sway bar stuff maybe we can put our collective together and figure out the sway bar.....to bad Ars to just ditch!



Looks like you might lose a inch or 2 without the helper spring...is it rated?

[Steve C]

Hi

I think I would be worried re tapping those holes and putting all that load on them. Maybe look into drilling all the way through and putting nut & bolt in place of the bolt.

Steve

[petevw]

I'll get some numbers off the springs tomorrow. What is the purpose of the dual spring setup? Pulling the bottom one out should get me to where i want.

What is turning me off of the swaybar is the way its mounted/welded off of the torsion tubes. Its mounts extend way below the pan and look way out of place.

I'll have to investigate the bolt and arm issue further.

[Bug@5speed(US)]

Here is a better pic of that rear lower adapter for 1/2 coilovers..

I will check my manual as I don't remember the size..
A

[alt+f4]

I believe its for ride comfort. the small spring has a really small rating, and is used for small light loads, but when you really get into working the suspension it fully compresses and the main springs take over. I don't know if it has any performance benefits.

[petevw]

I measured the bottom mounting hole of the shock at 14mm. The bolt itself is a M14 x 1.5 and i've chased it with a die. I don't think i'll use it again. The AL arm has a steel sleeve pressed in. The threads on both arms look bad on the inside.

I can run a M14 x 1.5 Tap through it if its suppose to be it. Then if i can't get some decent threads in it, i'll have to go with a bigger bolt and tap the arm larger to probably a M16. Then machine the head off of it, turn it down to 14mm, toss a thread on it and nut the end. Another option is to do what Steve C mentioned above, drill it right through, machine a face on it so a nut will fall square on it. Or get new arms. :mad:

Alex, do you know what it the thread on the inside on the arm? If its M14 x 1.25 or M14 x 1.75, that would explain the M14 x 1.5 bolt stripping it out.

The springs are marked,

Top black,
Eibach 41/99
ERS 140-60-120

Bottom Red
Eibach 27/98
ERS 40-60-55

How do we know the springrates?

alt+f4, noticed today the red bottom spring is softer as its the only one that moved when lifting the car to pull the other side apart. So what you are saying makes sense.:agree:

Pete

[Steve C]

Hi

Sometimes they use small springs as spacer so that when you jack the car up the spring doesn't fall of its perch.

If your going to drill the arm out, why not just drill it out to 14mm so a bolt will fit through and use a nut & bolt like I mentioned before.

Steve

[Simon]

From what i know they are 944T AL arms with Bilstein/Eibach coilovers and Remmele Uniball springplates. I don't know the details of the springrates.
AFAIK they are GWD/Gerd Weiser rear coil-overs.
I was about to call him anyway, so I will ask him about the spacing of the springs in combination with the 944 arms.
They are 60mm ID springs (see below), which AFAIK should fit.
At least they do on 944's.

What is the purpose of the dual spring setup? Pulling the bottom one out should get me to where i want.
I will ask Gerd Weiser about this too. I'd suggest to keep it.
The helper springs are there to keep some force on the main springs when the damper is fully extended. They also have some influence on the suspensions force-curve (only on the low forces, since they are rated lower than the main springs).

Alex, do you know what it the thread on the inside on the arm? If its M14 x 1.25 or M14 x 1.75, that would explain the M14 x 1.5 bolt stripping it out.
They are M14 x 1,5 x 85mm.

The springs are marked,

Top black,
Eibach 41/99
ERS 140-60-120

Bottom Red
Eibach 27/98
ERS 40-60-55

How do we know the springrates?
They are Eibach ERS springs.

For the main springs (the black ones):
- the 1st number is the free/extended length
- the 2nd number is the ID (Inside Diameter)
- the 3rd number is the springrate

Since these springs are "European" type springs (i.e. with a 60mm ID), the values in their names are in European/SI units.
So the free length as well as the Inside Diameter are in mm and the spring rate is in N/mm.

This means the main spring you have is a 140mm long, 60mm ID, 120 N/mm (685 lbs/inch) spring.
It's spring travel is 71mm and it's compressed/coil-bind length is 69mm.

The tender springs (as they are called) numbering works almost the same, except that the first number represents the spring travel instead of the free/extend length of the spring.
So:
- the 1st number is the spring travel
- the 2nd number is the ID (Inside Diameter)
- the 3rd number is the springrate
So the tender spring is a 40mm free travel, 60mm ID, 55 N/mm (314 lbs/inch) spring.
It's a linear spring which free/extended length is 68mm and it's compressed/coil-bind length is 24mm.



For more specs/the search engine, see:
http://eibach.com and go Eibach ERS springs in the top menu.
or their motorsport catalog:
http://eibach.com/eibach/img/ers-catalog-2004.pdf


Here is a better pic of that rear lower adapter for 1/2 coilovers..

I will check my manual as I don't remember the size..
A
Alex, I can't see any pictures?
If you have some, could you post them?
I am interested in those bolts as well (they should be 2 part bolts AFAIK).

[petevw]

Thanks for the info. Please let me know what GWD says.

I'll retap the sleeves, and hopefully it turns out well.

Alex, i can't see the picture either. Can you repost?

[wrenchnride247]

Pete, If you can't get a good thread in the there, you can use a helicoil, or a E-Z LOC insert. They have them for all different sizes. ;)

[Simon]

Pete, I haven't been able to reach him yet, but I will try again on monday.
Btw. Are you using an IRS pan? Or were the mounts for the trailing arms welded on?
Could you measure the extended length of the shocks (middle eye to eye)? I am looking for some double adjustable dampers that might fit.


I have been looking around for 944 coil-over options though, and most of them seem to use 2,25" = 57,15mm ID springs.
They are a little smaller than the 60mm Eibach ERS springs, it might be that those 1,5mm make (part of) the difference we need.

Attached is a picture from the Bilstein Cup coilover on a 944, using 2,25" ID springs. It doesn't interfere with the trailing arms and it's mounting eye is right against the trailing arm (ie not using something like the racers edge bolts to space the away from the trailing arms).
What is visible though, is that the bottom mounting eye is offset from the center of the shock.
What can be seen as well is that it's actually quiet a tight fit, with little clearance between the bottom spring perch and the trailing arm.
I would guess a 60mm ID spring might not fit in this case.

The 2nd attachment is a picture from a Koni 3012 damper + 2,25" ID springs.
It's mounting eye is in line with the centerline of the damper and it uses a spacer (racers edge one) to keep it from interfering with the trailing arms (+it acts as an adapter for 14mm->1/2")
It seems there is more space available with this setup, so a 60mm ID spring might work with this.

All in all it seems a small spacer might fix the problem.

[Simon]

Result from the conversation with GWD:
They have no experience with 944 trailing arms, so he doesn't know if it should fit or not.

He did offer me te send me a pair so I can test it myself.
That's customer-service! :)


Anyway:
I did some more digging and there is a rss club suspension from KW for the 944 (front and rear) which uses 60mm springs on both the front and the rear.
As far as I have been able to track it down it doesn't use any kind of spacer and the mounting eyes are in line with the centerline for the damper.

Like I said above: Try the Racers edge bolts (if the mounting eye fits) and don't forget to space the uppermount a little inwards too.