Strut coilover conversion? Any thoughts on how?

[mymomswagon]

Some of you know that I bought Cadillac camber plates for my Golf Sportwagen. The bummer surprise was strut tower clearance for the stock springs, which are around 6+" OD at widest and pigtailed on both ends. These wide diameter springs bind and restrict plate adjustment to around 3/5 of total adjustment.

So, since I'm running in M4, I've thought about some kind of coilover conversion to my current struts that would allow 2.5 id springs with a soft spring rate for the street, >=150, <=200, and use bump stops to manage coil bind / shaft bottoming. Smaller OD would free up camber adjustment to bring total camber to -3.0 or "more".

I've reached out to both Koni and Bilstein and none have off the shelf conversion kits for my car. So, wondering if it's possible to cut / weld something to secure a threaded sleeve.

Or, wondering, if I leave the standard spring perch on, can I simply cut a threaded sleeve (to about 3", strut tube length above the stock perch) to rest against the standard perch. I would think, with a long enough spring (10-12"), I could avoid worries of spring lifting off the perch or ugly noises.

Figured some of you folks have messed with this type of issue in the past.

Any thoughts?

[Loren]

A photo would help here.

[mymomswagon]

A photo would help here.

here's the fixed perch from above and below. Perch may not be welded. Note that the strut body tapers below the perch. first pic shows how close spring is to tower, a screwdriver blade fits but that's it and it still rubs occasionally.

[Loren]

Okay, so the clearance problem is with the spring itself, not the spring perch?

That being the case, you have two possibilties:
1. Leave the stock perch... retain backwards compatibility should you want to return it to stock.
2. Cut off the stock perch... shed some weight, have a cleaner appearance.

Either way, that's a pretty standard setup.

I've reached out to both Koni and Bilstein and none have off the shelf conversion kits for my car. So, wondering if it's possible to cut / weld something to secure a threaded sleeve.

Yup. You can either devise some kind of spacer that will fit the existing perches (your spring has to fit the upper perch, too) and give you a "platform" for a standard 2.5" ID threaded sleeve adjuster, or you could just weld some kind of a sleeve over the strut tube. The spacer approach would do no damage to the stock strut assembly if that is a goal. Welding, of course... is welding. Potential for damaging the strut with heat, but otherwise... you can always grind it off.

This is not unlike what I did on the Mirage, I just did the opposite. I had perches for a 2.5" flat end coil spring, and I needed to fit a tapered-end stock spring to it.

For the lower perch, you could probably pick up a used junk strut somewhere and use it to mock things up. For the upper perch... unless you have a spare camber plate kit, you're gonna have to really look at what you have and measure. And then, ultimately, take the car apart to mock things up and make sure everything fits before final fabrication.

[mymomswagon]

thanks!

I'd be willing to keep the stock perch and leaving the strut as is, meaning everything can go back to stock.

So for that scenario I think you're​ saying for the strut "get a spacer to provide a seat for a threaded sleeve, then thread a 2.5 id perch"

then I'd pick the right springs that, along with adjustability, will take me back close to stock ride height.

My upper perch is a Vorshlag (camber plate) part with a sealed radial bearing and spec'd similar to the stock mount. They also make 2.5id perches with same bearing set up. Would probably do that for the upper.

[Loren]

Okay, so the top is easy. (If not cheap)

Start be measuring the OD of your strut tube. Whatever sleeve you get has to fit over it.

Another possible solution that could be easier... See if you can find a non-barreled spring that fits the existing perches. There's a lot of strange stuff available for circle track racing.

[mymomswagon]

Okay, so the top is easy. (If not cheap)

Start be measuring the OD of your strut tube. Whatever sleeve you get has to fit over it.

Another possible solution that could be easier... See if you can find a non-barreled spring that fits the existing perches. There's a lot of strange stuff available for circle track racing.

yeah I've seen some of it. My current top vorshlag perch is 3.5 od and I know 3.75 is a thing for hyperco or eibach.

here's my recent circle track purchase for the rear shocks - bump springs. I must get bored between events:

[Native]

You go, Bill!

[Loren]

[mymomswagon]

yeah right? may not have thought this one thru thoroughly

[Loren]

Not at all, I just love watching stuff like this unfold. It's fun to do. It's fun to watch.

[mymomswagon]

Not at all, I just love watching stuff like this unfold. It's fun to do. It's fun to watch.

yeah I thought they were an excellent concept at 1am

....as long as they don't make noise...hmm I think I've hijacked my own thread

[aw614]

I think ground control has a coilover conversion for koni shocks, at least for the mk6/mk5 they do it looks like this
http://www.golfmk6.com/forums/showthread.php?t=110737

[mymomswagon]

I think ground control has a coilover conversion for koni shocks, at least for the mk6/mk5 they do it looks like this
http://www.golfmk6.com/forums/showthread.php?t=110737

thanks I'll browse it.

having 50mm struts on the wagon really narrows the bolt on choices compared to GTI

[mymomswagon]

I couldn't resist trying out the bump spring, did one side this am, packed it with the stiffer ends of the factory stops.

Can't say too much about them on test drive other than no noise and maybe I'm under-damped.

[mymomswagon]

back on the coil conversion idea...

The top of the strut body has a weld (see pic 2 in 3rd post) that encircles the strut body.
The strut body is 2" diameter (1.99..") above the weld at extends 2.75" roughly, above the weld.

I thought maybe that weld could serve as a stop point for a threaded sleeve. Cut a section of sleeve to fit the 2.75" inch section and let it rest on the weld.
But the weld's not even and I'd be somewhat concerned that the sleeve might mushroom?

So, thinking of putting a 2" collar on directly above the weld, such as:
https://www.amazon.com/Climax-H1C-200-R ... 3+1%2F4+od
epoxy it, locktite the lock screw. Hopefully a better surface for the sleeve to rest on. Add 2.5 id spring perch, springs and get new vorshlag top perches for 2.5 id.

Think that idea would hold or is it doomed to fail?

[Loren]

I think it could work. Your final "load bearing" point would still be the weld. But, the collar could take some of the load. And it would distribute the load evenly while keeping your threaded coilover sleeve from mushrooming around the weld.

I don't even think you'd need to expoxy it. It's going to be under constant spring tension, it's not going anywhere. As long as it's a sufficiently strong collar to not spread open, it should work.

You've seen the snap ring that they use to support the spring perch on a Koni shock, right? It doesn't take as much as you might think.

[mymomswagon]

I think it could work. Your final "load bearing" point would still be the weld. But, the collar could take some of the load. And it would distribute the load evenly while keeping your threaded coilover sleeve from mushrooming around the weld.

I don't even think you'd need to expoxy it. It's going to be under constant spring tension, it's not going anywhere. As long as it's a sufficiently strong collar to not spread open, it should work.

Thanks Loren. Time to go part shopping

[mymomswagon]

had to miss the enduro last weekend to take care of some family stuff, but before I left, put my simple spring conversion together.

after much calculation, I concluded I'd be okay with skipping a threaded sleeve and just use a steel collar, energy suspension isolators, 150# 10" swift 2.5" barrels and a 2.5" upper perch.

spring rate is slightly higher than stock. I cut my bump stops by roughly 3/4" in anticipation of possible ride height decrease.

ride height dropped about 5/8" at full plate adjustment. 1/8 due to shorter stack height with the new perch.

I didn't have good weight dist numbers or good unsprung weight, so I took some guesses - calc'd with 60% and 55% up front and 75lbs unsprung per corner. My expected range was roughly 0 to 1/2 lower. Didn't think about spring preload...noob . Definitely underestimated unsprung weight. In the end, I'm close to my range of expected drop. I could add height back with another set of collars or maybe play with at set of spring rubbers, but we'll see how this performs first.

Had some noise but did some investigating today-top nut on one side just needed a little more impact wrench. Silent now. Street behavior feels a little better than before.

Vorshlag (camber plates) claim approx -2.5° change at full adjust. New springs allow full adjust, so thinking I should be close to -3.0°. There appears to be sufficient room to slot the tower and add maybe another -0.5° to whatever I have now.

[Loren]

Nice work! Being that close to target with so many approximated variables is great!

Now, put some stiffer springs on it.

A little more spring rate would get you a little more height. And 150# seems absurdly soft for an "upgrade", especially for such a heavy car.

Remember, if you've got the rear suspension to where it's lifting a tire, as soon as that happens, ALL roll resistance goes to the front. You need a pretty significant front spring rate to ease that transition.

Go with a 1" shorter spring and something like a 200# rate... even that isn't very stiff. But, would be an improvement and put your ride height a little closer.