Front lowering using BMW coils and Koni shocks

[vwfye]

i very much would like to SEE how you did it. lengthy 'text' on the subject is, well.... lengthy.

and as you have described in other posts usually the rear sag is accompanied by neg camber in the rear wheels. i do not have that.

[raygreenwood]

The rear sag CAN be accompanied by negative camber....not always. In general...its hard to fins a 411/412 that has excessive rear sag and does not also have excessive camber. If your camber is good, count yourself lucky. It will probably only temporarily be that way if the car has sat for some time. Once you start driving it, those old bushings....at the wishbones and on the beam carrier mounting points....will start to show their aqe. Lengthy text is also ....informative....if you have the assembly in front of you. .
Also...drop me a pm...and I will send you the drawing of the adapter stub. One look at that and where it goes.....and a glance at the parts that are already in your system are all that you will need.

It will be sometime this August before I can photograph both a stock strut and the one in the car that has been modified to show side by side. Ray

[vwfye]

anyone knw what the load rate is for the blue coils?

[raygreenwood]

I don't know if I have ever seen published load rate. I had two sets tested...a yellow set from a variant and a blue set from a four door....numerous years ago. I would not call the tests scientific....though I went to a spring maker in Houston to have it done. I only had the loaded ...but extended measurements....meaning assembled strut spring length. I did not really have accurate loaded lengths of spring....with car weight on them. Actually I did....but did not trust them. These springs were ugly shot....which is rare to find. They had been on junkyard cars wherin......the trunks were loaded with engine parts for years.

The spring company wanted to know......compression rates....ie...speed of compression based on weight of front end and cantilever of body. They had programs taht fit many types of vehicles. The gist was...if they had enough information they could wind me a duplicate of the original.

The only real information I have found in literature is teh difference in wire thickness, coil diameter and number of coils founjd in the Haynes blue and Green manuals.

Other than those two abused sets of coils, I have rarely found front coils on 411/412, that had permanently altered height or exhibited weakened characteristics...at least from set to set.

The rear coils are a different story. I have found significant differences in sets. The yellow ones seem to get permanet sag at an earlier rate. The yellow ones are thicker and seem to be mainly able to carry large loads....but are not as stiff in rate to the blue. The blue coils tend to be faster reacting. That woudl make sense as I have rarely seen the blues on the variants. Iwill have to dig out the old paperwork and see if there is anything that can help you from the spring winder I went to.
It does suffice to say though from everything I have found....the front coils are waaaay overkill in load capacity for the type 4. But way under-damped to control rebound and compression rate. More than enough even for road racing with the right strut cartridge valving and bushing stiffness combination. The range of progressiveness is also nicely balanced and is the primary reason why just the addition of a properly valved and uprated cartridge leaves little else to change.
The rear sway bar is a weak link. The front is about adequate and then some.....but the rear leaves enough roll because of the weight disparity from front to rear.....that the rear will try to steer the front in quick directional changes. Ray

[vwfye]

here is why i asked...

i was thumbing through an old 412 manual i have... it is a copy of one that i already had, so it was never opened by me until last night. anyway, there were hand written notes in it from 1983. these notes had things like, "per VWoA..." written in the margins. one such item was "front end wander after 30,000 miles is a design issue. VWoA recommends either new springs or finding the front springs and struts from a BMW 320".
then it gives a bunch of measurements and spring rates for the BMW springs.

[raygreenwood]

The question I have is....was that per VWOA...or per someones local vw dealer guy. Yes...411/412 do wander after 30k miles or more. It has absolutely nothing to do with springs.
Springs will not cause wandering. They can cause excessive wheel tramp (if they are hideously shot...again...insanely rare unless you bent one).

What causes the 30-50k wander is a combination of the strut bushings (primarily the bonded ones) and the idler bushings (defective from the day they were installed...which is why that part was finally superceded with bronze because it brought that same problem across to the super-beetle)....and the centerlink. The centerlink in humid areas will only last marginally longer than the rubber seals on it. Once those are gone...the centerlink nylon bushings succumb in roughly 6 months. That wear is impossible to see or diagnose unless you remove the link.

I know that 320 reccommendation was NOT VWOA...but probably a dealer rep...because the bmw 320 did not exist within the final service envelope of the 411/412. There were no edicts from VWOA per the 411/412 much after 1979....that I am aware of. Also...there was no service done on struts by VWOA...ever. They were replaced as complete units . A complete assembled strut...and ball joint usually. The cost was approximately $550 us each strut unit.

this is probably where teh service tech or whoever it was...goit the notion that teh springs were at fault (usually not teh case). The new strut unit came wit ha new bushing/bearing assembly a the top.

The first 411's wer the worst. They had only a friction bearing....no ball bearing at all in teh strut bushing. That was superceded in 1971. I have only seen one set like that in this country. Notes in all shop manuals and from teh dealer say the bushing was changed to a ball bearing type expressly because the early friction bearing caused "indefinate dirional control"....wandering.

The problems with teh ball type.....that would be symmetrical stud pattern from about 8-71 on.....were no longer bearing related. The bonded rubber fatigues quickly and shear from the center boss which holds teh bearing. That causes inability to hold alignment settings.....excessive toe-in at speed...and variable castor and camber......again...wandering andtramlining (bump-steering).

The final iteration of the strut bushing was teh best of them. That would be in teh very late 412 and all of the late supers. It had a replaceable bushing and a replaceable bearing andfriction ring...all sepreate parts.

The only way to see teh problem with the bonded bushings...is with teh car off the ground and a small inspection mirror. When they are unloaded from body weight....the cracking is invisible to the un aided eye. Most people just look at them and cannot see anythingwrong with them. They also cause excessive sag when they are really bad. At their worst....the entire bearing boss will pull out of the rubber and seperate and dislocate the spring from teh strut. Been there too....it took a tow truck to get home.

The problem with the strut bushing is that its durometer was too soft. the flexing caused sloppy steering...and misalignment of the centerlink pins. It was usually teh start of the damage to teh centerlink. Ray

[VW411L]

Hello Wally,

May I know the BMW e30 spring that you used for your 412, is it factory standard BMW e30 spring or after market lowered spring? How much shorter to compare VW spring? If I use e30 spring, can I still use the original strut insert without changed to koni shock?


Perhaps you can answer me. Many Thanks

Roger

[Wally]

Hi Roger,
Most all of your q's are answered already in this topic iirc
They are stock springs..
Just did a 2600 km vacation tour last week