| Author |
Message |
ubercrap
Samba Moderator
Joined: July 01, 2004
Posts: 1060
Location: Ridley Park, PA
|
 Posted: Sat Oct 03, 2020 3:15 pm Post subject: Anyone try BMW e30 front struts inserts? |
 |
|
Since I know people have used the front springs because they're the same diam. and apparently a decent length/rate for the 411/412 lowering, has anyone tried the front struts inserts? The ones for the 51mm e30 housings look promising at a glance. From what I can find, I think they're around 43mm diam. and the body is about 16.75" long. Of course, this opens up a bunch of possibilities, since there are Koni adjustables, Bilstein sports, etc...still available for those cars.
_________________
'74 412 wagon
(2) '74 412 2dr. sedan
'73 412 2dr. sedan |
|
| Back to top |
|
 |
Hawker
Samba Member
Joined: October 03, 2012
Posts: 124
|
| Posted: Tue Oct 06, 2020 12:48 pm Post subject: Re: Anyone try BMW e30 front struts inserts? |
|
|
When it comes to suspension, Ray is the font of all knowledge.
Best regards,
Rob |
|
| Back to top |
|
|
raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21519
Location: Oklahoma City
|
| Posted: Tue Oct 06, 2020 6:44 pm Post subject: Re: Anyone try BMW e30 front struts inserts? |
|
|
| Hawker wrote: |
When it comes to suspension, Ray is the font of all knowledge.
Best regards,
Rob |
 ....well for certain versions.
Look up Bill K. He and I went round and round for a while until I realized what his thrust was...and he did a superb job. Gearheadgreg bought his old 412.
Bill K. starts....IIRC...with the same Audi strut cartridge I did....but he uses BMW springs (IIRC) to effect significant lowering while using a different spacer inside and possibly no adapter stub. He got it calibrated pretty well.
Again going off memory...I think he brought the rear down with some fabbing and Volvo K70 springs.
I always argue people to death when they are trying something that I have already tried and KNOW will not work or will cause breakage....like cutting springs...or just willy-nilly swapping in a strut insert that may fit....but has totally unknown valving.
Example...I do NOT use the Audi 4000 cartridge because it FITS. The fit sucks....but since its shorter ....we can fabricate around that. Its the VALVING thats important. REALLY great valving.
I looked so long for alternate cartridges....many years....pre-internet! Nothing useful that was easy to find here. But when i discovered how different valving was from car to car ......even in the same SIZE cartridge....I realized that even if I found cartridges that fit the 411/412 exactly....they would probably be from a front engined car and would possibly not work at all.
I proved this out to myself.....when I finally cross matched the 411/412 rear shocks and found out they came from the FRONT of an A-arm van with a V-8 engine and coil springs. Huge weight.
When I installed a set...shortly after I destroyed a set of five way adjustable Rancho 9000's spec'd for a 1/2 ton pickup rear end....on the back of my 412....I realized that the truck had huge leaf springs. Its shocks (that I installed on my 412) were just classic dampers. The 412 being rear engined and era transmission and long trailing wishbones with teh shocks at the end....well....the leverage multiplied by axle weight just shredded teh Rancho 9000's.
So....valving is EVERYTHING...and all else is just a mechanical problem to solve.
But....there are other ways and combinations...coupled with some fabbing that CAN work. You just have to be sure you can test it out. Ray |
|
| Back to top |
|
|
ubercrap
Samba Moderator
Joined: July 01, 2004
Posts: 1060
Location: Ridley Park, PA
|
| Posted: Tue Oct 06, 2020 8:25 pm Post subject: Re: Anyone try BMW e30 front struts inserts? |
|
|
Hey, yeah, thanks for chiming in Ray. The leverage of the suspension arm length and its effects on how the suspension oscillates must have more of an effect than a first glance indicates, given your experience, as well as the fact that springs and strut inserts, etc...from a front engined car of the same or greater weight have been a part of the mix in successfull mods, at least to the point of being reasonable in driveability in combination with lowering the front. Please tell me if I'm way off, but I'm picturing it like this: a long suspension arm with a lot of leverage, but not very heavily loaded(Type 4)= different type of oscillation control needed (damper valving)when compared to a short arm with litte leverage, but heavily loaded (most other car suspensions). At least when we're talking about the front.
_________________
'74 412 wagon
(2) '74 412 2dr. sedan
'73 412 2dr. sedan
Last edited by ubercrap on Wed Oct 07, 2020 6:42 am; edited 1 time in total |
|
| Back to top |
|
|
raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21519
Location: Oklahoma City
|
| Posted: Tue Oct 06, 2020 10:04 pm Post subject: Re: Anyone try BMW e30 front struts inserts? |
|
|
| ubercrap wrote: |
| Hey, yeah, thanks for chiming in Ray. The leverage of the suspension arm length and its effects on how the suspension oscillates must have more of an effect than a first glance indicates, given your experience, as well as the fact that springs and strut inserts, etc...from a front engined car of the same or greater weight have been a part of the mix in successfull mods, at least to the point of being reasonable in driveability in combination with lowering the front. Please tell me if I'm way off, but I'm picturing it like this: a long suspension arm with a lot of leverage, but not very heavily loaded(Type 4)= different type of oscillation control needed (damper valving)when compared to a short arm with litte leverage, but heavily loaded ost other car suspensions). At least when we're talking about the front. |
Yes.
The front 411/412 springs are very capable...but very progressive. They have WAY more capability than the car needs. Look at their total length. Yet...the front struts have maybe 4" max travel.
So...when you move the Audi cartridge up or down by changing the spacer...it REALLY changes the spring load. Still progressive ....but its initial starting load is higher. The stock damping had issues. The audi strut can handle it....but ....when you stiffen the spring by pre-loading it more...by lowering....you change the stroke....and may not even allow the spring to transfer its load to the damper. It can transfer it to any link that is weaker....which can be the spring in the ball joint. So there is more going on than just the damper and the spring.
Yes....and I hate to say this...but you can cut the spring to do something in between...along with changes to strut cartridge spacer and bump stop spacer....but you need to do that in really small icrements. Like you will literally need to disassemble teh struts about 30 times....chopping off about 1/2" of spring at a time. And if you go to far....you are done.
The rear shocks are the same way as the front. Both have very long arms, lots of leverage.
I dont know if you have dug through this. Not far off I will have it changed over to be on the Samba.
https://www.thesamba.com/vw/forum/viewtopic.php?t=624354&highlight
There is a link in my first paragraph that takes you to a thick document in my dropbox. Its 120 pages of all things front struts for 411 and 412....with a how to do it and what are the variations. ....mostly pictures.
Ray |
|
| Back to top |
|
|
Hawker
Samba Member
Joined: October 03, 2012
Posts: 124
|
| Posted: Wed Oct 07, 2020 11:36 am Post subject: Re: Anyone try BMW e30 front struts inserts? |
|
|
We are all eagerly awaiting the updated version Ray! 😁👍🏻🤞🏻
Rob |
|
| Back to top |
|
|
ubercrap
Samba Moderator
Joined: July 01, 2004
Posts: 1060
Location: Ridley Park, PA
|
| Posted: Thu Oct 08, 2020 6:58 pm Post subject: Re: Anyone try BMW e30 front struts inserts? |
|
|
Wow Ray- took a look through the document and, ah, it's going to be a bit before I understand it thoroughly.
_________________
'74 412 wagon
(2) '74 412 2dr. sedan
'73 412 2dr. sedan |
|
| Back to top |
|
|
|
