Front lowering using BMW coils and Koni shocks

[Bill K.]

In the US it's a BWM 318i, 4-cyl (pre mid'87) that has the 12.2 mm spring wire. I got a pair of used ones off a '85 2-door... The 325i (6-cyl) is 12.8 mm per the measurements I got at the yard. The recycler said the stripes are indicators of a matched set by color codes.

Some good reading on the Koni's here:
http://www.koni-na.com/faq.cfm#5
http://www.koni-na.com/pdf/tech.pdf

The Type 4 Koni's are labelled 86P-1832 Special "D".

[Specky VW freak]

Hi Ray,

Do you have a year and part number for the Audi 4000 inserts? Its a different model name in Europe (Audi 80 I think), but the part number should be the same.

I still have the strut top mount diagram you sent me ages ago and I'm finally about to embark on another 412 custom project, variant (wagon) this time.

Cheers!
Neal

[raygreenwood]

Let me look in my little black book. I did write down what I used. But bear in mind that I machined a pair of simple adapter stubs as well. Ican e-mail you the drawing and all measurements. Ray

[MattKab]

Hello, I'm back in 411 mode. I too, would like this info Ray.

'Mine is having some of my time soon, Today I got a good deal on a near perfect everything front end (minus calipers) + rear springs and dampers. Also an auto starter, m/c, trims that I'm missing, a $250 411/412 cover (NOAH, made in USA)- all for £100, 'had to. I've still not got £150 in this beast I'm not counting the 'uprated' MIG I needed

I'm gonna fix it up as standard to get it on the road, then re-lower it using one of these 2 methods. I'd like to try both, i might. I'm sure you'll agree, they are a nice car, worth keeping. A proper family car for a hardcore Veedubber. Maybe that's why I'm still single

The lad who gave me the car also has a set of those M.A.G. wheels in his garden, are they called Cosmic's? or are they called Gemini's? I can't remember.

That 412 in NZ is stunning!!!

Matt

[vwfye]

Wally, as I noted...there is little or no compression of the spring due to vehicle weight without load in the trunk. What I mean....by "little compression"....is relative. On a stock 411/412, you get about an inch max. Considering the stock, assembled uncompressed length is a bit over 18" for the measurement from perch to top plate.....that is a relatively small amount of compression. Adding 150lbs to the trunk...adds scant more compression. Maybe .75".

well, i added 256lbs to the front of my 412 at the fuel tank, not the nose and it dropped 6 13/16 inches! so, either my stock blue coils and struts are completely toast or something else isn't right.

[Wally]

. Adding 150lbs to the trunk...adds scant more compression. Maybe .75".

well, i added 256lbs to the front of my 412 at the fuel tank, not the nose and it dropped 6 13/16 inches! so, either my stock blue coils and struts are completely toast
or something else isn't right.

Yeah, Ray is wrong here .
150 lbs or 75 kg dropped my '74 model front with the blue springs about 5,5 cm. So, not as much as yours, but definately noteworthy.

[raygreenwood]

6 and 13/16's? Thats really odd. Generally filling the trunk...is enough to bring the front end level (getting rid of the nose high attitude)....and depending upon the actual weight of everything you pile in....at most I have been able to compress perhaps 1.5" below dead level in the front end. Last time I did that...I had a tranny I collected at the junk yard, an 80 lb tool box, a pair of rotors and struts and steering knuckles. Thats maybe 300 lbs.

The blue coils may not be bad. What you may be getting is a combination of distortion of the strut bushings (they are generally shot anyway), some heavy compression of the tires (what is your pressure and what is the side wall height before and after adding weight) and......if other components like bushings are old and worn...and now overloaded from teh added weight....it could give youe extra droop.

The cartridges being shot will make this worse as they will be bottomed out. Something also to look at. Is the rear lifting higher when the nose droops? What is teh condition of your rear bushings and shocks.

Sorry. I keep forgetting to drop in the part number for the strut cartrdiges. I will drop them in later today. Ray

[Wally]

..at most I have been able to compress perhaps 1.5" below dead level in the front end. Ray

Hmm, so its 2 inches to get it level and then 1,5 below level...
Thats 3,5 inches total, which is quite a bit more than the .75" I read above

[vwfye]

ray, the rear did not 'raise' and the side wall of my 195/50/15s with 35psi did not flatten out. so, i still get over 6 inches of drop.

[raygreenwood]

Where did you get 2" to get it level?
One thing you have to stop confusing with this car.....is what level of drop is required to set the front of the car level to the rear...(and that "level" is measured at the rocker panel edge just to the rear of the front fender and just forward of the rear fender).....and nowhere else.........and what level of drop is required to reduce the "gap" between the fender flare edge...and the tire as seen from the side. Those are two totally different things.

The amount of drop needed to bring the car level front to rear....for proper handling purposes....and better static castor angle...and better wind handling.......is right at .75".
In some cases I have seen it right at an inch depending on if you are having drop coming from either weak springs, total lack of rebound from compression once cartridges are pumped up (usually out of oil), bad control arm bushings, bad radius arm bushings, bad strut mounts...or usually all of the above.

This .75" drop...does almost absolutely nothing visually for you between tire and fender flare. In fact....if all is well in the rear as far as parts condition...it usually brings the rear upward just measurably....as the front goes downward.

If you FIRST....add the .75" drop....by means of mechanical modification like I did.....wherin the car sits level even when the trunk is empty......and then add several hundred pounds to the front end (not including a full fuel tank which would make it more)....you get about 1.5"1.75" further drop depending on how good all your other parts are.

Here is the nifty part of that......and where the visual confusion lies.
Not only are you compressing the coils....and giving a smaller gap between tire and fender flare in the process, you are also flexing at the control arm bushings. Its impossible not to do this as the strut compresses. The car gets very much lower looking to the ground because it flattens the angle of the control arms to the body.

As I have said many times in the past.....it takes very little lowering to actually make this car "look" a lot lower than it really is.

Where are you measuring this 6" and 13/16" from...and to where? Ray

[vwfye]

okay... apparently we are talking across each other. the 6+ inches are measured at the top of the wheel well arc.

i want my car to sit lower in the front. the current stance is unacceptable, and if i drop the nose 2" at the leading edge of the rocker panel, that still does not put the car level.


i spent 3 hours yesterday comparing the basic priciples of the t4 front end and the super beetle. now, remember that i never plan on loading up my front trunk... and from a physical standpoint, other than the t4 being unibody, they function the same. so i ask... why can't we lower the front exactly the same way the superbeetle crowd does it? i.e. why not adjustable strut towers? my father's super has adjustable front perches, shorter springs and struts from a kit. the thing drives and rides great.

[raygreenwood]

Ok......So...from the top of the wheel well arc. That means , when sitting next to the car, looking at the wheel, you are measuring from the lip of the fender in the center of the arch, to the ground...right?

Here are all of the distance "gaps" that you are closing by using weight to artificially lower the car.....which by the way....is not entirely wrong.

(1) The original .75-1.0" that makes the nose high attitude. Mind you...the front end only LOOKS alot out of level with the rear.....because even when the car is DEAD LEVEL...front to rear (measured at teh rocker panels edge), you still have excessive tire to fender gap. Its an ugly illusion. This excessive height...which is technically caused by an overly long and strong spring on the strut.......is there to counteract the weight of a full trunk. So...when you compress the coils just slightly by adding all of that weight. It can lower the front end to dead level.....as measured at the rocker panel. But... It closes the gap between tire and wheel well.....actually very little.
(2) On the original bonded style strut bushing (MK1 no bearing from 68 to 71, MkII from 71 to 73 with ball bearing)......you get stretch from the bushings. About 90% of all of them are torn, especially after 50k miles or over 7-10 years old. That kind of weight will stretch them about 1" to 1.5" when they are at their worst. . No Joke! This allows teh body...to technically sag down around the struts. Because of this, the weight gives the car a reasonable amount of lowering in appearance. The bushings alone.....generally close teh gap at the tire to wheel well viewpoint by about an inch.
So....you say....why does that 1" to 1.5" of droop/sag at the bushings...not translate exactly into the same amount of lowering at the fender to tire gap? Sometimes it does. What it depends upon is the condition of the rear springs and shocks and teh condition of the bushings under the front end (less the front end and more the rear). If there is any excessive weight induced sag...and even excessive camber in the rear.....then the front is excessively high in...because it levers upward due to teh rear drooping. The lowering of teh front end by weight and droop of bushing.....once the first "adjustment " section of coils on teh front springs are compressed.....will actually cause the rear end to lift....causing less apparent lowering of the body over the wheels.

(3) You need to measure the gap between the subframe and the ground. Before adding weight and after. The control arms.....have a joint at each end. On the inside.... its teh control arm bushing. On teh outside its the ball joint.
Adding weight in the trunk can push the body downward. If the strut springs are already loaded to the first stage....thats the top of the spring....what they call the ride comfort zone (the bottom is the load zone in a progressive spring like this)....and that would be that first initial .75" to 1" needed to make it level.....then the springs don't easily compress more.
What happens is that the subfrrame pivots downward on the control arms. To allow this since the springs are not compressing much more at this point.......the balljoints pivot on teh bottom of the strut.

So....the car gets closer to teh ground without much more strut compression. Measureing before and after at the subframe....as well as measuring the uncompressd and compressed weight of the coil spring on teh assembled and installed strut....will tell you a lot.

I suspect that you have the usual combination of several things...giving you a huge lowering effect. (1)The compresion to initial load point of the coils (2) lifting of the rear (you must measure it....its hard to see) (3) stretching of old strut bushings (4)pivoting on the control arms and ball joints (5)...and lastly...check the condition of the radius arm donuts and teh centering rings on them. If they are shot, teh radius arms droop....adding over-rotation to teh control arms. Ray
Here is something that can demonstrate how many angles are changing

[vwfye]

i want my car to sit lower in the front. the current stance is unacceptable, and if i drop the nose 2" at the leading edge of the rocker panel, that still does not put the car level.

ray, i do understand what you are saying... but as i stated here, even measureing the height at the rockers, not the wheel arch still does not put the car level with a 2" drop. and if you measure the rear wheel arch height before front end weight and after, you get a 1/8" difference.

now, as to the optical illusion... whether it is, or not, it is a look i can't stand. and as such, i believe i am going to take the same approach as the superbeetle crowd. adjustable perches, shorter coils and a shorter strut of some sort.
like i had said, i won't be using the front truck as a truck bed as far as load weight goes.

[raygreenwood]

Shorter coils will be a massive mistake in handling........unless you have new springs wound.......that are simultaneously shorter, have the same progressive load at that shorter length...and as you note lowering the perches. Also....superbeetle suspenion is only vaguely similar in that it is the same basic TYPE. There is nothing else similar about it. It has much shorter arms, less leverage, shorter cantilevered overhang in the front and lower weight. Super beetles are easy. 411/412's are not

What you also have to do...or all of this is a moot point....is get a strut cartridge with a shorter rod. If you do not do that.....you will have to cut so much load capability out of the coil in order to get the body to sit lower that you will not have enough compression control to keep from breaking things.

Also....if you stay with the existing strut rod length and a shorter coil....how are you going to keep the rod from going to full extension on rebound and causing wheel hop (been there...done that)....or from unseating the spring and damaging the perch.....been there done that.

I see people in a hurry to get rid of that ghastly appearance in the front end....without having a clue as to what causes it.

For instance.....saying that the rear end only rises up 1/8" when the front end drops. Are you measuring at the rocker panel? That will tell you if the entire chassis is level. Measuring the resulting gap at the fenderwell in the rear is a good indication of how much the front is lifting the rear. Lift the front, it drops teh rear. Lower the front it lifts the rear.

You noted something in your last post that struck a cord. You had to lower the front end over 6"...just to get a 2" drop at the forward edge of the rocker panel?....and the body is STILL not level? Meaning it is still nose high as measured at the rocker panel Right off the bat......the problem is not in the front end...its in the rear. If you have greatly excessive sag in the rear.....it will excessively lift the front. Also....what shocks are in the rear?

The only time I have ever seen what you are describing....is the time in high school when I wen't out and found some basic generic shocks that "seemed" to be about the right size . They had too short of a rod. It kept the rear clamped down and did not let the spring fully extend. It made the car look like the front end was on jacks. In that case....even adding weight to the front end....did little or nothing to lift the rear higher. This is because....the spring coils were so tightly loaded by the short rod that the dropping of the front end by adding weight only compressed teh front coils...but could not unload teh rears...because there was no place to unload them to. The short rod had the angle of rear trailing arms....locked.

its also possible....though very rare....that the rear coils are so shot...that you get really excessive sag. That will also pivot the front end up.

The point here...is that I have owned and worked on so many 411/412's...and more than one that had less than 50k miles on it. There is no way....you woule ever need to drop teh front end 2" to bring tehrocker panel level front to rear (regardless of wheel arm to tire gap)....or be able to drop the front end 6+ inches...and still not achieve level rocker panel....unless....UNLESS....there are some thing SERIOUSLY wrong in your suspension. The geometry you are describing....does not exist in a 411/412...wherin all ofr the suspension components are at least normal.

At this point....what all ..ahve you replaced, adjusted or serviced in your entire suspension? Ray

[raygreenwood]

By the way....the front strut cartridge for the Audi 4000 and 4000 s...which fits all but the quattro....is P# 365008. It is for KYB GR-2. They no longer llist the Gas-a-just. At one time they had a listing....but they would be way stiff anyway. With the adapter that I made (be happy to e-mail the blueprint).....I was able to lower my car in about two hours of work....to look like the pictures that are posted else where in this thread.

The handling is flat out superb with these struts. It is a couple hundered percent better than stock...and very stiff. Nicely valved. It will handle anything you can throw at it.

BUT....it is enough stiffer that it will wreck everything in your front end if you do not have it sorted out. You need brand new strut bushings, a bronze idler bushing, new centering rings and track control donuts. Ray