Stock Springs / E9 Coupes / Group Data Gathering Exercise / Understanding which springs result in what ride heights.

[paul cain]

I am starting a data log on stock front springs originally fitted to the E9 Coupes. Starting with the front springs.
Looking for willing participants to add their data to this log to attempt to understand the actual color codes of front springs and what is the resulting ride height.
This exercise is focused on stock springs. For now. Later on we will add in the Carl Nelson springs, Eibach, etc to the log.
The information in the Front Axle Specifications of the Factory Blue Books bares little in comparison to what was actually fitted on cars.
The idea is to document what color codes actually exist on cars and what this yields in terms of actual ride heights.
There is a simple measurement we are calling Dimension "A". Looking for E9 Coupe forum owners to contribute what is reality on their stock coupes.
For now, looking to have folks reply back with the following information on their known stock Coupes with:
You will need a measuring tape, (inches is fine), and a caliper to measure the thickness of the spring "wire". Bonus points if you send in a pic of a new color code.
Reply back I will update the spring log with your information.
Shooting for 10 data points.
Take a look at the attached excel spreadsheet and see if you want to join the project. Note the second tab.
Thank you to Chris Macha and Mike Pelly for their initial contributions

Data Requested:

1 Car details Model Year, US or Euro

2 Spring stripe colors

3 Dimension "A" for loaded ride height

4 Note if you still have the aluminum spacer installed

5 Wire diameter

 

[teahead]

Without spacers I presume?

 

[paul cain]

Without spacers I presume?

when you gather the data you would just note if you car does, or does not, have the original aluminum spacers installed.

 

[Arde]

Will this study answer the vexing question of whether springs wear or do not wear over he car's lifetime or the spring compression cycles?

 

[paul cain]

Will this study answer the vexing question of whether springs wear or do not wear over he car's lifetime or the spring compression cycles?

I would say not likely. What we would need to have for a conclusive answer is a Dimension A reading taken off a a brand new coupe in 197X -taken when new. We can get an idea once the data rolls in, by studying vintage photos and road test articles and observing the gap from the top of the tire to the finder lip. My experience is the factory springs are really well made (both metallurgy and post process tempering process control) and don't sag over time.

 

[Markos]

Perhaps some helpful content:

Spring Paint Codes e3 e9 e12 & e24

I am taking a close look at what the coil spring options are for my coupe. I have adjustable front struts which gives me some freedom otherwise I would just keep my CN lowered springs. But in considering my options I have been exploring BMW paint codes on springs. Posts in the e9 and 2002...

e9coupe.com

 

[boonies]

Hi Paul, This exercise firms up the plan to get underneath and do some deep cleaning, I had to scrub to get down to the original paint...

1 1972 3.0cs, USA

2 Spring stripe colors: Green & white (also seems like a red stripe)

3 Dimension "A" for loaded ride height: 40cm

4 Note if you still have the aluminum spacer installed: Yes, spacer is installed

5 Wire diameter: 15mm

 

[paul cain]

@Boonies thank you for your flawless execution of the spring request. This is exactly what we are after. I'll add your details to the data table. Thanks for making the effort!
Paul

 

[tygaboy]

Not sure it matters in this data gathering exercise but I'll offer this:
When we corner weight/set ride height, we always measure from a point on the chassis underside, generally the subframe or suspension mounting location, not from a wheel arch. It's not uncommon to see up to .5" side-to-side difference when using points on the body, just due to imperfections in manufacturing, previous repairs, etc. Using the chassis points means the suspension's working bits are even, side to side.
Hair splitting, maybe, but figured it wouldn't hurt to toss this out. Feel free to do the same!

 

[Arde]

I would say not likely. What we would need to have for a conclusive answer is a Dimension A reading taken off a a brand new coupe in 197X -taken when new. We can get an idea once the data rolls in, by studying vintage photos and road test articles and observing the gap from the top of the tire to the finder lip. My experience is the factory springs are really well made (both metallurgy and post process tempering process control) and don't sag over time.

Well I recall the economist that came up with the idea of natural experiments got a Nobel prize or something.

Natural experiment= observational study in which an event or a situation that allows for the random or seemingly random assignment of study subjects to different groups is exploited to answer a particular question.

I think if the dataset is large and includes cars that were driven little and a lot, and cars with springs replaced later in life, we face a natural experiment of sorts and can answer the sagging question.

 

[Oldbmwcoupes]

I love empirical studies. I’ll send data in both my 2800 cs and my 3.0 cs.

 

[mbmw]

Is this just for the front springs or the rear one's also?

 

[paul cain]

I love empirical studies. I’ll send data in both my 2800 cs and my 3.0 cs.

Thank you!

 

[paul cain]

Is this just for the front springs or the rear one's also?

If we get a few more responders, we will then look at the rear springs as well.

 

[Patton]

Paul, if I knew how to link to a previous post I would do so.

Alas, my computer skills are zero. Do a search on "Stance: Your Vote" and many chimed in with data.

In the meantime, I have a front and rear set of Carl Nelson springs, unused, that are available to anyone that wants them to complete a project.

My invoice from 2015 tells me the price was $395.

So, should anyone want them, give me a call 404-226-6678

Hope this helps.

RP

 

[paul cain]

I want to thank Lance (Boonies) for his comprehensive submission. See attached image of his car with a 15.74 cm ride height. All of the details are now in the Excel file. I've also added a new tab to show the side view image of each of these ride heights. See the fourth tab 'side view of ride heights'.

Who wants to be next up?

 

[adawil2002]

1973 Euro CSi
Front: Gold painted lowering, dimension A, 13.75/35cm, wire 9/16ths/15mm
Rear are stock, can't see the color dot(s)

 

[Ohmess]

Paul - This is a good idea. If you are adding rear spring data, you should ask respondents to indicate whether they have Euro or US rear spring pads.

 

[DWMBMW]

The original fronts on my 72 CSi were red and white (with a little Tiaga overspray) at 15mm. The rears were red only at about 13mm.
Never measured the ride height before I replaced them with CN lowering springs a couple of years ago but also attached is a pic of a pic I took in 1984 with the original springs and Boge shocks. No alum spacers but still pretty damn high.

 

[paul cain]

Spreadsheet has been updated with the final ride height for DWMBMW's 1972 3.0 CSi and Patricia Mayer's 1974 US Market with red/blue/blue spring. Aluminum spacers are still installed. Both cars are ready for Paris to Dakar!