Stock Rear Spring Rate? Options

[detoxcowboy]

I would like to know the stock rear spring rate for a 74 914 2.0 w/ perforomance package.. the black springs with the green paint....

[porschetub]

Mine are blue with no paint marks or writing PO said they are 100lb but he has told me other "stories" before (IMG:style_emoticons/default/dry.gif) ,seem great what ever they are with my Bilsteins and a "6".

[Mikey914]

If they are factory I can guarantee they are not 100#.

[Matty900]

I started to put some spring information together when our 100# springscame out https://914rubber.com/eibach-914-rubber-springs

[dr914@autoatlanta.com]

here is a bit of a study our spring guy did

[tomeric914]

Ghetto spring tester for springs with a rate less than 300lbs/inch:

1. Place bathroom scale on bottom plate of press

2. Place spring on bathroom scale

3. Place scrap 2x4 on top of spring under press

4. Zero bathroom scale

5. Compress spring 1"

6. Read bathroom scale

[johnhora]

For reference...
a pair of early springs off the same car...you can see the 2 green paint spots.
the top one is 4mm shorter....maybe from the driver side

[bbrock]

Ghetto spring tester for springs with a rate less than 300lbs/inch:

1. Place bathroom scale on bottom plate of press

2. Place spring on bathroom scale

3. Place scrap 2x4 on top of spring under press

4. Zero bathroom scale

5. Compress spring 1"

6. Read bathroom scale

Don't know how much difference it makes, but I read it is best to compress 1" to preload the sprig first, take a reading, then compress another inch and subtract the two measurements. Here's my ghetto spring tester i action. Would have been better to use a cheaper scale. These fancy electronic scales are only good for telling you how fat you are.

(IMG:http://www.914world.com/bbs2/uploads/post-20845-1549163184_thumb.jpg)

[maf914]

Brent B, bbrock,

Interesting. Nice test rig. Did it bind up where the horizontal upper board slides on the vertical members? It seems that might give a false reading.

How did your spring rate? (IMG:style_emoticons/default/idea.gif)

[bbrock]

Brent B, bbrock,

Interesting. Nice test rig. Did it bind up where the horizontal upper board slides on the vertical members? It seems that might give a false reading.

How did your spring rate? (IMG:style_emoticons/default/idea.gif)

No issues with binding. The mortises the uprights fit through were cut really loose (almost a half inch oversize). The uprights just held the top board in place enough to let me snug the nuts on the all-thread without flopping all over the place. The biggest problem was that stupid scale. It only reads for a few seconds so in the end, I wound up have to just heft the top board down with my own weight and quickly read the damn scale when I got down to the 1 or 2 inch mark. Springs tested at 50 lbs. give or take. I decided that was close enough to stock rates to clean them up and use them. Engine isn't in the car yet so we'll see. Based on the test result, I gave them one green dot. (IMG:style_emoticons/default/lol-2.gif)

(IMG:http://www.914world.com/bbs2/uploads/post-20845-1551674284_thumb.jpg)

[maf914]

Brent, Thanks for the response. That is funny about the scale shutting down, especially after going to the trouble of building the test rig. (IMG:style_emoticons/default/wacko.gif) Good work though.

BTW, Some time ago in the 90's I replaced the original sagging springs on my 76 with 100 lb Weltmeister springs (from Auto Atlanta) with red Koni shocks. They raised the ride height an inch or two. I should have measured before and after. But as for ride stiffness I couldn't really tell much difference.

[tomeric914]

Don't know how much difference it makes, but I read it is best to compress 1" to preload the sprig first, take a reading, then compress another inch and subtract the two measurements. Here's my ghetto spring tester i action. Would have been better to use a cheaper scale. These fancy electronic scales are only good for telling you how fat you are.

Yes, a good ol' mechanical scale is what I used. Stock springs aren't progressive so measuring just the first inch should yield the same rate per inch as the following 4". I recall taking measurements as far as the scale and jig would safely read just for giggles.

[DickSteinkamp]

BTW, Some time ago in the 90's I replaced the original sagging springs on my 76 with 100 lb Weltmeister springs (from Auto Atlanta) with red Koni shocks. They raised the ride height an inch or two. I should have measured before and after. But as for ride stiffness I couldn't really tell much difference.

When I did the V8 conversion on my 76 I was hopeful the extra weight of the V8 would bring the ride height down to where it should be. It actually took it down too far (I know...if it's too low, I'm too old (IMG:style_emoticons/default/sad.gif) ).

The Weltmeister 100 lb springs put it right where I wanted it...

(IMG:https://live.staticflickr.com/65535/48095019317_3377ce5d62_c.jpg)

[bbrock]

Yes, a good ol' mechanical scale is what I used. Stock springs aren't progressive so measuring just the first inch should yield the same rate per inch as the following 4". I recall taking measurements as far as the scale and jig would safely read just for giggles.

I had to check my notes to refresh my memory, but my springs measured lighter in the first inch. One spring measured 42 lbs. at 1 inch and 92 at 2 inches. (92 is minimum) It was really hard to get an accurate measurement at 3 inches with that stupid scale, but it appeared to be adding an additional 50ish pounds. No way could I squeeze those springs to 4" and get a reading.