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Posted by: Mathman Jul 23 2015, 03:53 PM

I have been feeling like my rear springs might be worn out, so I decided to buy some 100lb. springs. It should be noted that I am VERY much a newbie when it comes to the suspension system. In addition, let it be known that I am not currently into AX or any other racing applications.

That being said, I felt like the rear ride height was exceptionally low for my tastes. When I went to remove my springs, I discovered that I have the yellow Bilstein shocks with the six grooves and the little circlip to hold the bottom plate. My circlips were on the bottom groove.

So, I took off my spring, and compared it to my new 100lb. spring. My old spring is probably a good 3" longer than the new one. That seemed weird to me, so I decided to do a little more research.

I have always been told that you can't really change the rear ride height, but then I read some stuff that indicated you COULD change the ride height if you had the Bilsteins. So, I decided to move the circlip to the fourth groove (from the bottom) and install the old springs. After driving it around a bit, I like the ride height a lot more.

My questions are as follows:

1. Did I do anything wrong?

2. Should I use the new 100lb. springs or keep the old springs?

3. There are no markings on the old springs. I put a weight on both old and new springs, and they seemed to compress the same distance, but why would there be such a height difference? Any other way of telling whether my old springs are sprung?


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Posted by: 396 Jul 23 2015, 03:58 PM

My first thoughts, if there's no marking on the longer spring.
Your guess is better than most as the parts are in front of you.

Posted by: mepstein Jul 23 2015, 04:07 PM

The bilsteins are height adjustable. Set it to your preferred height. Doesn't matter what the springs look like off the car, just how they set and feel on the car. Sounds like your on the right track.

Posted by: Steve Jul 23 2015, 04:12 PM

I have a set of sp140 and sp180 and all the springs are the same length and they are all marked.
The 180 springs are shorter than the 140 springs.

Posted by: Dave_Darling Jul 23 2015, 04:16 PM

Pretty much all aftermarket springs for the 914 have a longer "free length" (length with no weight on them) than the stock springs. What you observed is quite normal.

With standard shocks, you cannot change the rear ride height. With the Bils you have, you can.

If you like the height where it is now, leave it. It'll be fine.

You can change the ride height in the front by tweaking the adjustment bolts at the rear of the A-arm. Check your Haynes manual for details.

Any time you change the ride height, you will change the camber on that end of the car. You'll also be changing the toe angle, but generally by a smaller amount. It's not the worst idea in the world to get an alignment after you have set the height to where you want it.

--DD

Posted by: siverson Jul 23 2015, 04:20 PM

As stated above, this all seems normal. Just install the new springs and keep removing/adjust the perch/re-installing until you get the rear ride height right where you want it.

-Steve

Posted by: whitetwinturbo Jul 23 2015, 04:39 PM

......excuse my hijack

I have mystery BLUE springs with no markings and would appreciate the knowledge of a expert to identify manufacturer and "weight" ie: 100, 180 or ???

Posted by: Travis Neff Jul 23 2015, 05:10 PM

That blue spring probably has an aluminum tag on the upper coils with the weight. I say this as it looks like the same Koni coilover setup I have with hypercoil springs.

Posted by: Larmo63 Jul 23 2015, 05:59 PM

I would put the new springs on the car with the shock clips set where you like the ride height.

Posted by: Dave_Darling Jul 24 2015, 09:09 AM

Take 'em off the car, measure the free length, then stack weights on them and measure the length again. That gives you lbs of weight, and inches of displacement. That will give you the rate in lbs/in.

--DD

Posted by: Philip W. Jul 24 2015, 10:07 AM

ive got the same shocks and springs, and also need to decide if i want to stay with the current set up or go back to a longer stock type spring- going to do a comparison this weekend. i have a tight fit with the 7" fuchs and might go back up to a 6/7 from the #2 slot i have it set at now, but when i did that in the past with different wheel set up i ddint like the bounciness. so i a am going to cmpare that to the longer 90# springs, see which rides better at the height i need. Just borrowed some spring compressors from a friend. will hve to see - i diont want to change the front as i had that all aligned last year after replacing the whole front end(a-arms, bushings, bearings, turbo tie rods and ball joints, 5 - lug etc. ).
take some pictures and we can compare notes. i'll be doing this tomorrow.

Phil

Posted by: whitetwinturbo Jul 25 2015, 09:20 PM

Now we talking about work! My lazy says someone must have the info on this blue mystery