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Front Strut Assy Length ?
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Kenodog  



Joined: 25 Jun 2003
Posts: 2584
Location: Vancouver,B.C.

PostPosted: Thu Apr 18, 2019 3:52 am    Post subject: Front Strut Assy Length ? Reply with quote

So I decided to swap the Koni struts on Sabine for a set of Bilsteins that I got in a parts lot a few years ago. The Bilsteins themselves are new but the PO repainted the housings and springs to pretty them up.

However, when I laid the two side by side I noticed a marked difference in lengths between them. Also, there is a bolt on the bottom of the Bilstein unit, bolting the strut cartridge itself into the housing. The gold painted springs are also thicker by 0.020" which would make them heavier. And that is compared to the 250# Weltmeister springs in the Koni assy.

All in all I'm confused....

I want to use the Bilsteins but they are about 1.5" shorter than the Konis which themselves are 1" lower than standard height....

Thoughts ?







Lee
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!tom  



Joined: 28 Aug 2006
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Location: Victoria, BC Canada

PostPosted: Thu Apr 18, 2019 4:25 am    Post subject: Reply with quote

You're going to want a shorter length if you have a stiffer spring to end up with the same ride height...
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Kenodog  



Joined: 25 Jun 2003
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PostPosted: Thu Apr 18, 2019 4:30 am    Post subject: Reply with quote

I understand that. My point is however that the Bilsteins you see in the pic are a total of almost THREE INCHES shorter than a stock 931 assembly....
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CÚdric  



Joined: 27 Aug 2004
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PostPosted: Thu Apr 18, 2019 4:37 am    Post subject: Reply with quote

I would have thought the bilsteins were close to std. It doesn't have to be an issue, since the springs are unknown the best would be to put them on the car and measure how much travel you have in droop and compression when it is in ride height. There are some general guide lines that works pretty well.
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924-76  



Joined: 05 Jun 2006
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PostPosted: Thu Apr 18, 2019 4:50 am    Post subject: Reply with quote

I would suspect the gold painted spring to be aftermarket lowering spring. Since you have no info/specs on it, I would install the 250# Weltmeister springs on the Bilsteins.
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Fifty50Plus  



Joined: 28 Feb 2008
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PostPosted: Thu Apr 18, 2019 6:28 am    Post subject: Reply with quote

Looks to me like the lower spring perch and the two holes where the strut bolts to the spindle are the same height. If you have a shorter, stiffer spring, mounted on any strut it will look shorter overall. When you mount the assembly to the chassis the car will be lower but not deflect as much because of the stiffer spring. Best way to measure the struts for height differences is to remove the upper perch, spring and shock. You may find that you have a shorter shock inside the strut and a shorter strut body (lower perch to top of strut).
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Kenodog  



Joined: 25 Jun 2003
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PostPosted: Thu Apr 18, 2019 6:36 am    Post subject: Reply with quote

The thing I find strange is there is a bolt coming up through the bottom of the lower strut housing which appears to go into the bottom of the insert. I am pretty sure this is from a later model 944 / 951.....



Lee
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safe  



Joined: 18 Mar 2017
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PostPosted: Thu Apr 18, 2019 6:33 pm    Post subject: Reply with quote

Kenodog wrote:
The thing I find strange is there is a bolt coming up through the bottom of the lower strut housing which appears to go into the bottom of the insert. I am pretty sure this is from a later model 944 / 951.....



Lee


At least in the 911 that is how a Bilstein insert is secured in the struts since they are an upside down construction.

Do you know what Bilstein insert there is in the green?
The sport and clubsport Bilsteins are somewhat shorter to compensate for a lower car. And since the insert sets the total length of the assembly (the springs is not loose by the looks of it) there is probably a short insert.
With stiffer springs you need a shorter assembly, try them on. The car won't be 3" lower than stock just because the struts are....
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TJC  



Joined: 04 Apr 2010
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PostPosted: Fri Apr 19, 2019 1:10 am    Post subject: Reply with quote

When making any modification from stock I tend to dislike any unknown. If it were up to me I would disassemble the Bilstein unit and measure the free length and pressure of the spring as well as removing the insert to confirm what it is.
If you are absolutely sure of the Koni set up with the Weltmeister springs this probably wouldn't be necessary but again I personally would at a minimum disassemble the unit just to at least compare spring specifications...yep, call it OCD.
This seems to be a more logical approach rather than installing them only to find out they're not conducive with your desired result.
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Kenodog  



Joined: 25 Jun 2003
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PostPosted: Fri Apr 19, 2019 5:50 am    Post subject: Reply with quote

Argh, the whole thing just smacks of effort man.But, I get it. I will disassemble the bilsteins and check the P/N on them. I have a feeling the lower housing is from a later model 944, thus the bottom screw holding the insert in. Then since I am 100% about the Weltmeister springs (I bought them) I will install those on the Bilts.

I may paint them gold though, I like that look....




Me
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safe  



Joined: 18 Mar 2017
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PostPosted: Fri Apr 19, 2019 7:11 am    Post subject: Reply with quote

Kenodog wrote:
Argh, the whole thing just smacks of effort man.But, I get it. I will disassemble the bilsteins and check the P/N on them. I have a feeling the lower housing is from a later model 944, thus the bottom screw holding the insert in. Then since I am 100% about the Weltmeister springs (I bought them) I will install those on the Bilts.

I may paint them gold though, I like that look....


Me


Changing springs wont make them longer....
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Kenodog  



Joined: 25 Jun 2003
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PostPosted: Fri Apr 19, 2019 1:31 pm    Post subject: Reply with quote

I pulled the springs from the Bilsteins and the only number Mr. Google will recognise is 380 / 150. These are apparently race valved struts for a late model 944 / 951. This would also explain the heavier springs of course. Although the new P/N shows threaded bodies on the current edition of this strut, mine do not have that. In fact, they are actually old enough to say "Made in West Germany' on them so I'm logically thinking that these are from a 951 / 951S car originally....

Thoughts ?



Leih
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morghen  



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PostPosted: Fri Apr 19, 2019 5:29 pm    Post subject: Reply with quote

Spring rate is a bit harsh imo, so they probably wont compress too much when on the car from their current length. The other ones look like they will compress quite a bit. Just be prepared to adjust the rear height and match the spring rate.
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TJC  



Joined: 04 Apr 2010
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PostPosted: Sat Apr 20, 2019 1:05 am    Post subject: Reply with quote

I'm curious as to whether you had the Koni/Welt combo installed on anything prior and if you were satisfied with the spring rate and ride height? Or, if anyone else you know or here on the board has? If so you may expect similar performance from the spring, probably a bit different feeling from the Billy and most likely a lower ride height.
Fortunately if it does turn out that it's not to your liking you have the bits to play with something else and it's not all that much work to change it.
I say go for it and as Morghen says attend to the rear accordingly!
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CÚdric  



Joined: 27 Aug 2004
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PostPosted: Sat Apr 20, 2019 1:26 am    Post subject: Reply with quote

I once had the welt 250s on my 931, the ride height was totally out of whack in std condition. I had to cut of some coils to get it right.
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