Spring Tester first use and initial calibration
06-20-2007, 06:48 AM
#1
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Spring Tester first use and initial calibration
<center><img src="http://pictureposter.audiworld.com/711/springtester3.jpg"></center><p>
Any spring's advertised rate is said to be accurate if the tested rate is within + or - 5% of its advertised rate. My first test is using a 6" length Eibach spring rated at 1,100lbs.
When testing, all springs must have a specific pre-load placed on them and then the tester's travel indicator and rate is "zero'd" and then via further compression arrive at their actual rate. I've determined thru trial & error that the pre-load for Eibach is 1/2" (12.7mm). And then that their rate is determined at 1" (25.4mm) travel beyond pre-load compressed height. When doing that I arrive at a number thats very close to the rate printed on each spring. I've actually found numbers that are even more accurate when using heavier springs as well as lighter springs. But that requires using different pre-load travel distances as well as different rate travel distances. With the 1/2" pre-load with 1" travel past that point provides the most consistant and repeatable rates for heavy "and" light sporings so thats the one I'll adopt for all baseline measurements at least for Eibach coilover springs.
Given this method the above Eibach spring rated at 1,100lbs shows an actual rate of 1,076lbs at 1/2" pre-load + 1" travel or 1.5" "OAT" (overall travel). This "OAT" reference will be used on all future references and you can assume it to mean .500" pre-load + 1" travel.
The Eibach is well within it's 5% manufacturing allowance for the rate printed on it. In fact using the above method for calculation it's total difference between the rate printed on the spring and "actual" rate is just at 2%. I also achieved 2% when testing an Eibach 250lb rate spring so I'm happy with the "MAD" (mean average deviation) using the above method for all Eibach coilover springs.
Accuracy of scale is +/- 1lb from 0-3,000 lbs.
Now ya gotta know whats coming next, soon as I swap back to stock spring seats. Here Vogey Vogey Vogey...
Any spring's advertised rate is said to be accurate if the tested rate is within + or - 5% of its advertised rate. My first test is using a 6" length Eibach spring rated at 1,100lbs.
When testing, all springs must have a specific pre-load placed on them and then the tester's travel indicator and rate is "zero'd" and then via further compression arrive at their actual rate. I've determined thru trial & error that the pre-load for Eibach is 1/2" (12.7mm). And then that their rate is determined at 1" (25.4mm) travel beyond pre-load compressed height. When doing that I arrive at a number thats very close to the rate printed on each spring. I've actually found numbers that are even more accurate when using heavier springs as well as lighter springs. But that requires using different pre-load travel distances as well as different rate travel distances. With the 1/2" pre-load with 1" travel past that point provides the most consistant and repeatable rates for heavy "and" light sporings so thats the one I'll adopt for all baseline measurements at least for Eibach coilover springs.
Given this method the above Eibach spring rated at 1,100lbs shows an actual rate of 1,076lbs at 1/2" pre-load + 1" travel or 1.5" "OAT" (overall travel). This "OAT" reference will be used on all future references and you can assume it to mean .500" pre-load + 1" travel.
The Eibach is well within it's 5% manufacturing allowance for the rate printed on it. In fact using the above method for calculation it's total difference between the rate printed on the spring and "actual" rate is just at 2%. I also achieved 2% when testing an Eibach 250lb rate spring so I'm happy with the "MAD" (mean average deviation) using the above method for all Eibach coilover springs.
Accuracy of scale is +/- 1lb from 0-3,000 lbs.
Now ya gotta know whats coming next, soon as I swap back to stock spring seats. Here Vogey Vogey Vogey...
06-20-2007, 07:57 AM
#4
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Thread Starter
Ok, here's the story on Vogtland Rev 1 B4 front springs...
Now bear in mind this is a progressive spring rather than a linear coilover spring so I'll make no claims as to the "rate" of the spring. I'll concentrate instead on it's length with 970lbs placed on it (the certified weight of the B4 front divided by 2 with a 214lb driver on-board). And on the additional weight required to send this spring into total coil-bind, where all coils in the spring become stacked solid.
At 970lbs on spring there exists a total of 1.720" of space remaing for spring travel measured between 3 coils. All other coils in spring at this rate are stacked solid. This in spite of just at 2.750" of travel remaining in the Bilstein strut before encountering it's internal bump-stop. Translation: when going over bumps/potholes the spring will stack solid over 1" before the strut travel runs out. Recipe for disaster!
Add a 175lb passenger in the front seat and spring travel is reduced reduced another .237" which now leaves only 1.483" of total travel for spring which is again less travel than than the shock travel remaining. Now the springs stack solid even quicker/easier than with only a driver on-board.
Spring goes into "full stack coil bind" at 1,272lbs or just 302lbs heavier than the weight of the car with a 214lb driver on board. Even less with a passenger on board. Nowhere near enough to prevent coil bind on all but the smoothest roads.
I'm not sitting in front of this set-up to take pics as I just don't trust the stock spring seats to hold this spring captive at/over 1,000lbs. But I'll need to make an adapter for testing stock springs that will also work for this spring. So I'll re-post about this with pics after I've made those. Just too freakin scarey!
At 970lbs on spring there exists a total of 1.720" of space remaing for spring travel measured between 3 coils. All other coils in spring at this rate are stacked solid. This in spite of just at 2.750" of travel remaining in the Bilstein strut before encountering it's internal bump-stop. Translation: when going over bumps/potholes the spring will stack solid over 1" before the strut travel runs out. Recipe for disaster!
Add a 175lb passenger in the front seat and spring travel is reduced reduced another .237" which now leaves only 1.483" of total travel for spring which is again less travel than than the shock travel remaining. Now the springs stack solid even quicker/easier than with only a driver on-board.
Spring goes into "full stack coil bind" at 1,272lbs or just 302lbs heavier than the weight of the car with a 214lb driver on board. Even less with a passenger on board. Nowhere near enough to prevent coil bind on all but the smoothest roads.
I'm not sitting in front of this set-up to take pics as I just don't trust the stock spring seats to hold this spring captive at/over 1,000lbs. But I'll need to make an adapter for testing stock springs that will also work for this spring. So I'll re-post about this with pics after I've made those. Just too freakin scarey!
06-20-2007, 08:45 AM
#6
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unlike how I feel Vogtland treated me/us I want to be fair with them...
my Vogtland B4 rear springs were flawless and I couldn't have been happier with them for what they are/were, ie; a very good aftermarket sport/lowering spring. And other model/year car owners are delighted with their Vogtland products front and rear.
I just think they dropped the ball with B4 owners on front springs. Never took us seriously in the beginning that there might be an issue or something wrong. Obviously tried to pawn a lesser spring from a different car on us originally as being specifically made for our car. And would still be doing it if we hadn't been a thorn in their side. Posted an obviously bogus TUV certification to show us it was correct and to reaffirm their "rightness." Then 2 years later made a new spring design and kept our money that entire time while we were mostly ignored. And never, not even once, did the distributor or manufacturer get back to us when they said they would or in any semblence of a timely manner if they did at all. I "think" we heard from distributor/manufacturer a total of 3-4 yimes in 2 years and the bulk of those VERY early-on as in the first 30 days when we originally got their attention and listened to them tell us we're wrong. Even when new springs were available "we" had to be the one that called them to find out. I don't personally believe they were ever going to voluntarily let us know as that meant giving something away for free. Not their way obviously even when they're patently wrong.
We just were NOT handled with any measure of good will, any semblence of reasonable customer service and basically dismissed as being ignorant and ungrateful for what they were providing us.
I just think they dropped the ball with B4 owners on front springs. Never took us seriously in the beginning that there might be an issue or something wrong. Obviously tried to pawn a lesser spring from a different car on us originally as being specifically made for our car. And would still be doing it if we hadn't been a thorn in their side. Posted an obviously bogus TUV certification to show us it was correct and to reaffirm their "rightness." Then 2 years later made a new spring design and kept our money that entire time while we were mostly ignored. And never, not even once, did the distributor or manufacturer get back to us when they said they would or in any semblence of a timely manner if they did at all. I "think" we heard from distributor/manufacturer a total of 3-4 yimes in 2 years and the bulk of those VERY early-on as in the first 30 days when we originally got their attention and listened to them tell us we're wrong. Even when new springs were available "we" had to be the one that called them to find out. I don't personally believe they were ever going to voluntarily let us know as that meant giving something away for free. Not their way obviously even when they're patently wrong.
We just were NOT handled with any measure of good will, any semblence of reasonable customer service and basically dismissed as being ignorant and ungrateful for what they were providing us.
06-20-2007, 08:57 AM
#7
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Sorry to (possibly?) steal the thread, but after reading you Rev1 B4 Vogtland test, I must say...
that when there is nobody in my car, the lower 3 coils are stacked. I have the new revision 2 springs. Are they're other front sport lowering springs for the B4 that do not stack at all? I have a feeling that this stacking causes the lower 3 coils to rub and make noise, which I'd rather be without.
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06-20-2007, 10:10 AM
#8
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My understanding
Is most of the aftermarket springs for the B4s are way to light in the front but just right in the rear. The fronts were basically B3 units but the extra weight up front due to the v6 and v6 components added more weight than they can handle.
Most of the springs I've check (for motorcycles) go by a c1 and c2 measurements. C1 was always 10mm and c2 varied based on applications, in my case it was 100mm.
Full coil bind must have knocked out your fillings!!
I was told to import some eibachs from europe if I ever wanted to run aftermarket springs with out going to coil overs. I happen to have the 95 sport springs which are 1/2 lower than stock and am told are a little stiffer. It would be great if you could prove that is true Mance.
Tom
Most of the springs I've check (for motorcycles) go by a c1 and c2 measurements. C1 was always 10mm and c2 varied based on applications, in my case it was 100mm.
Full coil bind must have knocked out your fillings!!
I was told to import some eibachs from europe if I ever wanted to run aftermarket springs with out going to coil overs. I happen to have the 95 sport springs which are 1/2 lower than stock and am told are a little stiffer. It would be great if you could prove that is true Mance.
Tom
06-20-2007, 02:11 PM
#9
AudiWorld Super User
Thread Starter
Truth is there is no good reason any coil spring "has" to stack coils in order to work...
<center><img src="http://pictureposter.audiworld.com/711/vogspring.jpg"></center><p>
or achieve any rate, any ride height or any ride quality. Of course it contributes to noise and there's a handful of other reasons it's a bad idea. In fact I know of no instance where it might be the best or even a very good way to approach spring-making. When suspension drops those coils separate slightly and make noise on compression when they slam back together. Also a close inspection of the wear pattern on those stacked coils shows they not only are in full contact with each other but they actually exhibit a "wipe pattern" which shows the coil windings wipe across each other perpendicular to the coil winding, ie; they deflect across each other back & forth when stacked. Stacking coils is also a good way to virtually assure the spring stacks solid before the strut bottoms out on it's internal/external bump-stop. So instead of getting the softer/dampened stop the car was designed for you virtually get a steel-on-steel suspension limiter which is total hell on the cars suspension. And it feels like your dash is being ripped out while you're in the driver's seat. It eats strut mounts and lower ball joints for lunch and blows strut tower openings upwards as it tries to drive the struts thru the hood from underneath when the springs stack solid.
Eibach and H&R both made springs for this car at one time and I hear Eibach is still available for it. And H&R "may" be an option as well. But for how much longer is anyone's guess. Tho 2.5" ID coilover springs will be around for the seeable future and well beyond the length of our statisitical lives.
Pic shows just a few of the wear and contact marks of the Vogtland Rev 1 spring. Lowest ring is constantly wearing via the 2nd coil sliding over it removing material on each swipe. 2nd coil OD is always hammering and contacting the stock lower perch ID where they meet even when perfectly centered within the perch. Something NEVER found on the stock Audi springs. And the 3 stacked coils are constantly beating each other up on rapid suspension rebound/damping. Truth is most class C "legal" firweworks you can buy today for 4th of July make less noise than these springs! And all of this spring trauma in less than 2 weeks use. I knew immediately something was SERIOUSLY wrong with these springs and removed them ASAP!! Doesn't take a building to fall on me ;-)
or achieve any rate, any ride height or any ride quality. Of course it contributes to noise and there's a handful of other reasons it's a bad idea. In fact I know of no instance where it might be the best or even a very good way to approach spring-making. When suspension drops those coils separate slightly and make noise on compression when they slam back together. Also a close inspection of the wear pattern on those stacked coils shows they not only are in full contact with each other but they actually exhibit a "wipe pattern" which shows the coil windings wipe across each other perpendicular to the coil winding, ie; they deflect across each other back & forth when stacked. Stacking coils is also a good way to virtually assure the spring stacks solid before the strut bottoms out on it's internal/external bump-stop. So instead of getting the softer/dampened stop the car was designed for you virtually get a steel-on-steel suspension limiter which is total hell on the cars suspension. And it feels like your dash is being ripped out while you're in the driver's seat. It eats strut mounts and lower ball joints for lunch and blows strut tower openings upwards as it tries to drive the struts thru the hood from underneath when the springs stack solid.
Eibach and H&R both made springs for this car at one time and I hear Eibach is still available for it. And H&R "may" be an option as well. But for how much longer is anyone's guess. Tho 2.5" ID coilover springs will be around for the seeable future and well beyond the length of our statisitical lives.
Pic shows just a few of the wear and contact marks of the Vogtland Rev 1 spring. Lowest ring is constantly wearing via the 2nd coil sliding over it removing material on each swipe. 2nd coil OD is always hammering and contacting the stock lower perch ID where they meet even when perfectly centered within the perch. Something NEVER found on the stock Audi springs. And the 3 stacked coils are constantly beating each other up on rapid suspension rebound/damping. Truth is most class C "legal" firweworks you can buy today for 4th of July make less noise than these springs! And all of this spring trauma in less than 2 weeks use. I knew immediately something was SERIOUSLY wrong with these springs and removed them ASAP!! Doesn't take a building to fall on me ;-)
06-20-2007, 06:44 PM
#10
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Wow, thanks for the great information! Any idea where I may start looking for Eibach springs? ...
Nothing on eBay, AudiFans, etc etc. Maybe call Eibach directly?
Just wondering if maybe you in your expertise have some suggestions of sources.
Just wondering if maybe you in your expertise have some suggestions of sources.