Joe (zyxt)

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4kq

Snoogins gave a detailed and accurate answer. We have talked about this since the dawn of the internet.

I'll simplify: Only a rich dope gets a adj coilover for a street car. I use them with a borrowed set of scales for autocross (sp). If you do not use scales you will probably make you handling WORSE.

The vast majority of advertised spring rates are either flat-out false or guesstimates done without checking (Lol, what's a spring tester?).

Sharon

BTW, don't know if I'd agree with your statements about adjustable coilovers aren't necessary for a street car. They aren't a competitve only purchase, as anyone with a desire to set and adjust height to their liking (as opposed to preset perches) will want them, or someone who wants to say make adjustments to height seasonally. Coilover height adjustment can be done while on the car, while springs+shocks generally require removal and reinstallation of the suspension.

Also, there is indeed something called a spring tester that will "dyno" a spring and tell you the actual rate. In fact, when I buy my hypercoils, I get both the manufacturer's rate and the actual rate as the shop has tested them (e.g., my 1200lbs springs were dyno'd at 1211 and 1203lbs). Its handy if you really want to know what you're getting, though its also more common with linear springs than progressive (note also that spring rates quoted for progessive springs are generally quoted at the max rate).

smallTTs

load variation at the test height? Or is that what you were testing? Please elaborate on the testing procedure. This sounds like nice equipment.

Sharon

My (linear) spring rates are simply the amount of force it takes to compress the springs 1". It's a linear equation (spring rate = force/spring deflection).

You can get cheap tester to measure a springs rate (companies like Longacre/Intercomp sell a basic portable hydraulic one for under $5-800, though manufacturers and probably your bigger race teams use more accurate computer equipment).

According to Hyperco, they can generate accurate graphs and tables of spring load per unit deflection in increments of 0.1in (2.5mm) from free length to solid stack. Hypercoil guarantees within 1% accuracy of the advertised rate, btw.

smallTTs

One of the reasons a spring company can guarantee RATE is that it is dependant upon wire diameter, coil diameter and number of active coils; all mechanical things which don't change. What isn't always constant is the load at a given compression. This determines your ride height in a non-adjustable setup, and can change or sag with use.

BTW, when you check your rate, do you first compress the springs to solid 1 or 2 times prior to testing? How accurately do you measure the 1 inch? For the numbers you quoted, you need to be accurate within about +/-.001 in.

Are you really using 1200 lb/in springs on an A/S4?.

Sharon

I'm not the one doing the testing. Hyperco tests them (in batches I presume), and the shop I buy them from verifies. On the spring itself, you'll see an etched rate of say 1000 from Hyperco, and separate sticker from whoever tested with the actual, say 1009. Most reputable suppliers can provide you a print out with the specific dyno info and coil specs. I don't have a spring tester in the garage :-). But I believe you have to apply load to the spring at the design length (compressing 1/2" or so) and then move 1" from there to get the rate.

I believe most commercial spring testers are indeed calibrated to .001" (at least Hyperco does per their site). I think Eibach says the same; I suspect that is an industry standard.

I have a few different springs sitting in my garage for my S4 varying between 700-1300lbs. What's on the car right now is 800F/1200R.

4kq

It comes up all the time because people like you (the original poster, not Sharon the racer) are too lazy to do any research on your own. Then you want some kind of pithy answer that supports your preconcieved answer.

Adj. coilovers on a street car are for poseurs who know nothing about handling, but like the look.

It is not a cost issue. You can make your own kit from GC or Carrera for cheap. It is a handling issue. You will find it almost impossible to gain any statistically significant improvement over a quality set of fixed height coilovers.

This is true even if you bother to get it set up on some scales (the vast majority of poseurs don't). What F:R % are you going to use and why? Tell me that and you prove you are not a poseur.

Scales are the first step, but what are your roll centers front and rear? Why? Which rates are you using? Why? What is your compression damping on your shocks? Why?

Coil "dyno" is a classic moron statement. A coil spring tester (as I described in my first post) is not a dynanometer. But poseurs have learned that the word dyno is cool.

smallTTs

They check many points to get the rate, BTW.

zain

And we wouldn't want to **** off the cranky people who have to time to troll the boards looking for posts to rag on, but not the time to just skip over threads that are uninteresting to them.

Chips, spring rates, dyno debates, oil weight, can an A4 take a..., all come up and will keep coming up. Audience changes, people come and go... whatever. Skip the post.

Seems like Sharon, (who never comes off like an idiot as far as I can tell) put "dyno" in quotations to calmly make the point that rate tester isn't a dyno.

I've met many non poseurs with coil-overs. Some know more about handling set up than others. Some are just using them to adjust ride height easily for seasonal driving condition changes. But hey, you know more than Sharon the subject, right?

But I'll stop. It's all been said before.