Progressive springs - disadvantages?
#1
06-24-2009, 01:47 PM
Progressive springs - disadvantages?
Ok, so i'm really hooked on HPDE's now.
I have a set of Eibach's still to be installed. Would anyone know what the disadvantages are with using progressive springs at the track? I can make a couple of guesses, and it has to do with transitions and keeping the line, but i don't know for sure.
Something tells me that having good set of aftermarket sways or braces will probably help more than lowering the car with Eibach's.
Thanks, all.
I have a set of Eibach's still to be installed. Would anyone know what the disadvantages are with using progressive springs at the track? I can make a couple of guesses, and it has to do with transitions and keeping the line, but i don't know for sure.
Something tells me that having good set of aftermarket sways or braces will probably help more than lowering the car with Eibach's.
Thanks, all.
#2
06-24-2009, 03:47 PM
You have it pretty well pegged.
Transitions between the rates are horrible.
& if you think about it;
in a turn the outboard side is under compression, down from mild to stiff,
while the inboard is lifted on the mild rate.
Progressives are a street spring plain & simple
...been there done that, will never do it again.
That's one of the main reasons I persisted with the 370Z springs.
Otherwise, if you really want a track setup, it's coilovers all the way.
Transitions between the rates are horrible.
& if you think about it;
in a turn the outboard side is under compression, down from mild to stiff,
while the inboard is lifted on the mild rate.
Progressives are a street spring plain & simple
...been there done that, will never do it again.
That's one of the main reasons I persisted with the 370Z springs.
Otherwise, if you really want a track setup, it's coilovers all the way.
#3
06-24-2009, 03:58 PM
Registered User
I found this on the net on a different site:
"I don't like progressive springs. With a good damper, there is no need for them. Like others have said, they're soft under small displacements and get stiffer as the spring compresses. They will make the ride more comfortable, but matching a damper to them is hard, so the damper will only be effective during part of the suspension travel. Usually it will have to be soft, so it doesn't overdamp the lower displacement part of the spring, so then it's too soft for the high displacement rates of the spring.
Basically, they're good for street cars and people who aren't really going to drive their car. I wouldn't suggest them for any type of autox/track days/drifting/etc. People will say they run them and that they do alright, and if they think that, then imagine how much better it could be with a good spring. They also won't provide as good feedback as a good linear spring which is very important when you're trying to go fast."
"I don't like progressive springs. With a good damper, there is no need for them. Like others have said, they're soft under small displacements and get stiffer as the spring compresses. They will make the ride more comfortable, but matching a damper to them is hard, so the damper will only be effective during part of the suspension travel. Usually it will have to be soft, so it doesn't overdamp the lower displacement part of the spring, so then it's too soft for the high displacement rates of the spring.
Basically, they're good for street cars and people who aren't really going to drive their car. I wouldn't suggest them for any type of autox/track days/drifting/etc. People will say they run them and that they do alright, and if they think that, then imagine how much better it could be with a good spring. They also won't provide as good feedback as a good linear spring which is very important when you're trying to go fast."
#5
06-24-2009, 07:06 PM
Thanks, guys.
What are your thoughts on this statement?
From http://forums.vwvortex.com/zerothread?id=3302577
What are your thoughts on this statement?
A linear spring rate has one rate throughout its deflection. This means, if you have 300 pounds per inch spring rate, it takes 300 pounds to compress that spring one inch. A 300 pounds per inch linear spring, compressed three inches, would equal a load of 900 pounds. As you can see, one progressive spring can do the work of two or more linear springs. This is a big advantage in modern automotive chassis design, fulfilling the needs of today's discerning customers.
So why are linear springs still popular? Linear springs are readily available and inexpensive, allowing most race teams to use several different sets depending on track conditions. Linear springs are also easy to work with because the spring rate never changes, allowing for quick chassis set-up. This user friendly appeal is why so many chassis tuners are critical of progressive rate springs. These chassis tuners do not have the know-how to use progressive rate springs, or if they do have the knowledge, the manufacturer that they use is not capable of producing the design specified. Springs with a high linear rate would be used on a smooth racetrack, while on a rough or bumpy road course; you would use a softer spring rate. Since many racetracks have different road surfaces a suspension that is adaptive to changing road surfaces is desired. Progressive rate springs can offer a chassis tuner the means to achieve a compliant suspension in the rough and a tight suspension for high-speed turns.
So why are linear springs still popular? Linear springs are readily available and inexpensive, allowing most race teams to use several different sets depending on track conditions. Linear springs are also easy to work with because the spring rate never changes, allowing for quick chassis set-up. This user friendly appeal is why so many chassis tuners are critical of progressive rate springs. These chassis tuners do not have the know-how to use progressive rate springs, or if they do have the knowledge, the manufacturer that they use is not capable of producing the design specified. Springs with a high linear rate would be used on a smooth racetrack, while on a rough or bumpy road course; you would use a softer spring rate. Since many racetracks have different road surfaces a suspension that is adaptive to changing road surfaces is desired. Progressive rate springs can offer a chassis tuner the means to achieve a compliant suspension in the rough and a tight suspension for high-speed turns.
#6
06-24-2009, 07:42 PM
^sounds like a marketing dept statement. 
They make it sound like you go from 300 then bang you're at 900.
That's not the case.
The rate increases on a linear line (gradually)
If a progressive rate spring has a rate at 200lbs and a second rate of 400lbs.
Which do you think would compress 1st.
The 1st stage will compress until it gets to 400 ...if it doesn't reach 100% 1st.
....Also they don't account for rebound on the other side.
When I had Eibachs I could feel the 1st stage collapsing into the 2nd.
They make it sound like you go from 300 then bang you're at 900.
That's not the case.
The rate increases on a linear line (gradually)
If a progressive rate spring has a rate at 200lbs and a second rate of 400lbs.
Which do you think would compress 1st.
The 1st stage will compress until it gets to 400 ...if it doesn't reach 100% 1st.
....Also they don't account for rebound on the other side.
When I had Eibachs I could feel the 1st stage collapsing into the 2nd.
#7
06-25-2009, 01:41 PM
LOL. Figures.
So i guess i need to offload these Eibach's and get a decent street/track coilover set instead. I guess there was a reason i could never get the Eibach's installed (lost a nut, torque wrench went bad, couldn't budge a nut, jack lost pressure, etc...) -- it's almost like someone didn't want me to install them at all!
Forgive me for asking, how's the 370 springs working out for you?
So i guess i need to offload these Eibach's and get a decent street/track coilover set instead. I guess there was a reason i could never get the Eibach's installed (lost a nut, torque wrench went bad, couldn't budge a nut, jack lost pressure, etc...) -- it's almost like someone didn't want me to install them at all!
Forgive me for asking, how's the 370 springs working out for you?
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