hsk8te2006
15+ Year Contributor
- 182
- 1
- Jun 9, 2007
-
Ann Arbor,
Michigan
Hi Folks,
Before I dive in too far, let me give you my goals first:
I drive a '96 GST spyder. Future plans will include power increase of 300-350 hp (I hope), but for now she's just barely above stock running 14psi of boost.
What I'm looking to do is change my suspension to build a street car lowered by a max of 1-1.5 inches that will handle better than stock. I have never raced the car, but I am considering possibly trying some road racing or autoX this summer, but not sure yet. My primary goals are to just aim for awsome handling on the street, and a little less whel gap, but NOT become too harsh a ride (It's best if the girlfreind still feels comfortable in my car, ya know?)
My first question is regarding spring rate and suspension frequencies. I've heard that springs which would support a suspenson frequency fo roughly 1.8Hz front, and 2.0Hz rear should fit my needs, so:
1.) When folks talk about ferquencies (as above), is that referring to the damped or undamped frequency?
Now, on to shocks...
Anyway, so far I've learned that it's important that whatever shock I go with has low levels of high speed compression (HSC) damping so bumps in the road aren't too harsh.
I've also learned that for performance I generally want at least a decent amount of Low speed rebound (LSR) damping.
From the reading I've done, a Koni yellow would tend to fit this description, and is the definite choice for harder springs (450/350 for example).
However, cost is always a concern, so I'm also considering the tokico illumias. I've read that they actually have even less HSC than the Koni's (at least on their softest setting), however they tend of have lower LSR (at least at the comfortable HSC setting), and if I turn up the settings to get mroe LSR for a stiffer spring, I'll end up with too much HSC, so illuminas tend to mate better with softer springs only.
Truth be told, as far as springs go I am still debating between something low-drop and a softer/PROGRESSIVE spring rate (trying to minimze bump induced compression again) like a Eibach Pro-kit or H&R OE Sport, or a set of coilovers like a linear rated Ground Controil with a higher rate which would also allow me to raise the car back up to stock height in winter (not absoluitely necessary, but potentially useful).
Whichs leads me to the following so far unaswered important questions about different shock/soring set-ups for my '96 GS-T Spyder:
2) If I were to go with a softer spring (pro-kits for example), in order to get enough LSR from the illuminas, would I have to turn it up so high that the HSC would start to become harsh?
3) Would Koni yellows over-damp (in LSR) a softer spring, or would I just need to use a softer rebound setting?
4) If I combine Koni yellow with linear rated stiffer GC coilovers (450/350 for example), will the ride quality over bumps suffer anyway from the linear (and thus stiff-right-away) springs (instead of softer then stiffer if they were progressive) regardless of the low HSC damping of the Koni yellow?
5) What is the effect of High Speed Rebound (HSR) damping (such as coming off a street bump) on comfort, and how do thse shocks perform in HSR?
Also a side note.. being that I have a spyder, even if the answer to question 4 above is no (the ride comfrt will still be comfortable with Koni yellows and hard springs), would I be better served to get softer spring rates and add a stiffer rear swar bar? (or both?)
Thank you everyone for whatever input you can offer!
Jonathan
Before I dive in too far, let me give you my goals first:
I drive a '96 GST spyder. Future plans will include power increase of 300-350 hp (I hope), but for now she's just barely above stock running 14psi of boost.
What I'm looking to do is change my suspension to build a street car lowered by a max of 1-1.5 inches that will handle better than stock. I have never raced the car, but I am considering possibly trying some road racing or autoX this summer, but not sure yet. My primary goals are to just aim for awsome handling on the street, and a little less whel gap, but NOT become too harsh a ride (It's best if the girlfreind still feels comfortable in my car, ya know?)
My first question is regarding spring rate and suspension frequencies. I've heard that springs which would support a suspenson frequency fo roughly 1.8Hz front, and 2.0Hz rear should fit my needs, so:
1.) When folks talk about ferquencies (as above), is that referring to the damped or undamped frequency?
Now, on to shocks...
Anyway, so far I've learned that it's important that whatever shock I go with has low levels of high speed compression (HSC) damping so bumps in the road aren't too harsh.
I've also learned that for performance I generally want at least a decent amount of Low speed rebound (LSR) damping.
From the reading I've done, a Koni yellow would tend to fit this description, and is the definite choice for harder springs (450/350 for example).
However, cost is always a concern, so I'm also considering the tokico illumias. I've read that they actually have even less HSC than the Koni's (at least on their softest setting), however they tend of have lower LSR (at least at the comfortable HSC setting), and if I turn up the settings to get mroe LSR for a stiffer spring, I'll end up with too much HSC, so illuminas tend to mate better with softer springs only.
Truth be told, as far as springs go I am still debating between something low-drop and a softer/PROGRESSIVE spring rate (trying to minimze bump induced compression again) like a Eibach Pro-kit or H&R OE Sport, or a set of coilovers like a linear rated Ground Controil with a higher rate which would also allow me to raise the car back up to stock height in winter (not absoluitely necessary, but potentially useful).
Whichs leads me to the following so far unaswered important questions about different shock/soring set-ups for my '96 GS-T Spyder:
2) If I were to go with a softer spring (pro-kits for example), in order to get enough LSR from the illuminas, would I have to turn it up so high that the HSC would start to become harsh?
3) Would Koni yellows over-damp (in LSR) a softer spring, or would I just need to use a softer rebound setting?
4) If I combine Koni yellow with linear rated stiffer GC coilovers (450/350 for example), will the ride quality over bumps suffer anyway from the linear (and thus stiff-right-away) springs (instead of softer then stiffer if they were progressive) regardless of the low HSC damping of the Koni yellow?
5) What is the effect of High Speed Rebound (HSR) damping (such as coming off a street bump) on comfort, and how do thse shocks perform in HSR?
Also a side note.. being that I have a spyder, even if the answer to question 4 above is no (the ride comfrt will still be comfortable with Koni yellows and hard springs), would I be better served to get softer spring rates and add a stiffer rear swar bar? (or both?)
Thank you everyone for whatever input you can offer!
Jonathan
