Yet another spring rate thread
#1
Yet another spring rate thread
So, for a subject that has been practically beat to death, it's hard to gather information for what I need. I've got a set of Koni sports, GC collars and FM top hats in the rear. I need springs, but my budget is calling for something like QA1's. Some autocross and somewhat daily driven, but I drive it hard on the street when I do. The QA1's only come in 50lb incriments, so I was thinking of 400/300 to be a good midrange, but I might lean towards 450/300. I do favor oversteer to understeer. I'll probably run a RB solid front sway. I don't claim to fully understand all of this, but I have a general idea of lower BF = smoother ride and higher FRC = more understeer. Anyone care to throw in your 2 cents?
On the FCMS site here are the specs using the 19mm/12mm solid sways.
400/300
BF - 1.09
Roll Stiff - 2,295
FRC - 48.8%
450/300
BF - 1.03
Roll Stiff - 2,411
FRC - 51.3%
On the FCMS site here are the specs using the 19mm/12mm solid sways.
400/300
BF - 1.09
Roll Stiff - 2,295
FRC - 48.8%
450/300
BF - 1.03
Roll Stiff - 2,411
FRC - 51.3%
Last edited by customstreetmachines; 09-23-2010 at 11:19 PM.
#8
yep yellows. so I'm getting the idea from many sources that rear rates really make the difference. I've heard of people loving a 450/250 setup, which brings the bounce frequency down, but really raises the front roll couple. I don't know in roll couple where the neutral line is between over and understeer. I'll be hitting the 250hp range soon, so that might cause a little oversteer of it's own. the opinions vary, so I'd like to know what you noticed (vs) stock with your setup?
#10
Boost Czar
iTrader: (62)
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,501
Total Cats: 4,080
my problem is turn in right now. It feel very neutral and I can stomp the gas around corners, but, when i want to turn the wheel fast and induce oversteer for a quick u-turn or something it just plows. this could be partly due to my lack of an alignment, but without my rear bar I really lost the turn-in response.
when I had FM springs and no rear bar I didn't notice this as much, so I think bringing the FRC back down a little should solve it still without being tail happy in other situations.
when I had FM springs and no rear bar I didn't notice this as much, so I think bringing the FRC back down a little should solve it still without being tail happy in other situations.
#11
my problem is turn in right now. It feel very neutral and I can stomp the gas around corners, but, when i want to turn the wheel fast and induce oversteer for a quick u-turn or something it just plows. this could be partly due to my lack of an alignment, but without my rear bar I really lost the turn-in response.
when I had FM springs and no rear bar I didn't notice this as much, so I think bringing the FRC back down a little should solve it still without being tail happy in other situations.
when I had FM springs and no rear bar I didn't notice this as much, so I think bringing the FRC back down a little should solve it still without being tail happy in other situations.
#12
Tour de Franzia
iTrader: (6)
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,085
Total Cats: 375
700/400
good valving and a couple clicks of adjustment in front and rear really made a HUGE difference.
RB front bar
FM rear bar
I wish I went 100lb higher front and rear. Well, I ordered 800/500 but someone received the wrong springs and I got to compromise and get my car on the track.
good valving and a couple clicks of adjustment in front and rear really made a HUGE difference.
RB front bar
FM rear bar
I wish I went 100lb higher front and rear. Well, I ordered 800/500 but someone received the wrong springs and I got to compromise and get my car on the track.
#15
my problem is turn in right now. It feel very neutral and I can stomp the gas around corners, but, when i want to turn the wheel fast and induce oversteer for a quick u-turn or something it just plows. this could be partly due to my lack of an alignment, but without my rear bar I really lost the turn-in response.
when I had FM springs and no rear bar I didn't notice this as much, so I think bringing the FRC back down a little should solve it still without being tail happy in other situations.
when I had FM springs and no rear bar I didn't notice this as much, so I think bringing the FRC back down a little should solve it still without being tail happy in other situations.
#16
from what I can gather on the fat cat calculator abs feedback I'm getting is that in a sense, FRC is neutral at 50%, which makes sense, bur driving conditions such as hard turn in, acceleration and other factors are hard to account for. I'm guessing this is why you guys running 700/400 and other high rates do better because you're less effected by these variables. I've come full circle to once again confuse myself.