Originally posted by bahearn Judging from past experience and comments, something like 250/200 or 225/175 would be a more reasonable compromise.
The problem is that those rates will not work on the car without using custome strut housings. You will need a 10 inch spring which will require you to run at stock height. Even then you may need to weld on a custum perch to get the car at that height. If you use a 8 inch spring it will likely coil bind before you run out of travel due to the spring being to soft and not having enough travel in the spring. I have been down this road. If you want a better ride get the Motivational struts for the shortened springs. This is a proven setup that will ride well. GC stetups need the stiffer front spring to prevent bottoming out and coil bind (two different issues not to be confused).
Re: Gnd Control coilover spring rate opinions? (long)
Quote:
Originally posted by Greg200SE-R Hey all,
I have a 98 200SX SE-R and am looking at the Ground Control coilovers for KYB AGXs. I currently have Progress drop springs at 180/150 and this is too soft. For the GCs, keeping ride comfort in mind, what are some good spring rates for a car that sees no track use? But, handling is important because lots of my performance driving is done on narrow windy mountain roads with a variety of sharp/sweeping 25 - 60mph corners. Potholes aren't uncommon. And, understeer is the main problem in my car's handling. Considering this, what would you guys suggest as spring rates? I heard 300fr/200rear was a good compromise between track/street. Should the rear be 100lbs lower than the fronts? I have a friend with a B15 Sentra riding on Tein SS coilovers at 336/280. I know that the B15 is about 1000 pounds heavier than my 200SX, but his Sentra's ride is PERFECT. NOrmally I see the B14 200SX spring rates suggested as roughly 50lbs less than the B15 Sentra's. So going by these suggestions, would 275/225 give me a similar ride? Compared to 300/200 though, 275/225 would bring the rear rates only 50lbs less than the front and increase the rear's stiffness relative to the front. To reduce understeer, would this help? Or do our cars perform better with a 100lb difference between f/r? anyone know through experience how all of these settings would work as far as performance and ride quality? I am also thinking of removing my front stock anti-roll bar to further help the understeer problem. Should I consider different spring rates in front to compensate? Thanks in advance.
Get some 300/250. The ride is not bad. 200 is to soft in the back. I like the ride of my 300/300 better then the ride of my 300/200. Also, the B15 is at most about 200lbs heavier. Really more like 100-150. I would suggest the 300/300 combo. Much better balance. Stiffening the rear does not effect the ride as greatly as you would think. I went from 200 to 300 in back and it was barely any harsher. It is better when you hit a bigger bump.
__________________
92 240SX Project Car.
Last edited by 98sr20ve : Apr 10th, 2003 at 10:40 AM.
Originally posted by 98sr20ve The problem is that those rates will not work on the car without using custome strut housings. You will need a 10 inch spring which will require you to run at stock height. Even then you may need to weld on a custum perch to get the car at that height. If you use a 8 inch spring it will likely coil bind before you run out of travel due to the spring being to soft and not having enough travel in the spring. I have been down this road. If you want a better ride get the Motivational struts for the shortened springs. This is a proven setup that will ride well. GC stetups need the stiffer front spring to prevent bottoming out and coil bind (two different issues not to be confused).
Just the man I was looking for....
GCs offer roughly a 2inch (?) adjustment range. Since you have been downthis road maybe you can share your past experience (although it will be based on a B14 and I am a B13 person).
Except trial and error, is there any semi-scientific way to calculate exactly (or very close to) what the ride height will be based on spring selection?
For example, you say that the solution psoted above will require riding at stock height. Is this with the perches fully low or what?
There should be some series of formulas that take into account the dimensions of the strut, spring characteristics, etc. and result in a nice little decision like:
"with stock struts get 10inch 250lbs springs to have a ride height from STOCK to STOCK-2inches".
And then we may account for shrtened struts, GC plates, Moti/SHighSpeed rear mounts and so on...
Chris
PS. I have also been down this road before (when I did not know better and had the 7" GCs fully up in order to get near stock ride height... naturally, it coilbinded -as deduced later- and I got rid of them since the ride was crappy!!!).
Now, I assume that the lightest setting on the bars corresponds to the "diameter" stiffness. I have no way of knowing what the other 2 positions mean in terms of stiffnes. A similar product from Whiteline in Australia has the 3 positions "spaced" by 2mm of bar thickness, so their 18mm rear adjustable can act as a 18-20-22mm bar. If this is the same with Progress, then we are looking at a sway bar that will be 100% stiffer than stock up front and 170% stiffer on the rear.
the way you can figure out the increased stiffness of the sway bar at different settings is, you have to know how long the "levers" are is from pivot point to enlink point. so if you have a progress bar with 3 attachment points, to find out how much stiffer one hole is over another is to first:
-find total stiffness of the progress bar over the stock bar (the last hole in the progress bar).
then you need a way of measuring the distance between centerline of the pivot on the car and the centerline of the last hole in the progress bar, lets say 200mm (*arbitrary number, in no way indicitive of the accual distace*).
-now lets say you move the endlink to the second (middle) hole. and say the distance is 180mm (*see disclaimer above*)from the pivot on the car. you would then divide 180mm by 200mm and the result would be 0.9 which would mean that the 200mm hole is 90% of the stiffness as the hole you just put the endlink in, or you just made the sway bar 10% stiffer than it was.
-if it was to go in to the inner most hole and that was 160mm the resulting change (from the equation above) would be that the bar in this configuration is 20% stiffer than the furthest most hole.
__________________
cranium
When push comes to shove, my car is uglier than yours.:)
Originally posted by hpro123 Just the man I was looking for....
GCs offer roughly a 2inch (?) adjustment range. Since you have been downthis road maybe you can share your past experience (although it will be based on a B14 and I am a B13 person).
Except trial and error, is there any semi-scientific way to calculate exactly (or very close to) what the ride height will be based on spring selection?
For example, you say that the solution psoted above will require riding at stock height. Is this with the perches fully low or what?
There should be some series of formulas that take into account the dimensions of the strut, spring characteristics, etc. and result in a nice little decision like:
"with stock struts get 10inch 250lbs springs to have a ride height from STOCK to STOCK-2inches".
And then we may account for shrtened struts, GC plates, Moti/SHighSpeed rear mounts and so on...
Chris
PS. I have also been down this road before (when I did not know better and had the 7" GCs fully up in order to get near stock ride height... naturally, it coilbinded -as deduced later- and I got rid of them since the ride was crappy!!!).
Yes and no. A 300 lbs spring will compress 1 inch with a 300 lbs load placed on it. My car after getting corner balanced had these weights Driver F=850, Passenger F=816, Driver R=524, Passenger R=501. Of you look up the specs on the groundcontrol site for that 300 lbs 7 inch spring you can see that it will compress only 4.4 inch’s before coil bind. An 850 lbs load would compress that spring about (at a 1:1 ratio) 2.83 inches. Leaving you a grand total of 1.57 inch’s of travel before that spring coil binds. Ever wonder why most GC kits ride like crap . That is the reason (especially if the car is set to high). An 8-inch spring can be compressed 4.89 inch’s so it is not much of an improvement in many ways. An 8 inch 250 lbs spring has 4.99 inches of travel before coil bind BUT it will be 3.4 inches into its travel already leaving you with only 1.6 inches of travel left. That combined with the reduced spring rate will like still cause the car to bottom out or coil bind (just based on my 8inch 300lbs spring experience on my car). You can get all this info from spring section of the GC website. It is possible that a 10-inch 250lbs spring would work but it would be at the bottom of the spring perch and may cause the car to be to high. You would need to try it to find out. At least with a 10 inch spring you don’t run out of spring travel until you compress it 6.38 inch’s. This is why I have a 10-inch 300lbs spring on my car. With the Koni struts I could weld a custom perch on a little lower. My 10-inch spring up front gives me 5.95 inches of travel before coil binding. Luxury city.
Put the Tein SS coilovers on today. First impression was "WOW, this is 300 times better than Sportlines." I even drove on one really nasty bumpy road. I was impressed with the travel and the rates(336F, 280R) even in the rough stuff. This good ride even comes when I have a feeling that I may have them set too low. If I get a chance tommorow I am going to measure how much suspension travel I have. The rate did get rid of some of the understeer, thats for sure. I didnt really drive all that hard being that I am still on 175/70/13 all seasons and I was on public roads. I hope to give them a good shake down soon. Maybe I a just young and tollerant, but I didnt feel that the rates are too harsh.
__________________
Patrick Scott
Yeah, thats a roll cage in there.
I shall call him...Mini-Me
I'm 37 and my next setup for my B14 daily driver is going to be even stiffer then my current 300/300. It's not that stiff with proper damping. My wife even likes it. Travel is the issue not the 300 lbs springs.
Linear Mode
