Spring Rate Database?
01-02-2006, 05:55 AM
#24
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So am I right to say some of these springs with progressive rates listed only have the peak characteristics posted? So would it be safe to go with a linear setup if you want true numbers?
01-09-2006, 05:12 AM
#25
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would it be possible to use the T2 nismo springs with Tokico D2 dampers? What counter reccemendations are there?? Is the spring rate too high to handle the springs? Is there a way to get them custom valved?
I'm trying to find a decent track spring, but beside the nismo T2 springs, there is nothing, everything is progressive/street oriented and either too soft or too high, barely better than stock revised suspension. Why isn't there anything linear in the 500 range with a 1" drop??????
I'm trying to find a decent track spring, but beside the nismo T2 springs, there is nothing, everything is progressive/street oriented and either too soft or too high, barely better than stock revised suspension. Why isn't there anything linear in the 500 range with a 1" drop??????
Last edited by ugylymofo; 01-09-2006 at 05:16 AM.
01-09-2006, 05:22 PM
#26
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because no one makes struts that can handle that high of a spring rate... and if they did and you bought both then you might as well buy some coilovers... thats my recommendation.... buy coilovers... the tein basics are affordable and have 504 spring rate and you can drop as much or as little as you want.
01-10-2006, 05:26 AM
#27
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I run T2 with S/A Koni's Spotrs and they are fine just have to run at full stiff or near that. There is also a T2 racer who ran last year with S/A Konis.
Just wanted to add to te discussion.
Just wanted to add to te discussion.
01-28-2008, 12:06 PM
#32
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I measured the FRONT lower arm length @14" and the spring closest point [length along arm from frame] @11" this results in a spring to wheel correction of 0.61 so a spring speced at 300 pounds per inch would really expert 300 x 0.61= 183 pounds per wheel inch. If you jacked up the wheel by 1" it would require 183 more pounds than static...........discounting sway bars this means the front roll rate stiffness is ~~183 lbs per inch.
So a 20% stiffer spring only truely increases FRONT roll stiffness by 20 x 0.61 or 12.2%.
Worse add in the sway bar and a 20% stiffer spring may only add 1/2 -3/4 so 6-9%.
So a 20% stiffer spring only truely increases FRONT roll stiffness by 20 x 0.61 or 12.2%.
Worse add in the sway bar and a 20% stiffer spring may only add 1/2 -3/4 so 6-9%.
Last edited by Q45tech; 01-28-2008 at 12:08 PM.
01-30-2008, 09:48 AM
#33
Originally Posted by Q45tech
I measured the FRONT lower arm length @14" and the spring closest point [length along arm from frame] @11" this results in a spring to wheel correction of 0.61 so a spring speced at 300 pounds per inch would really expert 300 x 0.61= 183 pounds per wheel inch. If you jacked up the wheel by 1" it would require 183 more pounds than static...........discounting sway bars this means the front roll rate stiffness is ~~183 lbs per inch.
So a 20% stiffer spring only truely increases FRONT roll stiffness by 20 x 0.61 or 12.2%.
Worse add in the sway bar and a 20% stiffer spring may only add 1/2 -3/4 so 6-9%.
So a 20% stiffer spring only truely increases FRONT roll stiffness by 20 x 0.61 or 12.2%.
Worse add in the sway bar and a 20% stiffer spring may only add 1/2 -3/4 so 6-9%.
Originally Posted by hippie
In response to some posting above here are some numbers that I measured with my Z.
The front end gains 1deg of camber per in. of bump....... .8 lower equals .8 deg more neg camber.......LS-1.8 RS-2 based on average static numbers
More camber will produce toe in, BUT lowering the car will produce toe out....about 1/32 out per side per in. of drop.....up to 1/16 out per in. per side with more travel. The rear gains toe in with bump....starts at 1/16 per in. and goes to 3/32.
The motion rates (as I measured and averaged them over full travel) are.... .688 F and .649 R (measured at center of spring)
theses rates with #690 springs equal at the wheel....326.6F 290.6R
stock revised...........146.3F 189.9R
The one thing that is easy to miss is that the Z relies on the front bump stops for spring rate. It is common for manufacturers to use soft springs for ride comfort along with a progressive bump stop that engages early to control big susp. movement. I haven't rated mine YET.
John, Your guestimates are close to what I figured when I did natural frequency calculations for my car. F w/850=2.3Hz Rw/600=2.1Hz
In reality the rear is too stiff (read SCARY) for a typical auto-x lot. It would proably be close for road course use.
mike
The front end gains 1deg of camber per in. of bump....... .8 lower equals .8 deg more neg camber.......LS-1.8 RS-2 based on average static numbers
More camber will produce toe in, BUT lowering the car will produce toe out....about 1/32 out per side per in. of drop.....up to 1/16 out per in. per side with more travel. The rear gains toe in with bump....starts at 1/16 per in. and goes to 3/32.
The motion rates (as I measured and averaged them over full travel) are.... .688 F and .649 R (measured at center of spring)
theses rates with #690 springs equal at the wheel....326.6F 290.6R
stock revised...........146.3F 189.9R
The one thing that is easy to miss is that the Z relies on the front bump stops for spring rate. It is common for manufacturers to use soft springs for ride comfort along with a progressive bump stop that engages early to control big susp. movement. I haven't rated mine YET.
John, Your guestimates are close to what I figured when I did natural frequency calculations for my car. F w/850=2.3Hz Rw/600=2.1Hz
In reality the rear is too stiff (read SCARY) for a typical auto-x lot. It would proably be close for road course use.
mike
07-27-2008, 06:18 AM
#36
Originally Posted by laze1
are stock springs Linear?
Oem springs 350Z’s 2003/2004
Front:314 Rear:342
Oem springs 350Z 2004.5/2005 (found 04 car's that have the revised susp.)
Front:314 Rear:427
Oem springs 350Z’s 2003/2004
Front:314 Rear:342
Oem springs 350Z 2004.5/2005 (found 04 car's that have the revised susp.)
Front:314 Rear:427
Front springs are tapered, fatter at the top where they narrow towards the bottom. This technically makes them slightly progressive, as would any spring in the front that uses the oem upper mount diameter and also uses the lower shock seat (stamped steel or add on's like Koni or Bilstein lower front spring seats). Exception is Bilstein Pss9, it uses the oem upper shock mount in the front, but uses a aluminum adaptor at the top on a linear spring.
So, yes the oem front springs are slightly progressive, but the min and max rates are too close to have any meaningfull impact on any type of performance driving, be it street or track. And most important of all, NO COIL BINDING occurs anywhere in travel as to suddenly change spring rate.
07-29-2008, 08:21 AM
#37
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Calculating is great but actually measuring the roll stiffness is better in that you get everything from tire to body flex included in number.
Tires actually lower stiffness rate [2 springs in series] by 5-9% depending on design and inflation. Add in the wheel, the hub, the spring seats and any rubber and the stiff springs become 7-18% softer after correcting for motion ratio.
Tires actually lower stiffness rate [2 springs in series] by 5-9% depending on design and inflation. Add in the wheel, the hub, the spring seats and any rubber and the stiff springs become 7-18% softer after correcting for motion ratio.
08-05-2008, 10:42 AM
#38
anyone know the spring rates on the Eibach sportline springs? i see specs on the pro kit but not the sport line ones...........
I am on the Nismo S-Tune Suspension and would like a more aggressive drop so i was thinking of swapping out the Nismo springs for the Eibachs but keeping the Nismo shocks? Would this be a bad idea?
only thing i can tell so far are both springs are progressive.......
any input would be much appreciated.
thanks
I am on the Nismo S-Tune Suspension and would like a more aggressive drop so i was thinking of swapping out the Nismo springs for the Eibachs but keeping the Nismo shocks? Would this be a bad idea?
only thing i can tell so far are both springs are progressive.......
any input would be much appreciated.
thanks
08-06-2008, 07:47 AM
#40
Originally Posted by LAKERSFAN
anyone know the spring rates on the Eibach sportline springs? i see specs on the pro kit but not the sport line ones...........
I am on the Nismo S-Tune Suspension and would like a more aggressive drop so i was thinking of swapping out the Nismo springs for the Eibachs but keeping the Nismo shocks? Would this be a bad idea?
only thing i can tell so far are both springs are progressive.......
any input would be much appreciated.
thanks
I am on the Nismo S-Tune Suspension and would like a more aggressive drop so i was thinking of swapping out the Nismo springs for the Eibachs but keeping the Nismo shocks? Would this be a bad idea?
only thing i can tell so far are both springs are progressive.......
any input would be much appreciated.
thanks
So,...
This is what you have now.
Nismo S-tune (twin tube construction, uses progressive springs)
350Z .8"/.8" drop
Spring rates 448/504
This is what you thinking about swapping onto the Nismo shocks.
Eibach 350Z sportline progressive springs 1.2"/1.2"
F: 239/400 R: 257/435
Should work, peak rates are within 50 and 70 pounds. That and the change to a wide rate spread in the front means the change will not be a plus on the performance side since the front Nismo springs are only mildly progressive. Also, I don't like seeing people go lower on less spring rate since the oem bumpstops are rather unforgiving. I would take the simple measure of finding a shop that know's how to measure travel and can install different bumpstops. Or you could just roll the dice like everyone else does.