Stock Spring Rate SC300 SC400
03-18-09, 04:58 PM
#1
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Stock Spring Rate SC300 SC400
I've been digging through the forum, I can't any concrete figures other than what someone had posted:
Considering that the Tanabe NF210 shown below claims that they don't go any higher then 5% of the original spring rates, the figure above is fairly close. So I'll list that as the stock figure until otherwise shown different. SC300 is thought to be slightly softer.
SC300:
Front :
Rear : ??
SC400:
Front: 357lb/in
Rear: 182lb/in
Other Spring Rates:
Tanabe NF210:
Front : 386lb/in
Rear : 184lb/in
JZA80 (US)
Front: 430lb/ft
Rear: 219lb/ft
I've only found stock spring rates published in one spot for a 92 SC400 - 357lb F and 182lb R.
SC300:
Front :
Rear : ??
SC400:
Front: 357lb/in
Rear: 182lb/in
Other Spring Rates:
Tanabe NF210:
Front : 386lb/in
Rear : 184lb/in
JZA80 (US)
Front: 430lb/ft
Rear: 219lb/ft
Last edited by DrLex; 03-23-09 at 03:25 PM.
07-15-10, 06:53 PM
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Actually Tanabe claims the NF210 is 10% or less firmer than the original suspension in the SC300.
If we take 10% as the maximum increase based on these numbers provided by Tanabe for the NF210
F: 386.4 lb/in
R: 184.8 lb/in
Then the stock SC300 spring rates should be no more than:
F: 347.76 lb/in
R: 166.32 lb/in
I'd still like to get a confirmation on these numbers though.
If we take 10% as the maximum increase based on these numbers provided by Tanabe for the NF210
F: 386.4 lb/in
R: 184.8 lb/in
Then the stock SC300 spring rates should be no more than:
F: 347.76 lb/in
R: 166.32 lb/in
I'd still like to get a confirmation on these numbers though.
07-15-10, 07:29 PM
#3
Figure it out!!!
Here's a formula, I think it's pretty accurate.
Spring Rate =
[G x Wire Diameter exp 4] / [8 x # of active coils x Coil Diameter exp 3]
G = Steel's torsion modulus (a constant)= 11,250,000
Wire Diameter = diameter of the wire used in the spring
exp = exponent
# active coils= coils on the spring that actually move when compressed/uncoil and aren't just the support coil
Avg. Coil Diamter = spring coil's diameter through the middle of the wire
Here's a formula, I think it's pretty accurate.
Spring Rate =
[G x Wire Diameter exp 4] / [8 x # of active coils x Coil Diameter exp 3]
G = Steel's torsion modulus (a constant)= 11,250,000
Wire Diameter = diameter of the wire used in the spring
exp = exponent
# active coils= coils on the spring that actually move when compressed/uncoil and aren't just the support coil
Avg. Coil Diamter = spring coil's diameter through the middle of the wire
07-18-10, 08:03 AM
#6
One problem I see with the equation is determining what steel was used to make the spring. The SC3/4 got updated springs at one point in its life, and we don't exactly know what changed as far as material goes. This equation works well for linear springs, but I suspect the springs may not be truly linear since OEM seems to allow looser tolerance than purebred racing brands.
Cheapest way to figure it out is to stack weights on it and measure the difference in height. Plot the curve to see the relationship between the two. Or if you have $1000 to spare, get a Longacre digital spring rater and it'll do it all for you.
Cheapest way to figure it out is to stack weights on it and measure the difference in height. Plot the curve to see the relationship between the two. Or if you have $1000 to spare, get a Longacre digital spring rater and it'll do it all for you.
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11-16-10, 08:40 AM
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Dr. Lex
"I've only found stock spring rates published in one spot for a 92 SC400 - 357lb F and 182lb R."
357 lbs/in = 6.37529433 kg / mm
182 lbs/in = 3.25015005 kg / mm
Since jpn products do kg/mm, so stock ride with jpn measurements is around 6kg F and 3kg R? That really soft since most coilovers springs goes around 16-20kg F and 8-12kg R.
"I've only found stock spring rates published in one spot for a 92 SC400 - 357lb F and 182lb R."
357 lbs/in = 6.37529433 kg / mm
182 lbs/in = 3.25015005 kg / mm
Since jpn products do kg/mm, so stock ride with jpn measurements is around 6kg F and 3kg R? That really soft since most coilovers springs goes around 16-20kg F and 8-12kg R.
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