[Poboy]

Ok, maybe the Holy Grail to those who've actually wanted to know.
With Bampf's help, I calculated the spring rates front and rear on my base prelude, totally stock.
The equation I used was from "How to Make Your Car Handle" by Fred Puhn.
W^4 x G divided by 8ND^3

W is the diameter of the spring wire
G is 12,000,000, a constant for steel springs
N is the # of active coils + 1/2
D is the diameter of the coil, measured from middle of wire to middle of wire.

The answer was a bit surprising -
178lb/in up front
190lb/in in the rear

 

[lOOkatme]

man...did you solve the equation and get stock spring rates haha those are stiff springs!HAHAHA

 

[burban33]

Now can you do that for neuspeed race springs?

 

[lOOkatme]

actually...wouldn't it matter how the springs were made?? hot rolled vrs. cold rolled springs??

shot peened?? cold working...hot working...I mean everything. there could be a huge difference between two different steels the same size. even carbon content in steel makes a HUGE difference.

 

[Poboy]

actually...wouldn't it matter how the springs were made?? hot rolled vrs. cold rolled springs??

shot peened?? cold working...hot working...I mean everything. there could be a huge difference between two different steels the same size. even carbon content in steel makes a HUGE difference.

I'm no metallurgist, but I think fabrication of the steel may affect strength of the steel, whereas coil size, wire diameter, and # of active coils determine spring stiffness/resistance to movement. Or maybe there's just a standard way of fabricating springs and Puhn just gave that constant.

As for whether I could do it for Neuspeed springs, no I can't because I don't have any. If you do, though, just make the same measurements I did, assuming Neuspeed used steel. Then just plug in the #'s.

 

[element h22]

what are the spring rates for the SH???

 

[Asian-Stylin]

I highly doubt that the number you got up there is correct. If anything the front spring rate would be much stiffer than the rear due to the Prelude's beautiful F/R weight distribution of 63/37 Talk about nose heavy

For the SH the spring rate for the front is a little stiffer than the base model because of the ATTS unit weighing down the front more, but the back is identical.

 

[lOOkatme]

I highly doubt that the number you got up there is correct. If anything the front spring rate would be much stiffer than the rear due to the Prelude's beautiful F/R weight distribution of 63/37 Talk about nose heavy

For the SH the spring rate for the front is a little stiffer than the base model because of the ATTS unit weighing down the front more, but the back is identical.

50 lbs isn't too much more.

 

[Asian-Stylin]

50 lbs isn't too much more.

it isn't too much more but it still matters somewhat.

 

[Poboy]

I highly doubt that the number you got up there is correct.

That's your perogative of course , but I followed the measurements/equation provided by the book. I'll post up the #'s I got if you want to check my math - I won't take it personal , math was never my strong suit.

I agree that the result was surprising, but I'm guessing they made the rear stiffer than the front in order to combat a little bit of the understeer the car has. It would understeer even more with stiffer front than rear rates.

 

[Poboy]

elementH22, if you have an SH, you should be able to measure the appropriate spring measurements I gave without taking anything off (besides the wheel). If you don't have calipers (which I didn't) some of they measurements are a little difficult. For the wire diameter, take a piece of string and wrap it around (only til the end meets the string again). Mark the string (or hold it) where it meets. Measure the length of string. That gives you the circumference. Divide by pi=3.1416 and that'll give you diameter. I would guess that the measurement would be the same as mine - 7/16". The other difficult measurement is the coil diameter, D in the equation. I made a caliper with two slats of wood, drilled holes in them and ran a long bolt through them. Then I measured the diameter of the outside of the coil and subtracted the diameter of the wire, 7/16". You subtract the wire diameter because D is supposed to be from middle of wire to middle of wire.
Count the # of active coils (ones that move) and add 1/2 for the seat coils because they are partially active.

 

[myflysi]

i said cut the shit