When I first got my car, I wondered if the front springs were stock or aftermarket. It's a 3.8 auto. Any parking curb I come up to, the lower air-dam hits it straight on. Does anyone know any measurements to verify stock height? spring length, air-dam to ground, k-member to ground, etc...? I'm the 5th owner of the car, and so I guess anything's possible.
A guess is that they all sag. After all the car is what, 18-ish years old.
I was looking at springs the other day and i discovered that on partsamerica.com they list the specs of the TRW springs. Anyway this is what it says for 3.8 with A/C:
INSIDE DIA.= 3.5 in.; BAR DIA.= 0.64 in.; FREE HEIGHT= 15.38 in.; SPRING RATE= 415 Lbs./In.; LOAD= 1820 Lbs.; LOAD HEIGHT= 11 in.; END 1= SQUARE; END 2= TANGENTIAL
And here is the Sport:
INSIDE DIA.= 3.5 in.; BAR DIA.= 0.64 in.; FREE HEIGHT= 15.84 in.; SPRING RATE= 417 Lbs./In.; LOAD= 1695 Lbs.; LOAD HEIGHT= 11.75 in.; END 1= SQUARE; END 2= TANGENTIAL
And a Heavy Duty listing:
INSIDE DIA.= 3.5 in.; BAR DIA.= 0.656 in.; FREE HEIGHT= 15.13 in.; SPRING RATE= 462 Lbs./In.; LOAD= 1900 Lbs.; LOAD HEIGHT= 11 in.; END 1= SQUARE; END 2= TANGENTIAL
Looks like the height of the stock front springs installed is 11" Hope that helps
The front isn't very susceptible to sag.
???
What magic keeps the front springs from sagging? Especially on a front engine car that's carrying close to 60% of its weight up there?
I made the statement that the front doesn't sag because
#1 - I've never seen a T-bird/Cougar with a sagging front end, but many with sagging rears.
#2 - I've never read of anybody complaining about a sagging front end, but many complaining about sagging rear ends.
I created a spreadsheet that calculated the shear stress at static spring length.
The front came out to ~88ksi.
The rear came out to ~55 ksi.
Therefore, it would seem that the front would fatigue first. But...I haven’t calculated the fatigue numbers yet.