So i had a 06 xB that i just traded in for the 08. I had the Espelir springs from the old one and my brother got bored and threw them into the 08. LOOKS GREAT! Rides Good TO! Better ride in the 08 then the 06. ill get some pics up when i get a chance.

 

u mean to say that you used the espelirs from your xB1 and installed them to your xB2???

 

aren't the spring rates completely different from the 06-08 due to the increased weight on the 08?

 

Yes, xB1 springs on a 2008 could be dangerous, despite what some people on the forum say.

 

dangerous how so? i would think it would be better then cutting the springs. yeah i used 06 in a 08

 

Ok no expert here but are the springs not based on the vehicle weight in which case yeah its great now but what happens goin over railroad tracks or hitting that unavoidable pothole?? Jsut curious for the answer to this question and Situation!!

 

Cutting springs is not a great idea either, but the wrong springs are worse.

When the spring bottoms out (it will, it was designed for a 600lb lighter car), the spring rate increases exponentially. When that happens, the tire loses traction with almost no warning. If this happens in the rear, you spin.

Over bumps, etc, when the springs bottom out, it puts a big load on the perches or bump stops. Hit a big enough bump and parts bend.

This is all assuming the springs are the right length...if they are too short, over large bumps, the rear springs could FALL OUT. If they are too long, the coils could bind before you get full travel.

 

I am running Goldline Gen1 springs till Tein's come out.

The spring rate is 180 or so, 30+ than stock gen1 springs. On the Gen2, it is like running H-Techs on the Gen1, I did that also. H-Techs are 129 and stock is 148.

And FYI these springs will not fall out.l

 

I got a PM asking me about spring rates. This was my response:

Handling-generally, higher is better because the car does not roll as much. The more it rolls, the less camber the tires have and the less grip they generate. This is only true up to a point. After that point, it is still good to have stiff springs because they make the handling more direct and predictable in a racing situation while giving up overall grip. The loss of grip is VERY pronounced when you start talking about poor conditions or a bumpy road. My Fiero is Race-Car stiff, and hitting a big bump while cornering makes the car skip sideways.

Comfort-generally, softer is better so the suspension takes more of the induced motion from bumps.

Shocks and struts-note that anything other than mild drop springs with a fairly mild rate will overpower the stock shocks and struts. This will lead to much faster wear and even that bounciness you sometimes see in extreme cases.

Spring rate (the number)-Spring rate refers to how much weight is necessary to compress the spring a known distance. Examples: 2.6kg/mm means that if you have the spring sitting in a room, and you put a 26 kg weight on it, the spring will compress exactly 10mm which is 1cm. The actual spring rate does not mean anything EXCEPT for comparing various springs for the same car. This is because of wheel rate (see below) and how much each car weighs. For instance, the 450lb/in springs I have in the back of my Fiero are very stiff for it because the car only weighs 2700 lbs. If you put those springs on a 8000 lb truck, it would probably bottom them out just sitting in a driveway. Spring rate really means nothing when comparing different cars.

Wheel rate-It is very similar to spring rate, but much more difficult to measure. To understand wheel rate, think of an open household door, with a hinge on one side and a handle on the other. If you want to close the door, it could take your whole body weight...if you pushed 1" from the hinge. If you pushed out on the edge with the handle, it might only take a pound or two of effort. Now imagine that the door frame where the hinge connects is the car body, the door itself is the control arm, and the handle is the tire. Pushing on the door is equivalent to what a spring does in a car. The further the spring is from the wheel, the lower the wheel rate, which is usually expressed as a percentage of spring rate.

Front/Rear balance-As I said, an increased spring rate, after a certain point, leads to a loss of grip. This is true (and very important) if you are only changing the front or the rear, or changing them both but to a different degree. The stiffer you make an end, the less grip it has. If you stiffen up the rear a bunch but don't screw with the front, the car will understeer(turn wheel but car keeps going straight) less, and will probably just oversteer (slide out/spin). Increasing the front but leaving the rear has the opposite effect.

Now, on to your question. What spring rate? Well, if you are lowering the car, you have to pick a stiffer spring to account for the reduced suspension travel (remember the weight on a spring? If the spring can only compress 60mm (say the old spring had 90mm) until it hits the bump stops and it still carries the same weight, it has to be 50% stiffer or the load capacity of the vehicle will be reduced and the spring will be bottom out over big bumps or in hard corners.

This is a video of me autocrossing my Fiero before I tuned the suspension. The previous owner had springs that were too weak in the rear. The car understeers (softer=more grip, more rear grip=understeer) until the rear bottoms out, when it suddenly switches to rapid, dangerous oversteer (spring bottoms out=no spring at all, spring rate=infinite, grip=severely affected). Pay no attention to the guy talking about Fieros in the background, he really has not idea what he is talking about.

http://www.youtube.com/watch?v=ToC63DhSmhQ

Why shouldn't you use 1st gen springs on the 2nd gen? Well, it weighs 600 lbs more, the spring is not designed for the car and does not have the capacity to carry the weight before it bottoms out. This can affect handling while turning hard, as seen in the video above. Will you die if you put in gen 1 springs? Probably not. Will it EVER come into play while you drive around? Aside from hitting the bumpstops more often, no, not necessarily. Will the springs fall out? Almost certainly not. Will you car handle and carry weight like it would with properly designed springs? Nope.


P. S. You use this information at your own risk. If you take my advice and I turn out to be a wacko with no clue and your slams into a wall just pulling out of your driveway, it is not my problem. Or, more realistically, take responsibility for your own actions and just realize you were stupid for doing 125 mph on bald tires on ice, down a mountain...towing a trailer full of orphans, nuns, and kittens.

 

So wait, you know the spring rates for the gen 2 stock and for the Teins? Where did you get this info?

 

No, I assumed they are close to the tC.

 

Ohh. Unfortunately, the rear suspension is completely different from the tC, and there is no guarantee about the front being anywhere close. (see "wheel rate" section above)

Your springs are almost certainly not going to fall out, but it is not impossible. If someone installs a spring in the rear that it too short when it is unloaded, even if it is stiff enough for the car, it is possible that the rear suspension could extend far enough to take ALL load off of the spring AND open up a gap big enough to let the spring out. This would be like, during a JUMP, even a mild one. If your springs are not loose at full droop (car on jackstands, but no weight on the rear axle) you don't really have to worry about it.

 

the springs cant fall out. the shocks limit the axle travel.

 

I was saying if someone was dumb enough to install rear springs short enough that when the shocks are at full extension, the springs are loose, there is a risk they could come out...

It would be damn near impossible though, you would need several different things to happen.

1. You would have to install rear springs that are very stiff and short, so that the car can still ride on them, but the free length is short...could only be done with a very high spring rate. I don't think there are any gen1 xB rear springs that would fit this bill.

2. You would have to hit a big bump or go over some kind of jump.

3. The springs would have to slip their perches while the car is in the air.

I doubt we will ever see it happen...ever. It would take a "perfect storm" of dumbass.

Ohh, and just to be clear, GOLDLINE GEN 1 xB REAR SPRINGS INSTALLED INTO THE REAR OF THE 2008 WILL NOT FALL OUT IF INSTALLED CORRECTLY.

I didn't mean to step on your toes Randode, as much as I appreciate your massive contribution to the community; I am just not a fan of using first gen springs under the 2008 from a technical standpoint.

 

its cool dude.
Goldline's fit the rear perfectly, but Goldline went out of business, so there are no more to be purchased anyway.