Sadly the Eibach does not come with endlinks. I mean I'm sure I can use my old ones but the stress of a bigger, stronger bar concerns me due to the age of the endlinks.

Thanks for the info on the Saner bar.

 

The endlinks will be fine if they're in good order. Which they may or may not be - usually the issue is corrosion on the threads and then the act of taking them off breaks them. I'd recommend using some pb blaster a couple days before, then putting anti-seize on the threads to lubricate them before you go to take them off. They'll most likely be fine then. If they do end up being bad you can just get them off and take off the sway bar and run with no sway bar driving very carefully while you order new ones.

If you have to use any force to get the endlink into a hole, then you have preload, which could be fixed by having adjustable endlinks. They did design the eibach bar for stock endlinks so you'll probably only have a little preload, which you won't even notice on the street. I don't have this bar but eibach said there shouldn't be much preload.

BTW stock is 8 lbs and eibach is 10.6 lbs in weight. Dunno about whiteline.

 

I heard the Nuespeed bar is about as stiff as the Eiback, but even a bit lighter. That's what I was thinking about going with. I think the saner is in the 30# range.

 

There are lots of different assumptions and quoted spring rates here and in other threads; as always your mileage will vary. Let me just point folks to two other relevant threads:
https://www.s2ki.com/forums/index.php?showtopic=822700 (Eibach swayabr review)
https://www.s2ki.com/forums/index.php?showtopic=818884 (my OE spring & swaybar analysis)

Also I think it's worth emphasizing that for the bar thicknesses we're talking about (an inch or more), a hollow bar is just a better solution. Remember, the stiffness depends on the FOURTH power of diameter, so almost all the stiffness is being provided by the outermost few mm of bar material; the rest is basically dead weight.

For example, the bar material from the centerline out to half the bar's radius contributes 25% of the bar's weight (0.5^2), but only 6.25% of the bar's stiffness (0.5^4). So a 32mm bar with 8mm wall thickness will be 94% as stiff but weigh 25% less. (This neglects the lever arms, but they are usually hollowed as well.)

Alternatively, you can get the same rate as the 32mm solid bar by, for example, using a hollow 34.4mm bar with 5mm walls, and the hollow bar would weigh 43% less! (Again neglecting the arms.)

So a hollow bar can save a surprising amount of weight, and there's really no concern about durability. They're all made of "spring steel" which is extremely tough, and the S2000 has unusually large bars to begin with. Here in SoCal, I joke that when the big one hits, the only thing left will be a pile of S2000 swaybars.

 

Good info. Thanks!

 

Spring rate testing and calculations vary. Your link gives 300 lb/in for stock. The 214 I quoted was directly from Eibach, so for purposes of comparing Eibach to stock, you should use 214 compared to the numbers I gave above so as to compare apples to apples.

Just FYI for those reading the thread.

Good link though

 

Regarding stiffness this is incorrect. As I posted earlier stiffness is RADIUS to the 4th power.

 

You're arguing semantics. Both are correct. Sure if you use diameter the equation has an extra 1/16 in it, but since radius and diameter are linearly proportional you could say that it depends on the 4th power of either one.

 

The relationship between radius and diameter is constant. Constants don't matter when you are talking about proportionality.

If you want to calculate the absolute stiffness instead of relative stiffness, then the distinction between radius and diameter is important, but there are several other factors you also have to include (length, shear modulus, moment arm length...)

 

If you are in the process of comparing sway bars, anything to the 4th power will yield an exponential difference. Using diameter which is incorrect will only increase the margin of error.