[Speed Junkie]

Originally Posted by mad-ass

You can adjust body roll(specifically inertia of body roll)with stiffer springs AND sway bars + lower center of gravity. So I hope that is not the only reason why you want to upgrade springs before you do sway bars(Do you have adjustable sway bars?).

I have stock S13 sway bars up front and aftermarket rear bar (whiteline I think. It has been a while). I was going to use an s14 front bar but I think I read x months ago that the bolt pattern wasn't the same or something. Either way my issue with roll is entirely caused by the roll center being so far from the CoG (large roll couple/moment).

Originally Posted by mad-ass

You know better not to compare McPherson to double wish bone

I know. That's why I mentioned exactly that on my previous post. And why I mentioned wheel rates. And by the way the wheel rate is a question of leverage, not dampening.

Originally Posted by mad-ass

If your end goal of this thread is to lessen your body roll...

My end goal was to figure out whether swift springs were worth $300+ of improvement. the question of roll was completely secondary. In fact, my plan was to keep the same 8/6 spring rate depending on how much the car rolled with knuckles.

Originally Posted by mad-ass

I would highly suggest you get into adjustable sway bars first before you even mess with anything on coilovers.

Like I said, I have aftermarket rears which drastically change the handling balance towards less understeer. the car is actually fairly mild and understeer slightly during steady state limit. So not sure if I want to get a larger front bar. The oem bars are pretty large anyways. So again, its a roll center thing before it is anything else.

Originally Posted by mad-ass

Yes stiffer springs does help with body roll, but that also comes with harsh ride going over bumps and uneven surfaces. and you even mentioned your primary focus of this car is not track racing, yet if your heart still desire to try out the Swift/Eibach springs, I would recommend that you buy them USED if at all possible.

Just need to fix the roll center, then we will see where we stand.

Originally Posted by mad-ass

I'll quote my self, "We still need to talk about actual spring rates and how they should be calculated to be used on a car based on ride height, weight and desired suspension travel." Yet making another full circle of the spring topic and why I think it's important to talk about spring rates to better tune the car for what you want to improve. But how a car should handle is up to the driver and what the purpose of it is. Since we are working with S-chassis here it'll be easy to tell what one may do with such car.
But what do I know, I just roll with Tein S-Tech lowering springs with biggest adjustable sway bars available on my S14.

The Silvias (I have an S13 with S14 SR and mid mount) have a 52/48 weight distribution. AND they have a far greater wheel rate at the front McPhersons than the rear multi link. So that 8 kg spring is already effectively applying more force than an equivalent 8 kg spring in the rear would. Except it's 6 in the rear lol. So that's a pretty rough ideal roll resistance distribution and tends to be pretty common for a variety of cars. the question remains, how much is having such a large roll couple at the front affecting the roll rate distribution.

I would almost guestimate that because of that, the front roll rate is actually lower than the rear 6kg spring. Again, in roll.


So yeah, before all else, the front knuckles need to be replaced.