Which springs will yield better handling in my GTA? Moog 5662's or 5664's? The exact spring rates for these are a somewhat of a mystery, but from what I've learned, the 5664's are about 750 lbs./in. and the 5662's are about 700 lbs./in. I'll be doing some light autocrossing in this car as well as tearing up some empty backroads. Which which front spring rate would you reccomend?

 

A light spring rate will give a soft ride but will compress easily in corners. A stiff spring rate will give a stiffer ride but won't compress as easy so the car won't dive as much in corners.

Cars like the Z28 and WS6 usually got the stiffer springs for better handling but also have a stiffer ride.

 

Thanks Stephen, both the 5662 and 5664 are quite stiff, and either would probably be an improvement over my worn-out originals. But would the 5664 be so stiff that it would negatively affect handling? Or is a stiffer spring always going to be better?

I'm not concerned with a comfortable ride, I just want it to handle really good.

 

Unless you are on really rough roads, the stiffer springs should be better than the softer ones. The stiffer the springs, the harder it is for the tires to maintain contact with the road surface if it's rough enough to cause the suspension to travel up and down too quickly/forcefully for the shocks to control it. That is part of the reason shocks are so important in the suspension set-up.
So, if you are going after handling, the springs won't matter as much as the shocks. Get some good shocks with or before your springs. I'm not talking about Monroes, or Gabriels, or junk like that. I'm talking about shocks made to work in a higher performance application. They are expensive (my KONIs, for example, were about $650). But, you have to pay if you want to play. You can do KONIs, Bilsteins, the higher end KYBs, or Tokicos if you are going with stock ride height.

 

I'll be running Tokico Illuminas with these springs. I think they should be able to control them.

 

Alright. Just wanted to make sure you considered shocks along with springs. Most people don't.
But, what I said still applies. If the roads are rough or have pot-holes, the stiffer springs will cause the suspension to be a little harder to control. They won't 'soak up' the irregularities as easily as softer springs. But, if the roads you are going to be out on aren't riddled with large rough spots or pot-holes, you'll most likely be better with the stiffer springs. Alot of the set-up has to do with what the driver likes as well.

 

Most of the roads around here are in really good shape. I can only think of one or two that would casue problems with some really stiff springs, and I'll rarely, if ever travel them in my car.

 

I'm glad that they've been repaving some of my favorite local roads. A few of them were getting pretty bad and the combination of the KONIs and the Pro-kit was too much for them. Made the kidneys hurt lol. Fresh paved roads are a blast in my car.

 

When you are talking about suspension you need to look at the complete group of parts as any one part will affect the rest of the system. So the front and rear need to be considered together. Chances are that either of those springs will be fine as long as the rear is balanced.

 

I know i'm late on this thread but..
You have 5662's stock. You have the rates correct.
The 5664's are the stock spring for convertibles (heavier car), and S15 trucks. I have them and I REALLY like them.
You won't be losing your fillings or anything. Add nice poly bushings, good shocks and good sway bars and you're laughing. With SFC's that car will feel like it's on rails.

 

Anyone else have any more opinions regarding the 5662's vs 5664's? I'm pretty much set on the 5664's. I just want to be sure...

 

I have an aftermarket SS hood on my Camaro and decided for the 5664. The way I figure it...lightening the front end should effectively increase the spring rate a bit. That being said...I am going to pair the 5664's with Koni Yellows to help dampen the tougher springs.