Hey guys just trying to get some more information before I make my final decision. If someone can give me some insight, I have an 05 sedan looking to drop it a bit and I have read alot about people putting in 350z springs. Im just wonderin being that mines an 05 does it matter what year 350z springs I find and is it a simple drop in for installation or will other modifications need to be done? Thanks

 

Search button, tons of threads on this topic...

To answer your question why not combine 2 together...350z fronts n coupe rear.

 

Most people do the G/Z combo.
I dont recall how late of model you can use but 03-08 sounds about right.
There was a slight change to the rear on 04.5 to a higher spring rate.
Check out the stickies here and in the suspension forum, you will find all the info you need on this topic.

 

Just get full suspension off a 04.5 or newer 350Z and you'll be happy.

 

yeah the early z rear springs are too stiff... and as a result, easy to find. i'll swich to later z rears when i find a pair

 

^Actually, the newer Z rear springs have a "stiffer" spring rate. 427lb/in.

 

revised 350z ('05 onwards) had softer rears than previous years due to customer complaints about bumpy ride. was reduced by around 60lb/in. i thought it was worldwide, maybe its just for the australian market

 

I ran 350z h-techs on my 03 and 04 G35 coupe. Loved it...

 

That might be the case there.

Everything that ive ever seen on this topic states that half way through 2004 (2004.5) Nissan revised the rear springs due to complaints that the car was too bouncy. As a result they increased the spring rate. I have run both revised and unrevised and the revised are infact stiffer.

 

^This.

Do a forum search... the spring rate went up to 427 halfway through 2004 (04.5) I can't remember what it was before, but I know I've seen it posted around a few times.

 

From 342 in 03-04.5 to 427 04.5 on up

 

interesting....... my understanding of the word bouncy would be the opposite of smooth... so they would make them softer to make the ride smoother.

My original springs were quite soft... the car drove like it was floating, not a BOUNCE to be felt...

where as now with the Z springs it is TOO BOUNCY, shaking my interior to pieces. The springs hardly compress, and when going on an angle into my driveway you can hear the body of the car and dashboard click and groan under stress

 

i have a 2004.5 350z full suspension strut coil spring in the classified for sale, lmk

 

The ride can be smooth and bouncy.

Think of it like this.
You have a spring thats 200lb in (takes 200lbs to compress it one inch) and you have 400lbs of weight being supported by it. When you go over a bump or dip in the road the spring will compress further than it should because its supporting more weight than its designed for. When the spring rebounds it will get stretched upward more than its designed to do because the (400) weight has more momentum then the spring can control. With the lighter spring rate you also have a shock that is valved for the lighter spring rate, which has an even harder time controlling that spring. The end result is a spring and shock that compresses and rebounds more than it should (for a smooth controlled ride). It will ride like you have worn out shocks all the time (bouncy).

By increasing the spring rate you also need a shock that is valved (stiffer) accordingly. The Higher spring rate (say 350lbs) asorbes more of the up and down momentum of the car going over bumps. The spring will push up more as the weight pushes down, and as the weight transfers back up, the spring has more (backbone/strenght) to pull that weight down. The end result is slightly less up and down movement that is controlled (not bouncy like an out of control spring). The higher spring rate is better matched for weight of the vehicle.

The 350Z being somewhat performance oriented it only makes sense to have a firmer more predictable spring. You dont want to be taking a corner and hit a bump with soft bouncy springs, your bound to lose control of the car.


I am no engineer, but that is my guess.

BTW those numbers are just random numbers for representation purposes.

 

Guys I appreciate all the information.. I have a guy close by who has the 03 350z springs. My sedan shocks have just been checked and they are fine. Would i be ok going with just the 350 springs? or you think i should get shocks aswell..