Hey guys, I got a 07 z and I ordered the swift spec r springs a few weeks ago. So today after school I had a few hours to kill before work, so I started the install, I followed a great tutorial I found online, and followed it step by step. I started with the rear since it was gonna be the easy part and one I lined every thing up I put it all back together and yes I used both bushings that the spring sits on, the top cone one and the one at the bottom. Well I figured I'd take it around the block and see how it performs, keep in mind, I've only done the rear and front Is still stock. So I get on the main road and once I get up to 45 the car is just floating, and nothing but body roll... I immediately turned around and went back home. I thought maybe it needs to settle so (5 hours later) I just drove it again and same scary feeling. Is this because the front ones are stock still? I'll have time to do the front ones this weekend. Just curious to what is causing this? Any Suggs is greatly appreciated. Thanks in advance

 

well my guess is that since you lowered the rear only so far, it of course rides stiffer, and that coupled with the nice riding front springs has you feeling weird is all. lower the front when you have time, and i bet you wont have any body roll and it'll be stiffer all around and be fine.

 

once you install the front springs you should be fine

 

You are going to get a bouncy feeling with all springs and the body roll will still be there for the most part. When you lower on stock struts you are reducing the length of the piston shaft on the strut and when that length shortens the strut does not react the same for rebound etc.

When i switched from Tanabe springs to BC racing coilovers it was one of the best mod swaps i had EVER done. With coilovers you can adjust the height, dampening and pre-load so there will be no bouncing, horrible rebound and dreaded body roll.

With what i read above you should not be having issues that much with swapping the rears and leaving the fronts stock. Since i am guessing swift spring rates are still fairly low so the spring rates wouldnt be that different and the height wouldnt affect anything.

When you install the rears the top cone thing should seat right in the middle of the spring, make sure you have the spring going the correct way as there is a top and a bottom especially if its a progressive spring, flipping it the wrong way would not be good. I am pretty sure you do NOT use the bottom item that you speak about. Inside the perch is an indent for the coil of the spring to seat right up against.

Also you will need to take the front strut out and i would recommend bringing to a suspension shop they can undo the top hat on the strut without having a catastrophic thing happen if you try and take it off without spring compressors.

Hope some of this helped!

 

Wow, I feel much better. It had me pretty worried. Thank you guys so much for such quick response and friendly advice.

 

Sound advice!!

 

Tell you what, i have installed numerous springs and coilovers on the 350Z.
If you need help PM me i get the PM notifications sent to my phone and i can walk you through whatever you need.... At this point i can do them with a blind fold! haha

I respond very quickly,

-Chad

 

No spring compressor is needed on the 350Z, by the time you run out of thread on the shock shaft, preload is gone.




The Z gets twitchy when the back end is lowered to much. The car is raked from the factory and handles better with a slight rake

 

I still say go with a spring compressor or at least take some slack of the stock front springs with some handheld spring compressors from Napa. Better safe then sorry.

 

Not needed, if you have a really good impact you can launch the strut approximatly 1 inch when you lay the strut on the side and zip the nut off.


Warning 370z and G37 will launch the strut, you need compressers to remove and install these springs.

 

There is almost no difference in the 350z suspension and 370z suspension.

 

Thanks alot chad, I will start on the front Saturday and will post to let everyone know if the issue is gone. Tnx again

 

The Swift Spec R's are also causing a "floating" feeling for other vehicles. Evo Xs with the Spec Rs are experiencing the same symptom on stock struts. The Spec Rs are not matched very well with oem shocks and make the car feel unsafe on the freeway.

 

I doubt that there is additional body roll from just installing the spring. It is the imbalance between the front and rear spring rates, along with insufficient damping and rebound to match the springs, that cause the unpleasant handling. Throw in bad alignment and the car will drive very badly.

 

Also throw in that the springs arent fully settled in.

 

Fixed for you

 

Maybe in the front, but not a issue in the rear.

2007 350Z oem spring rates
314/427

Swift 350Z Spec-R progressive springs 1.2”/1”
Spring rates in LBS initial/final Front: 291/392 Rear: 280/448

 

Believe these are progressive springs. Did you install upside-down? Photos helpful.


 

Where u located in SC 03redline??

 

I installed the rear ones that were labeled rear and I installed the with the writing saying swift the right way. Stead of saying swift upside down. And I made sure that the end on the spring caught that little notch at the bottom and was flush. Guess I'll do the front and see if that'll fix me up if not, I'll have to take the back apart and try again.😥