Ok, some time ago I pulled my Z shocks off and reinstalled the oem sport suspension shocks with my 350Z springs. I had several people PM me asking how I thought such a combo would ride and drive. I decided that I'd actually run the setup myself just so I could better answer the question.

Impressions:
What's good about the setup? You will lower the sedan 1" when you use 350Z/ G35 coupe springs on the sedan. Ride quality is a lot better then with the Z shocks, and the bounce of the Z shocks is compleatly gone. Overall ride quality is on par with the oem sport suspension, feeling a tiny bit firmer.


What's not good? You do not have the Z shocks superior control, turn in performance is about the same, ditto for brake dive and squat during acceleration and during gear changes. Everything was fine, until I took the car on the freeway. I soon discovered that any kind of bump or undulation in the road made feel very unsteady. The higher the speed the absolutely worse it got, it was not very pleasant to drive frankly. Next I started to test the car in some corners, the unsteady feeling came right back. The rear end felt totally disconnected, like it was encased in jello. Any kind of bump or undulation while cornering make the car very uneasy and unsteady. I do not recommend the setup at all, it would be all to easy for things to go wrong and for someone to eat it in a big way.

But, their is a silver lining. On a hunch, I pulled the rear Z springs off the car. I then pulled out the oem rubber upper spring seats and swapped in a pair that I had cut down by 3/4". Then I installed the oem rear sedan sport springs. Result, I compleatly cured the all Z spring setup's bad habits, car drives fine. It's not sporting enough for me (I want my Z shocks back on), but for someone that want's a 1"front 3/4" rear drop on linear springs it's a great setup, that is highly cost effective, used Z springs sell for $60-$75.

Here are a couple pics of my car on the front Z springs with rear oem sport springs on cut down rear upper spring seats.







Next review for me will be either sedan Eibachs or 350Z Tein H-techs.



"All that's necessary for the forces of evil to win in the world is for enough good men to do nothing.”
Edmund Burke

G35 6mt

 

Much appreciated review.
I'm trying to decide what to do with my sedan.
I have the sport suspension and am happy with it.
I just want to lower the car to make it look better, especially the front.
I was thinking Z springs or going to Eibachs but am not sure what is best.
Also, I really don't want to get into a camber kit if I don't have to.

<font color=blue>________________
04 Silverstone G35, 5AT, Prem, Aero
ES100 225/45-18 front 245/40-18 rear
Painted calipers, side marker signals
Debadged INFINITI</font color=blue>

 

Did you have a 4 wheel alignment done after the install? If not that would cause your handling problem. Shocks usually have little to do with the way the car feels on the highway.

2004 Infiniti G35S, 6MT, Premium, Sport, DP
Mods: JDM Clears, 20% tint, Z-tube, K&N Drop In
Track: 14.32 at 98.79 mph 2.2032 60ft

 

The car was aligned on the Z suspension. I returned the rear suspension to more aggresive settings to cure poor at the limit behavior. What is at issue is the sports shocks inability to maintain proper damping control when more is asked of them, the higher speeds cause the suspension to compress more over bumps and undulations, in town speed do not generate the vertical or horizontal engergy to cause as much compression or extention of the suspension. Shock behavior is something that most people miss when reviewing suspension setups, and it's something that most people do not have a clue in diagnosing. The sport shocks low speed valving is fine, high speed valving has a limitation. I would be inclined to suspect alignment, but said behavior did not exist with the Z shocks (superior high speed valving control, too weak rebound which is the cause of the bounce) or when I swapped in the oem sport springs in the rear. I do not rush reviews, I put a lot of miles on a setup so as to properly diagnose all issue's and leave no stone unturned.

Furthermore, I can add that another member I've been in contact with did the same experiment, Z springs on oem sport shocks. When I told him my feelings he replied, "There is definitely an "uneasyness" about the setup".

"All that's necessary for the forces of evil to win in the world is for enough good men to do nothing.”
Edmund Burke

G35 6mt

 

Hey! Are those my shocks!? Now I see what the experiment was...nice idea and review. But I need an even firmer suspension!

 

Yep they're your shocks.

So your 04 Z suspension isn't stiff enough, I understand, I want the same thing, just waiting for a couple of products to come out.

"All that's necessary for the forces of evil to win in the world is for enough good men to do nothing.”
Edmund Burke

G35 6mt

 

Why not go with Coupe struts, they'll be firmer then the stock setup but not as bouncy as the Z setup.

04 6MT Sedan - Z Tube, Stillen CAB, 04 Z Suspension

 

Compaired to Z shocks, coupe shocks have the same performance differences that oem sedan sport shocks have. But for the sedan owner wanting slight handling improvements that are cost effective (not as cost effective as front Z springs on oem rear springs however), the coupe suspension would be a excellent choice.

"All that's necessary for the forces of evil to win in the world is for enough good men to do nothing.”
Edmund Burke

G35 6mt

 

Yeah but the coupe suspension shouldn't provide the unstable highway ride that was described above.

04 6MT Sedan - Z Tube, Stillen CAB, 04 Z Suspension

 

Yes, exactly and that is the only reason I say the coupe shocks are a little bit stiffer. Inside info from Japan says that coupe shocks are valved the same as oem sedan sport shocks. But that cannot be true or I would not have seen the issues I did. Keep in mind that my comments on Z shocks vs coupe shocks come from back to back drives in both cars to each cars absolute handling limits.

"All that's necessary for the forces of evil to win in the world is for enough good men to do nothing.”
Edmund Burke

G35 6mt

 

I know this has been debated already, but w/ the 350Z springs, which shocks are the way to go for sedan owners? oem 350z shocks, or koni (for 350Z)? I'm getting pretty sick of how mushy the oem-sport setup is.

Drew
2003 G35 Sedan 6MT / Black / Graphite / Prem / Aero

 

The OEM struts are longer, perhaps the longer strut body presents a problem.

04 6MT Sedan - Z Tube, Stillen CAB, 04 Z Suspension

 

Gsedan nice study!! I put in B+G springs and notice what you were talking about at higher speeds, bounciness and unstable on turns with the end feeling like it will come out! Around turns its a lot better but nothing like the planted to the ground feeling I want, I guess maybe cause it isnt a true sports car (the sedan that is) after all. What can I do now to make it better? Ditch the springs and go your setup? Thanks, Martin


Martin
2003.5 BS G35
Nismo Aero/Sport Package
Injen CAI
B+G Springs
ADR M-Classic 19's..