I am thinking about putting the 350Z suspension on my sedan. I would like to thank everybody about their previous posts on this topic, especially Gsedan35 (Jim), they have been very helpful. It's been said that the 350Z shock's valving is superior to the sedan's sport shocks and this seems very reasonable. My questions have to do with the suspension/shock travel. What has been stated is that because the rods are longer in the sedan suspension that once the car is lowered the shocks now sit at a different operating point closer to the fully compressed position. The assertion is that this leaves less headroom for shock travel and therefore might cause the shocks to fail after many deep compressions.
What I am thinking is this: I am in disbelief that the Nissan engineers would have mated a shock to the suspension geometry that would bottom out (or get into an unsafe zone) before the end stops stopped the suspension travel. The only reason I can see that this would happen is if the fully compressed spring was used at the suspension stop, which is usually not the case. If this were the case, then the 350Z springs could allow the suspension to go further down than the stock sedan springs, but I would assume something else in the suspension would stop this (or the car would bottom out first).
On the flip side, if 350Z shocks were used on the sedan with the shorter rods it seems that there is a real danger of hurting the shock when the suspension is at full extension (when the car is doing a Dukes O' Hazard jump, or more likely because of a big pothole, etc.). What I am getting at is that the sedan shock rods are longer to accommodate the longer suspension travel, not just the shift in operating point. At full extension of the sedan suspension the 350Z shock rod might end up being the end stop (Ouch!) and this could cause a serious failure.
I know that many people are running the 350Z shocks and springs in the sedan with great handling sucess and that's good data. But the fact that no one has yet reported problems is not a complete validation on this extended travel issue, it's just a probabilistic validation.

Well that's a mouthful, anyway then, my questions then are these:

1. Has anyone assembled the sedan suspension with the 350Z shocks without the springs, front & rear and moved the suspension through it's travel range to see if the 350Z shocks limit the travel at full extension? (The Ouch! condition.)

2. Has anyone assembled the stock sedan suspension without the springs, front & rear and moved the suspension through its travel range to see if the stock shocks limit the travel at full compression. Full compression would be moving to the point where the 350Z spring would be fully compressed (calculated), or where the a bump stop limits it (whichever is first)?

This is the only way to validate the suspension under worst case conditions. (BTW, it's also the only way to validate different wheel/tire/offset combinations under worst case conditions when "plus sizing" with the wheel/tire on, for those of you who are trying to get really close to the limits without any chance of rubbing.

My last question is then this:

3. If you have been running this setup (350Z shocks and springs on a sedan) how many miles have you driven? And what's the terrain like in your area (potholes, etc.)?

I would like to thank everyone in advance for their replies. I only have one (or perhaps two) "shots" at getting the suspension right. After that my wife and kids will know I have a new mistress

Tom.

 

I think I can answer partially one of your questions. The rear shocks hit the bumpstop before reaching limit of compression. this is typical when lowering a car. It is also the reason why most people cut their bumpstops some.

another question. I have 4000 miles on my z springs/shocks. my road are crappy but relatively few potholes. I have bottomed out the rear end going into a driveway too fast.

the suspension itself is distorted some in the front end by this mod, and any halfway knowledgeable dealer should deny you warranty work on front suspension components. But to me, that is a fair tradeoff for increased negative camber in the front (where it is most lacking to begin with). I did not install a front end camber kit nor do I plan to. But if you did you may be able to restore the geometry. In my infinite wisdom (mostly from four wheeling with an independent front suspension (lifted jeep liberty) vehicle (IFS for short)), the front a arms and transverse link look very beefy and should handle the stress. The steering linkage is actually at less of an angle after a drop. I don't see any problems from this mod.

the rear suspension itself can be restored entirely to stock geometry with stock components.

Better Life thru Chemistry
Black on Black 03.5 Sedan 6MT - Goodyear F1 GS-D3's 225/55/17, Custom Intake Tube, '03 "Z" Suspension, Magnaflow resonator, 6 Wire 4 Guage Grounding Kit

 

Thanks for the reply. What I took from it is this: You want the negative camber in the front, and I agree this is probably superior. (Why else would the coupe have -1.5 degrees)? The fact that the steering linkage is more level is also an advantage. How about the lower suspension arm? My theory is that the Nissan engineers were disappointed that the coupe and sedan were so close in performance and kept detuning the sedan until the difference was more significant. Perhaps they kept raising the car until they got the difference they wanted. The steering linkage is some more evidence of this.

I am not sure I understand what you meant by "The rear shocks hit the bump stop before reaching limit of compression". Do you mean the shocks hit a bump stop or the suspension hits a bump stop (I have to admit I have not yet been under the car much).

When you said "the suspension itself is distorted some in the front end by this mod" do you mean permanently? Does something bend?

Thanks, Tom

Tom

 

The suspension hits the bumpstop before the shock reaches full compression, yes that is correct.

The Geometry is distorted, not any of the components, hence my long winded discussion on "beefiness" of the front suspension components. There is probably some extra stress put on the arms and tranverse link due to the geometry change, but in my opinion nothing that the thick *** aluminum pieces can't handle.

The only concern I have is that when we lower these cars, the right side camber is different than the left side. Perhaps it is due to installing a previously "settled" suspension on the car.



Better Life thru Chemistry
Black on Black 03.5 Sedan 6MT - Goodyear F1 GS-D3's 225/55/17, Custom Intake Tube, '03 "Z" Suspension, Magnaflow resonator, 6 Wire 4 Guage Grounding Kit