Nissan 370Z Forum - INFO on lowering the Z

So I did a little bit of research on lowering springs to gather as much information as I can. First, I contacted H&R hoping they would be of some help. They wouldn't even give me the spring rate, let alone any other info. Apparently the reason being, they do not want other people to copy their product which is understandable. I also contacted Swift on the other hand and they gave me really detailed information about their product and the reasons why they would make certain decisions about their springs.

Here is just a bit of information that I got from it that I figured people might want to know about when purchasing springs. One of the main reasons why Swift had to do so much R&D on the springs when releasing the springs is because there is in fact very little travel in the front shocks of the 370Z. When Swift came out with the springs they had to physically modify the spring rate curve to work with the OEM bumpstops of the Z. Which I believe you cannot hack out or cut.

They also told me that with the Spec R's there is only about 10mm of room before hitting the bump stop at ride height, but because of the design they were able to make the springs work with the bumpstop and still manage a comfortable ride. From what I understood from their representative was that this is possible through the spring rate curve, the rake of the tail and front end of the vehicle because depending on where the weight is centralized on the vehicle, the ride compliance and performance can be altered.

They have also tested other springs on the market and the reason why the ride can be so harsh with other springs is because the majority of springs on the market are already sitting on the bumpstops. The height difference between for example H&R and Swift is very subtle, the main reason being, the wheel rate of the vehicle is not one to one. So that half inch of travel in the shock is not directly translated into a half inch difference in the distance between the tire and wheel well. This is the reason why even though the Swift and H&R spring may not physically look like there is much of a difference in drop height but because of the stiffer rates and their testing they have come up with, is just about the limit the 370z can handle with the spring rates and the drop height. So Swift has a tad bit of travel still with the springs, and minimizes the unneeded movement of the shock while H&R is pretty much sitting on the bump stop.

Well anyways after talking to them it made my decision pretty clear. And I figured some people may be as research intensive as me when it comes to buying car parts (they are expensive after all!) and would want to digest this info before making a decision on their springs as well.