Never thought I would say this, but your all really over thinking things.

Tapered springs don't coil bind so you have no sudden rate change and because you do not have many active coil's with the narrower outside diameter, the softer rate will not be that much lower then the higher rate. The front springs on KW coilovers is also a tapered design, that spring varies in rate as follows, 485lbs to 525Lbs, a 40lbs spread without coilover bind isn't something I would really concern myself performance wise.

So, in this case I don't really see a compelling argument to avoid the new design because they happen to be slightly progressive.

Question you should really chase is, what if I want to run a different rear rate? Since this spring is likely unique to the Z and G, it's doubtfull other rear rates choices exist and I'm talking about in the warehouse in stock kind of existance, nothing less.

 

Pitch, angle and spacing have nothing to do with spring rate, not unless coils bind to reduce the number of active coils.

Spring rate is measured by,.....

Wire diameter
Outside coil diameter
Number of active coils

Not getting the correct answer can be tainted by a lack of knowledge, lack of company R&D resources and or simply not wanting to open what someone feel's would just be a big ole can of worms that they will have to get wrapped up in discussing, easy out suddenly becomes the easy answer. Even Tein techs aren't untouched by this, they said 350Z H-tech springs are progressive, they aren't.

 

Enough of this spring talk, here is a pic

I've got the new design, no gold perch, no clunk. These are awesome!

 

What is the ride height everyone is currently running at?

 

Im potentially getting these now, might sell my Tokico set this weekend, but I have a question.

Do any of the BC guru's see an adverse affect if I were to recreate the bottom rubber spring mount with a harder rubber to aid in firmness and response or should I just adjust the rear dampening for the same result?

It would be little effort for me to make this harder rubber part so Im just curious. Hell I could probably have made in delrin if I wanted to.

Also its not mentioned, but do the fronts offer camber adjustment?

 

In regards to the rubber spring mount.. I'm not sure exactly what you're asking here, but with the BC Racing setup, the stock rubber spring mount which attaches to the underside of the CAR, is taken off. In it's place is the upper spring perch for the springs, which comes as part of the set from BC. If you are referring to the thin piece of rubber which sits in the lower spring bucket, that is simply left in there and the revised BC setup spring, sits on top of it. I think you were referring to the rubber spring mount that the top of the stock rear springs sits on. You don't need that anymore with these, so don't worry about it.

The front of our cars don't have much camber adjustment. Depending on how low you set the BC Racing coilovers, you might consider getting new upper A arms...

 

thanks I've never looked at it, i thought the large rubber piece was at the bottom, nevermind then. the one on the bottom must just be there for NVH and does little to act as a rubber bushing like the top piece does, now i know.

 

No shocks or coilovers for our cars offer camber adjustment. There is absolutely no camber adjustment with the stock a-arms. If you want to adjust camber, you need front adjustable a-arms and rear camber kits.

 

you can adjust rear camber moderatley with OEM, no? (on a sedan anyway). Not front though.

 

Sorry, I just realized in my post above that I swapped front and rear on accident. The rears have very minimal camber adjustment. The fronts have none, on OEM.

 

alright guys i am hear to bring this thread back up to its original topic!!

today i finally made it over to bc in orlando from tampa, since i am the closest person to them that has had this problem, and i spent all afternoon from 4 to 9pm with pete at bc racing trying to get this figured out, why it was happening, and how we could solve it!!

i had the new rear spring setup for a few weeks and what gettin the knocking sound when i would hit a small bump in the road at a low speed. my knocking sound, sounds like it is coming from up high not at the spring!!

pete and i drove around so he could hear the nosie. we get back to the shop and take it all apart and check several things, one of them being the preload. since i had sufficent amount of preload we determined that was not the case.

so then we switched my rears to the old setup and went from the 10k spring to a 12k spring. we put those in and put it all back together, and went on another drive. knockings sound was still there, still sounding like it was up high and not down low.

get back to the shop, take it apart again and try to decide what to do next. we decided that the spring loaded adjusters sound like the could be making the noise. maybe from hitting the body of the car. so we take the adjusters off completely and go drive around again.

noise is still there, so we get back to the shop and take it all apart again. next we decide to look at the pillowball maybe that is moving too much and knocking on the allen heads on the inside, but we can not find any marks anywhere!! so since we have the upper plate off of the shock now, we think that hey maybe its moving around and bumping into the bolts. so we test fit it up and see that there is a lot of play in it, as the holes in the plate are larger than the bolts. so we found something that would fit snuggly around the bolt and inside the hole. luckily we found some thing and mounted the plate back up there, and it fit like a charm. didnt move at all, so we put everything back together and went for another drive. noise still occurs!!

once again back at the shop, we take it all apart. we decide that maybe since there is a small gap between the upper plate and the body that maybe its hitting there when going over a low speed bump and causing the noise. by this time it is now 9pm, so we decide to call it quits. pete is goin to look into getting some thin rubber like gaskets (like those that go on the upper spring mount between it and the car body) made to go between the upper plate and the car body, to see if this will solve the problem. hopefully it will!!

maybe you guys that are having the problem can look to see if you have a very thin gap between the plate and the body.

 

also for the person that asked if the kits were different, they are not.

the same upper plate is used on all 350z, g35, and g37 kits!! that is why it is weird that no 350z guys and very few g35 guys are having the problem, but there are several with g37s that are having the problem.

 

in this picture you can see the little rubber pad at the top of the preload adjuster for the rear springs. this is what we are thinking might need to be added to the upper plate on the shocks. hopefully it will work!!

 

Admittedly I didn’t read the entire post (kinda long… footnotes would be good) – but it seems as though I should be happy I gave up on these coilovers and went in a different direction.

FWIW, I wasn’t pleased at all with the lack of response regarding (what I consider) critical questions.

These may be the lord of suspension – and since I don’t have them I cant comment on the performance – but I wouldn’t hesitate to tell people I thought about it and wouldn’t consider them any further.

 

what questions? all i see is you asked about camber correction?? or am i missing something??

i dont think there was lack of responses, i think it was a lack of people not willing to try to help pete figure it out. there are very few people with this problem compared to the amount of kits that have been sold.

just be this is a very small secluded problem, there is no reason to knock them. they are working hard to figure out what the cause is, but without people being near them with the problem, its kinda hard to diagnose.

the knocking isnt causing any damage of any kind, so its not going to hurt anything.


i have installed several kits myself, and not a single one of them has had this problem!! my kit was the first kit to have this problem out of all the kits that i have installed!!