Yeah that doesn't make sense to me. Even the Cusco coilovers use the oem rear spring location, not on the dampner body (saw them with my own eye's at a meet).

How does that work with the rear motion ratio at .36? Does that mean that if a 100lbs spring rate is in place that the effective leverage applied at the wheel equal's a 36lbs spring rate at the wheel and the same spring at the front leverages 79lbs?

 

The front rates what I got I am not really sure how accurate .............because the "pigtail" is more pronounced on them and they dont fit into the perch. I am going to try it again today and take pictures.

 

Doesn't make sense to me either. I have yet to see coil-overs that do not use the stock mounting points.

Exactly. I have not measured the rears myself, but the wheel certainly has significant leverage on the spring being so inboard of the wheel hub. The beauty lies in the ability for stiffer springs to control body roll and wt. dist. without making the wheel rate too high to maintain full travel over irregularities.
EDIT: I'm a retard and couldn't figure out quotes

 

From the informations I have received in our quest for a spring package with the Konis...
The Eibachs are actaully about 85-90% linear
rates are 387 front and 430 rear.
The OEM rear rate is 340ish.

 

Your quoting the peak eibach rates, but they still have a significant rate spread between the initial rate and the final rate of 296/384 front 316/421 rear, (anyone can call them and get their spring rates to confirm), that's nearly a 100lbs spread that you'll experience. While cornering one side of the car is sprung at 384lbs front 421lbs rear while the other side of the car is at 296lbs front and 421lbs rear. Still too much of a performance compromise in the pursuit of ride quality.

 

Just passing information

 

BJ,

Did you ever get a chance to measure the OEM fronts?

Thanks!

 

I couldnt get an accurate reading on the fronts. I talked to the guys at motorsport and they couldnt find them either. Still looking.
BJ

 

The rates coming off BJ's spring tester differing from the rates I got, made me curious. I dusted off my boxed set of oem 2003 350Z springs and had another look. I hadn't written down all the previous measurements, so I measured them again, and again, and again,.........you get the idea. And this time I did not ask for someone else to do the rate math, found this neat web site that does it. http://www.racingpc.com/tips/coils-springs.htm



Front springs:
33/64" wire diameter (measured on all active coils)
spring Outside Diameter 4.5"
Number of active coils 5
Spring rate 314lbs




*******************************************

Rear springs:
35/64" wire diameter (measured on all active coils)
spring Outside Diameter 5.0625"
Number of active coils 4
Spring rate 342lbs



So needless to see, I have new oem rates.
314/342

 

Thanks Gsedan35.

It didn't make sense that Eibach would end up at a similar rate to the OEM springs. They usually end up 20-25% stiffer than OEM.

 

Anyone heard of B&G Spring?
What is the Spring rate on that?

 

I haven't bothered to call them, so I don't have their rates. They did tell me spring rates in the past, but so did Sprint, who now refuse to give out rates. H&R is another company that refuses to give out rates. If they can't give that out, how can anyone make a informed buying decision, just a shot in the dark, I don't think so.

If you want to find out the B&G rates I suggest that you give them a ring. Do not accept a generic "oh they are 20% stiffer". You need to know the specific rates or the info is totally uselesss.

 

Thank you so much for your advise. I have bilstein shocks, I currently use H tech, they suck. Anyways, I will call B&G. I already bought them, have not put it on yet. I hope they work well with Bilsteins. I heard Bilstein HD is different from KONI Yellows. What is the difference other than one is adjustable and other is not. How is the quality? I just have the Bilstein Shocks, it is called HD OEM Performance. Not PSS system. Any advise?

 

Why is it "Linear" Spring rates are preferable to "Progressive" Spring rates. I know the difference but not sure why one is preferred over the other. Racing application versus a street application?

Thanks
Major

 

Linear is good with a nice stiffer shock. Progressive is better with a soft shock.