You're right to some extent, and maybe i did phrase it a bit odd. But i think you are overlooking the load factor. If you are increasing the rate, you are reducing the amount of work the spring has to do. So although you decreased the space between coils, you also reduced the distance spring has to travel to support the same amount of weight. The stroke in such case does not need to be equal.

100ibs will compress a 25ib rated spring 4 inches
100ibs will compress a 50ibs rated spring 2 inches.

The open questions are; how many inches does the spring need to travel (total load capacity), and capable of traveling (maximum spring stroke). From there we can decide the window of operation and necessary spring rate change.

As long as the weight the spring has to support is the same, there is no reason to change the load capacity (assuming the previous load capacity was suitable in the first place). If you use the same length but increase or decrease the rate, you change the load, this is where the problem of binding and spring sag comes into play. So if you keep the load capacity the same for any given spring length, you shouldn't run the risk of binding a spring. OF course its a case of diminishing returns after changing the length too much.

A 2.5i.d 10inch x 12kg spring has a load capacity over 2 tons. That is about as much as the car would ever see. A 14kg x 10inch spring will have a capacity of over 4500ibs (over 9000ibs axle load!). The car will never see this in standard trim, nor would any tire support that. You'd need like 355 tires squared and a 1000ibs of downforce front and rear at like 60mph lmao.

As it stands. those springs are already too large. I'm going to go out on a limb and assume this car has never bound the coils or even got close to it.

Do you do any offroad excursions Spooler? Baha 1000? lol

I have been searching for some Penske's. No luck yet. Will need to make some phone calls if I go that route.

Noop, but I have compressed them to rubbing the inner fender on the Dragon at the Gravity cavity. There were a couple of spots like that on that road. I am waiting for my neck to heal a little more. I am going to try and make it to Z Nationals this year for some Road Atlanta track day fun.

Let your fingers do the walking, found someone on here via an old thread.

https://www.anzesuspension.com/

Rubbing front and rear? Was it rubbing at full lock or just over bumps going straight?

If you want to go with Penske's, its best you call them directly. They have a setup page dedicated to custom designs on the main site and its updated often. The Anze group is not very active online. I tried getting in touch with them a few years ago and they weren't very helpful. I can't say how they are now. PSI is my most trusted group so far. If you give them a call, most of the guys are very helpful. I usually deal with Beau or Ben. These guys can give you exact parts lists for almost all kits they sale or service. They don't charge or hassle you either for information.

Thanks for that info. The least pain points the better.

It was in a turn and only the front for the rubbing, not full lock. It wasn't bottomed out but it was close.

Man this thread is getting real expensive real quick lol.

It's only money. I pay for smiles per mile. We shall see. I need to get a few track days under my belt first.

Getting your car to behave the way you want/vision it to be is indeed satisfying. Money does buy smiles!

Well, since the weather has gotten cooler my issue has gone away. Guess the shock oil was getting too hot. I wonder how you combat this?

a different oil.

They do, may have to order them from across the pond though. AST 5200 Series : AST 2-Way 5200 - Nissan 370Z/Fairlady Z

If i'm not allowed to link then let me know mods. Dont remember the rule

Hot dang, my new rims are at the port in California.

where. i wanna go....take a look :rolleyes::excited:

No idea, They are at SSR.