Building a race car is easy. Tuning it to actually be fast or ubber optimized for a specific application is the hard/expensive/time consuming part. In a pro context, these R&D expenses typically far eclipse the cost of some bolt on parts. Several Porsche members have assured me they quickly turn a $100,000 vehicle into a $650,000 one. Now just think how many more cup cars and data is available there and how many more resources these guys have over you.
Like I said, in NSX Land, yeah I think you might want to count the sheep in the flock and assess the true extent of their pro motorsports experience more carefully... especially before taking blanket chassis setup advice as "you need to swap your springs".
For club enthusiasts... you just need to have a decent starting point, from which you can tweak from. For me that was about 1100lbs rear and 850lbs front last year. As far as setup theory- in my case I consulted opinions of people I trust on my specific application, and thus have the stiffer spring on the back due to the ME layout, high amount of down-force being generated with my aero package, and the split. It worked out to be remarkably neutral and highly predictable. I am still making small tweaks but out of the box not bad at all.
Theory suggests that the correct total amount of "anti-roll" is inclusive of spring rate, which complicates the issue but it is still safe to assume that it is better to start with less spring rate than too much when placing your order (assuming you had one set to choose from).
For me "1000-1100lb" range is absolutely not a problem. The JRZ's are valved for it, and our track was just re-paved and I suspect pro cars will be running higher rates from what I've garnered. To me blasting down the new straight away at PIR feels like driving on lightly rippled glass. I can feel the slight bob of the aero. At Pacific on the other hand clearing T1 I can barely see straight my head was so jarred in the braking zone. Bremerton feels to me like I could go way softer in rain.
I hope to pick-up some different rates here shortly so I can play and gain a wider understanding of the influences how some of these changes might impact things. Unfortunately, without the benefit of easy access due to the out-board stock design, it tends to make data collection slightly less relevant as you span events.
I will say this. I've read a lot of generic suspension books and heard a lot of opinions on the matter of rates. To me, the essential concept is to maximize grip through adequate suspension travel at each wheel. A heavier spring rate makes it difficult for an individual wheel to react to changes in road surface under roll so contact is lost. Likewise, too soft and you will have excessive roll, inconsistent aero, and other penalties. You must consider the suspension frequency and wheel rate. You have to look at the total equation of how everything is coming together.
Having said that, there is still no absolute correct number or recipe with two different race cars. Even the pro F1 teams with hundreds of hours on shakers don't always get it right.
My recommendation is forget about Mr Foo's in-box spring recommendations. Everyone has some seemingly irrelevant opinion on the matter about what rates "are best" or how best to setup your race car (which they probably have never driven).
Unless you have a pro chassis setup engineer handy trackside... what I've found is to just use your own vehicles specific setup characteristics, driver preference, course configuration, conditions, testing, feel, transponder, peers, common sense etc... to guide you. If in doubt about what your butt is telling you try the under-appreciated strap in a better driver mod to get a second opinion.
Look. NSX Prime has many different enthusiasts with vastly different setups, prep levels, budgets, and goals. No one shoe fits all. You know that stock cars run different rates left to right on the front at banked speedways? Aware that one rate may lend itself to better turn-in characteristics while sacrificing apex and exit speed or even braking characteristics? One can be fantastic at one course and horrible at another? Great in the wet and sucks in the dry?
In road racing some competitors may run very, very stiff, while another competitor may opt for very, very light springs with no rear sway bar. Guess what, they BOTH work. To a certain extent it's all in your driving style and what you like.
All things being equal, no one driver is going to be perfectly comfortable with the same setup anyway.
The crazy spring rates are the ones you get from some guy on a car forum that doesn't even have the common sense to ask where in the hell you are driving your car.
My 0.2
So now I have to dive Dave's little Super Charged grocery getter :biggrin:
