Fortune Auto 510

Brendan

Running 18k up front and may go up to 20k but I am an autocross sea urchin.

The nice thing about Fortunes is they have a crazy range of rate they can take before needing to be re-valved. Plus or minus 8k or so. If you get them be sure to pick up some bump stops and helper springs. Helper springs will really help with allowing the car to drive nicely on the street with higher main spring rates as they allow you to keep a good amount of droop. Bump stops will allow you go low without the risk of slapping chassis or having the tire rub the fender/bumper bracket.

Springs are easy to change. Get a good starting point and then learn what you like or dislike and make appropriate changes based on how the tires heat up and wear and how the car is driving.

As for divorced (oem type) vs true, I don't think it matters too much. I run divorced style cause of the da rules. Going true type changes the motion ratio so it will require you to run much softer springs in the rear.

I would start at 16k front and then depending on the rear coilover type you go with 14k for oem/divorced rear and maybe 5k rear if you true style. that will put you on the lower side of 2 hertz front and rear (2.2fr/2.1rr give or take a .02 or so depending on how heavy your wheels and brakes etc are)

Cheers, and remember, don't stress too much on getting it "right". Chances are wherever you start will be wrong. Spend more time learning how to understand what changes will do to affect how the car handles.

justin_boy

thank you for the help, i will stay divorced and take your advice on the spring rates

thanks again for everything

justin_boy

i think im going to do exactly that, (OEM 16k/14k) probably

btw your z looks insane with those 305's in the front. are they ze 40's?

what do you think about BC series ER?

Brendan

315*

Bc, fortune, feal etc I don't think it matters too much. As long as what you get is serviceable (preferably in the USA) and allows you to change spring rate, it's fine. The only reason I went with fortune was because of the wide range of spring tolerance. I'm sure there are pros to the other brands but that's why I chose mine.

justin_boy

Yeesh that’s beefy

I’ll be calling bc tomorrow and fortune auto

Gonna weigh out some options, liking the er series and 510’s are also looking good

I think I’m going to go with the 16/14 combo but my mind changes back and forth. Main concern is I don’t want to induce understeer, and have a hotchkis up front

ConekillerZ34

Inducing too much understeer isn't too easy to do. I run 1000lb/800lb (not exactly 18k/14k but close), and I have Hotchkis front and rear. I run my rear bar on the softest setting and the rear shocks cranked pretty far down (autocross setup). Even then there is plenty of room for oversteer left.

FWIW, I had Fortune Auto 510s on my last Z, and was quite satisfied for the price. The current owner just sent the dampers in for their first service, 5 years in, at a cost of $300.
On that car I ran only about 60% of the spring rates that I do now, but FA should be able to set it up however you like.

__________________
2016 Nismo 370Z | SCCA STU Autocross Build WIP
2015 GT-R Black Edition | Sold
2006 350Z SCCA STU prepped | Sold

justin_boy

ah gotcha, thank you for that info. I misunderstood that going too stiff in the front can cause understeer.

still in between bc's and fortune autos

ConekillerZ34

Technically speaking, too stiff in the front relative to the rear does induce undertsteer. My point is just that these cars rotate pretty happily, so that shouldn't be a major concern when deciding between differences in springrates, as long as you're in a reasonable range. 16k/18k fronts would need a really really low rear number to be problematic in that sense beyond what you can just fix with shock adjustments, and you can always change spring rates later.

__________________
2016 Nismo 370Z | SCCA STU Autocross Build WIP
2015 GT-R Black Edition | Sold
2006 350Z SCCA STU prepped | Sold