Dedicated AutoX/Track Spring Rates

///MSH

Update...I got all my measurements and calculated rates/ratios. Hats off to 03threefiftyz and everyone else who chimed-in. I'm now torn between Penske 7500 DA and Ohlins TTX....any objective reasoning to a preferred brand/builder is welcomed.

Also, the math says I could go between 1000-1200 lbs up front, and I would likely ratio that to the rear based on the factory split as a percentage (I like my current balance). I wonder if this is TOO stiff. Any thoughts as to where the limit is? I run 295/315 Hoosier A6's

Hope to have something on order within a week or so.....

__________________
2011 Nismo with...Stillen Gen3 CAI, FI LTH's, Stillen CBE with Springfielddyno rear section. Stillen under drive crank pulley, UpRev, and LW flywheel. Penske 8300DA Valved by ANZE, SPR FCA's, Stillen F/R adj. sway bars, Enkei PF01's, and Hoosier A6's

03threefiftyz

Ohlins will be more expensive, but I would pay it happily. Are you still using the factory diff? That will have a big role in balance if you upgrade to a clutch unit.

///MSH

Good point. I have plans on going with a Torsen-type rear diff. I reckon that would govern a slightly softer rear than factory split.

__________________
2011 Nismo with...Stillen Gen3 CAI, FI LTH's, Stillen CBE with Springfielddyno rear section. Stillen under drive crank pulley, UpRev, and LW flywheel. Penske 8300DA Valved by ANZE, SPR FCA's, Stillen F/R adj. sway bars, Enkei PF01's, and Hoosier A6's

03threefiftyz

I'm not a quaife fan at all...I prefer clutch type diffs.

gomer_110

So to bring this thread back from the dead.

According to the math I'm coming up with 1100 lb springs up front and 900 lb in the rear for suspension frequencies of 2.35hz (fr) and 2.31hz (rear). As it sits the corner weights are ~900lbs at each front corner and ~700 lbs at each rear corner. Car is used for autox. Will be using the stock spring locations as the rules prohibit going to a true coil over.

Are these too stiff or just right?

__________________
'11 370Z Nismo #528 Fast Intentions | Stillen | Motordyne | Uprev | CSF | Zspeed | Z1 Motorsports | AST | Swift | SPC | SPL | Whiteline | Hotchkis | Bride | Schroth | Robispec | Cusco | Nismo | Volk | Forgestar | Hoosier | RJM
'17 Titan Bone Stock

j-rho

I started at 1100/650 (Hotchkis front and rear bars) and it's in the ballpark. Without a rear bar I'd probably start at 1100/800. That that's with skinny little 255 street tires on 18x9's all around. Would go higher on big ST tires or R comps.

wrxrcr

I am building a 370z for str, what spring length should i go with? i am planning to maintain stock spring locations and use adjustable perches.