from my latest track thread @ roebling

current setup is eibach pro

with 3/4 tank of gas, my curb weight is 3904 lbs and corner weights are:

lf 1094 rf 1026
lr 905 rr 879

so with my current understeer and bottoming out on the front springs - i need help on figuring out just what spring rates i should get if i buy coils. im going with a linear setup. it will only be for 4-5 track sessions a year at this time so i need something streetable that will still do the trick. any ideas?

 

so far looks like im leaning towards a 12/10kg setup. anyone else want to chime in?

 

Hmmm...

Are you matching the shocks to the springs or the springs to the shocks? because they do need to properly match up...

More specifically, how much spring rate do you need to NOT bottom out? How much suspension travel do you want?

 

if i change out to continue tracking, im going coilovers so they'll be matched.

the majority of coil setups for the 37 seem to be 9-14kg front and 7-12kg rear with 0-4kg difference front to back. i figure going towards the stiffer side of that scale should be fine. talked to a couple shops and just reading around is why im leaning towards 12/10. again this will be a mostly street setup with 4-5 track events a year.

 

have you thought about sway bars? im in the same position as you, although i have not bottomed out my suspension on the track (at least, i dont think so). before your post i wanted to change the wheel rate when turning, since i am fine with stock suspension when going straight. after reading your post im wondering how many gs you pull on turns to bottom out the front? i saw your vids and maybe i just dont understand especially on street tires! part of the reason i am now worried since i am running NT05 and will run RE11 in the future. if the problem is just sever understeer, then i would think sway bars and tossing out the spare, tools, etc to lighten the rear will help solve that.

if you do get coilovers keep this thread or your 370z thread updated. there are people like me who are more interested in tracking the car than anything else. im 80% ready to get stillen sways.

 

All sways do are distribute load differently. They may help his problem now, but if he gets coils later, then the sways may not help then, or even hurt performance.

Most sways are made for the stock suspension, and will not distribute load the way the driver wants after suspension mods. Then you get into changing damping to 'compensate' for the sway, etc.

IMO, start with the coils first, and use adjustable sways to fine tune, and then adjust compression/rebound damping to further fine tune, and top off with an alignment.

 

i agree. for myself i intend to stay with the stock suspension as i neither have the funds nor time to get a proper track setup. i guess i read that w0 perhaps didnt want to have to go full coilover suspension to fix understeering.

im still surprised to hear about a broken endlink. i would have thought street tires would let go before the car would bottom out and break something.

 

I had great results with the Hotchkis sway bar upgrade added to a previously installed Eibach Pro Kit spring set up. Shaved over 2 seconds off my best time.

 

sways are a MUST on these cars. ive had stillen sways since 2 weeks into owning the car. its a 100% improvement in handling.

the reason i am bottoming out and you're not, is because i am running eibach springs. the 1" drop is too much for the stock shocks to handle at high loads. so i can either get stiffer shocks or just go ahead and get coils that are already matched. hope that clears things up.

 

w0ady, what if you got springs that sit at the same height (idle load), but with a higher spring rate? It wouldn't be as good as coils, since the rebound damping will be off, but at least it will prevent you from bottoming out and at far less cost.

 

clears up a lot, thanks w0! btw, i wanna see more pics of YOUR car in your track day thread @370z no need to be modest, im especially interested in your camera mount

edit: one more question, is your rear sway setup for 37% or 70% increased stiffness?

 

definitely an option but there are so few springs for the 37. i cant go lower because of my condos speed bumps and i dont want a super stiff spring since i drive 20k miles a year. the height and dampening adjustability of coils just makes more sense if im going to spend the $ and time yo uknow.
haha yea i have enough pics of my car so i dont really take many. ive got some action shots from november i can post. travis took a couple more this time that i should get soon. originally i had used a headrest mount i built for about $10 @ home depot. recently i picked up a delkin mini-gecko mount from amazon and stuck it to the inside top right of the windshield. rear sway is at 70% if i remember right.

new mount



old mount



november