suspension tuning?

[poshatch]

hey all, so im just sitting here after watching some great BMI and was thinking...i want to optimize the tunability of my suspension to get the best that i possibly can out of it and was hoping to get some experienced oppinions on the matter

1. spring rate and dampening affect both body roll and stroke? so on conditions where there are alot of bumps the dampening should be dialed down to obsorb more bumps but the trade off is body roll right?

2. how does adjusting dampening affect the tendency of the car to understeer, neutral steer, and over steer, front versus rear? for instance i drift on full stiff on all sides since the pad is always smooth and no problems with loosing front grip but in other situations id like to set up the car to be neutral to mild oversteer, suggesting a slightly softer front and stiffer rear?

3. anybody run no sway bars? currently ive been trying out no rear sway bar and it does seem to improve grip a bit, i have to really try to get it step out, drifting idealy no front and rear sway or all sway bars and grip ideally no rear or no sway bars?

[Philipio]

1. spring rate and dampening affect both body roll and stroke? so on conditions where there are alot of bumps the dampening should be dialed down to obsorb more bumps but the trade off is body roll right?

2. how does adjusting dampening affect the tendency of the car to understeer, neutral steer, and over steer, front versus rear? for instance i drift on full stiff on all sides since the pad is always smooth and no problems with loosing front grip but in other situations id like to set up the car to be neutral to mild oversteer, suggesting a slightly softer front and stiffer rear?

3. anybody run no sway bars? currently ive been trying out no rear sway bar and it does seem to improve grip a bit, i have to really try to get it step out, drifting idealy no front and rear sway or all sway bars and grip ideally no rear or no sway bars?

1. Right. If your car is extremely stiff you're going to have horrible traction issues over a very uneven surface.

2. To very simply answer the question, I personally put my coilovers at 75% dampening (12 out of 16) when I'm on a road course. 50% felt very soft and I could feel my car oscillate. Too stiff can very much be a bad thing.

3. I'm also interested in this idea. I've heard from multiple sources that running no rear sway bar helps in the grip department on our cars. I would really love a definitive answer on the subject.

[ashibah83]

3. I'm also interested in this idea. I've heard from multiple sources that running no rear sway bar helps in the grip department on our cars. I would really love a definitive answer on the subject.

no sway bar will increase grip on whatever axle your talking about, i run a Suspension Techniques rear sway bar with custom adjustable endlinks, and a stock front sway bar, i just changed out my LSD so now i have a bit of understeer, so ive been playing with the idea of no front sway bar

[poshatch]

1. Right. If your car is extremely stiff you're going to have horrible traction issues over a very uneven surface.

2. To very simply answer the question, I personally put my coilovers at 75% dampening (12 out of 16) when I'm on a road course. 50% felt very soft and I could feel my car oscillate. Too stiff can very much be a bad thing.

3. I'm also interested in this idea. I've heard from multiple sources that running no rear sway bar helps in the grip department on our cars. I would really love a definitive answer on the subject.

this sorta helps to know that i got some of the concepts down, i have no rear sway and it does help keep the end in place, i have to try pretty hard to get it to step out and if i did i dont know how long it would be able to maintain it haha, i suppose to compensate for the no rear sway the rear would have to be on full stiff (if this was for drifting)

today in my free time i might disconnect my front sway bar and see how that turns out (running no sway bars), although i hear the downside is more chasis flex (although this could be inaccurate)

as far as dialing dampening front versus rear, lets say that we are on a completely smooth surface like at the track (so adjusting stroke for bumps is not a factor)

more stiff in the front = less understeer/more oversteer?less stiff in the front = more understeer/less oversteer?more stiff in the rear = more understeer/less oversteer?less stiff in the rear = less understeer/more oversteer?

correct? so finding the correct balance of dampening to achieve close to neutral steer and slight oversteer would be changed depending on road course but for a smooth surface an almost full stiff situation is achieved? if not idealy a slightly softer front for squating to prevent locking brakes under hard braking?

[poshatch]

bumpkizzle

[allenms240]

Bump, I heard, stiffer rear for drifting (depending on the area of course) to break the back loose easier.

But im curious as to how to set up for both drift or grip.

[ChampionSound]

just play forza for a bit and you will learn!

[crakin]

^ heh

[poshatch]

is that a video game?

i dont play video games at all lol

still searchin for answers everybody chime in!

[poshatch]

super bump

[rbsileighty]

I kind of covered this in the thread below:zer...-much

Here is a good link for "dialing in" your current setup (minus damp):http://www.elephantracing.com/...p.htm

As far as damp goes... it's strongly tied to your springs and visa versa. The whole system would require a understanding of differencial equations to fully understand... but I'll try to find a good article and I'll post it in the other post I linked above

[poshatch]

ok thanks for the info, ill be going over it shortly

if it helps at all i can list as much info about my set up as possible:

coilovers: tein HE winding masters, 9kg front 7kg rear 24 way dampeningadj. front tension rods: 6.4? (stock caster, but will be increasing to roughly 7...once i get the lca's in a week) front toe is oem spec i think its slightly possitive, and -2.5 degrees camberpoly front sway bushings (stock bar and ends)rear subframe inserts and collarsadj. rear traction (unset, probably stock setting, dont know what this affects, i would like to know if this makes a difference for drifting vesus grip??)adj. rear toe (0 toe)adj. rear upper (-2.5 camber)rear sway bar taken out (but has poly bushings and stock ends as well)front and rear strut tower bracingfront z32 brake upgrade with 1" master cylinder (will be increasing rear rotors to 11.5" when i get the rest of the info on the swap)16x8 xxr 002 (=0 offset with 7mm spacer) all around with yokohama parada spec II 205-45-16 on roughly 55 psi (pretty soft and grippy)j30 vlsd, i want to shim it to 1.5 way, in the process of doing my friends at the moment, will be doing mine next (took his stock shim ftw)

the idea set up for me would be for slight oversteer, as you said in your article, im bias towards oversteer since i drift its much much more managable than understeer, although i dont hate it too much i would just rather have my car more netural and less prone to understeer

also, ive tried to make the car as level as possible, before i had the rear up slightly higher than the front to increase the rotation for drifting, i thought i would keep it close to level on all sides as a good base to try to start and tune the suspension

[poshatch]

so and update...

i really wanna try to use this subject to get as much info as i can about this subject...

anyhow, i removed the front sway bar (so currently running no sways) and it seems to be slightly more stabe, although i havnt had the opportunity to hit corners hard

also, i have put the car on full soft after driving on it on full stiff and when the opportunity arrises hit the corners sort of hard just to see if i can feel the extreme difference, i could feel the increased roll for sure, and i will be experimenting more often with getting dampening dialed in and also probably switch back to sways to see if that make a difference though or if im just imagining it

so i suppose the best way to phrase the question that arises is it possible to adjust dampening (my current spring rate) to achieve a more neutral steer

from my understanding weight distrubution pretty important in achieving neutral steer but im trying to figure out if its possible to achieve a simmilar set up without adjusting everything in my car