theheckwithyou

since i know nothing about suspension setup. i come to you guys for help!
as most of you are aware i have megan coilovers (thanks ed) and currently running these settings
Front: camber -2 , toe .001 in
Rear : i got no idea since i don't have camber bolts nor were they adjusted from whatever settings they are at now i think stock alignment settings

From the track(streets at willow) day i found some massive tire wear issues on the outer corner of the front tires. they look like bubbles are forming but they are forming equally. the left is worse than the right.

i have massive understeer between turn 3 till the bowl.

the question is obviously my alignment setup isn't done correctly for this track. what should my suspension setup be?

Shayhan27

iTrader: (4)

TOE out will give you more steering but wear the insides of the tires I would try to go neautral on the toe and maybe a little more agressive on the camber. Toe out in front toe in on the rear should get rid of understeer but if you run the car on the street this may not be a good idea. Im not a race car setup guy though maybe call a shop that races.

sigma pi

iTrader: (6)

ed has a thread

sigma pi

iTrader: (6)

and i get the same understeer im working on that tooo

left wear is from teh more right turns and faster rights

LifePlaza

post up your tire pressures too



My set up on my GC8 non coilover with a rear GC8 sway bar

6kg springs front
4kg springs rear
front damper set to 2 (4 setting)
rear damper set to 8 (8 setting)
front toe 6.3mm out
rear toe 0.0mm
Front camber 2.6
Rear camber 2.2

Tire pressure
front cold 28
rear cold 31

Sigma Pi (Nav)

ok question...

you mentioned understeer only leading into the bowl what is your throttle position and how much roll do you feel in the car???

Because on the subary it's a FWD based system on the AWD the split is not a 100% 50/50. So typically on throttle or partial throttle you will get the understeer issue....

The alignment will help some more toe out in the front gives you great initial response more tow in gives you more control in the turn.

In the rear more toe out will simulate a slight oversteering effect depending on where the front of the car is pointed. More toe in will cause a lazy *** effect. typically you won't have to deal wtih too much toe adjustment in the rear on these cars because of it's limitation if you can do .5 to 1deg of adjustment then i would screw with it but if it's small just run stock seeting.

Camber is basically allowing you to get more grip out of a turn it won't really do much for over or under steering issues. it will simulate a twitchy feeling when you have too much neg camber in the front or back thats because you are not using 100% of the tire patch.

Also corner balancing will play a huge roll in understeering, depending how your suspension loads and unloads at a given time.

I would fist off balance the car, drive it around for a bit and see where it stands make sure X balance is 50/50 or close to with with driver. you might want to make it 40/60 this way when you arer in a turn and the inner wheel starts to break traction the AWD will shift more power to the back???

you might want to try a rear sway bar to get the *** end to kick out. have it on the stiff setting...

FYI suspension is harder to tune than engines!!! cause it changes all the time and there is no baseline!

LifePlaza

for myself when my car set up was good, I would under steer at the peak of that apex. Slow in turn brake > throttle steer > WOT. I would unload the weight of the car and put it all on passenger side of the car, majority front driver side with the rear wheels just pushing it.

Its a strange line to take but its the same as a FWD car since thats what AWD is.

Sigma Pi (Nav)

Thats actually a nice way to take it if your car is understeering... your basically forcing the cat to HALT to change weight then feather the throttle to poke to see how much push you will get then WOT when your clear.

Thats actually what you want but thats for people that can feel what the car is doing so it's mostly driver compensation vs car setup.

On my Audi i had it set up as a RWD with a 40/60 split with the center diff modified and the front diff gear and rear diff gear was 1:1.75 rear taller than the front.

This allowed me to put more power to the rear and make it whip out by hitting the thorttle and everytime i let off the throttle it would tuck back in the line i want and push out of the turn. The front was just used to gain traction and help pull the sled through tight turns but long sweepers or quick transitions it acted like a RWD car.

But to tell you the truth i would rather have a car that oversteers vs under... i find it easy to correct an oversteering issue???

LifePlaza

its a natural reaction.


Lawson was behind me when I was in the Miata holding a dori dori line going up turn 2 at the end of the Apex.

sigma pi

iTrader: (6)

would left foot braking help

theheckwithyou

i'm playing with the throttle, there isn't a point where the throttle is fully down nor is it completely off. I think the feeling i get is the car doesn't want to rotate.

the car has been corner balanced if i'm not mistaken it should be 50% or 51% with me in it.

LifePlaza

When are you playing with the throttle? the only time I notice understeer or wheels scrub (when the unloaded tire drags since the weight is off it) is off throttle. I throttle steer for fraction of a second before I am back on WOT once I have my exit lined up.

theheckwithyou

between turn 3 and before the bowl.

Sigma Pi (Nav)

ok... internet diagnostic time... i swear i don't get any work done when you post crap up like this...

ok... Variables.
1. Tire pressure?
2. Tire size/ wheel offset?


you want front to rear balance on a car that you sit inline with the B-pillar on a sedan you typically want more weight in the front to help setup for a turn. but on a AWD drive car or FWD car you want slightly more on the rear so when you load the front going into a turn and you power out the rear has enough weight that it won't spin out and swap ends.

But this is what i can come up with based on the info listed above...

Your tire is probably rolling the side wall depending on tire pressure. Wheel off set if you have a staggered off set rear wheel sticks out more than the front. This should help in your understeering, but the rotation it's how your suspension is getting loaded.

the problem your understeering which is also known as push is the inner wheels are not getting the power down. the car is not able to pull forward (the direction you want due to nominal force). so you would probably need to stiffen up the front, add a fat rear bar in the back to help the rear over rotate.

But whats going on is you have 2 challanges.... 1 is your going up hill on a slight turn, your mostly on the throttle which will cause the car to push because... These are the situations where a diff comes in handy but with out buying the diff you will always have this issue you can compensate for it the best you can but it won't go away.

My suggestion....

1. Balance your car get a 50/50 Cross balance with you in it. Front to back get as close to 50/50 as you can but Cross will be more important.
2. Wheel spacers get a 5mm and 10mm
3. Do they make chassi braces??? get what you can on the front this will help prevent chassi deflection.
4. Run higher tire pressure??? don't know where your at now???

those things should help you out a bit...

in the long run get a sway bar possibly stiffer springs.

Sigma Pi (Nav)

Quick question????

You ever play with RC cars??? RC cars will teach you tons about suspension dynamics and chassi setup. You would think it's a toy but those toys they make a great tool when setting up a real car.