iNfEk

iTrader: (33)

ok so tell me about spring preload... how much spring tension is to much?

If I adjust the tension of the spring just enough to where there is no verticle movement but there is little horizontal movement is that ok?

Or

must I adjust is so that there is no verticle movement and no horizontal movement?

Beam

Hey Risk, with that much front bar, don't you find the car plows? I thought a heavy front/ relatively soft(er than the front) rear setup would exaggerate the understeer....what have you found?

vaj

iTrader: (7)

JM2C here... I <3 autox..

first off.. THOSE COILOVERS ARE ****.

Preload question - (even though no one asked me.) Preload should be set so that the spring TURNS easily with one hand but has no vertical movement. Have as little preload as possible. Too much and the springs will hold the car up, not the height adjustment. This leads to bump - BOING BOING boing.... Too little and its gonna be bump CLUNK CLUNK..

Heavy front bar vs light rear bar.

On Subarus, the stiff front sway bars help to limit the body roll, thus limiting travel on the suspension, consequently keeping camber more static. On a Subaru, the more the suspension compresses, the more positve the camber becomes. The result is understeer. Stiff FSB helps keep your negative camber negative @ auto-x. Also makes it feel like a live axle on anything other than smooth pavement but that's another story...

The rear has a better camber curve and needs a bit less bar to keep the car balanced. Set a bar stiff and, of course, it will oversteer.

Side note: If your tires aren't up to the task of the big front bars (or rears for that matter) you will get understeer. BFG KDW's plowed a little bit on my current setup (not an autox tire but all i had. )AO48 Yokos do not, car is neutral.

Sorry to be long winded. I think about this alot and thought I'd share it..

Dave

setup

-2.25 front camber
-1.7 rear camber
4.8 caster
0 toe all around.

27/29 set on 29 FSB
24-26 set on 24 RSB
helix coilovers set on stiff
14" ride height hubctr to fender front
13.5" ride height rear.
alk
srb

Risk3233

The big front bar lets me keep the camber during cornering. I do not notice too much corner entry understeer. You can limit understeer by driving style. I use a lot of the width of the track at corner entry and I use some small amount of trail braking at initial turn in.

I also don't have very high spring rates so I rely on big FSB to to help in corners. Our track is so rough and uneven that stiff spring rates aren't an option so instead I use large FSB and a large amount of caster with moderate spring rates up front.

I agree with the post above. I run a 24mm bar in back set to soft. I do not want the rear inside wheel to lift in corners. My car is able to absorb mid-corner bumps and still turn well. IMO getting the STi to corner means getting the front end to maintain traction and allow the rear to follow on corner exit. At that point, you can power on corner exit.

When I had the RSB and OEM FSB, the car would just understeer even more. IMO turning the STi isn't about inducing oversteer in the rear, but working in keeping the front end cornering.

I experience more corner exit understeer than on corner entry. I'm going to try a ball joint relocation kit down the road to see how that affects cornering.

iNfEk

iTrader: (33)

thank you for the infomation. I will go outside and remove the preload that i set on the coilovers last night since I was under the impression that i need to have no rotational movement and no verticle movement on the springs.

This is good info.

Any info on suspension tuning would help me a lot. Any books i could buy or download?

Jon

Risk3233

There are books out there that give suspension setup basics, but to really tweak the suspension, you need a lot of track testing. This involves not only driving, but also keeping records/logs of your settings and adjusting everytime you go on the track.

I keep a race log from every race/event. I track alignment, air pressure, ambient track surface temp, tire temps, rollover, etc.

vaj

iTrader: (7)

My friend Hawke has the sixgun racing ball joint relocation kit and he is very happy with its effect on front end grip. Puts lowered cars closer to the stock point on the camber curve.

Risk3233

With regards the ball joint relocation kit, that's what I've heard. I'm installing Ohlins fixed perches on my 04 STi as my next handling mod so I'll be adjusting to that change and making setup changes on those and then move on to the ball joint kit.

91sleeper

iTrader: (13)

while this sounds like a winner and something i definately will be doing, but that price seems just a bit high. must be my chang nature but i can't drop that much $$ on something right now. defiantely in the future if the price comes down.

islandx

iTrader: (3)

Wow you sound like you have thought alot about this. How is it that as you change the grip of a tire front AND rear that you will get a different handling balance ?

Forgive me, I always thought that if you add grip (ie, stickier tires) for both front and rear; the ultimate handling balance would remain the same, just give up at a higher speed/load.

This is of course assuming that driving style, and all other car settings remained the same.

Risk3233

I think you've kinda answered your own question. By increasing front to rear grip, the limits of adhesion are increased/raised.

This allows you to drive differently. There is no reason why you need to drive the same. Increased grip results in all kinds of different things on the track (i.e. slip angles, etc.).

Increased grip can turn a car that exhibits corner entry understeer to neutral entry. On my car, the OEM setup with a Perrin RSB resulted in corner entry understeer and the car did not like a lot of steering input on corner entry. Once my suspension went on the car including a large FSB, the car does not display corner entry understeer, and allows for some corner exit understeer. To combat this, I apply a small amount of trail brake (I know some disagree with this approach) after turn in but before apex. It seems to settle my car down for the apex so I can then just apply full throttle.

A different setup than mine would probably require a different driving style.

vaj

iTrader: (7)

Risk is right. All of these modifications cater to personal driving style. From what I've read, I believe Risk and I share similar auto-x habits and observations. Keeping logs is a great idea. I do the same for my car. The log book lives in the glovebox so I can note stuff around the island as well as the track.

ISLANDX- As far as tires and their effect... The easy answer is that the front and rear have different requirements for grip. The rear suspension has a much better camber curve and with less loading, needs less modifications to make it "work." Now the front end in the Subaru's is the "challenged" area. The front end needs lots of help to make it "work." I found that once I slapped on the r-comps I had the right elements in place to pull all of the rest of the suspension mods together. As risk described, this created a more neutral car where before I got lots of understeer (entry and exit of corner.) MUCH of this is style related. I have begun using less entry speed and a little "scandi-flick" to adjust the attitude of the car without losing speed. Hectic, but effective if done right.. I get it right about 30% of the time. LOL.

91SLEEPER - I agree that it's a lot of bread. FWIW this is a good mod if you've done any lowering, all the rest of the suspension bits and drive "competitively." Otherwise, the $400 could be spent on other susp. mods. Eventually, I'd like to get my car back on center in the camber curve but I'm working around it until I've got the bread... Thinking next year sometime. For now, it seems to be ok.. just not perfect.

INFEK - How about those CO's? They working well for you?

RISK - The Ohlins are awesome. You'll like em for what you seem to do with your STi. Since the perches are fixed, do you remember the height drop on these from stock? Just a question really.. but I think for your case the BJE's are a must have. I'm working around it for now but I'm wishing I had them. It would perfect my setup as it stands now. I'm still getting cooler front outside edges on my Yoko's @ auto-x with my Helix's maxed at 2.25deg negative. Only way to get more would be with the BJE's...

iNfEk

iTrader: (33)

vaj,

yes the coilovers are awesome form what i can tell right now since i'm still technically in the break in period.

our next auto-x event is on the 15th of october. hopefully i'll be able to get aligned and corner balanced by then providing my work schedule allows. it sucks that i'm only off on Sunday right now and every knows that nothing is oopen on sundays. to the people doing my schedule at work.

NOW THIS IS THE I-CLUB THAT I REMEMBER BACK IN THE DAY. we used to get in trouble from alex for creating technical threads and discussing them. this to me is technical but not as technical is this thread could be. I'd like to learn more about this part of my car to make me a better driver and so that i can control it

Thanks

Jon

Risk3233

As for drop measurement, I'll have to consult my logbook which is in my car, not in my glovebox, but in a visor caddy. Ultimately, your suspension setup and driving style will play off one another.

For example, here on Maui, our track surface is very rough and uneven. Higher spring rates just cause the car to skip and bounce all over the place. At our track, bump travel (droop) is your friend so you have to account for that in your setup and your driving style. Again, for my style at my home track, I use moderate spring rates (JDM Pinks) with large FSB and soft RSB. Lots of camber and caster. I routinely see 3rd gear pulls here on Maui. Our track is very long and very fast.

I got to drive the August event at Aloha Stadium (in a borrowed VW GTI) and my setup would probably not be the hot setup there since the track is smooth and very tight.

Also, my driving style accounts for the the less than smooth surface.

vaj, no kidding you do the "flick" in Solo. Man that's tough. That's too risky a manuever for me. I just use a little trail brake right before apex to set me up.

iNfEk

iTrader: (33)

i'm thinking about that 6guns piece. kinda pricey but if it works gotta pay to play.

also, how low is to low?

Jon