Suspension Setup Q?

[BlackParis]

My stock struts are completely blown... I am in desperate NEED of replacement... My car has just as much body roll as it did stock, but with springs and swaybars...

I already have Tanabe Springs, that lower the car .5 inches and are ~280 lb/in
Should I:

300$ for KYB GR-2 (non adjustable)

500$ for KYB AGX (Adjustable)

650$+ for height adjustable coilovers (NEX~600, Tien basic ~700)

I only have about 400$ right now, but I can probably save up more if I think it is worth it.... I know that for the struts I'll have to buy the spacer thing for the top hats...

I will be doing some Auto-X and Rally-x... I do DD the car but I'm not to worried about comfort one bit.... This car will become dedicated Rally-X car once I fix my Integra and can run that @ auto-x...

[sebhockey]

Go for the KYB AGX, this setup will be better than any sub $2,000 coilover sets.

[I Like It Sideways]

Where are you sourcing the KYB's from? I got my AGX's for $412 shipped last year. I can vouch for their daily driveability and their quality in rallyx. They've put up with quite a bit of abuse. I have the Ground Control coil sleeves to go with the AGX's, and so I get ride height adjustability and damping adjustability.

I don't know about AGX's being better than cheaper coilover sets (Megan Racing has a good product line ~ $800), but they are a good bang for your buck.

I wouldn't go with the Tein Basic simply because they aren't designed for rallyx. Then again neither are the AGX's. But I've had good experience with them

[BlackParis]

Ok How about AGX vs. Tokico D-Specs?

I'm just using ebay for prices... Where did you get em for 412$?

http://cgi.ebay.com/ebaymotors/KYB-AGX-STRUTS-SHOCKS-SUBARU-WRX-SEDAN-02-03_W0QQitemZ160138835927QQihZ006QQcategoryZ33590QQ ssPageNameZWDVWQQrdZ1QQcmdZViewItem
~475$

O and where is the adjustment knob on the AGX?

[I Like It Sideways]

On the fronts, there is a screw you turn, 4 way adjustable. On the rears, the knob is on the bottom portion of the strut housing, on the opposite side that the strut mounts to the knuckle.

I couldn't give any input on the D-specs :(
I'm currently looking for the supplier I got them from, once I find them I'll post them up


EDIT: Just looking around at other suppliers, I'm glad I got mine when I did, it looks like prices have been raised a hefty amount. Z-1 Performance usually has good prices, but they marked them up to $555. Haha go figure

[409industries]

I would definitely advise against using a Tein setup in the dirt. The Koni's or KYB's sound pretty good.

I was in a similar situation as you last month. I ended up just buying another set of stock struts used that had about 20K miles on them. They ride great!

[BlackParis]

Ok... One last dumb question...

I JUST... got my car aligned 2 weeks ago...

-2.7 camber front
-3.0 camber rear
0 degree toe f+r

and Amzingly 6.3 degrees of Caster ;) (I think stock setting was 4.8 )

Is that tooo much camber for dirt play? I have an auto-x in about a month, so I will get to test my settings out then...

Should I go with a little less camber for rally-x?

[UP2MTNS]

how did you get that much caster? do you have an antilift kit?

That's a lot of negative camber.....


I'm curious to see what the travel is for the two different KYB's vs the coilovers you mentioned???

[BlackParis]

yep ALK and Max-c "M" Plates..

I have them to half way, so I am picking up an extra 1.5 degree caster from them...

I have SPC cam bolts.. They allowed me to adjust out up to 2 whole degrees... ( I think if I cranked Everything to the most negative it can be, fronts would be around 5degrees camber :twisted: and rears could easily pull 4.5 :twisted: )

[JacksonRally]

That extra caster is what subies need, dirt or track. It should help reduce understeer. As far as the camber your settings should do just fine on/off road. I would run about 1/16 toe in in the rear though.

[lorenkb]

A little OT here, but I'm a suspension noob seeking knowledge...

Drtywgn, how does the extra caster reduce understeer? Is it because of the added camber while steering?

[UP2MTNS]

A little OT here, but I'm a suspension noob seeking knowledge...

Drtywgn, how does the extra caster reduce understeer? Is it because of the added camber while steering?

caster is the angle of your struts forward/back (in the direction of travel). so adding positive caster puts the wheels farther back and increase the front/rear weight ratio. Which is why its called an anti-lift kit....with more weight forward, the car will lift less while under power (particularly when cornering).

As far as helping reduce understeer....not sure about that. I guess technically the wheel base is shorter so your turn radius is shorter.

[BlackParis]

Addind caster also increases the Dynamic Camber, which should also improve grip ;)

[JacksonRally]

A little OT here, but I'm a suspension noob seeking knowledge...

Drtywgn, how does the extra caster reduce understeer? Is it because of the added camber while steering?

Weight transfer. You prob. will only notice little is your subie but put your car in the driveway sitting idle/still turn your wheel rapidly left and right you should notice that the car ossilates/body rolls slightly (hard to detect with stock caster settings). The direction you turn the wheel that side of the car will slightly lift due to the caster angle, in return it transfers weight to the outside tire giving you more traction and reducing the slip of that tire. You might try this with a truck or something with less anti-roll bar (even though our wagons are soft). Also (but even more difficult to explain) a dramatic increase in Ackerman helps reduce understeer....ahh I love vehicle/suspension design (its what I do)

[lorenkb]

Oh, now you've done it. You let the cat out of the bag on you designing suspension! Be prepared for lots of questions, the first being: What exactly is Ackerman?

Getting back to caster: When you turn the wheel, shouldn't both sides attempt to lift the car? I can see how it would add more camber, but I'm having a hard time picturing how just the inside wheel would attempt to lift the car.

[JacksonRally]

Oh, now you've done it. You let the cat out of the bag on you designing suspension! Be prepared for lots of questions, the first being: What exactly is Ackerman?

Getting back to caster: When you turn the wheel, shouldn't both sides attempt to lift the car? I can see how it would add more camber, but I'm having a hard time picturing how just the inside wheel would attempt to lift the car.

Explaining anything about suspension is difficult. OK theres also SAI(steering axis inclination) and/or KPI(king pin inclination) they are the same just 2 different names. Now draw an imaginary line from your lower balljoint to the pivot on the top of your strut, that is your SAI(the line actually ends at your tire contact patch, the closer to the center of the contact patch the better). If you are looking at the front of your car the lower points (lower balljoint) will be wider than the top (top pivot on strut) so the angle will fall inboard. With that angle inboard and looking at your car now from the side, angle it toward the rear and that is your caster angle. When the wheel turns on that axis the inside tire will lift the car/weight transfer to the outside tire. The lift is minimal with stock to mild caster settings, we just need to know that it weight transfers.

Ackerman has to do with steering geometry. Having Ackerman your inside tire (in a turn) will turn more than the outside tire. You want this because the inside tire travels less distance and on a tighter radius than the outside tire. Increasing this and/or making it progressive is desirable. Less rolling resistance and less inside tire scrub is the result.

It goes on and on.......

Yea I know what Im in for, and it will usually turn into some sort of argument. Whats more important is someone can learn something and go out and tune their car. After all its the driver thats gonna notice a change(especially the wrong ones)!!!

If it at all confusses you I can probably explain better in person with some simple household items. LOL

Kyle

[JacksonRally]

Also caster is where you get the "return to center" effect at the steering wheel. IE..your in a turn and you take your hands off the wheel your car should straighten out/steering returns to center. And maintains straight line stability......funny cars and dragsters have a ton of caster.

[lorenkb]

Aw man, I'm like a kid in a candy shop!

OK, so let me see if I understand this. If you were to have a zero degree SAI, adding caster would not in fact lift the inner turn side of the car. As soon as you have both SAI and caster is when this comes into effect. If for some crazy reason you hade SAI in the opposite direction you would be lifting the outside of the car instead.

Roger on the Ackerman, makes perfect sense.

Is there a way to add damping along with caster? I know that caster will provide the returning force to center, but you can still have an oscillation without the right amount of damping.

Loren

[409industries]

Caster is still somewhat of a mystery to me... how it affects other elements of alignment.

I finally said screw it and paid to get my car aligned by a shop i used to always go to, and my car feel much more stable than it has been in recent months...

[JacksonRally]

Close...but zero SAI and some caster will lift the car........(take a broomstick, place it on the floor upside down and vertical/completly level so you can spin it, now attach something to it at a 90 deg angle so it looks like the #7, and spin it the top of the 7 will remain horizontal, now keep the broomstick on the floor and lean it over then spin it on that axis, if you lean it over enough eventually the tip of the 7 will hit the ground...lifting the broomstick)

Think of zero SAI like an old school go-cart, the tire will "sweep" when turned and actually change wheelbase!! With SAI at the center of the tire contact patch on the ground the tire will pivot there and not sweep. Now the reason the SAI is inboard (top pivot on strut)and not vertical is because the whole strut suspension package would not fit inside the wheel...among other things. Now with a "dual a-arm setup" (upper and lower control arms) the SAI goes through the upper and lower balljoints.

[JacksonRally]

Caster is still somewhat of a mystery to me... how it affects other elements of alignment.

I finally said screw it and paid to get my car aligned by a shop i used to always go to, and my car feel much more stable than it has been in recent months...

Yea if you just dont have the time to mess with it go to an alignment shop. The biggest mistake people make is not having their car aligned after lowering it. In a perfect world it wouldnt matter, but thanks to this thing called bumpsteer you end up toeing out your front end. I have yet to pull apart my strut to cycle my wagon but I think subies are pretty good on almost zero bump steer but Im sure theres room for improvement. Either way its probably minimal and some toe out (though I dont like it) will increase your Ackerman :lol:

[JacksonRally]

BTW...SAI is fixed, it is built into the initial suspension design.

[lorenkb]

Close...but zero SAI and some caster will lift the car........(take a broomstick, place it on the floor upside down and vertical/completly level so you can spin it, now attach something to it at a 90 deg angle so it looks like the #7, and spin it the top of the 7 will remain horizontal, now keep the broomstick on the floor and lean it over then spin it on that axis, if you lean it over enough eventually the tip of the 7 will hit the ground...lifting the broomstick)

Think of zero SAI like an old school go-cart, the tire will "sweep" when turned and actually change wheelbase!! With SAI at the center of the tire contact patch on the ground the tire will pivot there and not sweep. Now the reason the SAI is inboard (top pivot on strut)and not vertical is because the whole strut suspension package would not fit inside the wheel...among other things. Now with a "dual a-arm setup" (upper and lower control arms) the SAI goes through the upper and lower balljoints.

Hmmm, I think I have some misconceptions about how the suspension/steering is physically set up. I'll have to jack the suby up and take a careful look. The way I am invisioning the suspension now I would think that zero SAI with camber would cause both sides to lift equally in a turn.

[JacksonRally]

Hey lorenkb looks like were gonna have to meet up at the next race or DI meet, I can probably shed more light in person.

[BlackParis]

Ok... So I need a new alignment... I bent one of my Rusty stock heavy Steel Control arms ;)

My buddy is selling a pair of '04 STi Aluminum Control arms, SO I am going to his place to pick those up saturday, ALONG woth a stock STi catback and an Aluminum STi hood ;)

[sebhockey]

Ok... So I need a new alignment... I bent one of my Rusty stock heavy Steel Control arms ;)

My buddy is selling a pair of '04 STi Aluminum Control arms, SO I am going to his place to pick those up saturday, ALONG woth a stock STi catback and an Aluminum STi hood ;)

Youre gonna need sti endlinks and rear sway bar too with those.

[I Like It Sideways]

Keep this information coming! Lots of excellent information in this thread. I've never read up on ackerman before.. and I could always use a refresher on caster. Good stuff

[RoadRunner]

I have GR2's on my 93. They're good, but only a little better than stock. I would go for the AGX's personally.

[BlackParis]

Ok... So I need a new alignment... I bent one of my Rusty stock heavy Steel Control arms ;)

My buddy is selling a pair of '04 STi Aluminum Control arms, SO I am going to his place to pick those up saturday, ALONG woth a stock STi catback and an Aluminum STi hood ;)

Youre gonna need sti endlinks and rear sway bar too with those.

Gheyness... LoL, well then I better get searching! Thanx!

I think he has one.. HOPEFULLY... If not I'll wait till I can afford ANOTHER Perrin...