Clipse3GT

iTrader: (10)

So over the fathers day weekend AutoX, I was running the Hoosier A6's. I started to get a wearing out the outside tire edge on the front tires...

I noticed the first 1-5 runs were typically pretty fast, then after the 5th run the tires started to "let go" started to get greasy. After much more research I found that there is a mixed bag of tire temps to run these tires at. From general notion, running lower tire temps up to the 120F range is key, over that an the A6's will get greasy and you need to get a water sprayer to cool them.

So I started running the tires at 38 psi front and 32-33 psi rear.

Note:

Car: EVO X AWD
Weight: ~3500 lbs
Front: -2.5 maxed per camber bolts
Rear: -1.3

Tires & Wheels

Enkei RPF1 18x10.5 +15
Hoosier A6 285/30/18

Suspension:

Swift Progressive springs
Springs ...................... Front Rate ........ Rear Rate ...... Front/Rear Drop
Swift Sport Mach ........ 2.7 - 4.3 kg ...... 2.3 - 4.4 kg .......... 1.0" / 0.6"

Front White Roll Center Alignment Kit

COBB Front Sway Bar (Softest Setting)
COBB Rear Sway Bar (Stiffest Setting)


I think that I am not running enough camber for the Hoosier A6 285/30/18 tires or that the suspension is TOO soft and I am running on the outside edge and the tire has much more grip that the suspension is able to handle.

My solution theory:

Replace: Front Rubber Control Arm Bushing with Urethane Whiteline Bushings
Replace: Front Rubber Control Arm Primary Bushing with Perrin Solid Metal Bearing Bushing (adds 1 degree of caster)

Replace: Suspension from the Stock Strut and Swift Spring Combo to:

Full Coilover Suspension:

Either:

AMR Engineering: 10k/11k Inverted Monotube Coilovers (built with custom valving)

or

AST 4100: non-inverted Monotube Coilovers (built with custom valving)


Or I am running totally wrong tires pressure...

I used the Hoosier tire charts...

Roadrace/Track Applications

Vehicle
Weight
Recommended
Hot Pressure
Cold
Pressure

1800-2200 lbs
34-37+
26-31

2200-2600 lbs
35-38+
27-32

2600-3000 lbs
37-41+
27-32

over 3000 lbs
38-43+
27-33


+ Higher pressures will improve the performance capability but will require a more sensitive feel to take advantage of the increase.


Shameless Plug...

tearitdown9

this tends to happen with those soft tires with the back and forth pitching of autocross courses...increased camber and better struts will help more even wear, but it will never be perfect...i have the same size tires only in a V710. i was too considering the ast struts but only the 5100 but ill probably end up with Robispec kw clubsports.
your car looks good out there....any vids?
cheers,
jon

ps how much power are you putting down? and how are you placing in your region in SM?\

GTWORX.com

iTrader: (35)

Right on....it's both!

Coilovers and more camber will help. The car is rolling too much with those ultra sticky tires due to the soft springs and it needs more static camber to account for the dynamic camber loss. Even with coilovers, you'll want more camber then -2.5.

I would do the bushigns you mentioned, those always help. Might be worth at least trying the stiffer setting on the front bar and see what happens.

I don't know anything about the AMRs and have not seen any data on them but would be interested if they offered it up.

AST is great and has been used with success on EVOs, BMWs, Subaurs, etc. The 5000's have been out for a while and the less expensive 4000's are currently in production, still waiting though. Built to order with Swift springs in any spring rate. The first shipment for EVO X is all spoken for at this point, so it would be a bit of a wait, possibly this fall/winter.

Ohlins are a good alternative that is available right now, but for your uses you would need custom springs and the price is getting up there.

- Andrew

evodave

iTrader: (546)

haha ....so now do you believe what i told you Kris! you need to do a few things

get real suspension ....you know what i recommend , and no your not going to get a caddy ride and a great autocross coilover , just leave your purse at the door cause even my car rides fine lol. The suspension is the main difference in our cars (just the custom kw's and hyperco's i run, i am only running rear sway) and the difference and alignment. Your making more power then me too .


After coilovers you need to let me know and come to the shop we can setup the car .... your car is GOING to lean no matter how stiff the springs, how aggressive the drop, how crazy the swaybar settings and so on...it has to you want it to , to some extent. Your alignment is whats killing you more then anything and honestly PER car basis its hard to judge your needs.

You need to get something to mark the outside of your tires (i have it), tire pyrometer (i have it) , REALLY good pressure gauge ( i have it) and then start at mid/upper 30s front and 3-5 psi lower rear (or higher if you want to make the car rotate more) then see at say -3 front,-2 rear what your pressures are changing to and what the temps across the tire are. Also, once ya roll them over and remove your marks you will get an idea (like i told you the second i saw your tires) more camber , but too much of a good thing is bad also. get past -3.5 and you can't stop in a straight line for crap lol.

I am working on getting some custom stuff going soon and i will chat with you this week about it. But what i want to achieve is someplace that will let me specify what i am looking for , then i want to team the shocks with hyperco's and the plates i want to use (prolly vorschlags) and some other tricks/goodies.

goofygrin

iTrader: (5)

What class are you running? Those bushing really f' you with SCCA classing rules.

The other guys have it right. -2.5* camber isn't nearly enough. A6's want >3*. Try and get it at the strut/knuckle mount rather than with camber plates though (as much as clearance allows). It keeps the SAI angle in check better. If you wanted to go the cheap route for this, get SPC camber bolts for the LOWER bolt hole (they'll work opposite what the instructions say in that hole) and you'll get another degree or so of negative camber. Easy and cheap way to experiment ($25 or so).

ETA: with A6's I was running well over 40psi in order to keep them from cording prematurely. The car felt very loose, but in actuality it had a TON of grip and I just had to quit being a sissy.

GSXR

iTrader: (3)

Holy body roll!

More camber and stiffer rear. I'm in the same boat. I'd like to get some coilovers and I'm leaning towards the KWs just for the double adjustable feature.

Hiboost

iTrader: (9)

The stickier the tires, the more important a well balanced, stiffer suspension can become. Like others have already suggested go with a nice Coilover setup with 10k front/12k rear springs if you are using this car on the street as well and shock settings on the stiffer side for auto-x will help limit how much body roll and tire roll you will get when throwing the car around. You'll still have to play with tire pressures somewhat but ditching those lowering springs with stock shocks is key to getting better results.

Those sway bars should be fine to stick with, but try and mvoe to -3* camber front and -2* camber rear in the alignment. Zero toe front and slight toe in at the rear should keep tires alive longest but if you are going all out you can do some slight toe out up front based on how aggressive you want the car to turn in and your willingness to replace tires.

kanyonkid

iTrader: (33)

damn thats alot of rubber!! And insane pix!! Your way past ready for some custom valved/setup coilovers... spend the money