interesting way to get rid of understeer

[hamlet9634]

ok.. haven't actually DONE this yet.. but the tires are sitting in my apt ready to go on when the weather clears up.

I have 1/2 tread yoko parada II (205/45/16) on the rear.

will have brand new falken azenis (215/45/16) on the front.

the yokos SUCK ASS.. slide around with NO grip. (i can spin wildly through 2nd gear right now).. had azenis before and they stick like glue..

think this'll give me some oversteer at the track?

[SiRman]

The ideal setup is to have all four tires sharing the cornering load equally. For a given corner speed you will need a certain amount of grip. If your rear tires are worn out, now the fronts have to work twice as hard to hold the car.

Yes your car may turn in quicker but the ultimate trade off will be mid corner holding grip, and you'll end up going slower or spinning out.

[hamlet9634]

except that as it is.. my car pushes right through the corners (the load ISn't being shared equally). I've already upgraded the rear sway bar, and it wasn't enough. I don't want to remove the front sway bar (making the car too soft up front maybe).

I'm trying to balance out an understeering car by transferring more grip up front.

[SiRman]

What kind of driving are you talking about, roadrace track or autocross?

Removing grip from the rear will not add grip to the front, just change the balance.The front will break away at the same point, and the rear will now break loose earlier.
Seems like maybe a driving technique issue. (I'm no trying to tell you what to do here, I'm not expert myself).

What is your suspension setup: what springs/ coilovers?

[hamlet9634]

JIC coilovers, with the original spring set-up (8Kg up front, 9 in back). I've got the front damper adjustment set to 4, the rear to 15 (hardest).

I'm planning on swapping out the rears for a set of harder springs (haven't decided on how hard, yet). And i'm talking about autocrossing mostly.

Here's the thing, though. Take a constant-radius offramp. If i start the corner at a given speed, and slowly accelerate mid-turn, the car pushes at the front. I'm not talking about slamming the accelerator here. Constant radius turn with slow acceleration. The front breaks away first. I WANT the car to be more neutral.. or even for the rear to break first.

And i'm not removing grip from the rear. I'm adding grip to the front while keeping the grip in rear the same. I tried this set-up with my previous car (street tires in the rear with azenis up front) with VERY good results. Moved way up in the standings in autox with the rear swinging around nicely around the corners.

[ConeCrazy02]

Best advice is to try it in a speed that you're comfortable with, then make your conclusion. I only wish I have the money to do this.

[BlasTech]

I have a silmilar setup, but with 8kg/10kg and the CTR sway bar in the back. Im still getting it tuned.

I also use azenis exclusively, and the only advice I can give you is that the suspension mainly effects the initial part of the turn.... after that (once the load has done its transferrence) its a matter of a couple of small things and one big thing: your input.

Toe settings can be adjusted on both font and rear to lend more cornering stability, and tire pressures (especially on Azenis) will effect the rate of breakaway and stabiltiy in cornering. I used to have my rear tire pressures high, to make the rear come around, but I found it would get to squirrelly in slaloms, so I switched to lowering the rears about 6lbs less than the fronts, and this will also give you breakaway, but at a more gradual pace....this only works with azenis to the best of my knowledge.

As for driver input, once you are accelerating through a sweeping turn, the weight of the car shifts (gradually) to the rear wheels, and you start to scrub uo front. If you lift the throttle... just a bit, the rear will scoot around a few degrees, and you can get back on it. Practice this in auto-x, not the road, because you can lose control and come around if you lift too much.

A more advanced technique is trail braking, where you gently use the breaks while giving gas through the turn to shift the weight forward, as well as break the rear wheel's traction. I cant do this, yet.

There's not any reason you shouldnt be able to get some wild oversteer with your setup, unless your alignment is totally f'd up.

Now on the other hand...

In Japan, its not uncommon for togue guys to use different tires (grade or size) front and back, especially on fwd cars (they do downhill pretty well for obvious reasons). So its not necessarily wrong, its just not commonly practiced in the US, so people dont know how to do it properly. Of course, in the long run, there is some drawback, as you cant rotate your tires.

If I were you, Id ask Chris Shenefield ( chris@redshiftmotorsports.com ) a past STS national champion (in an older civic) and a guy who's supposedly now getting into the American drifting scene. He may have some insigts about using different tires too.

Also find Chunky, who has autocrossed with a dual tire setup.

It sounds like you're in the position to just try it, by buying a pair of Azenis...and if it doesnt work, get another pair... but PLEASE, dont find out its too wild by dying on an exit ramp! :angel:

[SiRman]

That may work for autoX, where you aren't doing super fast sweepers.

Something doesn't seem right though.
In my car(Spoon springs,22mm CTR rear sway, stock tires,ALex front strut brace just added):
On a on ramp the inside rear is usually the fisrt to start chirping.
The rear def. breaks before the front.
As I apply more throttle exiting the turn(+90km/h) then the front starts to push a little.

[SiRman]

There ya go Blastech is here, he's the auotX man!

[BlasTech]

Originally posted by SiRman
There ya go Blastech is here, he's the auotX man!

Heh, I'm still a little minnow. There's guys in my clubs who can get in my car and own the day, then walk off like, "whatever".

Im just a bit obsessive. :D


I have to admit, I've thought about throwing the stockies on the back for a spin, but I imagine the initial breakaway will be too hard to control to justify the mid-corner benefits.

[Eee Pee]

Your idea is something a lot of E prepared drivers do, including me.
I run 20x9.5x13 in front, and 20x8x13 in the rear.
These are Hoosier road race slicks.

The idea is to maximize the front grip, hence a 9.5 inch wide front tire.
Maximize the front grip, and tune the balance of the car in the rear with the tire, and wheel rate of the suspension.

The only difference is, E prepared cars are in search of ultimate grip.
We run a narrower rear tire so we can get some heat into the tire, more heat, more grip.
Maximize ultimate grip, get the balance the way you prefer with the spring rate, and drive the heck out of the car.

If you have ever seen a JDM race car with wider, and bigger front tires, it's the same concept.
Maximize front grip at all costs, then tune the balance of the car with whatever means you have availiable.

Congrats, you've taken a step forward.

Excellent.:D

Here's a JDM setup for ya for some inspiration.
http://www.imagestation.com/picture/sraid55/paa773a94969011b1d2b2209aa31f8c62/fc7ebdc2.jpg:D

[hamlet9634]

glad there's some guys out there that have tried something like this.

and yes, i plan to learn how to use this set-up on the track (auto-x) in controlled conditions. I rarely drive at the limits in the real world (too scary).

First the tires.

Hey BIas tech, do you feel balanced with 8/10 springs, or do you think 8/11 or more of a difference would add to your set-up?

Unfortunately, it isn't JUST tire size i'm playing with, though. Azenis has a world more grip than the yokos, so i'm using a grippier tire in a wider size.. which might prove scary.. and azenis doesn't come in enough sizes to just play with size.

Yeah, i'm nervous about this.. but we'll see how it works. Full report when i get to run this .. which won't be for a couple months at least.

[BlasTech]

Originally posted by hamlet9634


Hey BIastech, do you feel balanced with 8/10 springs, or do you think 8/11 or more of a difference would add to your set-up?


Ill let you know as the season goes on...I'm keeping an online autocross diary this year at http://www.dmcknight.net.

As for the one practice event I've had on them, it was raining and cold, and I had some oversteer with an uprecedented ability to correct and recover, so there's good and bad...I'm coming from a pretty successful year of autocrossing on almost-stock suspension in STS, so its like starting over with a different (better-looking) car.

In Austin, I autocross in 3 clubs in 'tire melting heat' so by the end of April, I hope to have a decent tune-in for general auto-x on the JICs.

Eee Pee, when are you gonna take your EP out for G-stock?

[chunky]

Originally posted by Eee Pee
Your idea is something a lot of E prepared drivers do, including me.
I run 20x9.5x13 in front, and 20x8x13 in the rear.
These are Hoosier road race slicks.

The idea is to maximize the front grip, hence a 9.5 inch wide front tire.
Maximize the front grip, and tune the balance of the car in the rear with the tire, and wheel rate of the suspension.

The only difference is, E prepared cars are in search of ultimate grip.
We run a narrower rear tire so we can get some heat into the tire, more heat, more grip.
Maximize ultimate grip, get the balance the way you prefer with the spring rate, and drive the heck out of the car.

If you have ever seen a JDM race car with wider, and bigger front tires, it's the same concept.
Maximize front grip at all costs, then tune the balance of the car with whatever means you have availiable.

Congrats, you've taken a step forward.

Excellent.:D

Here's a JDM setup for ya for some inspiration.
http://www.imagestation.com/picture/sraid55/paa773a94969011b1d2b2209aa31f8c62/fc7ebdc2.jpg:D

my sentiments exactly. there's nothing wrong with staggering the wheel sizes.

For awhile, I had to do the same. I was on a stock setup with 225/50/15 tires in front, and stock in rear. The car rotated nicely, and behaved as if there was a rear sway on corner entry. However, if i made a mistake, the less availible grip in the rear made it more difficult to recover.

For an auto-x setup, staggering tire sizes would yield excellent results b/c corner entry is the name of the game in auto-x. However, on a road course, I'm not sure that i would run a large stagger due to the fact that having that much grip up front, and that little in the rear makes it difficult to recover from mistakes.

With my current setup (see sig) the car feels neutral in all but the hardest turns. I still want a stiffer rear, but the car is really fast the way things are now.

[Eee Pee]

Originally posted by BlasTech
Eee Pee, when are you gonna take your EP out for G-stock?
Well, I know better than to mess with the Ep3 for GS...
I wish it was a good car for GS, but the body roll, high ride height, and small rear bar just don't cut it.

If anything it's a good candidate for STS.
But when one has a fairly fully built E Prepared car, on slicks, that's pretty fast, it's (STS) just not where I want to go.

Pardon my whoring....
http://www.imagestation.com/picture/sraid74/pf34087e905f6afe4e3f561d77219e049/fb64653e.jpg
http://www.imagestation.com/picture/sraid60/p3f3a98080ef4e26f363c79dec4bf2e02/fc565e84.jpg

[glw]

insert -2