Trail Braking and Rotation Questions

[Dezoris]

So just finished first two autox.
First weekend in FRS (RS3) and second in S2000. (RS3v2)

Totally different cars but one thing that bothers me is while the FRS is far more stable in the rear and putting power down is rarely an issue, I cannot get the car to trail brake with or without pedal dance

In terms of autox I'd say it critical.
So without changing much what are my options?

• Firm up rear rebound of shocks?
• Less rear toe?
• Rear sway bar?
• Brake Pad choices?

(If you had any questions about switching to the Sony Action Cam the S2000 video should convince you.)



S2000 Run:
[ame="https://www.youtube.com/watch?v=mnhplGM2F38"]S2000 Autox Test Hankook RS3 v2 | In Car Only - YouTube[/ame]





FRS Run:
[ame="https://www.youtube.com/watch?v=aDWA8YeknWY"]Supercharged FRS BRZ Autox Test | In Car Only - YouTube[/ame]

[juliog]

Originally Posted by Dezoris

I cannot get the car to trail brake with or without pedal dance

Do you mean the car is still actively messing with your braking or?

Also I see you are running RS v2, noticed any difference relative to v1 so far?

[Dezoris]

Originally Posted by juliog

Do you mean the car is still actively messing with your braking or?

Also I see you are running RS v2, noticed any difference relative to v1 so far?

I don't feel the car interfering, it just feels like there is no rear brake bias or the rear won't unload enough to trail the ass around. Should I soften the rear?

The v2s got up to temp fast and did not have that rubbery feel to them like the old tires did when cold. But once the temps rose the tire pressures jumped almost 8PSI. (50F to 65F Outside) I had to keep the pressures low to keep them from feeling slippery.

Since I am still near full tread depth and its only my first autox on them, it's hard to make any conclusions. They are still a fast tire but for me they felt more slippery in the heat. Thats not scientific and I dont have track time on them yet.

[juliog]

Running same pads F/R?

[CSG Mike]

What year AP2? Stock suspension?

S2k's have a slight rear bias

[rice_classic]

Originally Posted by Dezoris

(If you had any questions about switching to the Sony Action Cam the S2000 video should convince you.)

Sure does look good. That image stabilization is remarkable.

[Dezoris]

Originally Posted by juliog

Running same pads F/R?

Actually no and thats one thing I am going to change before this weekend to test. Currently it runs HawkHP Front (supposedly worse than stock) and OEM rear.

For this weekend going to 1521 squared.

Originally Posted by CSG Mike

What year AP2? Stock suspension?

S2k's have a slight rear bias

Completely stock car, aside from modified alignment, RS3 tires 225/255s. Carbo1521s Squared from you and old Centric Cyro Blanks Front.
2005 MY. (Pre DBW and TCS non-sense.)

Originally Posted by rice_classic

Sure does look good. That image stabilization is remarkable.

If you saw how much the camera was vibrating on the mount its crazy how well it works. It does cut into the sharpness of the image but for car videos I will take loss of that over having stable footage.

[Element Tuning]

Let's see you have wider tires in the rear than the front and you have more brake pad up front but oem in the rear. I have no idea why it won't rotate.

You should have stuffed the 255s up front

[Dezoris]

Originally Posted by Element Tuning

Let's see you have wider tires in the rear than the front and you have more brake pad up front but oem in the rear. I have no idea why it won't rotate.

You should have stuffed the 255s up front

That was the S2000 tire specs.

FRS has 235 squared.

[icemang17]

interesting....I find my FRS quite loose.....almost too much really....but the stock tires don't help either.... If you need more rotation you can adjust tire pressures by increasing the end you want less traction, but that could hurt putting power down too

You could try aligment....a touch more toe out up front should help rotate the car...or less toe in out back

[rice_classic]

Take off the front sway bar. If you're trying to induce rotation with trail braking and it's not happening then you can make the front work better or the rear work worse. It's RWD so don't make the rear work worse. Take off front sway which should allow the front to work its contact patch better. Also make sure you have enough camber to maximize front contact patch. The S2k has a pretty aggressive dynamic camber gain up front, the FRS has almost none so it will probably need more static camber to do the same thing.


Without going into a technical dissertation on shocks and springs I will just say, set your shock valving to accommodate spring rate, after that leave them alone. Do your setup aydjustments with ride height, spring rate, sways and alignment.

[SubiePig]

What swaybars are on the car now? What are the spring rates on the Ohlins? Defiantly use same pads front and back.

[CSG Mike]

Originally Posted by icemang17

interesting....I find my FRS quite loose.....almost too much really....but the stock tires don't help either.... If you need more rotation you can adjust tire pressures by increasing the end you want less traction, but that could hurt putting power down too

You could try aligment....a touch more toe out up front should help rotate the car...or less toe in out back

Is your FRS loose, your steering input too rough, or are you just too aggressive with the gas?

The FRS understeers at terminal cornering speeds, regardless of tires. If *just* a tire change magically eliminates your oversteering, then the oversteer was driver induced; you don't change the balance or dynamics of the car with just a tire change.

[Dezoris]

Originally Posted by rice_classic

Take off the front sway bar. If you're trying to induce rotation with trail braking and it's not happening then you can make the front work better or the rear work worse. It's RWD so don't make the rear work worse. Take off front sway which should allow the front to work its contact patch better. Also make sure you have enough camber to maximize front contact patch. The S2k has a pretty aggressive dynamic camber gain up front, the FRS has almost none so it will probably need more static camber to do the same thing.


Without going into a technical dissertation on shocks and springs I will just say, set your shock valving to accommodate spring rate, after that leave them alone. Do your setup aydjustments with ride height, spring rate, sways and alignment.

I will attempt to disconnect it, if going with square pads don't do anything.
I feel like the damper settings are very good. I have a tone of grip and stability. I attached my alignment, with my driver weight and gear on.

Originally Posted by SubiePig

What swaybars are on the car now? What are the spring rates on the Ohlins? Defiantly use same pads front and back.

I went back to stock sway bars because Ohlins did all their design with that in mind.

Spring rates are 343lbs all corners.