I have an slight issue dealing with keeping the car stable under hard braking. On my track (shannonville, for those who knows) at the end of the straight I am required to slow the car down from 170km/h to about 100km/h or so within a very short distance.

When i brake hard, my car gets squiggly and unstable. I am running stock AP1 wheels with 205/225 RA1s with Seidouya pads in the front and endless street pads in th back. When I used to run HP+ in the back in combination of the same pads in the front I felt the car was more stable under hard braking, but that was a while back so I dont remember all that well..

My question is, what can be done to improve braking stability while keeping the same tire size? My gut instinct tells me to get a more aggressive pad in the back to match the stopping power of the front.

Btw, I rode in borbor's 245 non staggared setup on the same weekend and his car could brake a lot more stable than mine. He is running carbotech XP10s in the front (i believe) and OEM in the back..

Any help is greatly appreciated!

 

Instability under braking can also be an alignment issue. How's the front toe set? When's the last time you had it set?

As far as your pads go, is that a combination that's supposed to work? Why not try some proven compounds?

 

I am running zero toe in the front. I had it set at the beginning of the track season in april, maybe that is the problem.

Pads wise the one I am running on the front are in the similar performance range as the USDM race pads. The problem with the rear pads is that I wrongfully picked a pad that is too mild for track use. I am curious as to if I swap out the rear pads for some more aggressive compound whether braking stability would increase.

Aside from alignment, brake pad compound, and tire sizing, are there any other factors that affect braking stability at high speeds? Maybe aero? ..

Thanks guys

 

if you have coil-overs, corner balance may help.

 

Are you running unshaved RA1's? The first time I ever used R comps (unshaved Nitto NT01's), the car would squirm left and right in the hard braking zones. It went away after a couple of track days.

 

Set rear toe-in to at least 1'8" total (1/16" per side).

 

yeah i am running spoon coilovers and bald RA1s (my rear tires are pretty worn).

Twohoos, whats that in degrees? thanks

 

Bill:

my tires are actually 255 RT615
trust me, my front end darts under braking; that's why i have this problem where I creep slightly before turning in; but that's just my mental block because I started to fix it w/ success in the last session.

 

the more toe out you have in front and rear, the more unstable the car will be under braking. The trade off is that toe out makes the car snappier and more responsive.

So you can have a relatively "quicker" steering and more responsive car with more toe out (relatively), or you can have a more stable car that feels a little more lethargic.

I think the best track setup is just a tiny bit of toe in in the front (like 1/16th overall) and a little more in the back.

Alignment is your issue.

-dc

 

gt wing would help a lot