Thursday, August 16, 2012

Brembo GT Information Source, Part 8: Troubleshooting

Update 1
I think that my adjustable struts (Tokico D-specs), which allowed for flat stance braking, were not allowing enough weight transfer on the front wheels.
I've re-adjusted them a half turn softer, the car does some tilting under braking and I THINK i may have resolved this. I'll test some more when the weather gets better and post the results.

I'm at 5.5 turns of adjustment all around now.(D-spec)
Update 2
My issue with the brakes was never addressed quite satisfactory. There always was a tendency for the front to lock up and confuse the ABS, resulting in scary braking.
Especially at an intersection with red light camera. There they turned the yellow light duration to someting like 0.5 seconds and you have to make a quick decision to stop as soon as yellow shows up...

So, I decided to buy rear brake pads from Subaru, to test the info that I got repeatedly from the Brembo distributor, that these were engineered for the OEM rear brakes.

The first thing I noticed is that the OEM brake pads were wider by 1/8" on the contact patch.
Long story short, now I'm in better shape.

Update 3
Noticing that my Brembo provided DS1000 Ferodos are really thin now and seeing how firction coefficient-sensitive this setup is, I am trying to find out what has the same coefficient with those.
I have gotten an answer from Ferodo.
They were nice enough to clarify that the product is actually HP1000 and that it is a compound they use with Brembo for brake pads and the equivalent material in the racing range is DS2500.
The FM1000 is used for HP (high performance) applications by Brembo.

So I ended up getting the StopTech Street Performance brake pads for the front and rear of the car.

I also replaced the rear trailing arm front and rear bushings. The front with Sti pillow ball and the rear with Sti Group N.

I drove couple days with the Stoptech pads in the front and the Subaru genuine pads in the rear.

The Brembo OEM brake pads that come with the Brembo GT have a very high grip when cold even and continue with a very high initial grip, when they warm up.

There was no way for the OEM Subaru pads to keep up with that.
With the Stoptech in the front, the OEM rear pads had a chance to bite a bit and it took quite a bit of bedding at moderate speed, for the rears to start to be felt.

Once I replaced the rears too, I went for another set of bedding.
The one thing I'm still trying to figure out is that, after 2 sets of 10 slow-downs, the rear calipers got really hot, while the front ones, you could put your finger on the caliper and keep it there, the caliper was cool.

Maybe bedding pads on the Brembo GT takes something more severe than 10 slowdowns from 60 to 10 MPH.

I guess what they forget to advise you of, with this particular BBK kit is that it is ballanced, if you run the same brake pads front AND in your OEM rear calipers. DS2500 for the really small 2002 rear brakes are around $140. Probably worth it, at the track.
The Stoptech SP are a much better deal.

Getting the bushings done helps to even it out. I did have the Sti front control arms in the front, which were brand new and added rigidity to the front brakes.

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