I recently changed my brake fluid to Super Blue.
Went to driving school -enjoyed the hell out of it, but felt the brakes were weak.
I had ferodos with me, but decided to do one driving school on stock pads just to see how they feel.
The rear of the car was not stable at all.
I was affraid of braking and loosing grip in the rear of the car.
It seemed to go side to side.
I thought I needed more rear downforce, but I do not know anymore.

During daily driving right now the car feels like it lost its braking power.
What could be the reason?

1. Is it the brake fluid? Is it not going to perform as well as stock on daily basis?

2. Maybe the stock pads lost their effectivness after warming up to high temp?

3. Could it be that after changing fluid there is some air in the system now?
If so should I simply bleed it again?

Also, what do you think was the reason for the car to be not stable on the track
braking from 120mph and 130mph?

Thanks for your help.

 

Were you downshifting and braking at the same time?

 

your brakes bled correctly?

 

Yes, it sounds like you have some air in your system. How exactly did you flush the system when you switched to Super Blue? By pumping the pedal? By using a pressure bleeder? Depending on the technique you used, you may have actually introduced air into the system.


What track were you on that would allow you to get up to 130 mph!? That's pretty outrageous. Anyway, there's no real way for you to have shifted your brake bias to the rear just by a fluid change (if that's even what you're suggesting...I'm not clear on that). Even if you had air in the system, that would only make your pedal soft. But it would not affect bias at all.

My feeling is that you were probably trail braking a bit without realizing it. You can get away with this at relatively low speeds (partly because of the amount of grip the car has and partly because the electronic brake-force distribution system helps sort things out), so you may have gotten into the habit without even realizing it. However, if you're braking hard from 130 mph and you're not perfectly straight, the car WILL get squirrely for sure.

Emre

 

"where you downshifting and braking at the same time"

Yes

"your brakes bled correctly?"

I hope so. I was pumping my pedal with the engine off.
Going from rr, rl. fr, fl.
A friend of mine helped me.

"there is no way to shift your brake bias to the rear just by changing fluid"

That is what I wanted to hear.

"what track were you on that would allow you to reach 130mph"

Watkins Glen NY. I love that track. On the back straight it was more like 135mph.

"my feeling is that you were trail braking without realizing it"

If trail braking is going into turn with a slight brake application to improve front tire bite then I was.
But I still kept the car straight until a turn-in point.

What is trail braking? Is it what I described?
It is good to do it , right?
Also, how is super blue on daily driving?

Maybe I just have to work on my driving.

I have to admit I was much smoother with my BMW on that track.
I did about 12 days on that track with it.

With Evo it was a first time.
Going there again in 3 weeks- will work on it.

 

yeah...Watkins Glen is a very fun and fast track.....130mph before entering "bus-stop" must be exciting last yr I was driving my ITR....can't wait to try out the Evo on that track !

Ok...back to the topic.

I suggest you check the alignment before going back there....it may improve the rear-end not stable problem. Another thing to look for is the thinkness on both rear break pad, if one is so much thinker than the other one....it will cause the unstable.
Sometime when you use same brake pad in front and rear will cause the unstable problem...it did happen to my ITR when I used HP+ at all 4 corner, once I took out the rear one and use something else, problem solved. Since I yet to track my Evo...I'm not sure is it the cause but by running at autox I think the stock f&r pad are good couple so far

as other already said, changing brake fluid will not change brake bias unless you put different brake line in f&r. (ss vs rubber)

as for soft pedal....did you bleed both bleeder on every caliper ? you may want to rebleed them again but i doubt you need to flush all the fluid.


I actually not surprise to hear that you are much smoother on your bmw than Evo. NA car like bmw is so forgiving and smooth on power (i track my e36 when I start) My evo will be my first turbo car to drive on track......with 100 more hp than my ITR....i think the same thing will happen to me as well.

 

I should have guessed! You know, I never liked the Glen that much in my old car (E30 318is). I had so little power and such great handling that I would just have the pedal to the floor the whole time. I'd be driving the line perfectly, but STILL get passed by less experienced guys in E36 and E46 M3's just because of their sheer power. Not a lot of fun But I'm sure it would be a blast in the Evo!


Yes, it's basically what you've described: trailing off the brake after you've already started to turn in. It will unsettle the rear of the car.

As to whether it's "good" that all depends on the corner and your level of skill. I wouldn't do it at the end of the back straight into the bus-stop! It would be totally unnecessary and potentially dangerous. It works well in sharp, low-speed corners when you want to get the back to rotate. A perfect example would be corner 5-B at Mosport.

Emre

 

Greg,

I think you received some good answers already, but I thought I should add my 2c as well.

It looks like you are experiencing "fluid fade", meaning you might have boiled the fuild braking from those speeds; which is not suprising with the ATE SuperBlue, it is not the best fluid for tracking and especially at Watkins Glenn.

Stock pads are certainly not suited for tracking either IMHO, might work for slower tracks with long straights (too have enough cooling time), but generally it is a good idea to have track pads. Most track pads will resist heat build up better and also offer higher braking torque at a wider range of temps.

This is important because most of us learn proper braking quite late not paying enough attention to various techniques. At our levels (I'll put ourselves in novice - not related to the HPDE run groups, but trackers with no formal training), one simple technique is to be concious about braking, braking hard and for short durations. Once you touch the brakes, the heat builds up, somewhat independent of how hard we push the pedal. If you ride the brakes too long, heat will keep building up and easily surpass "wet boiling" point of the fuild. Fluid fade will occur before pad fade in most cases and knowing the fluid characteristics and taking care of it will go a long way.

Trail braking as Kaya mentioned is a very difficult technique to master and is best applied in slow to medium corners. Also, trail braking increase the rate of heat build up.

So, in short, be concious about your braking technique and try to use less brakes, as much silly as it sounds, it is one of the most effective way to manage heat build up.

Also, on a related note, I am one of those that advocates not rowing down the gears while braking. This is controversial issue even at professional levels, but engine braking power is nil compared the negative torque the brakes generate. While you are rowing down the gears in a braking zone, you will need to heel and toe and it will keep your concentration away from proper braking; we do not have dog gear boxes and down shifting requires considerable effort compared to the available time to do it right. I would suggest, just braking in the braking zone, and shifting at the very last moment to the proper gear with a touch of heel and toe prior to turn-in.

Once you master proper braking in various situations and can do perfect heel and toe, things may be different; but frankly I still do not row the gears; the disadvantages significantly out-weigh its benefits IMHO.

 

[QUOTE=GREGPOL]"where you downshifting and braking at the same time"

Yes
QUOTE]

Don't forget about the power the engine can add to your braking. This can cause the rears to begin to lose traction....leaving nothing the ABS can do about it. IF this is the reason heel/toe (throttle blip) would be the answer.