Brakes, Brakes, and more Brakes

[LostSalad]

Originally Posted by Fish Eagle

No cooldown laps in between. I'll rarely do more than 10 laps per session, but normally about 8. That's a warmup lap, and 7 hot laps. I only sometimes do end of session cooldown laps on track, depending on where I am. I'll never do a cool down lap at the Z - too dangerous. I come off the track hot and just go for a leisurely tootle around the grounds, ending up with a visit to the members area for a chat with the marshal and some spectating up there.

Hmm ok. The cooldown laps I did were all after the checkered flag went, and most people were off track already (or cooling down themselves). What is it about Zwartkops in particular that makes it bad?

Originally Posted by Fish Eagle

Adjust your driving style slightly. I can almost guarantee that you're bumping into the ABS quite often. Try to avoid doing that because ABS really hammers your brakes. Try to brake just below the ABS kick-in threshold, which gives you more effective and cooler braking. It's a common misconception that as one gets faster, you hammer your brakes more. It's the opposite - with practice you learn to modulate your braking better which reduces temps and wear.

Yup, there are obviously loads of factors involved, but as you get faster and get more speed at the end of the straight, you are probably also able to carry more speed through the corner to offset the difference. And as you say, using the brakes sensibly of course. EDIT: now that I think about it, my heel-toe technique could use a bit of work. I don't always keep an even pressure on the brake when blipping the throttle, especially when dropping 2 gears onto the table-top.

I try my best to threshold brake but yeah, especially on downhills, it's easy to get onto the ABS. What makes it harder on the brakes in particular? Is it temperature fluctuations or something to do with how the pads respond to different pressures?

So on that note about ABS - now that I got myself some Bridgestones instead of the slippery OEM tyres, I'll obviously be able to brake harder without locking up and triggering the ABS. So being able to brake harder = harder on brakes, but not triggering ABS = lighter on brakes. Any idea if this will improve or degrade my situation?

[Fish Eagle]

Originally Posted by LostSalad

What is it about Zwartkops in particular that makes it bad?

I normally go off track before the end of the session, and trying to do a cool-down lap in heavy Supertrax traffic is kamikaze foolishness.

Originally Posted by LostSalad

What makes it harder on the brakes in particular? Is it temperature fluctuations or something to do with how the pads respond to different pressures?

I don't know. I've read that several times in the tracking section of this forum, and I've experienced it myself. More ABS use = start fading quicker.

Originally Posted by LostSalad

So being able to brake harder = harder on brakes

I don't think so. It's the same amount of momentum being converted into heat energy, whether one brakes harder or not. I certainly haven't found that sticky tyres put more strain on my brakes...

[FT_86_SM_GP]

Just called Toyota to quote me on changing brake pads (front and rear) and bedding them in, they quoted me R1400 and some change..



Guess I better find myself that tool to change my own brake pads and disc

[sav]

Ouch. You pretty much need one or 2 spanners only. Undo the top bolt on the caliper and swing them over.

[Fish Eagle]

Originally Posted by FT_86_SM_GP

Just called Toyota to quote me on changing brake pads (front and rear) and bedding them in, they quoted me R1400 and some change..



Guess I better find myself that tool to change my own brake pads and disc

Crazy mad price. DIY - it's very easy.
To change pads you need a 14mm ringspanner.
I slacken the top bolt and remove the bottom bolt, then the caliper doesn't hang on the pipe.
The toughest is pushing the pots back when fitting new pads - needs some force.
Once you've done it a few times, you can do it in your sleep.

[LostSalad]

Originally Posted by FT_86_SM_GP

Just called Toyota to quote me on changing brake pads (front and rear) and bedding them in, they quoted me R1400 and some change..



Guess I better find myself that tool to change my own brake pads and disc

I'm not mechanically inclined, so it took me a while to do. You need to make double-sure you have all the tools up-front. The DIYs on this forum are extremely comprehensive, though, so it's definitely doable.

If you're only doing the pads, you just need a 14mm socket and possibly a C-Clamp to depress the calliper pistons. It's not too bad. As long as you can safely lift the car it's hard to screw up.

If you're doing disks, it's a bit more work. Sure, @Fish Eagle mentioned that he does his quickly now, but for a first time job if you don't work on cars, just be ready for it to taker longer than you anticipated. Also, the 17mm bolts mounting the calliper are a lot tighter than the 14mm bolts holding it closed. These can be a pain to crack loose because there isn't a lot of space to fit a breaker bar.

You also need to decide how seriously you take the recommended torque specs. I wanted peace of mind, so I bought 2 torque wrenches to cover all my bases. Same for measuring the disk runout - you will need a dial indicator. You can decide to skip these steps of course. Chances are the disks are perfectly manufactured and will "just work", and that a bolt that is "nice and tight" won't cause issues.

I'm willing to loan tools with a collateral, so if they come back it's , but if they don't, we can avoid the

[sav]

C-clamp works great. Or use your thumbs...

[Fish Eagle]

Originally Posted by sav

Or use your thumbs...

With your thumbs!! Remind me not to pick a fight with you

I normally use a big screwdriver as a lever - works OK.
A clamp is much better, but I can never find one.
The probability of finding the right tool in your workshop is directly but inversely proportional to the number of adult male children that you have.

[sav]

ROTFLOL!! Sometimes it's the only way.

I agree though, having the right tool and actually being able to find it are two completely different things.

[sav]

Originally Posted by sav

Some more information on Performance Friction since I'm sure not many on here have heard about them:
http://www.pfc.parts/toyota-gt86-cup/






They come with very decent shims and thick powder coated backing plates which will not rust.

These have been bedded in and tested out in Nelspruit/Sabie/Bulembu/etc - very happy with them so far.

[Fish Eagle]

Originally Posted by sav

These have been bedded in and tested out in Nelspruit/Sabie/Bulembu/etc - very happy with them so far.

They look like good quality, and I'm interested to see what evolves...
Cost?

[sav]

Will keep you posted. Was R1800 from International Race Supplies. Contact person is Mike Bond. Pads were recommended by Pyro Performance.

[Fish Eagle]

Fitted new PB discs today, R2700 delivered Nelspruit.
My previous PB discs lasted 16 track days

I've recently done 4 track days on stock discs as a stopgap and to see how they shape up after using PB.
For day 1 & 2 they were fine, day 3 they were OK'ish, but by day 4 they were shuddering badly...

[FT_86_SM_GP]

I finally got down to ordering Endless PB05 pads (Front) and Bendix(Rear) from Powerbrake last night,

I emailed Francois to find out the 'correct' or 'proper' bed-in process, and got this response, hope this is useful, will try it out, what do you guys think about this process?

"Bed-in Cycle:

1. Drive slowly for 1 week (at least 200km’s) after fitting the new pads. Use moderate brake applications during this time and try to avoid long brake applications from speeds in excess of 100 kph. Normal urban commuting, using your brakes from moderate speeds about once per kilometre is ideal. Long stretches of open road driving do not count, as the brakes are not being used. Increase following distances during this time making provision for “green fade” in an emergency stop. Never left foot brake or drag the brakes!

After this ...

2. Drive a few kilometres, using the brakes gently to bring them up to a moderate operating temperature.

3. Perform 6 consecutive brake applications of increasing intensity from 100 km/h down to 30 km/h. If wheel lock-up (or ABS activation) is referred to as a 100% brake effort then you should be aiming to build up to a 60 - 70% brake effort for the last two applications. The applications should be performed consecutively, accelerating normally back up to 100 km/h after each application, before braking again.

4. If possible, do NOT come to a complete stop throughout the 6 brake applications described above. Doing so can result in ‘pad etching’ during which friction material is unevenly deposited onto the brake disc causing DTV and brake judder. The etching will be visible as the outline of a brake pad on the disc surface. (To learn more about pad etching and DTV click here)

5. It is possible to experience “green fade” from the 4th or 5th application onwards - this is not an issue.

6. Drive on, using the brake as little as possible, for a number of kilometres allowing the brakes to cool substantially in the air-stream before parking the vehicle and allowing the brakes to cool completely. This cooling cycle is important.

Regards


Francois "