Track Day Braking/Boiling

gaffer1986 · January 31, 2015, 22:53

I've done two trackdays in my 1zz with new but standard brakes. The first time I boiled the brake fluid within 10 mins, the second track day I went with new dot 4 brake fluid and boiled it again fairly quickly.

On each occasion I managed to finish the track day because my brakes could stop the car superbly, I just have to press the brake pedal really far.

Has anyone got any advice on how to stop it boiling, will performance brake fluid be enough and work well in an MR2 that predominantly gets used for the daily commute by my other half? I don't want to spend more than I need to because I feel it's more enjoyable when you don't have to spend big bucks having fun, but if you feel I need to upgrade the brakes to prevent the fluid boiling I will do whatever it takes.

If it's any help, the rear brakes do have a little bit of smoke and smell after each session on track, not sure if I should ignore this? The front brakes seem to have an easier job.

Any help is appreciated.

Thanks.

1979scotte · January 31, 2015, 23:06

Most guys who track their 2 go for 5.1 and some uprated pads.
Maybe ask the guys in the motor sport section what they think?
Perhaps vented disks would help in some way?

tomaky · January 31, 2015, 23:07

Go braded hoses and 5.1 dot should stop all boiling, about £75 in parts and easy to fit, some have done 5.1 dot in stock lines, again should sort it.

tomaky · January 31, 2015, 23:07

Stock disks are vented scot you wally.

1979scotte · January 31, 2015, 23:14

Yes silly me i meant grooved or drilled.

gaffer1986 · January 31, 2015, 23:31

Thanks for your posts, will upgrading the pads and putting braided hoses on help prevent the braked fluid from boiling?

tomaky · February 1, 2015, 00:39

Its more using the 5.1 dot as it has a higher boiling point, stock hoses wernt really made for 5.1 dot. However braided will take what ever you throw at them.

mikey P · February 1, 2015, 10:27

You need higher boiling temp doesn't matter if dot 4 or dot 5.1. 5 can't mix with dot 4 so would be a real pain bleeding all the old stuff out. Also it has a shorter life than dot 4 (which can last years for road use) but dot 5 typically needs changing alot more regulaly. Personally run something called ATE super blue its pretty cheap and has a higher boil temp than most dot4 and some 5.1 its also easy to bleed as its bright blue. Held up well on a track day. Not sure braded pipes really do anything. (They are all braded as stock anyway just under a rubber cover, to protect them).

1979scotte · February 1, 2015, 10:42

I'm sure Matt P always recommended Super Blue and he thought braided lines were a waste of money. I still bought some though.

AndyM · February 1, 2015, 10:48

Quote from: "mikey P"Not sure braded pipes really do anything. (They are all braded as stock anyway just under a rubber cover, to protect them).

Are you sure about this? I'm 99.9% sure the stock ones are just rubber (no braiding inside or out).

Either way, I noticed an immediate positive difference to pedal feel when swapping out the stock lines to my Goodridge braided lines so worthwhile in my opinion for the minimal cost. s:)

s:)

tomaky · February 1, 2015, 10:50

+1

Hybrids · February 1, 2015, 11:35

Cut a stock flexi's and it will have a cord braiding, but not as substantial as aftermarket steel braided hoses.

The brake issue on track sounds more like pad fade, I have raced on Dot4 and not managed to boil it, brake fade creates a gas between the pad & disc IIRC and extra effort is required to overcome it.
If you have boiled your fluid it will now have moisture trapped and even when cool the brakes will feel spongy.

Fire a PM to Freakybrakes on the GB, Stuart is far more knowledgeable than I on brakes

gaffer1986 · February 1, 2015, 13:13

Quote from: "Hybrids"Cut a stock flexi's and it will have a cord braiding, but not as substantial as aftermarket steel braided hoses.

The brake issue on track sounds more like pad fade, I have raced on Dot4 and not managed to boil it, brake fade creates a gas between the pad & disc IIRC and extra effort is required to overcome it.
If you have boiled your fluid it will now have moisture trapped and even when cool the brakes will feel spongy.

Fire a PM to Freakybrakes on the GB, Stuart is far more knowledgeable than I on brakes

Don't think it's brake fade because the car still stop quickly and the pedal is still long and spongy after the track day, until I replace the fluid.

gaffer1986 · February 1, 2015, 13:15

Quote from: "mikey P"You need higher boiling temp doesn't matter if dot 4 or dot 5.1. 5 can't mix with dot 4 so would be a real pain bleeding all the old stuff out. Also it has a shorter life than dot 4 (which can last years for road use) but dot 5 typically needs changing alot more regulaly. Personally run something called ATE super blue its pretty cheap and has a higher boil temp than most dot4 and some 5.1 its also easy to bleed as its bright blue. Held up well on a track day. Not sure braded pipes really do anything. (They are all braded as stock anyway just under a rubber cover, to protect them).

Thanks for the tip, I will try and get some ATE super blue, if this doesn't work then I will do the braided hoses as this seems to have a mixed opinion.

mikey P · February 1, 2015, 16:11

Quote from: "AndyM"
Quote from: "mikey P"Not sure braded pipes really do anything. (They are all braded as stock anyway just under a rubber cover, to protect them).

Are you sure about this? I'm 99.9% sure the stock ones are just rubber (no braiding inside or out).

Either way, I noticed an immediate positive difference to pedal feel when swapping out the stock lines to my Goodridge braided lines so worthwhile in my opinion for the minimal cost. s:) s:)

Its opinion based but as you will have added new fluid when fitting braided lines i suspect its the changing to new fluid and bleeding them that makes them feel better. All stock brake lines have braiding inside them to stop them expanding, they simply wouldn't stop the car if they were just rubber, as rubber would exspand far easier than pushing the pads on to the disc with enough force.

Anonymous · February 1, 2015, 16:24

Hoses will give better pedal feel, won't improve boiling or fade though.

Braided hoses are an upgrade, especially considering the age of the rubber hoses on our cars now, they will be perished to some degree and will flex some.

ChrisGB · February 1, 2015, 22:29

I would try Motul RBF600 or RBF660. I've run the 600 for years and the standard Toyota pads give up before the fluid. Only time i ever had fade was going down the mountain circuit the "wrong way" into Ramsey, with lots of boost, R888s and a couple of chasing 911s. That was pads, not fluid. Bear in mind that if you have any hint of sticking in any calliper, they will run very hot on track and will likely boil the fluid on the affected corner as a result of the pads not being able to back off and lose heat down the straights. The stock brakes are normally regarded as a strong point on the MR2, but with age, sticky callipers are common. I suspect painting callipers doesn't help with heat loss either.

Upgraded hoses won't help with fade, but I found they improved feel under very heavy braking.

Was it your car I spotted at Boreham services on the A12 last Saturday lunchtime by any chance?

Chris

gaffer1986 · February 8, 2015, 10:47

Quote from: "ChrisGB"I would try Motul RBF600 or RBF660. I've run the 600 for years and the standard Toyota pads give up before the fluid. Only time i ever had fade was going down the mountain circuit the "wrong way" into Ramsey, with lots of boost, R888s and a couple of chasing 911s. That was pads, not fluid. Bear in mind that if you have any hint of sticking in any calliper, they will run very hot on track and will likely boil the fluid on the affected corner as a result of the pads not being able to back off and lose heat down the straights. The stock brakes are normally regarded as a strong point on the MR2, but with age, sticky callipers are common. I suspect painting callipers doesn't help with heat loss either.

Upgraded hoses won't help with fade, but I found they improved feel under very heavy braking.

Was it your car I spotted at Boreham services on the A12 last Saturday lunchtime by any chance?

Chris

That sounds like my car, it's really my girlfriend's car to be honest and she works at the royal mail depot in Chelmsford. Thanks for your advice with the fluid, I have to admit I've always thought the a caliper was sticking because in traffic sometimes the car stops itself at really low speeds as if I'm touching the brakes gently but I'm not, barely noticeable though.

gaffer1986 · February 8, 2015, 10:48

I've had the brakes bled but the pedal still feels really spongy. Any advice on what else could cause it to be spongy? What about the master cylinder or ABS system?

tomaky · February 8, 2015, 10:58

Pads ready for bin?

gaffer1986 · February 8, 2015, 13:18

Lots of meat on them, would that make the pedal spongy? The pedal gets hard if I pump the brakes.

mikey P · February 8, 2015, 16:49

Still air in there then how much old fluid did you bleed out, did you bleed them your self.

Anonymous · February 8, 2015, 18:32

They can be tricky to bleed, I took two attempts

gaffer1986 · February 8, 2015, 22:25

A mechanic bled them, I'm not sure how well he bled them, I may be get someone else to put the blue stuff in so it's easier to tell when finished bleeding.

men3cac · February 9, 2015, 06:43

Just a thought- I'd assume braided lines transfer heat out of the fluid better than stock rubber ones? If anybody says it doesn't I'll ignore you to help with the man maths :-) :-) :-)