Brake Fluid

[GhostyDog]

Hey,

Spent most of yesterday going round and round Oulton Park and by the end of the day was having total brake failure (pedal to the floor) I'm running 305 brembos with Performance Friction Fast Road Spec Pads and Goodrich Braided hoses and dot5.1 fluid but it appears the fluid I had in there just wasn;t good enough.

What should I be looking to replace it with?

found this stuff on Opie Oils which might do the trick

http://www.opieoils.co.uk/p-862-silkolene-pro-race...

Cheers

GD

[Chris Wilson]

The ultimate fluid for brakes stressed thermally is Castrol SRF, but it's expensive. It is the fluid of choice for racers who have to make what are basically inadequately sized brakes work on track due to the particular series regulations. You really shouldn't need it, and it would be far better to get more air ducted to the front brakes, and / or fit something bigger. SRF absorbs water very readily, so should be changed regualrly.

[NBirkitt]

A cost-effective product for a road & track car is Ate Super Blue, available from any branch of Euro Car Parts. I've just had a fluid change on my GTI 1.8T prior to the VW and Audi track day at Castle Combe on Saturday July 24. It has Dry Boiling Point of 280°C (50° above DoT 4) and WBP of 200°C (45° above DoT 4), as used by Porsche...

[GreigM]

Castrol SRF - don't fk about with anything else - it costs about £40 for a litre - its quite simply the best and IMHO you shouldn't even try anything else. The DOT rating is almost irrelevant - just buy SRF.

[GhostyDog]

I went with ATE Super Blue ordered it from performance oils on Monday arrived today.

[Munter]

GhostyDog said:

dot 5.1 fluid

There's your problem. The higher the DOT number does not mean the higher the temperature. The standard also includes things like how much water the fluid can absorb and how low the temperatures are that the fluid can be used in.

Due to the other factors required to get DOT 5.1 those fluids cannot work at the temperatures DOT 4 Racing fluids can work at.
Some DOT 4 fluids will have a lower boiling point than the best DOT 5.1 fluids. But all DOT 5.1 fluids will have a lower boiling point than the best high temperature DOT 4 fluids.

I've used the Silkolene stuff from Opie before and found it without fault on the MX5 going around Bedford. (I wore through a set of pads that day, so wasn't taking it easy on them).

It's now got the ATE Superblue in it. And I have to say I think I've lost some feel to the brakes. BUT it has a higher wet boiling point. So it'll last a bit longer.

Swing. Roundabout. Pay your money and make your choice! (But base your choice on temperature ratings not DOT numbers)

[edh]

I'm not being entirely facetious when I suggest that maybe you're braking too much?

You have a pretty capable sounding setup there. What tyres are you using?

Maybe just some ducting to the centre of the discs will do the trick.

[GhostyDog]

edh said:

I'm not being entirely facetious when I suggest that maybe you're braking too much?

You have a pretty capable sounding setup there. What tyres are you using?

Maybe just some ducting to the centre of the discs will do the trick.

The 305s are renowned for getting very hot so much so that as of September 2003 they stopped putting 305s on GTAs and replaced them with an entirely different 330 Brembo set up

This is really just a stop gap until I upgrade to a 330 Alloy Bell KSport 8 Pot Kit.

Tyres on the front are Toyo Proxes T1-R but I'll be swapping to match the rears Goodyear Eagle F1s or Michelin PS2/3s

I was braking way before what was required anyway as I knew the brakes were the weakest part of the car on a track day, this is the first day time I've been on track with this car but other than the brake juice dying it was awesome

[Munter]

GhostyDog said:

I was braking way before what was required anyway as I knew the brakes were the weakest part of the car on a track day, this is the first day time I've been on track with this car but other than the brake juice dying it was awesome

Ah. Long slow braking is worse than short hard braking. If that's what you mean you were doing. Your aim should be to spend the longest period you can without the pads touching the disks. This reduces heat transfer and increases cooling time.

The longer the pad spends touching the brake disk, the more heat it'll pass through to the fluid.

[Simon Mason]

SRF is simply a well known brand name. It is certainly not the the best fluid these days.

ATE Super Blue is more than good enough for track day use. If you still have problem its definately something else.

One thought, are you sure you have the brake dics the right way round. They should be blowing air out of the centre of the disc, not drawing it in. I've seen that cause overheating issues before.

[philevo6]

Simon Mason said:

SRF is simply a well known brand name. It is certainly not the the best fluid these days.

ATE Super Blue is more than good enough for track day use. If you still have problem its definately something else.

One thought, are you sure you have the brake dics the right way round. They should be blowing air out of the centre of the disc, not drawing it in. I've seen that cause overheating issues before.

If srf isnt the best then what is????...for trackday use.!

Check out the wet/dry boiling points for all the top fluids....im sure srf beats them all.

Just a well known brand name..?...LOL

[rdjohn]

I was concerned when I first tried ATE Super Blue, and so I did want to post early just in case others were not confident; but for me, it really does seem fine - my BEC is very light and so I can stand on the brakes very close to the tightest corners.

[GhostyDog]

Munter said:

GhostyDog said:

I was braking way before what was required anyway as I knew the brakes were the weakest part of the car on a track day, this is the first day time I've been on track with this car but other than the brake juice dying it was awesome

Ah. Long slow braking is worse than short hard braking. If that's what you mean you were doing. Your aim should be to spend the longest period you can without the pads touching the disks. This reduces heat transfer and increases cooling time.

The longer the pad spends touching the brake disk, the more heat it'll pass through to the fluid.

Yes but taking into consideration.

Limited run off at Oulton Park
History of poor braking performance
I had a passenger I didn't want to kill
No track day insurance

I'd much rather NOT go tanking into a corner to find the brakes have just dissapeared, when it happened it was literally brakes fine one corner, gone the next in the penultimate session. In the final session they lasted about 4 laps before I had to come off but after cooling still got me home without any problems.

I'm planning on having some track tuition anyway once the new brakes are fitted so hopefully after that I shouldn't have a reoccurance of total fade as long as everything is maintained properly.

[Munter]

GhostyDog said:

Munter said:

GhostyDog said:

I was braking way before what was required anyway as I knew the brakes were the weakest part of the car on a track day, this is the first day time I've been on track with this car but other than the brake juice dying it was awesome

Ah. Long slow braking is worse than short hard braking. If that's what you mean you were doing. Your aim should be to spend the longest period you can without the pads touching the disks. This reduces heat transfer and increases cooling time.

The longer the pad spends touching the brake disk, the more heat it'll pass through to the fluid.

Yes but taking into consideration.

Limited run off at Oulton Park
History of poor braking performance
I had a passenger I didn't want to kill
No track day insurance

Pah I laugh in the face of such considerations!

Particularly the passenger. They knew what they were doing....honest.

[agent006]

philevo6 said:

Check out the wet/dry boiling points for all the top fluids....im sure srf beats them all.

SRF does have the highest boiling point. However it doesn't have twice the boiling point of its competition, but does cost twice as much.

I use some Motul race stuff, which is barely 20 degrees short of SRF's boiling point, but costs £18 a litre not close to £50.

There is also the point that you really should be considering improved (or indeed any) cooling if you're boiling the brakes. Proper ducting is the single thing that has most improved my braking setup.

[GhostyDog]

agent006 said:

philevo6 said:

Check out the wet/dry boiling points for all the top fluids....im sure srf beats them all.

SRF does have the highest boiling point. However it doesn't have twice the boiling point of its competition, but does cost twice as much.

I use some Motul race stuff, which is barely 20 degrees short of SRF's boiling point, but costs £18 a litre not close to £50.

There is also the point that you really should be considering improved (or indeed any) cooling if you're boiling the brakes. Proper ducting is the single thing that has most improved my braking setup.

I think part of the problem is that I have changed to smaller wheels, when I bought the car I had 19" OZ Superleggera's which allowed for better cooling, I have to wonder and this is purely conjecture that the design of multi spoked wheels act something like a heat sink drawing heat away from the heat source to be dissipated to air.

My current wheels, GTA Teledials, don't have these properties and after the track day sessions the wheels were too hot to touch never mind the brakes.

[edh]

GhostyDog said:

edh said:

I'm not being entirely facetious when I suggest that maybe you're braking too much?

You have a pretty capable sounding setup there. What tyres are you using?

Maybe just some ducting to the centre of the discs will do the trick.

The 305s are renowned for getting very hot so much so that as of September 2003 they stopped putting 305s on GTAs and replaced them with an entirely different 330 Brembo set up

This is really just a stop gap until I upgrade to a 330 Alloy Bell KSport 8 Pot Kit.

Tyres on the front are Toyo Proxes T1-R but I'll be swapping to match the rears Goodyear Eagle F1s or Michelin PS2/3s

I was braking way before what was required anyway as I knew the brakes were the weakest part of the car on a track day, this is the first day time I've been on track with this car but other than the brake juice dying it was awesome

So you're killing the brakes on road tyres? I find that quite amazing. Ducting has got to be the cheapeast (and best) answer - together with Simon's point about checking the disc orientation. I'll bet as you get more comfortable with that car on the track you'll use your brakes less and things will improve.

I also suspect that "big brake kits" are usually unnecessary. I know my current track car (970kg, 180bhp Civic) isn't exactly comparable (even though it is probably faster ) - but the first thing the Civic/CRX "forum experts" told me was "standard brakes are rubbish, not suitable for track use etc.." Guess what? with 1155's and A048's the braking performance is just fine. My last car (944 turbo 300hp, 1450kg) might a better comparison. The standard (late model) 4 pot brembos are spectacularly good with the right pads & decent cooling, but again people will tell you that "you need Big Blacks etc..".

[edh]

GhostyDog said:

edh said:

I'm not being entirely facetious when I suggest that maybe you're braking too much?

You have a pretty capable sounding setup there. What tyres are you using?

Maybe just some ducting to the centre of the discs will do the trick.

The 305s are renowned for getting very hot so much so that as of September 2003 they stopped putting 305s on GTAs and replaced them with an entirely different 330 Brembo set up

This is really just a stop gap until I upgrade to a 330 Alloy Bell KSport 8 Pot Kit.

Tyres on the front are Toyo Proxes T1-R but I'll be swapping to match the rears Goodyear Eagle F1s or Michelin PS2/3s

I was braking way before what was required anyway as I knew the brakes were the weakest part of the car on a track day, this is the first day time I've been on track with this car but other than the brake juice dying it was awesome

So you're killing the brakes on road tyres? I find that quite amazing. Ducting has got to be the cheapeast (and best) answer - together with Simon's point about checking the disc orientation. I'll bet as you get more comfortable with that car on the track you'll use your brakes less and things will improve.

I also suspect that "big brake kits" are usually unnecessary. I know my current track car (970kg, 180bhp Civic) isn't exactly comparable (even though it is probably faster ) - but the first thing the Civic/CRX "forum experts" told me was "standard brakes are rubbish, not suitable for track use etc.." Guess what? with 1155's and A048's the braking performance is just fine. My last car (944 turbo 300hp, 1450kg) might a better comparison. The standard (late model) 4 pot brembos are spectacularly good with the right pads & decent cooling, but again people will tell you that "you need Big Blacks etc..".

[MartinM]

Motul RBF 600 is the stuff to have. As some have stated before, higher DOT numbers do not necessarily equal nigher boiling points.

Not tried RBF 660 yet but it apparently has an even higher boiling point.

HTH

[DiscoColin]

agent006 said:

philevo6 said:

Check out the wet/dry boiling points for all the top fluids....im sure srf beats them all.

SRF does have the highest boiling point. However it doesn't have twice the boiling point of its competition, but does cost twice as much.

However, put another way : you are talking about an extra 20 quid every year to 18 months on the cost of running a car at track days. If this is really consequential then you perhaps need a new hobby...?