Cooking Fluid..

[Adoom]

I seem to recall the racing trucks spraying water up through the cooling vanes internally on the discs. Spraying water in any way onto the braking face of the disc doesn't seem that smart to me. Most certainly not with windscreen washers! It's unlikely you could mount them in a place to do that with out them melting and without water going everywhere. They will need to be very close to the rotor

What's wrong with windscreen washer pumps? It's just a water pump, and it cost bugger all. A magic expensive branded pump is still going to pump water.

If you want to cable tie the pumps to the calipers, yes they are going to melt. But there is this thing called a PIPE, it's used to transport fluids, like our water, from one place to another. So you can mount the pumps in the glovebox if you really wanted to.

I was thinking more like... Spraying, a mist, not a jet of water in the ducts.
As far as I am aware, brake ducting should duct air into the center of the disc, the air then exits the discs through the vanes. Wet air will have a higher heat carrying capacity than dry air. In theory, it will be more effective at taking heat away from the brake disc. It's the same concept as water injection.

[Shrike]

To bad you cant circulate the brake fluid through a small oil cooler but would require a pump

[Mr Revhead]

Do they v8s use sprayers or caliper cooling?

[Adoom]

Apparently they do http://www.nagtroc.org/forums/index.php?/topic/41533-water-cooled-mist-brakes/

[Mr Revhead]

Oh good find. It's the opposite of what I thought.
Although a mist via ducts is still a bit different from direct spraying.
When playing with it is say start small and increase slowly!

[gt4dude]

Whats your ducting system? Is it straight and unrestrictive? Maybe a inline fan to push air on the brakes during lowwer speeds?

The fan would just become a restriction when airflow was needed most though, mate.

Not if set up right, or whats the point of a turbo? A fan would be able to push air down the ducting at lowwer speeds when air force on the intakes is low. I'm a hvac tech so deal with fans n ducting day to day, selecting the right ducting and fan is the same in a way as turbo n intercooler.

thats why turbinators and e-superchargers are so impressive!

[2jayzgte]

Have you ever tried running a more aggressive pad compound on the rear to try and shift some of the bias that way, without having to go to a manual brake bias level adjuster?

My suggestion is water cooling, as once you have paid for the pump and lines, then its just tap water from then on so costs are a one-off affair.

I just brake a little bit less aggressively when on the track, in order to try and keep the temps under control, because as you mentioned, you can get more laps that way. I know its not going to help you set any PB's but I just prefer to do 8-10 laps at 90% than 4-5 due to pushing the brakes too hard.

Did you ever find out if the TRD callipers have the same applied force as the factory 4pots? I recall us discussing it with Dave earlier in the year in taupo, and we were saying that there are others running the 4 pots that are getting better braking life than your set up, and we were pondering whether or not they did the same job.

Swapping over to some factory 4 pots might eliminate some possibilitys in regards to seeing if the bias is the same. Its possibly your TRD callipers require more fluid displacement than the normal 4 pots, and as such, theyre stealing valuable fluid, clamping, and bias from the rear.

Just a theory...

I have spoken to Dave about this for awhile I'm under the guise that the TRD brakes have the same stopping force just less flex as they are a one piece forged calliper a more direct feel through the pedal.

I see Patrick has now run into the same problems with the factory 4-pots aswell last time out at Taupo so I'm not sure where this leaves us as he boiled his fluid aswell.

I gotta think its the slicks that are a huge cause of this as they just supply so much more grip under hard braking and the callipers will be working to there limits I guess and when it comes down to it they are really just a fast road calliper not really designed for what we are doing.

[LEAKER]

May be time for a full upgrade. I have been looking into upgrades and it seems that value for money the k sport packages are really good. I'm sure people are going to tell me they're not but all the info I read from people that actually have them fitted have raved about them opposed to people that just want to talk shit and have no real experiance with them.

[pc]

Are you sure that it's the fluid that's cooking/boiling?
Maybe you're just running the pads at a temperature that it too high for the pad... Have you tried the DTC70?

[fangsport]

have you tried insulating the pad from the piston by using non-conducting material?? something like Hardies could reduce heat transfer

[rollaholic]

im no race guru but my first thought was water spray too, closely followed by more expensive brakes.

have you got those fancy floating hat type rotors?

[Dell'Orto]

May be time for a full upgrade. I have been looking into upgrades and it seems that value for money the k sport packages are really good. I'm sure people are going to tell me they're not but all the info I read from people that actually have them fitted have raved about them opposed to people that just want to talk shit and have no real experiance with them.

He has TRD monoblock calipers, would run those ahead of K-Sport any day

[Mr Ree]

Was about to say exactly the same thing ^

K sport 'might' be an upgrade for some cars with small brakes, but the supras 4/2 set up is more brake than most drivers need. It would definitely would be a downgrade to go to the ksport option.

[2jayzgte]

Are you sure that it's the fluid that's cooking/boiling?
Maybe you're just running the pads at a temperature that it too high for the pad... Have you tried the DTC70?

Definitely boiling fluid have to bleed the brakes at least twice at my last 2 track outings during the day.

Running the pad at higher temp than they are designed for is a fair assessment I believe I'm doing that aswell.

The main reason as mentioned already is slicks and the factory bias in my eyes the car is road car and I'm asking it to do things it really wasn't designed for throw in the fact its 1620 KG with me and half tank of gas in it probably also doesn't help also.

My theory to decrease heat in the fronts is ask the rears to do more work a simple but needed mod without spending big $$$$$ I'm thinking but I'll see how we go.

[Snaps]

Another path to go is to make sure the rotors can get rid of heat faster (this is the basic idea behind air ducts), as this cools the rotor, which means more heat is absorbed from the pads when they're in contact with the rotor, which means it's less likely to boil fluid.

I'm not sure if it's all that feasible, but it's worth a mention - have you considered running different rotors? Either:

- A larger diameter, which would probably require mounting the caliper further outward (would need a custom bracket), OR
- A better cooling vane pattern instead of just curved vanes (i.e. the Kangaroo Paw design). I don't know if anyone makes an aftermarket version of these for the Supra, but you may be able to retrofit them from another vehicle. Unless you can get a replacement Supra rotor, this way is probably worse, as it requires you to customise/machine a rotor every time you wear one out.

Just some things to think about, hope you manage to get it sorted, as losing brakes on the track is one of the worst things that can happen!

[Grrrrrrr!]

Just some things to think about, hope you manage to get it sorted, as losing brakes anywhere is one of the worst things that can happen!

FTFY

[2jayzgte]

Another path to go is to make sure the rotors can get rid of heat faster (this is the basic idea behind air ducts), as this cools the rotor, which means more heat is absorbed from the pads when they're in contact with the rotor, which means it's less likely to boil fluid.

I'm not sure if it's all that feasible, but it's worth a mention - have you considered running different rotors? Either:

- A larger diameter, which would probably require mounting the caliper further outward (would need a custom bracket), OR
- A better cooling vane pattern instead of just curved vanes (i.e. the Kangaroo Paw design). I don't know if anyone makes an aftermarket version of these for the Supra, but you may be able to retrofit them from another vehicle. Unless you can get a replacement Supra rotor, this way is probably worse, as it requires you to customise/machine a rotor every time you wear one out.

Just some things to think about, hope you manage to get it sorted, as losing brakes on the track is one of the worst things that can happen!

Branden you could be onto something there heat soak I also think is a problem and your solution to allow the heat to escape off the back of the backing plate is also a feasible idea.

The reason I am thinking of going the bias route is because of ease of the modification and cost I got a Wilwood proportioning valve for nothing so all it is is retro fitting that then setting the brakes up accordingly.I think its the easiest way to go I have thought of going bigger rotors but again the costs involved I have'nt fully checked out but I still think I'll run into the same issues as the front brakes will be working just as hard.

Argh this is starting to give me a headache lol..lol...

Again guys thanks for all the feed-back I'm off to talk to the guys that look after my car and run some idea's past them see what they think.

[Mr Revhead]

Your not still running the backing plates are you? If so they need to go!

[85AW20v]

The backing plates were one of the first things to go on my AW and now I'm ducting air into the centre of the rotor so it gets pumped out through the rotor vanes in the same way a centrifugal pump works.

Thinking about the water cooling, having it spray into the centre of the rotor and out through the vanes might help although maybe trying to keep the caliper cool as well as the rotor would be a better option as that is where the fluid is boiling.

Someone mentioned insulating the pad from the caliper with Hardies. Would industrial formica be a better product as whatever is used would need to handle the heat as well as the pressure.

[Mr Ree]

Coryn and I bought some titanium backing plates last year, which helped slighty, but still, critical mass is eventually reached.