KiLLJ0Y

iTrader: (1)

is DOT 4 fluid OK to use for AUTO-X events? my friends in their Subaru STI's change their fluid to DOT 4 before events.. i was told this is what i should be using when the brakes are under a lot of heat.

side question.. i need to get a new Master cylinder.. is there a better one than stock?

right now i have 1LE fronts and LS1 rears.. thanks

89 Iroc Z

Yes it is better to use Dot 4. Dot 4 is higher spec then dot 3 and rated for more heat.

DuronClocker

iTrader: (1)

Just make sure you bleed your brakes occasionally. DOT4 fluid doesn't absorb water vapors. It just pushes them around, and if they get into the caliper, they can boil and turn to gas, which means squishy brake pedal with weak brakes.

Its not something that happens right away, but bleed your brakes every so often. I run Valvoline synthetic DOT4 fluid in my car with C4HD fronts and LS1 rears and I haven't had any problems at all.

Rayzer999

I agree with DuronClocker on this one. Also make sure that you purge the system of DOT 3 before you move to 4. I have heard that the mixture is not good! Can cause some issues.

As for the master - there are some options. I hear some people changing the stock 3gens for 4th gens. You can also find some aftermaket larger ones from summit, etc. - plumbing could be an issue, (I hate flaring!)...

RTFC

Dave,
Yes you "can" pour Valvevoline DOT4 synthetic right in on top of normal dot3 brake fluid. Its the best fluid availiable over the counter at most any local autoparts stores- very easily accessable (non-special order) and inexpensive unlike most of the upscale racing brake fluids.

Its what I use in every car I own. It has a very high dry and wet boiling points. 502*dry/343*wet.
You are never going to need anythiung higher than that unless you are large track roadracing or short track circle racing.

Best bang for the buck by far.

KiLLJ0Y

iTrader: (1)

well thats good..

thanks Dean, and everyone else.

now what about good 1LE pads? i was thinking about using Hawks Pads.. but i know you also liked the Stillen pads, but i wasnt sure if they fit my application.

askulte

Autox does not generate much heat, so I wouldn't be concerned about needing new fluid. As long as the fluid has been changed yearly, and hasn't been boiled, you should be just fine. Dot3 and 4 can be mixed. As for pads, stay away from real race pads. They need some heat to work, which autox won't generate, until after a few stops. Street/Strip (intermediate) pads should be great.

DuronClocker is thinking of the silicone Dot5 fluid, which can't be mixed with Dot3 or Dot4. Even though the dot5 doesn't absorb water, it gives a very spongy feel, and isn't recommended.

OG Racing has the ATE Super Blue fluid for $9.95 (Dot4, 536degF dry, 392degF wet), which makes the flush easy to see, as you'll get the blue fluid out of the caliper once the flush is complete. They have std gold color as well, so you can alternate. Most of my road racing friends are using this too...

http://www.ogracing.com/eshop/itemde...12&showbrake=1

lonsal

iTrader: (2)

It is rated Dot 3 / Dot 4. I use it exclusively too and agree with the compatibility with Dot 3 fluid. Go ahead and purge the old fluid anyway. The common sense rule is to change it every 2 years.

Lon

thirdgen88

I've also heard of Dot 5.1 fluid?? Its supposedly glycol based (not the silicone stuff) and has a higher heat rating than even Dot 4.

KiLLJ0Y

iTrader: (1)

well the type of auto X they do up here..(i dont think it should be called auto X) is an SCCA event.. out on the nevada/utah boarder at Wendover on an old military air base.. we went last week..

what they do is run 3 cars at staggard intervals.. you get 1 warm up lap, then run 10 laps.. lots of chicaynes(cant spell) and hair pin turns.. the straightaways, people were hitting about 90-120mph.. so heat build up in the calipers is pretty high.

my friend has the 2005 STI subaru with the 4 piston brembo calipers.. they come gold painted.. but are now a dark orange color from heat. the other guys had Mitsu EVO VIII with same calipers but came red.. and are now a dark crimson..

there was a 4thgen SS out there that was on 4 R compound tires that was almost running the same speeds as the AWD turbo cars..

fastest lap of the day was my other friends EVO with 56.66 the camaro did 57.XX

so brakes, tires, and shocks are the big thing.

askulte

That sounds like a lot more fun that in the NorthEast. I could see how you get heat into the brakes and tires that way. We're lucky to get six 30 second runs in a day. Anyways, I've just finished fabbing the prototype brake duct hats for the 1LE brakes, so that should help keep things much cooler than just a 3" hose aimed at the center of the rotor. I haven't gotten data from thermocouple testing yet, but will during the next track day I make.

Andris

KiLLJ0Y

iTrader: (1)

thats awesome.. get pictures up as soon as you can

Gladstoneiroc

iTrader: (1)

I also use the Valvevoline DOT4 synthetic, but only cause my headers create so much heat. I read somewhere that Ford produces a Dot 3 that has the same temperature values as Silicone dot 5, something to ponder.

askulte

The Ford HD (Dot3 - # C6AZ-19542-AA) brake fluid has a good reputation as an inexpensive, decent fluid. The wet boiling point isn't as good as the Dot4's, but if you flush frequently enough, it shouldn't be a worry. One other thing I didn't see mentioned is that the Dot3's and 4's are hygroscopic, which means they absorb water. Once a can of brake fluid has been opened, it starts absorbing water, so don't use fluid that's been sitting open on the shelf for 6 months. Save that for the clutch...

KiLLJ0Y

iTrader: (1)

ok i asked my neighbor the name of the even we were in and he said its an SCCA Road Racing 10 Lap event..

the cool factor about this.. only 15 cars were in the event.. its every 6 weeks, and normal turn out is 10 cars.. very relaxed environment..