Nope. The problem is that DOT4 fluid is more suceptable to water contamination, so you should bleed it more often. On the street use only (yes, even running the Dragon) I would bleed out DOT 4 fluid annually, where as with DOT3 I would go 3 years or so without bleeding (or bleed when I replace pads whichever comes first.)

The water won't make the brakes feel spongy on it's own. However, it lowers the boiling point of the fluid and can result in fade if you overheat the fluid.

The car I take to the track, spends 95% of it's life on the street. I run DOT4 ATE Superblue in her year-round. The car I ONLY drive on the street, I run DOT3.

 

So you're recommending a 99.9% street car run 4?

EDIT: PS. Bleeding/refilling the brakes once a year isn't bad. I do the tranny and diff that often, I could easily redo the brake fluid then.

 

I used to run a high temp DOT3 since it was cheap. I was skeptical on the expensive DOT4 fluids.

I tried motul rbf 600 this year and I'm now SOLD. Won't put anything less in now.

 

What was the difference you perceived? Reduced fade? Better pedal feel? Stiffer?

 

[QUOTE=mbilderback,Aug 11 2005, 01:57 PM] So you're recommending a 99.9% street car run 4?

EDIT: PS. Bleeding/refilling the brakes once a year isn't bad.

 

Depends on what that 0.1% is.

Would you fly on an airplane whose wings only stayed attached for 99.9% of the flight?

There is nothing wrong with running DOT4 fluids on the street. I do it. If you never track your car, there is no advantage to it. If you ever track your car, there is a big advantage to it.

Brake fluid is cheap enough that really we all should probably flush the brakes at least every year. It's not necessary, per se, but it will help avoid long-term corrosion issues in the brake system.

 

What if the 0.1% is like 10 auto-xes a year?

I DD my S, so .1% of my mileage is like 15 miles, that can be a lot of auto-xes.

 

Brake fluid is a binary thing. Either you don't boil it, or you do. If you do, big problems. If you don't, there is no way to tell the difference between any of the DOT3, DOT4, or DOT5.1 type fluids. The only difference is that some will boil more easily than others.

 

I really doubt that any number of auto-x events will require high temp brake fluid.

 

OK...I don't know if the intentions were to be BS'ing but apparently the statement isn't 100% accurate. Given the level of the topic it's a fair statement, sans science.

As far as autox, if the fluid is able to cool down it doesn't matter how many times a year you heat it up as long as the max temp isn't boiling. Intensity is the key, not frequency.

Also, if you're tracking and/or autoxing you're probably changing pads, and maybe rotors, more than once a year so bleading shouldn't probably be associated with solely that project.

Front brake ducting is a good option also..our front bumpers make it a pretty easy project.