So my cousin uses MOTUL DOT 5 in his lotus with stock brakes. He has advised that I use MOTUL DOT 4 or 5...

Does that sound right?

In the last bike I had, I used MOTUL DOT 5.1 since I was using Kevlar braided lines.

The Stoptech BBK comes with 4 Piston front and rear with 14" rotors all around... they also replace the brake lines with SS lines. I am going with street pads which I can easily swap out come track day so what fluid should I go with?

Thanks.

 

DOT 4 is fine. It doesn't have to be MOTUL. You also need to find out what is compatible with your brake system. DOT 5 is silicone based and may not be compatible with the rubber, plastic, and metal components, which is why DOT 5.1 was introduced.

So typically, DOT 3, 4, and 5.1 are compatible with each other if your system already has any specific recommendations.

DOT 5 is a separate entity and must only be used if specifically called for.

 

Valvoline makes a performance dot 4 with a raised temp reading. You can find it in some parts stores. It has all the properties you are looking for.

 

NEVER use DOT 5! It's silicone based and NOT compatible with Dot 3-4-5.1 fluids. To use DOT 5, you have to 100% clean out the old brake fluid.

Just because you have a BBK, doesn't necessarily mean you need a super high performance fluid. Depends on your use. If it's 99% street then most any QUALITY brake fluid will work fine. As you won't be able to get your fluid to the boiling point of most brands.

If you frequently track or canyon carve you car, then consider a fluid with a higher boiling point. But as a general rule, as the performance of the fluid goes up (ie.. higher reistance to boiling), so does it's moisture absorbtion rate. As the fluid retains more moisture (water), the boiling point plummets rapidly. ie.. if you use a super high performance fluid but fail to replace it once a year, you might actually end up having a fluid with WORSE performance vs a fluid more resistant to absorbtion (but with a lower intial boiling point)

 

My Stoptech's came with Motul (Dot 4-RBF600 I think, although it has been sometime and I am overseas so I cannot look now). You can buy it at most motorcycle shops.

I would double check to see if yours comes with fluid, I ordered mine from CZP, but they dropshipped from Stoptech, and it included 3 bottles (in the Stoptech box).

 

Oh, as far as pads....

I have tried the Axxis Ultimates, Hawk HP+'s and HPS's with the Stoptech's. For normal driving, the HPS's are great, relatively dust free and QUITE. Their performance is no where near the HP+'s, and the Ultimates seemed about the same as the HP+'s. Both are very dusty and you get lots of noise.

The HP+ and Ultimates are good for light-light track and Auto-X, the HPS may suffice for some auto-X, but absolutely should not be used for track use.

For me, the HPS's are fine 98% of the time. Like I said, I could tell the others were slightly better, but not worth the noise and dust (and increased rotor wear).

If you plan to go full track, you will want to invest in some good track pads, of which I have tried none, so I cannot comment.

 

Porterfield in Costa Mesa, CA is a great place for brake stuff; fluids, pads, rotors, etc. http://www.porterfield-brakes.com/

I will be using the RBF600 in our Saleen but plan to change it once a year and bleed before any track event.

Once I improve the brakes on the G, I will likely try the Valvoline fluid, as I have heard nothing but good things it, especially for a car that only sees the track a couple times a year.

 

+1 on the DOT 4 Valvoline in the gold bottle. I only track 2-3 times a year and I haven't boiled the fluid yet. Plus it's cheap and readily available at most auto part stores.

 

stoptech BBK comes with brake fluid - motul 600 or something - use it.

 

How do you know if you've boiled your fluid? I've tracked the car aggressively twice so far. Late braking and passing STi's on the ensuing straight owns me. What are the symptoms I should be looking out for, aside from understeering into the wall. How does it compare to my pads being glazed?

 

I didn't know that?

Well for the $$$, I am sure glad they include the fluid!

 

Well the only thing I can say is that your pedal will be mushy and will require more effort to achieve the same braking before boiling the fluid. In the extreme case the pedal would go all the way down to the floor. I always bleed my brakes before every track day as a precautionary measure and so far I haven't seen anything too bad come out of my calipers.

About brake fade here is something descriptive I found on the net.

"4) When brake fade occurs, do you lose all braking, or just some?

Yes. Fade is not usually an "all or nothing" situation. Fade is a loss braking effectiveness due to a reduction in the coefficient of friction between the pads and the rotors. The surface of the pads may get slick because the binder in the compound melts, or because of severe outgassing from the binder. In extreme cases, you can put 300 pounds of pressure on a rock-hard, high pedal with virtually no braking effect - BTDT! In mild cases, you may just notice a slight reduction in braking effectiveness.
"

 

If a brake fluid ever boils it should be replaced immediately as a chemical change occurs. It takes 4-6 minutes after stopping for the boil when no cooling air flow is present.
http://delphi.com/pdf/techpapers/1999-01-0483.PDF
http://www.babcox.com/editorial/bf/bf40142.htm
http://www.volvoclub.org.uk/faq/Brak...omparison.html

Why it is just easier [safer] to just change after each track day..for the street once per year is usually good enough.

Notice from the chart that after 6 months every fluid boils at a lower temperature -- worse by 40-80F.

 

One think Motul advertises is that their 5.1 is designed for ABS systems.
Don't know if it's more marketing or fact.

 

We do?

separate note:
I was able to have a conversation with the Motul guys at SEMA this past year. Motul RBF 600 has a higher boiling point than 5.1 It is also used in most racing applications. That's why it's RBF, racing brake fluid. Now this fluid is also very usable on the street as well. Most of the guys here run it on their street cars.

RBF600 did not qualify for the 5.1 rating because of it's viscosity. 5.1 is a thinner fluid which allow the ABS units to pulsate faster. It also performs a little better under colder temperature settings. RBF 600 is also fully ABS compatible though.