Dr Chill

It seems that Castrol SRF is compatible with Motul and other high temp blue DOT 4 fluids. After bleeding my brakes, the master cylinder was just below the min mark. Would you just have added the other fluid since nobody at the track had SRF? I just left it alone and ran the way it was because I didn't remember if SRF was compatible.

wallyman424

if i remember correctly srf says not to combine it with other fluids.

no harm no foul though.

WNDOPDLR

Curious minds want to know. If it not compatible with other fluids, how do you change to SRF or from it to some other fluid. It would be virtually impossible to get the other fluid completely out of the system and there will always be some residual mixing of fluids unless you flush quarts through the system. At the price of SRF, tht would be a very expensive proposition.

Rob Willis

I wouldn't mix fluids, just my .02 cents.

John Shiels

they all say don't mix If you don't mix you will use more of thiers. If they are all the same DOT rating I am sure it is fine you won't get optimal performance of a SRF.

xsiveone

You can mix it as far as I know, but I'd only do it if you positively can't find more SRF and then flush the system after the track event. The problem with mixing is it greatly compromises the benefits of the Castrol SRF by reducing the boiling point.

wallyman424

they way to think about it, is that by mixing you don't do any "harm." you just reduce whatever advantage the srf had to the specs of the lower BP mixed fluid.

i like srf, i HATE the pricetag, but it reduced the bleeding and flushing i have to do.

Mikelly

I had this issue at the last HPDE w/ THSCC... Bled $150 worth of fluid thru the system... I was specifically told that the SRF "stuff" doesn't mix with any other "Stuff" well...

It's your brakes, and these cars are really expensive to repair when your brakes fail on you at the worse moment. Spend the money and be glad you did.

Mike

Gary2KC5

This stuff is pretty costly compared to Motul or ATE, so I been in your situation before...just needing another couple of ounces.

they should make the bottle just a little bigger.

I WOULD NOT mix SRF with other stuff though, it states not to and I would think there is a difference between SRF and other stuff.

I would have an issue mixing Motul with ATE though.

Dr Chill

Well, I just ordered 2 more quarts of SRF for $66 a quart which is the best price I could find. I plan on draining the MC and filling it with new SRF, but I'm going to add a drop of blue just to add color so I know when the new stuff is flushed through.


Anyone know the actual brake fluid capacity of these cars?

xsiveone

This is the text that I see at just about every site that sells Castrol SRF. My guess is Castrol probably wrote it and the dealers just use it.

The paragraph talking about mixing fluids is in bold below.

Note: The particular dealer that I copy and pasted this text from added their own warning at the bottom even though Castrol's literature says that you can mix it, but it's not recommended because it compromises the Castrol SRF fluid.

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TECHNICAL INFORMATION

Castrol SRF Racing Brake Fluid is an ultra high performance product formulated specifically to satisfy the ever increasing stresses placed upon the braking systems used in international motorsport. The exceptional performance of Castrol SRF is due to a novel silicon ester technology pioneered by Castrol and unique to the extent that it has been granted patent-protection in numerous countries throughout the world.

Castrol SRF evolved as a direct result of Castrol's ongoing Research and Development program for brake fluids which identified this silicon ester technology as providing considerable performance benefits when compared with conventional glycol ether borate ester fluids.

Following exhaustive laboratory tests at Castrol's International Technology Centre in the UK, the final formulation for Castrol SRF was subjected to an extensive road-test programme on the Gross Glockner and Stelvio passes high in the Austrian and Italian Alps. It then underwent an independent track test program conducted by a famous Formula One racing team. Their assessment was that "Castrol SRF is the best racing brake fluid we have ever used."

Subsequently, Castrol SRF was offered to top flight racing and rally teams throughout the world including most of the Formula One teams, the all-conquering Jaguar and Mercedes -Benz sports car teams and the Audi, Nissan and Toyota rally teams. Enthusiastic recommendation by these experts soon created an immense interest in Castrol SRF throughout the whole spectrum of national and international motorsport. Today, Castrol SRF is regarded by the international motorsport community as being without equal and it is chosen not only by factory-supported teams but by private competitors throughout the world.

All conventional brake fluids used in cars and motor cycles are hygroscopic, that is, they absorb water from their surroundings. Strange though it may seem, the flexible hoses incorporated in braking systems are permeable to water and in time enough, water can find its way into the system via the hoses, and seriously affect the brake fluid's performance. This water reduces the boiling point of the fluid (ie, it lowers the temperature at which gas bubbles begin to form). When these bubbles form, they turn a virtually incompressible liquid into a mixture of gas and liquid which can be compressed quite considerably, thus severely reducing the efficiency of the brakes. In this situation, a driver finds that the brakes feel spongy. Brake-pedal travel will increase and it may be necessary to 'pump' the pedal to get the brakes to function effectively. However, when the brake fluid reaches a temperature at which the water in the fluid causes gas to be produced, which is equal to the volume swept by the piston in the rake master-cylinder, vapor-lock occurs and the brakes become inoperative. When this happens, the first indication the driver has that something is wrong is when he applies the brakes. The pedal goes down to the floor and the car carries on at undiminished - and possibly fatal speed.

The silicon ester technology in Castrol SRF addresses this problem in two ways. Firstly, Castrol SRF is less hygroscopic than conventional brake fluids - it absorbs less water in a given time. Secondly, unlike conventional glycol ether fluids, Castrol SRF reacts chemically with the absorbed water to reduce its adverse effects, thus preventing the fluid's high temperature performance and safety margins from deteriorating as rapidly as they would otherwise do.

Castrol SRF exceeds the US Federal Standards FMVSS 116 DOT 3 and DOT 4, ISO 4925, JIS K2233 and current SAE J1703 and is miscible with all conventional brake fluids conforming to these standards. However, mixing Castrol SRF and conventional brake fluids will reduce the benefits of Castrol SRF. It is strongly recommended that conventional brake fluid be drained from the system before flushing and re-filling with Castrol SRF.

The wet boiling point of Castrol SRF, 270 C, is vastly superior to the minimum requirement of 155 C demanded by the current US DOT 4 specification. The product's typical dry boiling point of 310 C is likewise outstanding. This ability to withstand temperatures in excess of 300 C, and its superior resistance to the effects of absorbed water, have established Castrol SRF as the world's premier fluid for the hydraulic brakes used in all forms of motorsport.

NOTE: DO NOT MIX CASTROL SRF WITH OTHER BRAKE FLUIDS

Z06Norway

can SRF be used on a new 2007 Z06 ?
noticed it was silicone based, i thought this was a no no on our cars ?


TIA


Rune

John Shiels

like I guessed. I have mixed it in a pinch. Only later to find 3 liters in the garage buried later