Mike RT4

Catrol SRF in my opinion - it's wet boiling point is higher than most fluids dry boiling point. However, you are better off looking at all the data sheets and comparing them yourself .

B serious

Castrol SRF is also $17.5million/drop (exaggeration).

In reality, isn't it like $60/liter?

So if this guy is just doing HPDE days and/or DD'ing it....its still not the best choice.

B serious

Maybe I'm thinking too logically. Maybe he's just curious about the BEST FLUID YOU CAN BUY. But what point would that question serve? And again...what constitutes the best?? Its still not answerable.

Since logic is out....the best fluid is fluid you can make yourself to be the best. Be like some kind of brake fluid Walter White.

Mike RT4

Yes, but it is quantifiabley the "best" - as in highest boiling point (to me that is the "best" in terms of what you want from a brake fluid) . It's not like suspension which is more subjective and requires clarification of use etc. Brake fluid only has one use IMO (to repeatedly stop the car from high speed without boiling and causing peddle issues ).

SRF meets that remit with a dry boiling point in excess of 300°C (close to 600°F)

Wet boiling point 260°C (500°F).

Last time I checked, these figures were the highest of any available (certainly within the UK).

However, I haven't checked for any developments to see if any new fluids are better, as Castrol SRF is just the "go to" fluid in my opinion, as other than the usual required time period maintenance changes (brake fluid is naturally hygroscopic, which means it absorbs water during it's life (hence why it has two temp ranges given - a dry and a wet), it is a fit and forget item.

As to the cost, most quality products seem expensive, but when you are swapping the cheaper fluids 2-3 times a year because their performance is dropping off noticeably, the cost of this is invariably more expensive than the SRF that can least 1-2 years without needing to be changed....

B serious

Some brake fluids are more hygroscopic than others. So use environment may be a factor if longevity is a concern. An expensive racing brake fluid may or may not become contaminated faster. Fluids on race cars are changed more often than those on street cars.

And SRF is an absolute and total waste if its not being used for racing purposes. You'd have to be dreaming to think you need it on a street car that you like to drive hard.

B serious

If ONE best fluid existed...why would any other fluid exist?

Is there a fluid that is extremely hydrophobic, and has a dry/wet boiling point higher than anything else, that keeps all the seals in the system conditioned perfectly, while also being sold everywhere, and available for $5/liter?

No.

Jah2000

I don't track, so I just use Valvoline Dot 3&4.. it has a decently high dry/wet boiling point and is available everywhere.

Slowcrash_101

Ate typ200 is my fluid of choice I get a quart for $12 locally.

Mike RT4

Castrol SRF lasts 1-2 years no problem in extreme track use. I read on here of people changing their brake fluids every other track day (which would end up much more expensive than the Castrol SRF). I don't understand why someone would criticise it on price, but be prepared to spend far more on an inferior fluid over the same period of time (due to having to replace it more frequently). Seems a bit of a false economy to me (and that is without the high temp benefits)....

However, I can only comment on my experience. I discovered SRF over 15 years ago and haven't used anything other than this fluid in all my cars since then. It gives the added bonus of knowing that I am NEVER going to have an issue with the dreaded peddle to the floor, which is a real confidence boost when on track. It allows you to constantly brake as deep and as late as the pads and tyres will let you without that horrible doubt in the back of your mind, that it's all going to go wrong .

It's certainly not the cheapest, but when has the "best" ever been ? The Miata does everything that an S2000 does and is cheaper, but funnily enough we all choose to pay the extra for the better car .

B serious

You wouldn't have pedal problems on the street with something like Valvoline DOT4 either.

To use your own comparison, what you're describing is like buying a S2000 because its "better" than a Miata and then never going past 2K rpm with it.

Its your money. I'm sure you've got piles of it. Spend it how you want.

But.... "best"?