How much of a difference does brake fluid make?

Giant Purple Snorklewacker wrote: Don't berkeley around with brake fluid. At best it ruins your fun with a spongy pedal. At worst... it can be the difference between a podium in the prize money or a 140mph ride across the grass ending in a roll-over crash with a 20g impact. Ya know... just using one example Wilwood EXP 600 is my affordable racing brake fluid of choice. You can find everywhere at the same price. NAPA even carries it. When choosing, you are most concerned with the wet boiling point number compared to other brands. $19 for 626 dry, 417 wet is a pretty good value.

In your opinion why does the wet point matter more than the dry point?

Snrub wrote: In your opinion why does the wet point matter more than the dry point?

Because glycol based brake fluid is hygroscopic. The second you open the jar the dry boiling point is compromised by the environment. The stuff draws in moisture from the air. The longer it's in an open jar, sitting in the car, when you pump up that pressure bleeder full of humid summer air, even heat/cool cycles of system parts introduce condensation. That all ruins that top number by some indeterminable amount the second you crack the seal on the jar.

The wet boiling point is given for a system that has absorbed 3% water and so you will always be better than that unless you actually poured water into the master cylinder on purpose. So... plan for the worst, hope for the best. Comparing bottom numbers you at least know where the floor is. The higher the better.

EDIT: If you are the sort of person who bleeds the system before every race and purges it every few then you can pretty much ignore all of the above but you will find that all of the "decent" racing fluids are pretty close in spec unless you spend astronomical dollars for them. I usually don't OCD on bleeding. I flush before the season, bleed once or twice during and leave it be. I never have had issues with ATE or Wilwood racing fluid.

Motul RBF and Carbotech pads. (I've heard Performance Friction is good, but they don't have a pad for my application.)

Every time I strayed from this combo, I regretted it.

Example: Decided to do some DEs instead of Chump and went with ATE super blue and Porterfield R4-S. Brand new pads, bedded in and one track day at AMP. This is on a ~200hp, 2500# car with 205/225 50 15 Hankooks on it. One event. And the super blue was super black afterward. Totally cooked. I know these aren't race pads, but I thought they would do for a lapping day. Nope.

Went to Motul and XP10s front and XP12s rear, and used about ~20% of my pads at the same track with no fade.

^R4S is a street pad - and you totally overheated them racing - which totally cooked the brake fluid.

the brake fluid may have been fine if you had the right pads for the application.

In reply to amg_rx7:

+1 R4-S is a functional equivalent to a Hawk HPS and has no place on a racetrack.

Giant Purple Snorklewacker wrote: Because glycol based brake fluid is hygroscopic. The second you open the jar the dry boiling point is compromised by the environment. The stuff draws in moisture from the air. The longer it's in an open jar, sitting in the car, when you pump up that pressure bleeder full of humid summer air, even heat/cool cycles of system parts introduce condensation. That all ruins that top number by some indeterminable amount the second you crack the seal on the jar. The wet boiling point is given for a system that has absorbed 3% water and so you will always be better than that unless you actually poured water into the master cylinder on purpose. So... plan for the worst, hope for the best. Comparing bottom numbers you at least know where the floor is. The higher the better. EDIT: If you are the sort of person who bleeds the system before every race and purges it every few then you can pretty much ignore all of the above but you will find that all of the "decent" racing fluids are pretty close in spec unless you spend astronomical dollars for them. I usually don't OCD on bleeding. I flush before the season, bleed once or twice during and leave it be. I never have had issues with ATE or Wilwood racing fluid.

I've operated under the assumption that if I'm heavily bleeding the brakes (purge?) every year (my current situation) or even for folks doing this say every 2 years that DOT3 Ford spec is a good way to go. Thoughts? Where I live the Wilwood fluid is not readily available.

Giant Purple Snorklewacker wrote: In reply to amg_rx7: +1 R4-S is a functional equivalent to a Hawk HPS and has no place on a racetrack.

I understand that and knew that going in.

"Good for autocrossing, some drivers schools, solo events, and rally’s."

Figured that might get it done for a DE on narrowish street tires in a lightish car. Nope.

Not a swipe at either the pad or fluid mfg, but they aren't suited for DE use. Also, in my experience, the Carbotechs cost 2-3x as much as lesser pads, but return that with better longevity.

Moral of the story is don't cheap out on brake pads or fluid.

Snrub wrote:

Giant Purple Snorklewacker wrote: Because glycol based brake fluid is hygroscopic. The second you open the jar the dry boiling point is compromised by the environment. The stuff draws in moisture from the air. The longer it's in an open jar, sitting in the car, when you pump up that pressure bleeder full of humid summer air, even heat/cool cycles of system parts introduce condensation. That all ruins that top number by some indeterminable amount the second you crack the seal on the jar. The wet boiling point is given for a system that has absorbed 3% water and so you will always be better than that unless you actually poured water into the master cylinder on purpose. So... plan for the worst, hope for the best. Comparing bottom numbers you at least know where the floor is. The higher the better. EDIT: If you are the sort of person who bleeds the system before every race and purges it every few then you can pretty much ignore all of the above but you will find that all of the "decent" racing fluids are pretty close in spec unless you spend astronomical dollars for them. I usually don't OCD on bleeding. I flush before the season, bleed once or twice during and leave it be. I never have had issues with ATE or Wilwood racing fluid.

I've operated under the assumption that if I'm heavily bleeding the brakes (purge?) every year (my current situation) or even for folks doing this say every 2 years that DOT3 Ford spec is a good way to go. Thoughts? Where I live the Wilwood fluid is not readily available.

I thought that I heard that Motocraft changed their formulation a few years ago? I bleed brakes and clutch between every DE. It just takes a few minutes and provides a good opportunity to inspect your suspension, wheels and tires.

There are a lot of fluids that may work, but there are few that are known to work.

XP10's are awesome. I've also had a good luck with the Hawk HP+ (2005 Mazda6).

Tyler H wrote: Not a swipe at either the pad or fluid mfg, but they aren't suited for DE use.

I've raced 3 back-to-back all out 35 minute sprint races in 100F temps at Summit point using ATE blue in a 2500lb car that hits 145 twice a lap. It works the brakes hard.

The ATE stuff is fine if it's fresh. You had some other variable gone astray (pads/cooling/over-braking?). You can't really go wrong with your stated choices but there are plenty of racing brake pad compounds, fluids, etc that will work fine too.

fornetti14 wrote: XP10's are awesome. I've also had a good luck with the Hawk HP+ (2005 Mazda6).

Try the Hawk DTC-60 or 70 compounds. They are much, much better for race track work.

HP+ might get by on street tires, very light car, etc but I think you will find the real racing compounds much more consistent and modulation friendly. Performance Friction makes great stuff too but it's $$$.

Giant Purple Snorklewacker wrote: I thought that I heard that Motocraft changed their formulation a few years ago? I bleed brakes and clutch between every DE. It just takes a few minutes and provides a good opportunity to inspect your suspension, wheels and tires.

There are a lot of fluids that may work, but there are few that are known to work.

I don't know about Motocraft specifically, but lots of run of the mill brands produce Ford spec variants of fluid. I heard about the DOT3 Ford spec fluid years ago from several different racers. I'd be interested to hear if anyone has any concrete information suggesting it's a bad idea to use it or any usage parameters that differ from my understanding.

Snrub wrote:

Giant Purple Snorklewacker wrote: I thought that I heard that Motocraft changed their formulation a few years ago? I bleed brakes and clutch between every DE. It just takes a few minutes and provides a good opportunity to inspect your suspension, wheels and tires.

There are a lot of fluids that may work, but there are few that are known to work. I don't know about Motocraft specifically, but lots of run of the mill brands produce Ford spec variants of fluid. I heard about the DOT3 Ford spec fluid years ago from several different racers. I'd be interested to hear if anyone has any concrete information suggesting it's a bad idea to use it or any usage parameters that differ from my understanding.

You misquoted me - someone else was talking Ford stuff - my standby is Wilwood EXP Racing Brake fluid with ATE and some other stuff as a backup plan.

Tyler H wrote:

Giant Purple Snorklewacker wrote: In reply to amg_rx7: +1 R4-S is a functional equivalent to a Hawk HPS and has no place on a racetrack.

I understand that and knew that going in. "Good for autocrossing, some drivers schools, solo events, and rally’s." Figured that might get it done for a DE on narrowish street tires in a lightish car. Nope. Not a swipe at either the pad or fluid mfg, but they aren't suited for DE use. Also, in my experience, the Carbotechs cost 2-3x as much as lesser pads, but return that with better longevity. Moral of the story is don't cheap out on brake pads or fluid.

Interesting, ATE Blue worked just fine for me in both my motorcycles and my Miata for track work. Of course, both had proper pads.

I need to find something locally to bleed my brakes this week, Wilwoods on all 4 corners of the Miata with a 1.6 still, so probably anything will work.

Snrub wrote: Where I live the Wilwood fluid is not readily available.

Do you have amazon.com where you live? Speedway, Summit, Jegs too... they all carry it.