DOT 4 vs. "SuperBlue" for HDPE's

[Ski_Banker]

Putting in the speedbleeders in a total non-event. I am mechanically challenged and it took all of 10 minutes to swap them out. Piece of cake!

Thanks - anyone have thoughts on my other q's?

 

[dquarasr2]

Thanks - anyone have thoughts on my other q's?

You pretty much would want to change the fluid right before every event. The oldest fluid I use for a track event is about 3 months, especially here in So. Fla. But realistically, the extra insurance you gain for your $12 is worth it, say, if your fluid is two months old and there's a track event on the horizon; change it.

When I change the fluid, I empty the reservoir as much as I can (I use an ear irrigating syringe), then full it with fresh stuff. Bleeding the system starting from the wheel furthest from the reservoir, then moving toward the closest, or RR, LR, RF, LF. If the fluid is gross dirty like coffee, then it's easy to see how many pumps and drains are required to ensure the caliper has fresh stuff from the reservior. Otherwise, if you can't tell from the color just fill one of those brake bleeder cups (about four-five ounces) for the RR, a little less than that for the LR, less still for RF, and even less for LF. You should just about use up a bottle of Motul 600 (or around 16 ounces). You might as well use the whole bottle, as you can't store it on a shelf and use it later.

That would be your 90% flush, effectively giving you your max boiling point again, somewhere close to 600 degrees.

 

[docjohn]

I change my fluid(motul 600) twice a year and do 8-12 track days each year,no problems.

 

[Ski_Banker]

You pretty much would want to change the fluid right before every event. The oldest fluid I use for a track event is about 3 months, especially here in So. Fla. But realistically, the extra insurance you gain for your $12 is worth it, say, if your fluid is two months old and there's a track event on the horizon; change it.

When I change the fluid, I empty the reservoir as much as I can (I use an ear irrigating syringe), then full it with fresh stuff. Bleeding the system starting from the wheel furthest from the reservoir, then moving toward the closest, or RR, LR, RF, LF. If the fluid is gross dirty like coffee, then it's easy to see how many pumps and drains are required to ensure the caliper has fresh stuff from the reservior. Otherwise, if you can't tell from the color just fill one of those brake bleeder cups (about four-five ounces) for the RR, a little less than that for the LR, less still for RF, and even less for LF. You should just about use up a bottle of Motul 600 (or around 16 ounces). You might as well use the whole bottle, as you can't store it on a shelf and use it later.

That would be your 90% flush, effectively giving you your max boiling point again, somewhere close to 600 degrees.

Awesome, just what I wanted to hear. Looks like I'll be picking up the SS lines, speedbleeder, and a quart of Motul 600. :smile:

 

[nsxtasy]

As long as you've changed your fluid within the previous 6 months of any track event, its boiling point will probably be within 30 degrees of the dry boiling point listed on the bottle. With one of the best fluids out there, that's plenty.

Changing your fluid before every track event is like changing your oil before every track event; it won't hurt anything (other than your wallet), but it's overkill.

 

[dquarasr2]

As long as you've changed your fluid within the previous 6 months of any track event, its boiling point will probably be within 30 degrees of the dry boiling point listed on the bottle. With one of the best fluids out there, that's plenty.

Changing your fluid before every track event is like changing your oil before every track event; it won't hurt anything (other than your wallet), but it's overkill.

The problem is that I didn't know the absorption rate. I have seen graphs stating the boiling point degradation based on percentage of water absorbed, but I had never seen anything that told me how quickly fluid absorbs water. When I asked one of my very experienced friends whether I should change it, the answer I got was "you really need me to answer that?", meaning, don't bother thinking about it, just change it.

You're right, it's probably OK to go six months, but again, with humidity in this geographic area 80-90% all summer long, I didn't want to ever take a chance.

Skibanker, when are your next plans to do a track event? I'm going to Sebring on November 11. (Is that you I see on the Florida Turnpike between I-75 and Okeechobee Road, southbound in the mornings every so often?)

If you get totally stuck, I'd be happy to help you with your fluid change.

 

[Hrant]

If concerned that much about the effects of humidity, do a simple test. Leave it for 9 mos and then send a sample to Blackstone labs specifying what you want to focus in the analysis. For $20 they might save you the hassle of changing the fluid every 6 months :wink:

 

[Ski_Banker]

The problem is that I didn't know the absorption rate. I have seen graphs stating the boiling point degradation based on percentage of water absorbed, but I had never seen anything that told me how quickly fluid absorbs water. When I asked one of my very experienced friends whether I should change it, the answer I got was "you really need me to answer that?", meaning, don't bother thinking about it, just change it.

You're right, it's probably OK to go six months, but again, with humidity in this geographic area 80-90% all summer long, I didn't want to ever take a chance.

Skibanker, when are your next plans to do a track event? I'm going to Sebring on November 11. (Is that you I see on the Florida Turnpike between I-75 and Okeechobee Road, southbound in the mornings every so often?)

If you get totally stuck, I'd be happy to help you with your fluid change.

Yeah, humidity down here is what would really zap the fluid I think. I've seen other posts on how quickly Motul degrades in "normal humidity" and its quite a bit faster than stock fluid. Higher baseline though. I'm just getting into tracking, but would think every few months would be fine here in Florida, unless you want absolute max performance every time (and frankly, for $12 bucks...why not?)

I want to do the Nov Sebring event, but all the beginner slots were full when I last looked. Same thing happened with Homestead last weekend with Chin - all full. But I may very well take you up on the brake bleed 101 course...sadly, I might as well be wearing an apron and baking cookies when it comes to this stuff.

Not me on I-75, although I'm up in Lauderdale on weekends sometimes.

Andrew

 

[nsxnut]

If concerned that much about the effects of humidity, do a simple test. Leave it for 9 mos and then send a sample to Blackstone labs specifying what you want to focus in the analysis. For $20 they might save you the hassle of changing the fluid every 6 months :wink:

Yea but you are spending 20 bucks to test at best $15 of fluid.

Oh well...

 

[92 white 0650]

Re: It's called testing

Yea but you are spending 20 bucks to test at best $15 of fluid.

Don, Don, Don, pay attention, will ya? I'm the last person to defend Hrant's nerdy proclivity, but he's simply saying that spending $20 once to decide whether to spend $15 and 30 minutes once an event or once a year is money well spent. Do the math.

 

[Hrant]

Thank you, thank you, thank you ....... :biggrin:

 

[nsxhk]

Re: It's called testing

Don, Don, Don, pay attention, will ya? I'm the last person to defend Hrant's nerdy proclivity, but he's simply saying that spending $20 once to decide whether to spend $15 and 30 minutes once an event or once a year is money well spent. Do the math.

Funny guy :biggrin:

 

[nsxtasy]

If concerned that much about the effects of humidity, do a simple test. Leave it for 9 mos and then send a sample to Blackstone labs specifying what you want to focus in the analysis.

Better yet, if your dealer or independent mechanic has one of the gadgets to test the fluid's boiling point, they're usually happy to do it for free. John Vasos of Acura of Brookfield often brings his to the track with him...

 

[nsx2tall]

I think this depends on where you are at on the performance curve.
I have a friend that runs a very fast vintage race car. He bleads his breaks before every race. Yes every race. He is on the extreame high end of the curve. I am no where near this level.

If you are going to an hpde event onece or twice a year and are still learning
and not really pushing things than the above would surly be overkill.

I have a different perspective on this. I find that as a novice I over use my brakes (too much braking into corners e.g. slower cornering speed). Don't be too quick to exclude yourself from the performance curve-- it just might be the wrong kind of performance.:biggrin:

 

[latzke]

I have a different perspective on this. I find that as a novice I over use my brakes (too much braking into corners e.g. slower cornering speed). Don't be too quick to exclude yourself from the performance curve-- it just might be the wrong kind of performance.:biggrin:

You also have folks with significantly more horsepower than stock (supercharges, turbos, etc). More HP = more speed = more kinetic energy to be converted into thermal energy upon braking = hotter brakes = hotter fluid (unless you can increase cooling by a larger amount...which is rare).

That leads to a general statement on this matter: Seems like Gerard van Santen would be toward high-end of the performance curve, and his NSX is supercharged, and he participates in races (no cool-down lap like can be had during an HPDE). I'm very tempted to think that changing fluid every event is overkill when he says, "I change my brake fluid once a year after each winter and that works fine for me."

 

[Hrant]

Tires make a huge difference. With R compound, you will carry more speed and still brake less than street tires assuming no more HP.

 

[latzke]

Better yet, if your dealer or independent mechanic has one of the gadgets to test the fluid's boiling point, they're usually happy to do it for free. John Vasos of Acura of Brookfield often brings his to the track with him...

I assume this means he tests yours.

How does your boiling point at the beginning of the season (just changed) compare to the boiling point after one month/even, and how does that compare to boiling point at the end of the season (6 months of track events & living in average relitave humidity of 80% in the morning and 62% in the afternoon)?

 

[latzke]

Tires make a huge difference. With R compound, you will carry more speed and still brake less than street tires assuming no more HP.

You'll also carry more speed into the braking zone since you carried more speed out of (and maybe were able to get on the gas sooner when exiting) the last corner.

 

[nsxtasy]

I assume this means he tests yours.

Mine and lots of other folks. (People who track their cars frequently are a big part of his clientele.)

How does your boiling point at the beginning of the season (just changed) compare to the boiling point after one month/even, and how does that compare to boiling point at the end of the season (6 months of track events & living in average relitave humidity of 80% in the morning and 62% in the afternoon)?

At the beginning, it's usually close to the figure shown on the label (i.e. 593 degrees F for Motul RBF 600). The boiling point declines by anywhere from 5 to 10 degrees F per month, so it's still more than adequate at the end of the season.

 

[2slow2speed]

You also have folks with significantly more horsepower than stock (supercharges, turbos, etc). More HP = more speed = more kinetic energy to be converted into thermal energy upon braking = hotter brakes = hotter fluid (unless you can increase cooling by a larger amount...which is rare).

That leads to a general statement on this matter: Seems like Gerard van Santen would be toward high-end of the performance curve, and his NSX is supercharged, and he participates in races (no cool-down lap like can be had during an HPDE). I'm very tempted to think that changing fluid every event is overkill when he says, "I change my brake fluid once a year after each winter and that works fine for me."

Hmm..

Maybe you are jumping to conclusions too soon

IIRC Gerard's brakes are not stock , when I switched from the NA2 brakes to the Stoptech BBK, I didn't have any problems with the fluid boiling and only switched the fluid about every 6 months.

Back when I used to have the NA2 brakes I would have to bleed the brakes frequently because my rear rotor temps were way hotter than my fronts and I would get bubbles on my rear calipers.

So the brake system that is being used is also another factor to consider too along with the many other variables that folks have brought up already.

 

[dquarasr2]

Mine and lots of other folks. (People who track their cars frequently are a big part of his clientele.)

At the beginning, it's usually close to the figure shown on the label (i.e. 593 degrees F for Motul RBF 600). The boiling point declines by anywhere from 5 to 10 degrees F per month, so it's still more than adequate at the end of the season.

BAM! That's what I was looking for! Now I know I'm probably safe changing it as little as every six months. Thanks for yet another informative post!

And thanks, Hrant, I had never heard of Blackstone.

Ski, if you have nothing better to do November 11, drive over to Sebring and ride some laps.

 

[Alan C.]

BAM! That's what I was looking for! Now I know I'm probably safe changing it as little as every six months. Thanks for yet another informative post!

For the little bit of time it takes to bleed the brakes I can't understand why you wouldn't do it. You probably won't have a wreck today but I bet you still have insurance. Insurance is why I bleed every event. I've got a nice NSX in this hand and a $14 bottle of brake in the other hand ;-)

I do agree with nsxtasty on the Motul. It is much better than the ATE product and I have yet to have a problem with it. But then I .......

Last year for the first Putnam NASA TT event I used ATE Blue in a new to me '02' 911. Thought I had Motul at home but found otherwise Friday night. I had ATE and flushed the system with it, had ATE in it when I bought it, and went to the track. The last session of the day I had severe brake fade, pedal on the floor! Came in bled the brakes and all was fine. I am hard on the brakes, insurance again for me.

I was able to get the lap record for TTB at Putnam that weekend and beat the guy that ultimately won TTB at the Nationals.

Bottom line, I can't imagine coming out of Oak Tree at VIR heading up that long straight knowing my brake fluid was 6 months old. I just couldn't do it.

 

[nsxtasy]

If you look at it that way, maybe you should change to new fluid before every track session, several times a day...

 

[Alan C.]

I have bled the brakes after every day prior to using Motul:wink: It may be a seemingly waste of time but in almost 20 years of De's and racing I have yet to bend a car for lack of brakes.

 

[nsxtasy]

I have never bled the brakes. I change my Motul every spring, and that's the only thing I do with the fluid. And in over twenty years of track events I have yet to bend a car for lack of brakes, and I have yet to boil the fluid.