[Rodan]

Thanks. I ended up ordering the Castrol, it's really not that much more $$.

I've run the Motul in bikes and cars, with stock and aftermarket brakes and I've always been happy. Most recently in a track only car on <100tw tires with big Wilwoods and aggressive pads... but it's a light car with lots of thermal capacity in the brake hardware.

[GunMetalGrey]

Has anyone used Motul 660 over 600?

I just picked up 660 since there was no 600 available in stock.

[mlee]

Originally Posted by GunMetalGrey

I have an appointment set for this Friday and going to use Motul 600 for now

How long would you expect Motul 600 Full Synth to last compared to Castrol SRF if I do about one tracking day a month?
I also see Motul 600 and 660, seems the difference is wet vs dry boiling point

I'd go with Castrol SRF but it won't arrive until after my first tracking event, plus the track is low speed with lots of technical corners.
I may switch to Castrol SRF before Area 27 in August

I plan to change mine once a year but really depends on how many track days you do. Maybe others have more experience in this area than I do.

Originally Posted by GunMetalGrey

Has anyone used Motul 660 over 600?

I just picked up 660 since there was no 600 available in stock.

I'm using 660. It's got an even higher flash point so better but a tad more expensive too.

It's hard to tell differences in brake DOT4 fluid from the drivers seat. But you will definitely know when you have DOT3.

[GunMetalGrey]

Originally Posted by mlee

I plan to change mine once a year but really depends on how many track days you do. Maybe others have more experience in this area than I do.

I'm using 660. It's got an even higher flash point so better but a tad more expensive too.

It's hard to tell differences in brake DOT4 fluid from the drivers seat. But you will definitely know when you have DOT3.

Thanks for the feedback, I was starting to wonder if I missed something since everyone said they are using Motul 600 and no ones seems to mention 660

[Norm Peterson]

RBF600 is perhaps the most commonly chosen fluid when people move up to something in the 600-ish dry boiling/400-ish wet boiling neighborhood. For many people, that seems to be sufficient, so they stick with it.

660 has a little higher dry BP than 600 (617F vs 594F claimed), but depending on whose data you look at the 660's wet bp may be lower than the 600's. For that reason, 660 may take a little more maintenance in order to maintain its temperature advantage.


Norm

[Osbornsm]

Originally Posted by Norm Peterson

RBF600 is perhaps the most commonly chosen fluid when people move up to something in the 600-ish dry boiling/400-ish wet boiling neighborhood. For many people, that seems to be sufficient, so they stick with it.

660 has a little higher dry BP than 600 (617F vs 594F claimed), but depending on whose data you look at the 660's wet bp may be lower than the 600's. For that reason, 660 may take a little more maintenance in order to maintain its temperature advantage.

Norm

That, and for the price of Motul 660 you should just get castrol SRF anyway.

[mlee]

Originally Posted by Osbornsm

That, and for the price of Motul 660 you should just get castrol SRF anyway.

Why would you do that Castrol is more expensive and I seriously doubt anyone in this group is going to experience any difference.

[Ryephile]

Originally Posted by mlee

Why would you do that Castrol is more expensive and I seriously doubt anyone in this group is going to experience any difference.

There are several of us that run temp stickers on our calipers. With track pads that lack thermal shims, caliper temps are upwards of 450°F, enough to boil every DOT4 except one.

Dry boiling point is a nearly useless measurement. In reality, as soon as you open the container, it'll no longer be at the dry boiling point and will work its way to the wet boiling point. The specification you should be looking at is the wet boiling point.

Castrol SRF is the benchmark for doing it right for track prep. Everything else is a compromise. Motul 660 is a marketing trick; their RBF600 is a better fluid with a higher wet boiling point for less money.

1 liter of ATE Typ 200 is $17 w/ 396F WBP
1 liter of Motul RBF600 is $37 w/ 421F WBP
1 liter of Motul RBF660 is $58 w/ 401 WBP, a bad value given it's only a few degrees better than Typ 200 for over 3x the price.
1 liter of Castrol SRF is $70 w/ 521 WBP

Pegasus has a handy chart that shows the usual suspects:
https://www.pegasusautoracing.com/gr...pID=BRAKEFLUID

[GunMetalGrey]

Originally Posted by Ryephile

There are several of us that run temp stickers on our calipers. With track pads that lack thermal shims, caliper temps are upwards of 450°F, enough to boil every DOT4 except one.

Dry boiling point is a nearly useless measurement. In reality, as soon as you open the container, it'll no longer be at the dry boiling point and will work its way to the wet boiling point. The specification you should be looking at is the wet boiling point.

Castrol SRF is the benchmark for doing it right for track prep. Everything else is a compromise. Motul 660 is a marketing trick; their RBF600 is a better fluid with a higher wet boiling point for less money.

1 liter of ATE Typ 200 is $17 w/ 396F WBP
1 liter of Motul RBF600 is $37 w/ 421F WBP
1 liter of Motul RBF660 is $58 w/ 401 WBP, a bad value given it's only a few degrees better than Typ 200 for over 3x the price.
1 liter of Castrol SRF is $70 w/ 521 WBP

Pegasus has a handy chart that shows the usual suspects:
https://www.pegasusautoracing.com/gr...pID=BRAKEFLUID

I was wondering how to evaluate the importance of wet vs dry boiling point in real life practical terms... So really that soon huh? (As soon as the brake fluid is in the car)

That's a serious difference in WBT!

Castrol is $100 a litre on Amazon.ca and the Motul 660 was $56 at my local auto parts store.
No one seems to stock Castrol locally where I live in B.C. Canada
Will move to Castrol SRF next for sure especially once I hit up a track that is harder on brakes.

[kropscamaro16]

Originally Posted by GunMetalGrey

Has anyone used Motul 660 over 600?

I just picked up 660 since there was no 600 available in stock.

im upgrading from 600 to 660 this weekend was gonna do the castrol srf but its $$$$

[mlee]

Originally Posted by Ryephile

There are several of us that run temp stickers on our calipers. With track pads that lack thermal shims, caliper temps are upwards of 450°F, enough to boil every DOT4 except one.

Dry boiling point is a nearly useless measurement. In reality, as soon as you open the container, it'll no longer be at the dry boiling point and will work its way to the wet boiling point. The specification you should be looking at is the wet boiling point.

Castrol SRF is the benchmark for doing it right for track prep. Everything else is a compromise. Motul 660 is a marketing trick; their RBF600 is a better fluid with a higher wet boiling point for less money.

1 liter of ATE Typ 200 is $17 w/ 396F WBP
1 liter of Motul RBF600 is $37 w/ 421F WBP
1 liter of Motul RBF660 is $58 w/ 401 WBP, a bad value given it's only a few degrees better than Typ 200 for over 3x the price.
1 liter of Castrol SRF is $70 w/ 521 WBP

Pegasus has a handy chart that shows the usual suspects:
https://www.pegasusautoracing.com/gr...pID=BRAKEFLUID

[GunMetalGrey]

Originally Posted by kropscamaro16

im upgrading from 600 to 660 this weekend was gonna do the castrol srf but its $$$$

Sounds like you should go with Castrol SRF or stick with 600 based on what I'm hearing here on the forum, that's what I'm going to do when I get a chance

[Rodan]

I just got two liters of Castrol SRF from Amazon for $62/liter.

[kropscamaro16]

Originally Posted by GunMetalGrey

Sounds like you should go with Castrol SRF or stick with 600 based on what I'm hearing here on the forum, that's what I'm going to do when I get a chance

eh i dont run super hard or do alot of track days so anything better than what i have will be fine i trust my buddys shop they know there shit


no doubt the castrol srf is better but just way more $$ so o well