While you're in there...HPDE track prep

[maytag]

Originally Posted by JayG

Maytag is correct, you will cook almost any pads before boiling 600, unless its old and has a lot of moisture in it. I used 600 for a couple of years tracking and never had any issues. I would flush each year and bleed before every track weekend. 660 is good for more than just 1 weekend, at least 2 or 3.

Caveat here, that I've purchased 660 and have it on the shelf, but I haven't ever used it because everything I read steers me away from needing it.
The issue with 660 is that it has a lower] wet boiling point than the 600. (600 is 216°c, compared to 660's 205°c). Dry is higher, but wet is lower.
I already bleed the 600 before every track weekend, and flush a couple of times per season. Obviously this is required because of the hygroscopic nature of brake fluid. Heat cycling exacerbates this. So with a LOWER wet boiling point in the 660 I'll need to bleed & flush MORE frequently than I do with the 600.
I've only boiled 600 once (which is why I went to a more frequent bleed / flush interval). As long as that's the case, I don't know why I'd want to change to the 660, creating more work for myself :dance:

Of course YMMV.