FWIW, here's a post from Dave Zeckhausen, who was one of the most knowledgeable SHO guys (until he went to a 540i 6-speed!).
Actually, if you don't drive aggressively, the stock Ford High Performance brake fluid will do fine. However, if you like to drive aggressively, or like to even autocross or race your car, then the factory brake fluid will not be very suitable. When driving under the above conditions, you have to have a break fluid that has a very high boiling point, since if your brake fluid starts to boil, that can't be very good. Also, over time, moisture will enter and be absorbed into the brake fluid lowering the boiling point temperature over time. That's why it's a good idea to flush out and replace your brake fluid every year or so to keep the moisture out. Also, some brake fluids tend to absorb moisture much more rapidly than others. The Ford Dot 4 high performance brake fluid tends to be very hydroscopic and will absorb moisture very quickly lowering it's boiling temperature rapidly. That's why it's important to buy a brake fluid that comes in a metal can instead of plastic, since moisture will make it's way into the brake fluid if it's in a plastic bottle. The ATE Type 300, or Super Blue Racing (same thing, just a difference in color), and the Castrol LMA (low moisture activity) are examples of 2 brake fluids that absorb moisture very slowly. For regular street city driving, a brake fluid that absorbs moisture slowly is desirable since unlike a race car that changes it's brake fluid after every race, you'll probably be keeping it in your car for a year or two. When I had my SHO, I used the ATE Super Blue Racing because it has an excellent wet and dry boiling point temperature, and because it doesn't absorb moisture very quickly, I wouldn't have to worry about it for a while. Castrol SRF is the best when it comes to brake fluid, but I can't afford something that costs $74 a liter. ATE Super Blue Racing provides almost the performance of Castrol SRF, but only costs $10 a liter.
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I agree with Mitch that brake fluid should be changed regularly to keep moisture and corrosion out of your system. But before you run out and use a racing brake fluid, you should consider how you will use it. A racing brake fluid is designed to be changed frequently, usually before every race. Typical racing fluid absorbs moisture very quickly, so within a few months you will be running with a much lower boiling point and encouraging corrosion in your braking system.
The statement by Performance Friction that "ABS function is enhanced due to the high boiling point and non-compressibility" is pure marketing hype. ALL brake fluid (except DOT 5 silicone) is non-compressible and, hopefully, not boiling while you are driving! The fact that they don't list a wet boiling point makes me a bit suspicious.
If it was really good, they would be a DOT 4 fluid and not a DOT 3 fluid. And there is no such thing as a "Z-rated" brake fluid. That is also a marketing creation that PF has come up with.
(After writing this, I called up Performance Friction in Clover, South Carolina and spoke to an engineer. He claimed a wet boiling point which "exceeds the DOT 3 value of 284 Fahrenheit". He read this right off a can of fluid. He admitted that Ford Heavy Duty DOT 3 tested out better than their stuff but that non-Ford owners may be reluctant to use it for "religious" reasons.)
Lets look at what the DOT ratings mean. The table below shows the MINIMUM wet and dry boiling points for DOT 2, 3, 4, and 5 brake fluid in degrees Fahrenheit.
DOT 2 DOT 3 DOT 4 DOT 5
Dry Boiling point 374 401 446 500
Wet boiling point 284 311 356
The DOT 2 spec is for drum brakes and is obsolete. If you have any DOT 2 in your garage, throw it away! DOT 5 is for silicone brake fluid. Silicone brake fluid (DOT 5) should be avoided because it is not compatible with regular brake fluid, it is hard to pour without introducing bubbles and thus results in soft pedal feel, and moisture still gets into your system and will pool in low areas like your calipers and encourage rapid corrosion. STAY AWAY!
That leaves DOT 3 and DOT 4 fluids. These fluids are compatible with each other and may be interchanged or mixed with no ill effects. Let's look at some popular brake fluids and their boiling points:
Castrol LMA DOT 3/4 446 311
Ford Heavy Duty DOT 3 550 290
ATE Super Blue Racing 536 392
ATE TYP 200 536 392
Motul Racing 600 585 421
Castrol SRF 590 518
Performance Friction 550 284
Castrol LMA is very good at rejecting moisture and may be kept in your brake system for a couple years. The LMA stands for "Low Moisture Absorption". This is the minimum quality stuff that I would use in my Impala. It comes in plastic containers which do not have a long shelf life. Don't buy lots of this stuff at a time because moisture can make its way through the plastic containers.
Ford Heavy Duty DOT 3 is VERY inexpensive and is popular among racers because of its excellent dry boiling point. It absorbs moisture quickly, but the racers don't care since they change their fluid frequently. Comes in metal cans so it may be stored. I would not use this in my Impala for the street.
ATE Super Blue Racing and ATE TYP 200 are the same brake fluid in two different colors (blue and amber, respectively). BMW recommends this brake fluid for their street cars because it, like Castrol LMA, absorbs moisture very slowly. The advantage over LMA is that ATE has a much better wet boiling point. You can put this stuff in your car and forget about it for a long time. An excellent choice for a weekend track car which also sees regular street duty. Comes in metal cans. This is what I use in all my street cars.
Motul Racing 600 is a very exotic and expensive synthetic fluid with high wet and dry boiling points. I use this exclusively in my race cars. Too expensive for the street and requires frequent changing due to its hydroscopic nature. Sold in plastic bottles.
Castrol SRF is a hyper-exotic and hyper-expensive brake fluid that is generally used by wealthy Porsche owners at track events. I've seen prices of $78 per liter for this stuff. It is not suitable for the street because it absorbs moisture quickly. Sold in metal cans. I can't afford this stuff!
Performance Friction High Performance DOT 3 has a good dry boiling point but a crummy wet boiling point. It comes in metal cans which is good for shelf life and sells for $7.87 per 16 ounce container. If you are even considering this fluid, I would go with the cheaper Ford Heavy Duty DOT 3. In either case, change this fluid frequently due to the poor wet boiling point.
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My post to the Impala SS digest generated a flurry of requests for where to buy ATE Super Blue Racing and TYP 200 brake fluids. I know of two mail-order sources for the fluid:
Imparts sells it for $13 per liter in quantities of 2 or more.
The Ultimate Garage sells it for $9 per liter for 2 or more.
I listed both sources because they both sell really neat stuff in addition to brake fluid. Personally, I would go for the $9 cans of brake fluid, but that's up to you. ;-)
Hope this helps!
1991 Taurus SHO
1996 Impala SS