So if the 8 comes with DOT-4 from the factory, why does the owner's manual tell you to replace with (copied from the manual)...."Brake/Clutch fluid SAE J1703 or FMVSS116 DOT-3"?

 

probably a 'low end' DOT4 like the Valvoline SuperSyn or something

you brake too hard craig lol

 

Source? The first time I used stock brakes/fluid at the track I got major brake fade when they heated up. Before the next track day I had the dealership flush and replace it with DOT 4, and no problems.

 

i put in new high temp ford HD fluid 550 dry the day before and went to laguna for one track day on (good) street tires and stock brakes.

vaporized my pads and cracked two of the rotors, required replacing all the rotors.

the dealership wouldnt replace the cracked rotors because they were all blue and scored.

dont think the stock system is up to it. sears is a little easier on brakes, but i was an expensive single day for me.

you might be better off boiling stock fluid than taking out your whole brake system. :P

james

 

I can't believe that Laguna would be harder on brakes than Road America, but I am running on stock rotors that have stood up to quite a bit of use on that track, with Motul 600 and Carbotech XP8 pads, and haven't had any problems at all.

 

No manufacturer will spec DOT3 any longer for production fill. DOT3 has been obsolete for many years, but it's spec'ed in the manual because that's the most common fluid performance criteria and it's the easiest to find in auto parts stores. The difference in minimum wet boiling point between a DOT3 and a DOT4 is only about 25 degrees F.

More often than not the reason the fluid fails is not because it's DOT3 or crappy DOT4, but because owners are under the impression that brake fluid lasts forever. If you're looking for a long-term fill solution for brake fluid, don't get the stuff that has the highest dry boiling point. Find the stuff that has the highest wet boiling point. In my experience, even the best brake fluids become "wet" after about 4-5 months in today's plastic reservoirs.

I guarantee that if you flushed your brakes with the crummiest DOT4 fluid and went to the track the next day you would be just fine. I'd rather flush frequently with cheap fluid than flush every two years with the $55/qt stuff.

It's been said that after a year, DOT4 fluid will lose about 70 degrees F boiling point. Yeeeeiiikkes.

edit: n00bs on tracks use the brakes WAY too often and WAY too gently, and they overheat. As you get faster you will learn to use the brakes correctly and you'll likely find the stock system to be perfectly adequate. If not, the first thing I'd change is the pads (to something with a good coefficient of friction at high temps - i.e. something track oriented). Then the fluid.

John

 

Amen, preach on brotha. I've had the privilege of tracking 5 different cars since 2002, all of which had stock brake systems and track pads. The brakes on the RX-8 are head and shoulders above the other 4 cars on track.

John mentions common braking issues for newer track drivers - using too much brake. There is nothing that wears out pads\boils fluid faster than long braking zones. Even if you're braking gently, a long braking zone creates a ton of heat and doesn't give you as much time to dissipate that heat. Compress your braking zones - shorter, harder braking. It may seem counterintuitive, but your fluid and pads will thank you.

 

The best way to ensure your braking system can handle a track day is to keep your sessions to 20 minutes or shorter.

The RX-8 is so new that it's unlikely to be an issue, unless you track the car pretty often. I'd say change the fluid every couple of years and use a good fluid like ATE or Motul.

 

Ack. No. Not every couple of years. Every year, maximum. If you're tracking and you're hard on brakes, every six months, maximum. The fluids with the high boiling point are still just as hygroscopic as the cheapie fluids.

 

i flush mine before every event

 

I flush the system completely twice a year and just flush the calipers every 2 events.

 

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This alone means nothing, there are MANY vendors of DOT4 fluid, all with vastly different wet and dry boiling points.

 

Maybe we know each other...

But..Id say your braking/drivinghabits are to blame...not the hardware.

 

why are you going around and bumping old threads?

 

I warped my front rotors on stock pads and fluid on my first track day.
No problem since I went with Castrol DOT 4. I change the fluid before every track day.

 

Thanks for reiterating what we've all been saying.

 

how did you manage to warp the rotors?

 

Cuz..I had input?


If you didnt care..why'd you reply?

 

boredom and a free post