djh

FYI, like "mountain-grown coffee" all brake fluid is synthetic.

Dave

mayhem

iTrader: (9)

Valvoline synth is the name, so I don't know what else he would call it. VSP is a good cheap choice, but requires frequent bleeding like Motul.

Out of the dozens of times I've been at Putnam I've never boiled the fluid, but I'm not saying it's not possible. Putnam is generally easy on the brakes compared to other tracks and I have lost the brakes at a few other tracks.(CMP, Mid-O, Gingerman, Autobahn...) I don't want to say it's your driving style, but I'm not taking that off the table. In your situation more cooling can't hurt. Good luck!

coolnick

iTrader: (9)

Yeah I am pretty sure it was my driving style. I was a lot more concious of time spent on the brake pedal at Mid Oh and I didn't have any problems this time. The ducts are for further peace of mind.

Autoxevo

iTrader: (6)

Have you thought about the titanium shims from Girodisc?

http://girodisc.com/catalog/product_...roducts_id=209

coolnick

iTrader: (9)

Yeah I thought about them for about 15 seconds while LOLing.

djh

Jeez, Chris, I'm just trying to point out that Valvoline (a subsidiary of Ashland) is more marketing than technology. And that they're not alone, some companies like to label their brake fluid as "synthetic" for the appeal when, in fact, all brake fluid is.

Dave

Fireball

iTrader: (15)

STOP laughing. Let me tell you, I've done some testing and they work INCREDIBLY well.

Last track session, I put new pads on and didn't have enough space to put 1 of the shims on. After that day, I took out the pads to check them and the side with no shim, started cracking the dust boots because of the heat!! The other side was perfect!

They DO make a HUGE difference and I DO strongly recommend them!

Ludikraut

iTrader: (17)

^ Do the titanium spacers completely replace the stock (steel/al?) spacers?

l8r)

Galant VR-4 #34

iTrader: (4)

The best combo ive used on the Evo is the Hawk DTC 70s with the SRF and AMS cooling kit. I have boiled every fluid mentioned on this posting with the DTCs except the SRF. The only time ive boiled the SRF was when using PF01 pads that are more aggressive than the Hawks and that was on a track that didnt allow for proper cooling. You should keep your questions to like cars, since those light Hondas and other cars can use other set ups you just cant get away with. I could use nearly any good fluid on my Honda race car being that it weighed 2400 pounds. The long straight 3000' you spoke of is actually better for your brakes, not worse, as it will get them nice and cool before you need them. Its the multiple semi fast turns requiring repeated braking then onto a short straight that doesnt give your brakes a chance to cool and then you have to brake fairly heavy, that are the real issue. Like turn 10 at Summit point. I use ATE blue for one reason, to flush out my other fluid I also just got the AMS tit. backing plates. Also, asking a guy that runs one lap doesnt really make sense. He is basically running a time attack and they really arent gonna get that hot running 1 or 2 hot laps, You should ask people that run wide out for 30-40 minute sessions or in your case, maybe ask some of the fast HPDE guys.

Good luck, and get rid of that ATE !!
Marty

Galant VR-4 #34

iTrader: (4)

Yes, the AMS ones do. "backing plates"

coolnick

iTrader: (9)

No they don't.

In layman's terms, the rate of heat transfer is equal to the temp difference between the back of the pad and the pistons divided by the R value of the insulating material. In this case the R value is equal to the thickness of the shim divided by the k value of the material and the area of the shim.

If you look at the equation you will note that the only variable used to compare the titanium and the stainless steel shim is the k value.

Titanium k = 21.9 (W/m*K)

Stainless Steel (304) = 14.9 (W/m*K)

So, q (rate of heat transfer) = [(temp of pad - temp of piston) * k * area] / shim thickness


You will notice that the k value is now in the top of the equation, so the rate of heat transfer is directly proportional to the k value of the material. Look at the k values of the two materials again. Notice the stainless steel has a smaller k value? Yeah, that means it transfers heat at a slower rate.


Girodisk probably honestly believes they work, but they need to have their heads examined. In any case the relative thickness of the shim compared to the pad means that the shim is doing nearly nothing. If you are adding the Ti shims in addition to the factory shims you are doubling your R value, or slowing down the heat transfer by a factor of 2, but I assure you it will make no measurable difference because doubling nearly nothing is still nearly nothing.


So if any of you actually read that you will see why I LOL every time I see someone spend money on those things.

Fireball

iTrader: (15)

Well, I don't know where you came up with all those formulas, or whatever, half of it didn't make sense (perhaps that was the point), but I know from USING them, in REAL WORLD conditions, that it helps.

Believe what you will, but the cost of those has more than paid for itself already.

Everything I've read everywhere, is that Titanium is a VERY poor heat transferring material.

Also, those shims are at least 3-4 times thicker than the factory "shims" and they are the entire size of the backing plate, rather than less than 1/2 the size as the factory shims.

And who is having brake fade/boiling problems and who is not?

I'm using the factory air guides and running at perhaps one of the hardest tracks in the country on brakes and making it through my sessions without problems.

coolnick

iTrader: (9)

I am an engineer. I design aircraft engine parts. Titanium is used for its strength to weight ratio, not its thermal properties. I posted the thermal properties of Ti vs SS. Those are not numbers I made up, those are material properties. My Hawk pads came with stainless shims, as I assume any other pad would. Believe what you want, but you are highly mistaken. The 2 mm thick shim is doing nothing. If you look at the other variables that go into heat transfer to the fluid I can say without a doubt the difference in material used in the shim is the least important variable.

I boiled the fluid on Putnam, the easiest track ever. I made two changes and did not boil the fluid on Mid Ohio, one of the more demanding tracks. The changes were the fluid and my driving style. Which one was more important? My driving style by a long shot.

So I guess I will LOL at you.


And of course I will add my regular disclaimer here. I am a rank amateur on the road course and do not go for the lap record every lap. I am there to learn how to drive the car on a track, not to prove anything. But I can and did prove that titanium shims = waste of money.

ez

iTrader: (15)

Coolnick,

I have never tested these shims personally, but I'd like to point out something you may have missed here.

The thermal conductivity for Ti is indeed 21.9 W/m-K. But if you notice, Girodisk advertises the material as alloy Ti 6AL-4V. The spec for this material is 6.7 W/m-K (iirc)

Are they thick enough to do the job? It looks that way, but I'll have to wait for a bit more experience and data before I consider them personally.

Cheers!

coolnick

iTrader: (9)

Good thing I added that^^. That is the most ridiculous thing I have ever heard in my life. No of course they aren't thick enough to do anything the stainless shims weren't doing. The real factor in heat management is time spent on the pedal. Minimize the time on the pedal and you maximize the time spent cooling. Now if I can only remember this at the track I'll be in good shape.