mitsuorder

iTrader: (106)

so who's got the best ss brake lines on the market and where can I pick up some ATE Super Blue, I'm pretty much ready to do this.

BRKENG

To speak a second about the brakes on the EVO.
I have the same problem with my brakes but i am a brake engineer and I understand the dynamics involved with racing style brakes.

These brakes need to be Hot or heated up to be very effective.
Theres a term we use called "cold effectiveness" . The more aggressive the brakes are the less effective the brakes will be on first applies and on subsequent first applies after fast straight runs. I actually slightly feather my brakes just a bit to close the running clearance and preheat the brake before a critical stop or slowdown. One other thing to note is that the first 500 miles of a friction materials life is critical to its overall life. The material is formed and cured with a specific process. If you jump on those brakes right away the material may not cure correctly and can jeopardize overall effectiveness. In brake engineering we call that "burnishing". The initial burnishing of the brakes is important.

I suspect that the STI brakes probably don't cool off as much as the EVO does. I think the STI probably has the right mixture of heat to cooling where as the EVO probably overcools the brakes and cold effectiveness really plays a factor at that point. One great way to figure this out is to do a test.

Run the STI down a 5 mile stretch and apply the brakes at a specific interval. Use a temperature gun(if you can get one) to measure the heat eminating from the wheels.

Repeat with the EVO. If I am right the EVO brakes should be almost 30-50 degrees cooler.

Tim

evo55

Can't go wrong on both. The only reason I went to EVO was because the 2.0 liter motor is the same used in the WRC. The road version of STI's 2.5 is not the same as the WRC STI. At least the EVO is very close to the WRC Mitsubishi. Both are nice cars.

Hooptie157

iTrader: (8)

Good God Tim!! Nice explanation. I'll have to try that one day with a heat gun.

BTW I forgot to mention that my EVO has 10,700 miles while the STI has a scant 3870. My brakes have plently of meat left on them but this could have been a factor.

After I ripped my friends car he said it felt like a loose ***** afterwards Cuz I worked it!!!!

UFO

iTrader: (7)

Well, that doesn't really make sense considering neither the STi or Evo are raced in WRC anymore and the 2.0 motor in our cars certainly is not the same as in the WRC car.

Regarding the Evo brakes: I also suffer from some serious brake fade in my hooptie and would like to fix it. The only reason I have not flushed the system and switched to ATE Blue is because I have heard that the fluid goes 'off' quickly and needs replacing more often. True?

JDF

Did you happen to time the runs of each vehicle? It would be interesting to see how the overall times compared.

Hooptie157

iTrader: (8)

No I didn't time the runs. I used to when I had my Type R but I didn't this time. If I would have had a larger turnout for my meet we could have had some friendly competitions runs between cars. I'm definatly doing that next meet!!!!

BRKENG

Sorry its so long but I need space to explain hehe

Well what is the problem that you have....

Brake Fade or Cold Effectiveness?

From what Ive felt on my EVO Brake Fade is fine, but........

Cold effectiveness on the EVo sux.

Brake fade occurs after several demanding applies of .5 - .8g .
Such as during a road curse with several winding turns requiring you to set the suspension and prepare for a turn. If the brake are cooled properly, this should not really occurr on a good racing set up. I have taken my car (EVO VIII) on our track her at work and ran it through the paces. The brakes worked like a champ. great modulation, short onset stroke, great effectiveness during successive applies.

But Cold effectiveness however is something else. Most confuse this with fade. Lets say you go through a few S turns and come out accellerate down a straight stretch and hit the brakes again...
your brakes are gonna not feel the same as the S turn applies....
Usually feel really dull or like you have to lay into them more.

This is where the EVO needs work. Anything you do to cool the brakes more will only hurt this effect. This is why i havent gone with slotted or crossdrilled brakes.

IMO the first thing to do would be to go with stainless steel braided jounce hoses ( the hose from the hard line to the caliper).

This will NOT take care of your cold effectiveness but this it what it WILL do.

The stock hoses expand during even light decel. In addition brake fluid expands as it heats up. This causes the hose to expand and give you a slight bit more stroke and a slight bit more of a spungy feel to the brakes. You can mask this effectiveness feel by cutting down on the onset stroke due to hose expansion.
The SS hose will expand VERY little during applies. This may give you what your looking for.

So....
My suggestion is this.
1. Go with SS Jounce hose first. See what you think.
If your still not happy
2. Try a different friction material.
If your still not happy
3. Try a different brake fluid (may help keep fluid from heating up....hot brake fluid is bad btw)
If your still not happy
4. New rotors
If you still cant stand it........
Try partially blocking a cooling vent for the brakes to keep some heat in them. Be careful though , because then you may run into the other spectrum where you overheat the brakes...and that is always disastrous! Use this advise at your own discretion I'm not responsible if you burn em up!

If that doesnt work go buy an STI..ugh!

Sorry to answer the earlier question about the Brake fluid. It is true more performance brake fluids should be changed at least every 2 years or 30k because high performance brake fluid absorbs water and water is very bad for a brake system.

Hooptie157

iTrader: (8)

BRKENG: Great explanation and I think I was experience the Cold effectiveness problem you mentioned. I had just gotten finished with a steady 180 turn which I had to brake hard into. Then I was going downhill into a sweeping left into a hard right. When braking into the right is when I had the problem which sounds like cold effectiveness.

I'm going to look into your solutions ASAP, thanks for the input.

propellerhead

iTrader: (3)

To me that quote is indicative of brake fluid that has reached it's boiling point. This is most likely due to the fact that because brake fluid is hygroscopic it absorbs water from the air. This lowers the BP and when the fluid boils (vaporizes) and expands it forces fluid back up into the reservoir and also will result in a mushy pedal as the vaporized fluid is compressed.

The simple fact of the matter is that brake fluid is going to get hot. Either you have to mitigate the heat build up (slotted/drilled rotors or increase the swept area) or raise and maintain a higher boiling point (fresh brake fluid).

IMO, this guy's issue is caused by old, crappy brake fluid. Change it; it's cheap and easy.

BRKENG

If its an EVO VIII
How old could the brake fluid be? I year? 35000 miles?
I seriously doubt its the brake fluid, I have the same experience with 2000 miles on my EVO. Believe me if he was experiencing fluid boil he would be darn close to a foot to floor(in brake engineering that means no braking at all...not even partial braking). A new car with less than 50,000 miles on it, with a good system such that the EVO has shouldn't boil, unless there is another issue going on...i.e. brake drag, blocked cooling ducts, master cylinder partial apply etc.

Sure changing the fluid helps but Dot 3 does real well to keep out water. Of course it varies from manufacturer to manufacturer. But generally Dot 3 is good for the life of a normal passenger vehicle. If your rallying evry weekend or motorxing everyweekend you may want to change the fluid every 30000 miles. Even then thats excessive.

There are millions of vehicles on the road today with 100K + miles that have NEVER changed the brake fluid. Most never need it.

USP45

iTrader: (13)

I have a question relating to the changing of the brake fluid. One of the next things that I am going to do to my Evo is to install some stainless lines. When I do this I might go ahead and change over to ATE Super Blue, or I may just stay with a DOT 3 fluid, I have not decided yet. My question however is how do you bleed or completely change the fluid in a car equiped with ABS? I seem to remember reading somewhere that the process for doing a complete changover on a car equiped with ABS is somewhat different from doing on a car without. Now, I do know how to bleed a system and do the brake system, but is there anything different that needs to be done on an ABS equiped car? From what I have just read I may be better off with a normal DOT 3 fluid if the Evo's braking system is as efficient at cooling itself down as BRKENG says it is, but what precautions do I need to take if I only change the lines? There would still be a lot of bleeding to be done.

Mister2zx3

I can roast fluid in under 100 miles. FWIW I change by brake fluid in all my cars every six months or after every track day or spirited romp. Which ever occurs sooner. ANything that keeps brakes *HOT* for over 30 mins requires fluid change in my book.. Depending on how you use your brakes, fluid is a cheap easy change and is sure less expensive then a fender, or rim, etc..

If your getting low pedal, that sounds like fade or boiled fluid. Poor initial bite or long stops might be from pads not up to temp.

BRKENG

Well it cant hurt to change the brake fluid often but seems excessive. I don't do any track racing and don't design hardcore racing systems. However we heat up our test vehicles fluid often without problems. We don't see problems on our test vehicles.

On our test stands we test Master cylinders filled with fluid immersed to 120C (248F) in brake units for at least 3 days and 85000 cycles while being applied with absolutely no problems. Dot 3 Brake fluid holds up pretty well.

[Q UOTE]Originally posted by joeycoates
My question however is how do you bleed or completely change the fluid in a car equiped with ABS? I seem to remember reading somewhere that the process for doing a complete changover on a car equiped with ABS is somewhat different from doing on a car without. Now, I do know how to bleed a system and do the brake system, but is there anything different that needs to be done on an ABS equiped car? From what I have just read I may be better off with a normal DOT 3 fluid if the Evo's braking system is as efficient at cooling itself down as BRKENG says it is, but what precautions do I need to take if I only change the lines? There would still be a lot of bleeding to be done. [/QUOTE]

Yes! Bleeding a car with ABS is more intensive then non ABS. It depends on what your doing though. If you just change the hoses and DONT apply the brakes while the hoses are off. You shouldnt have to worry about the ABS system trapping air. But if you completely change the brake fluid its tricky. There are a 3 ways you can do this.

Look in the how to section to find out how to bleed a brake system.

But if you get any air in the system and it makes it to the ABS unit this is how you can get the air out. Drive the car and get the ABS unit to cycle a few times over some bumpy roads. The bumpy road will do 2 things....knock the bubbles loose and provide gaps for the tire to sense spinning and cycle the ABS for you.Then bleed again . Do this a few times until you get the desired pedal feel. This is how we field bleed ABS vehicles when we cant use a pressure bleeder.

propellerhead

iTrader: (3)

I guess I've bought into all the hype. I would also bet those "millions" of vehicles that have never had their fluid changed are NEVER road raced or driven hard. You and I know exactly the type of driver that would let their brake fluid go for that long without changing. They aren't the ones you'd want to be anywhere near while they are driving at speed.

Despite the appearance of my post being a flame we're actually in agreement in terms of the steps to mitigate any issues. You've advocated swapping the brake lines as a first step and changing the brake fluid as the third. In my mind, once you've got the bleeder out (which you're going to have to do if you're doing SS lines), you might as well flush the entire system. Sticking with a high quality DOT3 fluid is probably adequate for 90% of the enthusiasts on this board.

Once you've chosen to maintain your own brake system and you've invested in a bleeder, arguing about brake fluid service intervals is a moot point. I flush nearly everytime I touch my brakes. It's almost easier than changing the oil. I'll certainly flush them when it comes time to change the pads. Call me a nut.