E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   E46Fanatics > Tuning & Tech > Suspension & Braking

Suspension & Braking
Have some questions about suspension or brake setups for your E46 BMW? Get all your answers here!

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 10-08-2012, 06:20 AM   #1
djmcmath
Registered User
 
Join Date: Oct 2007
Location: Rockville, MD
Posts: 72
My Ride: BMW 330i
Brake Fade -- looking for budget solution to track problem

So I'm having some problems with brake fade at the track, and am looking for a way to stave off the fade for just a little bit longer, or possibly diagnose something I'm doing wrong.

Here's the story:
Track Day #1: I go out on street tires with (almost) stock brakes. I flushed ATE Super through the system the week before, when I replaced the rubber hoses with braided metal ones. Brakes faded part way through the third session; not horrible, just mushy enough to concern me. They hadn't cooled enough by the 4th session to go back out, so I aborted the last session. Brakes were responding normally half an hour after I left the track.

Track Day #2: Installed slotted rotors and Mintex Extreme pads, bled with Amsoil's brake fluid. I go out on street tires and fade isn't evident until halfway through the last session. Not too bad.

Track Day #3: Bled with Amsoil again, shifted over to slicks (tired of chewing up my street tires). Added ghetto-style brake ducts (2" silicon tubing from front bumper to the inside of the rotor). Fade started early in the 3rd session. There was a long break between sessions 3 and 4, so they weren't terrible in the 4th session, but ... the pedal was a lot softer than I like. Drove home, then drove back out to the track the next morning -- pedal STILL mushy. I ran the first session (wet track) on street tires, slowly, and the brake fade wasn't really an issue because we were all moving so slowly. Second session was dry track, and the pedal was nearly to the floor. Bad. So I pitted in an aborted the rest of the day.


Glazed pads? Inadequate pads? Bad master cylinder? Overheated the fluid and destroyed it, and just need to flush better fluid through it? Just too much extra force from running on slicks, and the brakes can't hack it? 2" brake ducts not quite enough?

Open to ideas here. It's not urgent -- I'm not going back to the track until the spring. But I'd like to start working towards a solution to this thing. Losing track time (that I've paid for!) because my brakes can't hack it is painful.


Thanks,
Dan
djmcmath is offline   Reply With Quote
Ads by Google

Guests, get your FREE E46Fanatics.com membership to remove this ad.
Old 10-08-2012, 06:42 AM   #2
subieworx
Registered User
 
Join Date: Nov 2011
Location: cincinnati
Posts: 72
My Ride: ZHP, 335, E53, E30
The big question is how did the pedal feel on the first couple fade events? Was it soft with no stopping power or was it hard with no stopping power? Each are signs of fade, just in different areas. A soft pedal with no stopping power is fade of the fluid in that you have gotten the fluid too hot and are boiling it. The second is fade of the pad.

The first couple sound more like pad fade whereas the last sounds like fluid fade.
subieworx is offline   Reply With Quote
Old 10-08-2012, 04:38 PM   #3
djmcmath
Registered User
 
Join Date: Oct 2007
Location: Rockville, MD
Posts: 72
My Ride: BMW 330i
Subie -- thanks for the answer, that's some good diagnostics.

Details of "fade": The pedal feels soft, but if I push harder, I can still get stopping power. As the session continues, the fade gets worse, in that I have to push harder to get the same kind of stop. If I pump the pedal, it gets a little better with each successive pump of the pedal. The symptoms typically disappear within an hour or two of leaving the track. Saturday night, after fading pretty hard in the 4th session, symptoms persisted until the next morning (more than an hour of freeway driving later and a night outside in 50F (10C) ambient).

If I'm boiling the fluid, then I need to keep my brakes cooler, so improve my ducting? And switch to a different brake fluid? (Amsoil wet/dry boiling numbers are 410F/580F, which seems like it should be more than adequate, and within a few degrees of ATE Super's points.) Do different brake pads transfer heat differently, or is switching pads likely to be a dead end?

Thanks,
Dan
djmcmath is offline   Reply With Quote
Old 10-08-2012, 07:59 PM   #4
subieworx
Registered User
 
Join Date: Nov 2011
Location: cincinnati
Posts: 72
My Ride: ZHP, 335, E53, E30
That definitely sounds like fluid fade and that fluid should be adequate although I have never personally used it.

How many track days have you done? I have done a lot of on track instructing over the years and find that new drivers have much more problems with fade than seasoned drivers as they use the brakes half as hard as they should for twice the distance which builds a ton more heat than using brakes properly.
subieworx is offline   Reply With Quote
Old 10-08-2012, 09:12 PM   #5
lucky_doggg7
Registered User
 
Join Date: Mar 2008
Location: OC
Posts: 282
My Ride: 2005 M3
Stop using ATE Super Blue or the equivalent gold colored fluid. This brake fluid does not get the job done. If you are serious, use Motul 600 and your fade problems should go away. As for pads, find a copy of Grassroots Motorsports, the October 2011 issue where James Clay (Owner) of Bimmerworld did a very nice test of seven brands of brake pads. I prefer Porterfield, which ranked well in the test, and I also like very much Pagid, which is THE Porsche Motorsport pad.
lucky_doggg7 is offline   Reply With Quote
Old 10-09-2012, 02:31 AM   #6
Minnoe07
Registered User
 
Join Date: Oct 2006
Location: Lawrenceville, GA
Posts: 1,225
My Ride: 2004 BMW 330Ci
As a reference, I use ATE super blue racing fluid, braided lines, hawk ht-10 racing pads front and back, and BMW Motorsport "2 peice rotors" cross drilled up front and a performance directionally vaned cross drilled rotor in the back. Since I switched to this setup, I have not had any fade issues driving in the mountains, Carolina Motorsports Park, or Atlanta Motorsports Park. I am also supercharged so i would have more braking to do than you would. AMP has a pretty fast back straight where you are braking from 120+ mph to about 30-40 mph.

I would also suggest, like previously mentioned, relearning braking zones and proper techniques there so that you are not over working your brakes.
__________________



2004 330Ci 6 Speed; UUC Sway Bars; Powerflex RTAB's and FCAB's; KW V2 Coilovers; 3.38 OS Giken LSD
Z4 Finned Diff Cover; Headers; M-Tech II Rear Bumper and CF Diffusor; CF Trunk; CSL Front Bumper
M3 CF Hood; DICE I-Pod Kit; JTD Rear Shock Mounts; UUC Front Strut Bar; O2 Simulators
ESS TS2 Twin Screw Supercharger


Last edited by Minnoe07; 10-09-2012 at 02:33 AM.
Minnoe07 is offline   Reply With Quote
Old 10-09-2012, 05:00 PM   #7
djmcmath
Registered User
 
Join Date: Oct 2007
Location: Rockville, MD
Posts: 72
My Ride: BMW 330i
Subie - I've only done the 3 days I mention above, so I admit to being an amateur. Further, I know I'm not braking as efficiently as I could be, you're absolutely right. I guess you're suggesting that the real solution is to just brake smarter? I like it - totally fits my budget.

Minnoe - thanks for the data point. It's encouraging to know that someone with more power can stop effectively without a significantly more costly system than mine.

Should I be concerned about the "pumping" of the pedal, or the long recovery time?

Thanks,
Dan
djmcmath is offline   Reply With Quote
Old 10-09-2012, 07:03 PM   #8
subieworx
Registered User
 
Join Date: Nov 2011
Location: cincinnati
Posts: 72
My Ride: ZHP, 335, E53, E30
The pumping of the pedal and long recovery time are normal when that happens. Often the only way to fix it is to bleed the brakes. I would not be concerned.

As far as your braking technique one thing I always like to teach to my students is to use the full effectiveness of the brakes. Most people are so used to driving on the street that they don't actually know what their brakes are capable of and such don't brake hard enough on track. The exercise I use to teach them how to get used to braking on track after they are used to braking too easily on track is to have them keep the braking point the same , as most people are worried they won't make the corner hence the early braking, and to simply mash the pedal as hard as possible until engaging abs. This will result in the car over slowing and stopping much more quickly then they are used to. After a few times of doing this they realize the brakes have plenty to slow they car and we start pushing the brake point further.

As a means of comparison. I often track my 335 when I don't feel like taking my race miata. It makes 400 whp and weighs 3500 pounds. Much more power and much heavier than I would assume of your car. I run stock brakes entirely except with hawk hp+ pads and motul rbf600 fluid and rarely have issues.
subieworx is offline   Reply With Quote
Old 10-09-2012, 09:19 PM   #9
teamdfl
Slow in, slower out
 
Join Date: Dec 1969
Location: Awesome, NJ
Posts: 4,534
My Ride: 325it
Use less brake. You are driving too slow.
__________________
Mod the driver first. Participate in your local BMWCCA driving school. Have you joined BMWCCA yet?

My Track Schedule

The solution to the lack of headroom in the X6

teamdfl is offline   Reply With Quote
Old 10-10-2012, 06:31 AM   #10
djmcmath
Registered User
 
Join Date: Oct 2007
Location: Rockville, MD
Posts: 72
My Ride: BMW 330i
Wow, ok. Thanks for the wisdom. I'll bleed my brakes and change my driving style. Next time out, I'll try your technique to push the limits and see if that fixes my "brake too early but not hard enough" problem.

Thanks,
Dan
djmcmath is offline   Reply With Quote
Old 10-10-2012, 07:43 AM   #11
jared_wiesner
Registered User
 
Join Date: Aug 2009
Location: Ontario Canada
Posts: 678
My Ride: 1999 328i
A lot of whats been posted above may not be the advice you need to hear. I can't run ATE Super Blue on the track in my car and I brake quite late and very hard. I boil the fluid in the matter of a couple laps. A switch to Pro Speed RS683 brake fluid + the addition of ducting has cured this. A good driver can fade the brakes in no time if your driving hard enough. Sure, I could baby the car and make the brakes last, but then I wouldn't be enjoying myself or getting the most out of the car.
__________________

Check out my band - The Marked

1999 BMW 328i (Daily Driver) - m54b30 intake manifold, ebay headers, Rebirth Motorsports CAI, Rogue Engineering underive pulleys, Epic Motorsports Remote Dyno Tune, Custom 3 inch exhaust with Burns Merge, Schrick 264/248 Cams
1967 Buick Skylark - 430 Buick Big Block Swap.
jared_wiesner is offline   Reply With Quote
Reply

Tags
brake fade, track

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Censor is ON





All times are GMT -5. The time now is 04:46 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
(c) 1999 - 2011 performanceIX Inc - privacy policy - terms of use