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Originally posted by dubkatz:
Originally posted by 99fordsvt:
Ah - so just what IF I have a bad EBD feature in my ABS?
Hey Rara, Todd and Jim
have you ever in your years of experience with brakes ever seen anything go wrong with ebd or any other kind of bd system?
Call me 
but im gonna go out on a limb and guess no. Just a guess though. 
No
Jim Johnson
98 SVT
03 Escape Limited
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Originally posted by Rara:
so, let me get this straight, you want to know why your rear brakes are working normally? and refuse to believe any explanations of how they work normally? and still insist that something is wrong, because your rear rotors don't get as hot as the front rotors?
And you have the balls to insist that I don't understand what is going on? all based on your excessively scientific thermal data gathering technique of throwing snow on the rotors?
RARA,
Take a pill man. RE-read some posts. Your ego is all tangled up in your short hairs. Please show me WHERE I insisted that you don't know what is going on overall with braking systems?
Here's my key early statement that maybe you should re-read
"Thanks - I certainly realize that the fronts handle a majority of the braking (>70%) but that fact doesn't mean a case can't arise where the backs are still far under-biased from where they should be."
But you can tell somehow that my braking system is normal and know there is NEVER a case where a vehicle has far under biased rear brakes. Uhhh ........
I basically said that "thanks for the interesting posts" but they don't pertain to my specific thread starting problem that occurs FAR UNDER threshold (on the limit of lockup) braking.
Your posts and several others were all about weight transfer and such that is important at high braking levels, but not a significant factor at low braking levels that I still experience my braking issue at. Why isn't that clear?
I said straight up that I didn't have an IR temp gauge. Please take a poll of how many CEG'ers do. But I do own a few 4 wheel disk brake vehicles and NONE of them have the observable massive temp difference from front to back that I have on my CSVT. YES - I said all of this earlier.
But now I am a dumba$$ because "my brakes are working correctly" and I don't know it. Well then please tell me why other 4 wheel disk vehicles I've checked are much closer to balanced on temp? They must not be the normal ones?
OK - let's hear your professional braking engineer explanation of that?
And laugh all you want but an audible sizzle at least tells you the the temp is above a key level. Whereas I know the back was only 110-120 deg F max. This is about a major rear braking deficiency, not the fine tune situation you led the thread to.
When fine tuning - of course use the right tools. When searching initially for a major imbalance, more crude tools are still informative. Sorry for not first showing up to the forums with my IR and wireless type K thermocouple 18 bit A/D data sampled at 150 Hz during laps at Waterford with 18 blindly picked test drivers. This was an initial get ideas thread and you turn it into an ego blabbing insult fest.
Being an engineer - you should know better.
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"Absolut Rara."
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"Absolut Rara."
Joined: Sep 2000
Posts: 3,223 |
ok, let's try this again then.
First, what vehicles are you comparing against?
What pads are you running in those vehicles, and what are you running in your contour, both front and rear? Different vehicles have completely different brake system designs, with normal operating temps varying from ambient to over 900 *F under typical usages. Just because they are different from another vehicle doesn't mean they are bad.
Also, your "sizzle" test does not necessarily indicate a problem at all. you say 110-120 *F max, but water/ice doesn't boil or "sizzle" until 212 *F . . . further, how is the system performing? Does the car stop properly?
I hate to "brake" it to you, but it still is all about weight transfer and axle loading whether its a .3g stop or a 1.0g stop. If there is little wieght on that axle, those brakes will do little work, and won't get very hot. It's simple physics.
You are taking an extremely inaccurate test and comparison, and using it to demand an explanation of what is wrong with your brakes when there very likely isn't anything wrong. And when you do get an explanation, you dismiss it, and throw a hissy fit becuase no one is giving you the answer you want to hear.
Tell you what, you bring your car over to my house, I'll grab an IR temp probe, and we can do a back to back comparison of your contour and mine for rotor temps after similar stops. Would that make you happy?
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Originally posted by Rara:
Also, your "sizzle" test does not necessarily indicate a problem at all. you say 110-120 *F max, but water/ice doesn't boil or "sizzle" until 212 *F . . . further, how is the system performing? Does the car stop properly?
Like I said - Re-read the posts.
From me:
"I think I have a major brake bias problem on my 99 SVT. After a hard stop, I can touch the REAR rotors and they feel maybe like 110 deg F. The FRONTS are nearly smoking hot (pretty technical eh?) and sizzle when snow is tossed on them. I wouldn't dare touch them."
Exactly my point - the REARS are about 110F and the FRONTS sizzle, which you say (and I don't disagree) is above 212F.
Ah - so now you aren't dissing the sizzle test so much after all with that major temp difference, huh?
"Hissy fit" if the shoe fits, but frankly I'm not waiting for a certain answer - just the one that effectively solves the problem.
Jeez - you are one confrontational guy, at least tonight.
Hope we can patch things up because before you didn't seem so bent on flaming people who were honestly just looking for solid info to resolve a problem.
I dare not say spew any more data or vehicle types until I gather some reliable data - I might get flamed. But I maintain I still have the problem below 0.3g, so don't continue on your weight transfer rant.
The car stops very crappy - very slightly pulling to the right.
But good suggestion to compare to another Contour. I know another car (3.0 like mine, not that it matters) to try it on.
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"I dare not say spew any more data or vehicle types until I gather some reliable data"
Hell, why start now?
Please let this man's foolishness fade to the bottom of the pages...I'll promise not to even read it any more.
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Great - so at least we have one "brake expert" off this thread.
This is unbelievable - a guy tells you that his plane is missing a chunk of one wing, and you launch in a treatise of how all planes yaw slightly due to non-linear aerodynamic loading - that you are the experts, his wing is fine, and how he should shutup, at least until he provides CMM data of a wingscan.
Your recommendation was to put new rotors pads and calipers on the car when I stated right up front that I had already done that.
I've got an idea - since 80% of braking and temperature rise is in the front, maybe the rears could be downsized a bit (saving cost and weight) then maybe the temps would be slightly more equal? ..........hmmmmm
(of course they are downsized in the rear and temps should at least in the same ballpark)
Being a brake expert, he obviously had all those IR brake temps on hand from Contours to share with us all. Instead I'm told to add weight in my trunk so the rear will "Hunker down" ..... now that is technical. Bad brakes? "add some weight" .... great advice TCE.
TIMEOUT guys - When is it a CEG crime to come for help to the forums (and try to keep the topic on track) when your back brakes aren't working even close to right?
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Alright... I am not a brake expert.. (and those "self proclaimed ones aren't SELF proclaimed.. they ARE...)
HOWEVER.. I HAVE read.. re-read, and triple read the posts you made.. and still don't get why you are confused..
Rear brakes do near none of the work.. you admit to <30%... others say <10 or even less than that..
Your REAR rotors are 110-ish.. you say... and fronts, at least 212... okay.. so.. if the rears do near nothing.. and the fronts: most of the work.. WHY IS IT NOT NORMAL for the fronts to be MUCH hotter?..
I have an IR probe here, (my father does, actually... and I took the liberty of doing those test runs for you.
98.5 SVT
4 wheel disc (for purpose of data.. obviously svts have all disc)
Temperature of rotors before each run 62-64�ºF
Temperature: 55�º
Run 1
10mph
82.2/83.2/78.0/78.9 (FL/FR/RL/RR)
Run 2
20mph
96.0/96.6/83.1/82.8(FL/FR/RL/RR)
Run 3
50mph
218.5/221.6/111.4/112.8 (FL/FR/RL/RR)
The rotors started off at air temps, but I drove and heated them, then allowed them to cool to 62�º before beginning my run.. that was my controlled temp.
All of these runs were done at "moderate stopping rates" of an ~.5G or so. I know this isn't your <.3G perfect scenario.. but I did this JUST to see what you would have to say... All runs were cooled between with 30 minutes of non-use and ambient temperatures were returned.
Now.. as a side question.. Why does my car exhibit a slightly higher temp on one side (Right side...) when braking? I feel no pull, and it stops straight....
DISCLAIMER: This test is in no way scientific, or mistake-free.. merely an attempt at creating something more concrete than snow...
Ray
Last edited by Ray; 03/18/05 05:33 AM.
'99 CSVT - Silver #222/276
In a constant state of blow-off euphoria.
Originally posted by Kremitthefrog:
I like to wear dresses and use binoculars to watch grandmas across the street.
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Ray,
Thanks, great work and it proves the "without data you are only an opinion" cliche.
While I believe your test was useful, it would also be useful to check them after 30 minutes of stop and go city driving. The early temps from ambient (as you tested) are likely to be dominated by heating the rotor's thermal mass, than representative of the steady state temp after saturation when only convection and to a lesser extent radiation (RARA isn't the only Engineer around) determine resultant rotor temp.
I expect differences to be dramatic - probably raising the front vs. rear temp delta even higher that your initial tests.
My only question is "What if I repeat your test (which I have to now), and get 330 F fronts and 75 F rears, instead of your 218F and 110 F nominally?
Underbiased rears (from where they SHOULD be) for me maybe?
Hmmmm..... maybe I can go to the CEG forums and be flamed trying to get some ideas then.
I don't really dispute the "expert" status of those you refer to as their earlier proportioning posts are informative, but how can their advice on this particular item be "expert" if they obviously haven't even read the situation (new parts initially, thinks I said 110F sizzled). Kind of like a Judge who can give the expert verdict before hearing the evidence.
I've never been confused on the fact that most cars have higher front brake temps. I buy it. Also all the load transfer stuff from even TCE. Great stuff. I'm not confused at all.
In only the second post here I said:
"Thanks - I certainly realize that the fronts handle a majority of the braking (>70%) but that fact doesn't mean a case can't arise where the backs are still far under-biased from where they SHOULD be."
Key word SHOULD.
Thanks again.
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Hard-core CEG'er
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this is the ultimate "beating a dead horse thread"
No matter who and what is said this guy still thinks something is wrong, so let him think it.
98 csvt t-red.. sho-shop intake, b&m, fidanza, spec1 clutch, Torsen, DMD,optimized Y& TB, Brullen, rear strut bar,h&r's,17" konig traffik's.
"I say what I mean and I do what i say"
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"Absolut Rara."
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"Absolut Rara."
Joined: Sep 2000
Posts: 3,223 |
Originally posted by 99fordsvt:
In only the second post here I said:
"Thanks - I certainly realize that the fronts handle a majority of the braking (>70%) but that fact doesn't mean a case can't arise where the backs are still far under-biased from where they SHOULD be."
Key word SHOULD.
Thanks again.
Brake bias needs to be developed to handle the WORST case scenario; you absolutely never want to lock the rears first.
You are basing your opinion of what they "should be" on extremely limited information. Further, the ratio of rotor mass relative to the amount of work done is a lot higher in the rear so naturally temps are going to be lower.
I think Ray did a great job w/ his test there to show that what you are seeing is perfectly normal; his measurements correlated very will w/ your "tests".
You keep accusing people of not reading your posts. but you seem to just not follow what people are telling you, I don't know if its becuase you aren't reading them or what.
You liken it to a pilot saying a chunk of wing is missing, and people saying its fine, its not, its more like there isn't a chunk missing and you think it is.
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