Unbelievable Braking!

[John F. Russo]

I stopped my car from a speed of 60 mph in a distance of 78 feet (plus or minus 4 feet). (SergntMac said: "Car and Driver magazine, published in April, 2003"..."...Kenny Brown Marauder S call for a stopping distance of 171 feet, from 70 MPH to zero".)
This does not fit the facts from the stopping distances of other high performance cars and other cars. About 120 cars of various brands and makes were listed in Road & Track Test Summary 9/04 issue on p. 150. Here are a few data points from the summary.

[Column Heading]
"Braking from 60 mph, ft"

"Corvette Z06 107 ft.
Porsche 911 GT1 98 ft.
Lotus Elise 105 ft."
(These three cars were the shortest distances on the list.)

What did I do wrong? Is it possible that my brakes and tires are that good?

I'll discuss the method that I used to determine my distance after I get an initial response from everyone.

ADDENDUM 8:30 PM 8/31
A car will travel 88 ft. in one second at 60 mph. So it makes a big difference when to start counting the distance. Is it when you pass a marker with your foot ready to step on the brakes (method used by me) or other method. I don't know what method Road and Track used in ther listing.
At the very end of the braking, I could hear the ABS starting to work. I did not skid on any wheel. In fact if I could get more braking power, I know I could get an even shorter distance. I have strong legs and I was pressing very hard. Next time I'll use both feet. Can I break anything with such force being applied?
TEST CONDITIONS: I was going 60 mph in the breakdown lane at an ambient temperature of 85 F. I practiced passing a landmark by looking to the right at a sign for about five signs. After I finally felt confident and had the entire technique down pat, I made an official run. I intend to try this again. The breakdown lane does not have the same surface conditions as a regular highway surface. I'm not sure if it is better or worse. All my tires are inflated at 32 psig, the same as the test car (Mack's car) used in the "Car & Driver" article.
How this all started was when I had reported that I have had vibrating rotor problems with my brakes, I was told (by Baer) to go out and really burn the accumulated glaze off the rotors. I did this and was very surprised to see how fast the car stopped. My curiousity begged me to make an actual determination of the actual distance. I like to see someone else try my technique or better yet use the "official" method. I may call Road & Track to find out.





Bye the way, I list the details of my car so that others can be encouraged to do the same. It is not to boast about what I have. I'm very interested in what others are doing to their cars. I notice this practive has been declining.

______________________________ _____________________
2003 Dark Blue Pearl 300B (Canadian) w/Light Flint (reversed
traction control, mini spare, trunked 6 disc CD changer,
clock-in-the-radio, heated front seats/mirrors, hood light)
-Born 12/10/02; converted new then used 2/28/03
-26,000 miles
-18.5 mpg at a steady speed of 80 mph, one tank of gas
-Stock transmission (upgraded with Performance Automatic
clutches and band after stock tranny failed in 8,800 miles)
-Wheel locks (Ford); godshead valve stem caps
-Badgeless front grille by “Zack”
-Zaino waxing; RainX
Kenny Brown: 6th “Signature Series” conversion (450 hp) Born
3/28/03 (first drove it)
-Vortech supercharger (3 to 7 psig boost)
-377 RWTQ
-4.10 gears
-14 in. BaerClaw front brakes, two piston, slotted rotors
-MMX Driveshaft
-Precision, triple disc, P/N469018-3 Precision, triple disc, P/N469018-3
-Ford Racing Stud and Girdle
-Pirelli P-Zero Asimmetrico (front 255/45ZR18 99Y; rear
255/50ZR18 102Y)
-Dead pedal
-FordChip
-3/4 of a coil from each front stock spring removed to produce
the “same” effect as an Eibach spring
-Ground clearance: 5 in.
______________________________ ___________________________
1961 Ford Galaxie, 2 dr. Club Victoria, 390CID, 375hp, 4 barrel (gone)

[stevengerard]

though I would not doubt you have great brakes, especially because its a KB car, I like you are sceptical about the stopping distance. I am actually working on an interactive application that demonstrates stopping distance and tests show there is a large human error in perceptiuon of reaction time/stopping distance. Though, the thought that they could work that well is great to know for us wanting to improve our brakes..

[martyo]

Is it possible that my brakes and tires are that good?

Your brakes probably just have better positive warpage than many of the comparative cars.

[ADE 1000]

Is it possible that my brakes and tires are that good?



No. Baer brakes or not, I couldn't envision a scenario in which a 4000+lb Marauder could outbrake any of the cars you listed above.

Your testing method is obviously different than that of Road & Track and all of the other car mags.

[GordonB]

John,
Love your choice of MM colors! Also love your braking results.
However, pls share with us how you are able to haul down the beast from 60 to 0 in less than 4 car lengths (78 ft) -- according to my physics calculations, it is nearly impossible without locking up 14" Baer brakes that you have and skidding beyond 778 feet.
Thanks,
GordonB

[rookie1]

you measured the skid marks from their beginning to the tree you ran into?

[Krytin]

you measured the skid marks from their beginning to the tree you ran into?
You're to much! ROFLMAO!

[Silver_04]

I can't figure it out. Just looking at the theoretical energy your brakes had to dissipate I get the following:

KE=1/2*mv^2 (all units converted to metric)

For MM
KE=1/2*(1814.37kg)*(26.8m/s)^2
KE=651576 J

And for a Z06 (just picked one of the cars to keep the calculations clean)
KE=1/2*(1413kg)*(26.8m/s)^2
KE=507569 J

A Z06's brakes have 144139 fewer Joules to dissipate and took 29 more feet.

Now to get to the nitty gritty, we need to know adhesion or friction factors for Z06 tire/surface contact and MM tire/surface contact as well as brake clamping forces, rotor/pad surface contact area, and I imagine many more parameters.

[Silver_04]

Ah, this should help. LINKY (http://hyperphysics.phy-astr.gsu.edu/hbase/crstp.html)

Much simpler than I originally thought. It appears as if the vehicle mass falls out of the equation and the only real unknown we are left with is the coefficient of friction between the tires and ground. And the friction equation and KE equation shown would also equal the amount of energy dissipated by the brakes. More than one way to skin a cat he he he.

[Marauderman]

Well...All I know is...that when I let Ms.M drive # 7 for the first (and only time so far) , she had it up to 100mph and the light was turning RED ahead of us--( it was an area of about 1000 feet I suppose before the light) but just the same --it was coming up fast--and I said.." you gonna run it or stop..?..she says....gonna stop ..ok?..."---at which point I hold on-- cause I have not at this point put my Bear breaks to a REAL test--so here goes----and phoof!! we slow down just perfect and no skids ....was really impresssed....so were the others cars near by!!!.......and after 10 months --still no problems of ANY kind from them..........so my .02 worth---which means nothing except I would like to know your method as well--hummm..must try the 60 to stop method as well and measure it sometime with these Baers just to see.........Tom

[woaface]

Braking tests in magazines are done without skidding tires or locking up brakes. Your basically pushing as hard as you can on them without a panic stop.

[SergntMac]

The published specs of the Kenny Brown Marauder S call for a stopping distance of 171 feet, from 70 MPH to zero. This was confirmed by independent testing by Car and Driver magazine, published in April, 2003. The brake system in place was a 14" BearClaw kit in front, and OEM brakes in the rear. The tires in place were the Pirelli P-Zero Assymetricos, front 255/45/18, and rear 255/50/18, inflated to 32 PSI.

We're not sure how John reached his conclusions, how he tested what, and what his "78 feet" mean. What do y'all say we wait John's next shoe to drop, please?

[woaface]

60 and 70mph is only 10 mph but usually shows considerable feet in stopping distances. 130mph tests can take well over 600-700 feet.

Mac, can you clarify for me whether Car and Driver reiterating what Kenny Brown said or did all of their tests pull off the same/similar numbers?

[HwyCruiser]

Oooo, I love brake threads... where's Todd@TCE when we need him?

The G-Timer has a braking distance feature that is triggered by deceleration. I imagine it would be one of the most accurate measurement because it removes reaction time from the picture, no?

Trying to avoid engaging the anti-locks would bring in a significant margin of error due to perception of force. I guess you'd keep trying to achieve a shorter and shorter distance with intermediate cooldown periods until the anti-locks start to engage and call the shortest distance it? The cooldown period would minimize the temperature endurance effects of the system.

Still, the result would be one of those geewhiz figures like 3rd gear peak hp that are rarely enjoyed in real life (unless your BillyGMan of course).

Sounds like a fun weekend research project though :D.

- JD

[Dan]

Well...All I know is...that when I let Ms.M drive # 7 for the first (and only time so far) , she had it up to 100mph and the light was turning RED ahead of us--( it was an area of about 1000 feet I suppose before the light) but just the same --it was coming up fast--and I said.." you gonna run it or stop..?..she says....gonna stop ..ok?..."---at which point I hold on-- cause I have not at this point put my Bear breaks to a REAL test--so here goes----and phoof!! we slow down just perfect and no skids ....was really impresssed....so were the others cars near by!!!.......and after 10 months --still no problems of ANY kind from them..........so my .02 worth---which means nothing except I would like to know your method as well--hummm..must try the 60 to stop method as well and measure it sometime with these Baers just to see.........Tom

I suggest that you let the wife drive on the 60-0 test. :lol:

[Smokie]

I'm glad the braking distance button has finally been pushed, we analyze and scrutinize every little thing we do to our cars in exquisite detail....except for our brakes.

We don't have any solid stopping distance data for our car with all the different brake systems that are available thru this forum.

Let me explain what I mean: A stock MM. stops from 60 to 0 in xxx amount of feet.

Choice from vendor A in xxx amount of feet.
Choice from vendor B in xxx amount of feet.
Choice from vendor C in xxx amount of feet.

We have no such data, and it surprises me that no one seems to care which system offers the best actual stopping distance for the buck.

Just curious thats all.:dunno:

[Dan]

I wonder if it has to do with lessons learned from the supercharger wars.

Remember those? I don't but I have heard about them.

It would be great to see some of those tests. I wonder how we would make something like that happen.

-Dan

[SergntMac]

Mac, can you clarify for me whether Car and Driver reiterating what Kenny Brown said or did all of their tests pull off the same/similar numbers?
I thought I said that already...Ummm...Okay, what ever...No, wait, let's read it again...Together? I don't want you to lose your place.

The published specs of the Kenny Brown Marauder S call for a stopping distance of 171 feet, from 70 MPH to zero. This was confirmed by independent testing by Car and Driver magazine, published in April, 2003. The brake system in place was a 14" BearClaw kit in front, and OEM brakes in the rear. The tires in place were the Pirelli P-Zero Assymetricos, front 255/45/18, and rear 255/50/18, inflated to 32 PSI.
Gee...I thought I said it all and rather clearly right here, James. "Confirmed by independent testing" and "published in April, 2003" kinda tell me stuff, what does it tell you? BTW, you can buy your own copy of this C&D article on ebay, if you need hardcopy?


I'm glad the braking distance button has finally been pushed, we analyze and scrutinize every little thing we do to our cars in exquisite detail....except for our brakes.
Agreed, Javier...Where are our base performance numbers on braking power? For that matter, any base nukbers on any "mod" we suggest here? Who says our "Watts link" needs replacing and why? I'm not having any problems with mine...

[Silver_04]

Am I hearing a call for a Marauder mod evaluation day?

I volunteer mine for Stock '04 Marauder baseline testing. Mine's a real runner :burnout:

[John F. Russo]

you measured the skid marks from their beginning to the tree you ran into?

Wow, you're good. How did you know that?

I did run into a tree on a superb accident that happened to me 6 months ago. I have chronicled everything but haven't had the post the story. The memory is seared in my brain.

I was skidding sideways down a major highway for what seemed to be an interminable time. Then went into the breakdown lane slightly grazing a tree.

I have proven that my car on a 11 F day will not turn over. The question for the best and brightest is would it turn over on a 90 F day?

[John F. Russo]

I have added some pertinent comments in my first posting that clarifies my test conditions.

I have to move more quickly to your numerous responses.

[John F. Russo]

Your brakes probably just have better positive warpage than many of the comparative cars.


You're right! I have been told by my dealer that I have had "rotor warpage" that has caused my steering wheel vibration. My brake testing was done on these rotors, or as you call them, "positive" warped rotors. For whatever reason there was no vibration at all during my test.

I'm not savy about this conclusion. In any case Baer Corp. (Ben O'Connor of Arizona )asked me to return my second set of rotors from my car. I think they may be interested to confirm the cause my condition. So I hope to hear about their evaluation.

I now have my third set of rotors and will be redoing the brake distance test again. According to the Baer break-in procedures, the last test ( 5- 50% successive braking runs, then 5-75% successive braking runs, and lastly is 6 hard breaking tests to get the temperature of the rotors over 900 F. So I'll check my stopping distance again.

[John F. Russo]

I can't figure it out. Just looking at the theoretical energy your brakes had to dissipate I get the following:

KE=1/2*mv^2 (all units converted to metric)

For MM
KE=1/2*(1814.37kg)*(26.8m/s)^2
KE=651576 J

And for a Z06 (just picked one of the cars to keep the calculations clean)
KE=1/2*(1413kg)*(26.8m/s)^2
KE=507569 J

A Z06's brakes have 144139 fewer Joules to dissipate and took 29 more feet.

Now to get to the nitty gritty, we need to know adhesion or friction factors for Z06 tire/surface contact and MM tire/surface contact as well as brake clamping forces, rotor/pad surface contact area, and I imagine many more parameters.


I remember that equation! Thanks for reminding me about it.

[Marauderman]

Who says our "Watts link" needs replacing and why? I'm not having any problems with mine...
...I was wondering the same thing Mac....I, like you, am having no problems--put it thru some good paces on turns ....and yeah---whats the big deal for changing them --we already got that set up--works ok for me!!! especially with the Mac/Zack Arms----need I say more!!..just my .o2 as well.....Tom

[stevengerard]

remember what ToddTCE said (i believe), braking isn't all distance, it also has to do with fade and feel. Thats what the braided lines do, they provide better fell and also prevent expansion so more pressure goes towards braking instead of expanding the lines.

[Agent M79]

Yeah. My braking is unbelievable. Yabba Dabba Doo.

[jgc61sr2002]

remember what ToddTCE said (i believe), braking isn't all distance, it also has to do with fade and feel. Thats what the braided lines do, they provide better fell and also prevent expansion so more pressure goes towards braking instead of expanding the lines.



Excellent point. The factory rubber hoses (lines) tend to expand some what under extreme braking conditions.

[RCSignals]

For that matter, any base nukbers on any "mod" we suggest here? Who says our "Watts link" needs replacing and why? I'm not having any problems with mine...

Considering what the WATTS link does, I doubt you'll feel any difference unless you are maybe doing some very wild, hard slalom type driving, and then in that, just changing the bushings may make the difference.

But then you don't get the 'Bling' factor. :cloud9:

[martyo]

But then you don't get the 'Bling' factor. :cloud9:


It don't mean a thing if you ain't got the bling....

:rasta:

[MARAUDER S/C #5]

[QUOTE=SergntMac Who says our "Watts link" needs replacing and why? I'm not having any problems with mine...[/QUOTE]

I agree.

[MARAUDER S/C #5]

I now have my third set of rotors and will be redoing the brake distance test again. According to the Baer break-in procedures, the last test ( 5- 50% successive braking runs, then 5-75% successive braking runs, and lastly is 6 hard breaking tests to get the temperature of the rotors over 900 F. So I'll check my stopping distance again.My car is supercharged and my STOCK brakes work fine, all original and no break in procedure required. My stopping distance 60-0 is ........good enough to not hit what is in front of me! Braking has a lot to do with driving skills, you need to leave youself enough room to stop.;)

[martyo]

I agree.

Yeah Rick, but when was the last time you drove your car past the end of your driveway?

:neener:

[jakdad]

Wow, you're good. How did you know that?

I did run into a tree on a superb accident that happened to me 6 months ago. I have chronicled everything but haven't had the post the story. The memory is seared in my brain.

I was skidding sideways down a major highway for what seemed to be an interminable time. Then went into the breakdown lane slightly grazing a tree.

I have proven that my car on a 11 F day will not turn over. The question for the best and brightest is would it turn over on a 90 F day? John, How large of an anchor did you throw out the window and was it 'chute assisted!!!??

[Dan]

I see what your saying however the conventional wisdom is that such a large HP increase dictates a brake improvement. Every case is different., though, and there are few absolutes.

In prior posts you have said that you never exceed the speed limit. My thoughts on that are that you would probably also not slalom your car in corners or that you are one of the more mild drivers around. That being the case, you really wouldn't need a brake upgrade because your driving style doesn't lend itself to it.

I, on the other hand, would probably want to use the power of an S/C coming out of most corners or hang on to my momentum as long as I can into a corner. For the type of driving a brake upgrade would be greatly helpful.

I guess all that I am saying is everyone is different.

Best,

Dan

[MARAUDER S/C #5]

Yeah Rick, but when was the last time you drove your car past the end of your driveway?

:neener:
Sunday, I went to a car show in Falmouth (on Cape Cod) where Mrs. MSC#5 and I got to meet MM03MOK and BostonMarauder. I put about 100 miles on the car with no braking or watts link problems. :razz:

[wesman]

I have been looking into big brake kits for a while now. I read a very informative article in Car and Driver a few years ago where they tested several upgrades for the WRX back to back. For one panic stop from low speed (60mph) the tires and the coefficient of friction with the road is mostly what matters. There was very little difference from stock to high $ kits. Its on the 10th or 20th hard stop that a big brake kit shines. Like on a track. For one hard stop from 160mph the stockers will give up right away.

[Dan]

That sounds dead on from all that I have heard.

The higher end brakes cool more quickly/dissapate heat more quickly/better resist warpage, etc. All of this leads up to a benefit after repeated hard use or constant hard pressure.

Try to binder down a car from 120-0 and you might be fine at the end of the stop. Take it up and do it again and good luck on the next stop. Ditto for any type of road course driving. After 2 hot laps at Lime Rock (8 turns in 1.5 miles per lap) the stock brakes of most cars like ours will give a soft. dull pedal feel or be warped. Toss on a set of hi-per brakes and you get good stopping from lap to lap to lap.

-Dan

[RCSignals]

Quote:
Originally Posted by martyo
Yeah Rick, but when was the last time you drove your car past the end of your driveway?







Sunday, I went to a car show in Falmouth (on Cape Cod) where Mrs. MSC#5 and I got to meet MM03MOK and BostonMarauder. I put about 100 miles on the car with no braking or watts link problems. :razz:

It's OK Rick, just ask sMarty when the last time he drove his car past the end of his driveway :party:

[martyo]

Quote:
Originally Posted by martyo
Yeah Rick, but when was the last time you drove your car past the end of your driveway?








It's OK Rick, just ask sMarty when the last time he drove his car past the end of his driveway :party:


That's easy. March something or another....

On the other hand, Rick doesn't have pictures of his Garage Queen like this (takne well after March):

http://mysite.verizon.net/vze3wmxh/sitebuildercontent/sitebuilderpictures/IMG_1001.jpg


DISCLAIMER: I am just teasing Rick! :P

[Agent M79]

I have been looking into big brake kits for a while now. I read a very informative article in Car and Driver a few years ago where they tested several upgrades for the WRX back to back. For one panic stop from low speed (60mph) the tires and the coefficient of friction with the road is mostly what matters. There was very little difference from stock to high $ kits. Its on the 10th or 20th hard stop that a big brake kit shines. Like on a track. For one hard stop from 160mph the stockers will give up right away.

I can tell you from back to back driving experiences that a MM with Baer's up front stops much faster than stockers.

The WRX is hot out of the box and an upgrade would, as you said, make for better back to back stops but not greatly improve single stop performance.

The MM is luke warm out of the box so you get better single stop braking as the bonus to better multi-stop braking.

[MARAUDER S/C #5]

:nerd:



DISCLAIMER: I am just teasing Rick! :P:argh:...................... .

[martyo]

:nerd: :argh:.......................

Oh yeah? Drive down here and say that! I dare ya!! :neener:

[RCSignals]

you're scaring me here! :hide:

[Dan]

Oh yeah? Drive down here and say that! I dare ya!! :neener:

An easy threat to make. It's too far. :)

Why put a supercharger in your car if you aren't gonna use it?

I don't understand. (Dan confused) :stooges:

Oh, and in case anyone needed to know for sure....
:hijack:

-Dan

[woaface]

I know what YOU said MAc, but I was pretty sure there was something along the lines of "Kenny Brown says...and we believe it" in the article. I don't have the magazine, do you?