Maybe this holds the answer?

No idea if the numbers are right or not, but they look pretty legit.

I know if we had all the info on a braking system, namely just force of the caliper, it wouldn't be hard to determine the torque capacity of one single disc brake.

http://sth2.com/Z-car/Brakemath.xls

 

I would venture to guess Bones knows a little more about this.
Just saying......

 

Go try it. Maybe my 100 MPH was a little too extreme because of how dependent the braking system capacity is.

But go in a parking lot doing 30 MPH, floor it and then put the brakes to the floor. The older the vehicle the better so we can rule out electronic intervention. As long as your brakes are in good working order, I bet you'll come to a complete stop.

I know Bones is very knowledgeable with this stuff. I know that's what he does for a living. I just find it extremely hard to believe passenger car engines produce enough torque to overcome disc brakes.

 

intuition > subject matter expertise

 

intuition > subject matter expertise

I'm not saying he is wrong or right. He was commenting on my 100 MPH scenario which is definitely flawed.

If engines can overcome brakes, then brake torquing would be an impossible feat to achieve with a vehicle.

My observations simply aren't intuition. Like I said, if I had a typical brake force that a caliper applies to a disc, I could easily calculate what torque a disc brake can hold.

 

If engines can overcome brakes, then brake torquing would be an impossible feat to achieve with a vehicle.

go brake torque anything except a RWD vehicle and see what happens.

Even most RWD vehicles will be able to push through brakes once the vehicle is rolling.

 

Its what he does for a living.
So theres that.

Are you going to argue law enforcement with Hombre?
Or electrical with CC?
Or fabrication with monkey?

 

Its what he does for a living.
So theres that.

Are you going to argue law enforcement with Hombre?
Or electrical with CC?
Or fabrication with monkey?

What's your point?

I have certifications and what I do for a living to back up my knowledge.

Not trying to compare Bones to Obama, but just because Obama is president doesn't mean he's a political expert now does it?

Your logic is flawed. Anyone, regardless of what they do for a living even if it is their area of expertise can still be wrong. No one is immune to that. I can be wrong too just like every other human being on this planet.

 

I may pull my scan tool out tonight and try this with my car. I can monitor the the throttle and see if the ECU starts closing it with the brake applied.

 

Brakes do not over power all car engines. I drag race and with the brakes fully applied to keep the car in place while stalling it up, there is a point where the car will just push forward and through the brakes.

Also 3 seconds is a lifetime to turn a car off in a dangerous situation.

 

I am guessing that engine is not stock?
But neutral is just a flick away...

 

That car was a stock LS1 with a stock trans. With street tires it would just start spinning and with drag tires it would push right though the brakes with a stock converter.

Other junk boxes Ive tried to do brake torques in same thing push or spin. FWD will just push through the fronts and drag the rears from a dead stop. If you are already moving and stay on the gas I doubt the brakes will over power the wheels until the wheels arent getting anymore power from the engine.

 

i know nothing about the prius. with that being said i do know a little bit about fords.

I dont know what kind of braking system toyota uses on the prius either. I was just thinking about the fords. and i know that the hybrid used regenerative braking.
and that the hcu controls the pressure in the system rather than in being controlled through the brake pedal. However i am not familiar with any safety features built into the hybrid braking system.

Now i dont believe regenerative braking would be enough to stop a car at wot. I have nothing to back that up, its just an opinion. if the hcu didn't apply pressure to the system and at wot the vacuum booster would loose vacuum after a couple pumps of the brake pedal. and the car would not stop. and i dont think anybody would have had their foot on the pedal for however long he was driving for, hell my leg gets tired after bleeding brakes. :sonicjay:

again i have no idea how all this would tie into the prius. just my thoughts on using the brakes at wot will loose vacuum and not stop.

carry on.

 

http://www.popularmechanics.com/automotive/how_to/4348506.html

 

On a stretch of road behind my work, I got up to about 55 MPH in second gear. 60 MPH is pretty much redline in 2nd gear. I kept the throttle to the floor, and put the brake to the floor. The car immediately started to slow down. The turbo was still hissing, and my boost gauge was still reading 15 psi, all the way until it started to bog in second gear and almost stall at about 15 MPH. I did the same thing with 1st gear wound out with the same results.

If the throttle would have closed because the brake pedal was pushed, the turbo still wouldn't have been making pressure. I don't think it would have came to a complete stop, but it still slowed the vehicle done a considerable amount.

300 ft lbs of torque, in second gear with the ratio is 1.952 with a 4.063 final drive to the front wheels and the brakes still slowed the vehicle down considerably.

Not saying the same will be true for all vehicles, but take it for what it's worth.

 

http://www.businessweek.com/news/20...2010-03-15/ford-had-20-acceleration-deaths-as-regulators-cited-human-error.html

 

http://www.businessweek.com/news/20...2010-03-15/ford-had-20-acceleration-deaths-as-regulators-cited-human-error.html

douchemonkey, give it a rest.

‘Brakes Always Win’
“Few motor vehicle defect allegations have been more exhaustively investigated and more definitively refuted than claims of sudden unintended acceleration when it involves a shift from park or neutral into a gear,” Chrysler said in a statement.
“Thorough testing to investigate reports of unintended acceleration demonstrates one overriding fact: When the brakes are applied, the vehicle stops; the brakes always win,” the company said in the statement. “Even if the accelerator is nailed to the floor, a driver can stop the vehicle by applying the brakes.”

someone at chrysler thinks douchemonkey is right :/

the brakes bones designs must be inferior to chryslers!

 

douchemonkey, give it a rest.

 

I'm with this guy

 

I wish i would have been in this argument all along. For one, I have lost my brakes before due to over heating and I was not on an e way doing 90, I was in down town detroit racing between stop lights. Before I knew it I was in the intersection with my foot pressing as hard as I could on the brakes. I guarantee my car would have accelerated to what ever speed if I would have mashed the gas. Also Greesemonkey, you really think the power assist doesnt help add any more torque to the braking system? OK. Just like using a longer wrench doesnt add any torque to loosening a nut, your still just using your hand to move it. By the way I have lots of race car brake data if you would like to see it. When race cars get stuck at WOT they dont slow down.

 

:sonicjay:

Of course brake fade is going to lead to brake failure and not being able to stop.

Using a longer wrench doesn't multiply torque? Are you fucking high?

 

Some people are not good at this.

 

Nope, that's why I'll delete him from facebook too.

 

still going huh?

 

Why don't we just chalk it up to evolution? Some people are going to be high ons and pull this shit. It's just the way the world works.

 

I know I'm bring this one back from the dead a bit, but I just found this info in the May issue of Motor Trend, page 58.

Unintended Acceleration

Can the engine outpower the brakes?

We accelerated to 60 MPH, floored the gas, and then nailed the brakes. The recalled Toyota and the 2011 Sonata were the only two that automatically cut engine power while the brake was applied, and as a result stopping distances were virtually unchanged (as they were with the still revving Nissan).

Braking Distances from 60 MPH


Chevrolet Malibu
Brake Pedal Only: 130 ft
At Wide-Open Throttle: 167 ft
Approx Braking HP: 534 HP


Ford Fusion
Brake Pedal Only: 124 ft
At Wide-Open Throttle: 152 ft
Approx Braking HP: 559 HP


Honda Accord
Brake Pedal Only: 125 ft
At Wide-Open Throttle: 129 ft
Approx Braking HP: 544 HP


Hyundai Sonata
Brake Pedal Only: 123 ft
At Wide-Open Throttle: 124 ft
Approx Braking HP: 545 HP


Nissan Altima
Brake Pedal Only: 124 ft
At Wide-Open Throttle: 124 ft
Approx Braking HP: 525 HP


Subaru Legacy
Brake Pedal Only: 121 ft
At Wide-Open Throttle: 124 ft
Approx Braking HP: 587 HP


Toyota Camry
Brake Pedal Only: 128 ft
At Wide-Open Throttle: 128 ft
Approx Braking HP: 537 HP

 

Our research has shown, though, that in panic situations, the average driver doesn't usualyl do the right thing. (Its still an age where people try to pump/modulate the pedal on ABS, for pete's sake).

Brake systems on any modern car overpower even a WOT engine. This comes up all the time, like the Jeep shifter interlock case years back, or the Audi's launching themselves out of parking garages years before that.

But they only work when the operator stops freaking out, gets off the gas, two feet on the brekae and puts it to the floor. And you'd be suprised how often they don't.

 

Yes, very true.

 

For the record, I've never seen anyone doing a 'brake-torque' with both feet on the brake pedal, pushing hard enough to flex their seat frames.... Just saying.

But, if someone could plumb in a gauge, put the line pressure to 150bar, and report back how it went, that'd be great.

 

at one of my old jobs, I had a field vehicle assigned to me. it was an old cop-patrol car - shamu-style caprice.

I didn't flex the seat frame, but it did break... ended up driving it back to the yard with the backrest sitting in the rear seat :teehee:

 

i was passed by a speeding toyota last week and i couldn't stop laughing. hahah

 

i couldn't stop laughing. hahah

I would sue. There should a laugh-override installed somewhere.