I know. But the bullies here couldnt care less whats the Truth: one has to want it, work diligently to find it... And so simple thing as this is.

Good video u have there, thks.

Actually driving w/o brakes doesnt drop track time dramatically. Yes, time is somewhat worse, but when -IF- one learns different driving lines, and how to 'brake' w/o brakes, difference isnt too big. Top speeds cannot be as high, but average time in the curves compensates. Our icey roads and lake tracks teach how.

Fastest method [shortest distance] to stop a four wheeled vehicle, is to cause it spin. And again u bullies, personal attacks b/c of this statement are fruitless, cause that statemt is not mine, but world champ rally driver's statement, btw which dont grow in US, so shut up. I can utilize spin at will up to a point, in any emergency I choose... That spin is not blondie-spin, but a spin where driver is in full ctrl, for viewer its like magic. Pls dont ever never try/learn how - on public roads.

 

all i have to say is WOW

this thread was almost as informative as it was educational (on many levels)

jeff/matt
dude, people on this board know that u guys know ur sh#t. if someone doesn't accept ur explanations don't waste ur time. it's really sad seeing such experienced and knowledgeable people try so friggin hard to teach "others". if people won't listen then good bye and good night and be done with them. otherwise, really nice data guys and grace imports too...


i'm surprised that no one has mentioned the issue of surface area. it's my understanding that drums - having more surface area - have greater stopping power. isn't this why big rigs have kept drums on their rear axles where the load is mostly?

as for if it is worth the mod, as was mentioned, u do have to swap out the e-brake cables. drums are much easier (for me) to adjust while discs (so the younger generation tells me) are easier to replace the pads.

i'm not sure how the cutting drums vs cutting rotors issue goes with respect to ease, pricing and availability.

i do know that i absolutely hate that screw in piston that is so common on rear calipers with an e-brake.

just my $.02


whatever happened to the "cents" sign i used to have on my commodore 128?

 

I agree, driving without the rear brakes did not make the lap times so much worse. But the rear brakes was not in very good condition when I started so maybe they weren´t as efficient as they should have been. driving witout any brakes at all however would make the lap times terrible, the difference in time would be huge since the corner speed is the same regrdless of what you do before the corner. The best mod you can do on your car if you intend to drive it on a racetrack is imo a brake upgrade.

Yoy can vary the line by braking later and longer into the corner, wich results in a higher speed in the middle of it but you must wait a bit longer before stepping on it (tighter line into the corner). Or brake early, slower in the middle and early acceleration (wide line in and higer speed before next corner). If you measure from before you start braking and all the way to the next braking point both ways are equally fast if performed good. It is just a matter of tactics.

 

Yes, all 4caliper hi quality upgrade is always better than stock. For a family car its necessary if desire is to better results in racing. Daily drive, not needed if u already have a wife...

"Dont touch the brake": The more u hone, the better the 'no brakes' tactics will become. How one selects driving lines is crucial. It may be scary in the beginnig, but after u win uself, really no problem. Again, not on public roads. Keep all 4brakes in top condition. Again, not on public roads. Keep all 4brakes in top condition. Again, not on public roads. Keep all 4brakes in top condition. Again, not on public roads. Keep all 4brakes in top condition.

 

ha ha, I think you made your point Hav a nice day everyone.

 

Findin Facts is fun.

-------------------------------------------------

DaWifey's90:
Persons and/or theire knowledge is not in question. In Freedom, all Facts can be questioned in peace. That is never allowed by Saddam, Evolutionists, Here..

The Facts 1-8 still stand. Btw, those Facts are not mine nor Nissan's...

The Only Scientific Method: "Prove all things; hold fast that which is good. " ...Only Bible can continue from this: "Abstain from all appearance of evil."

 

Hmm how come ALL racing cars feature rear brakes. Yes facts are fun. ACtually the fastest way to stop a 4 wheeled vehicle is to crash into a very solid thing. But it's not recommended

 

yeah ask Alex_V about crashing into solid things. hehe

 

You took my statement COMPLETELY out of context. Testing doesn't mean **** if you're just randomly adding/removing things from the car.

Read my post again. Reading comprehension ownz joo. I very clearly stated what happens with the rears on STREET DRIVING.
StopTech did said tests using several brake kits on a few 350Zs. you can see the proof here:
http://www.zeckhausen.com/testing_brakes.htm


I for one don't have the time, equipment, facilities, or money to perform your said tests. But again, reading comprehension ownz joo. Back to a repost of my previous thread.

Now for your next post.....
Really? I'd like you to come and drive on a few of the tracks I drive on a regular basis without brakes. There are several corners where you would DIE if your brakes failed. killed. dead. you'd be smashed on rocks or guardrail or concrete wall in a burning pile of dead car.
slow down with the engine brake? you can't do that when your straightaway speed is above 130mph and your need to enter the corner at 50mph!!!
sure.. throw it sideways.. and RUIN A SET OF TIRES IN ONE CORNER.

Your theory is fine if you're driving on ice and you can just throw it sideways and gas it in another direction. doesn't work when you're on concrete at 100mph. you throw it sideways and you kiss a set of tires goodbye.. It may also work fine on a 130hp Miata that never gets above 115mph on the track. they simply turn the front wheel and start scrubbing speed enough to go through the large sweepers without lifting off the throttle. but, yet again, as soon as they get to turn 3, they're standing on the brakes.. Spec Miatas are the lowest hp/weight cars out there, so in theory are the slowest and should have to brake the least going into corners... yet they still run Hawk BLUE race pads, which don't even start working until about 300 deg F! if they didn't use their brakes in the corners, then the rotors would be ruined in just a couple of races because of the pads. under 300F, those things are more abrasive than concrete and will eat away a set of rotors in literally 50 stops. I've been there, done that as well.

Using the brakes is REQUIRED for quick times on a race track. Since I'm going out to TWS this weekend for a 2 day track event, I'll be sure to make a few laps keeping my straightaway speeds down enough so I don't have to brake in the corners and I will report back with lap times. I can tell you now that they're going to be somehwere approx 20 seconds slower on a 2 minute course.

WRONG!!!! YET AGAIN!!!
The static coefficient of friction of rubber is much higher than the dynamic coefficient of friction.
This means you can stop faster with the tires glued to the road than in a skid. years of testing by racers, vehicle, and tire manufactuers ALL show that a tire grips the road best when it's at approx a 5% slip. that means the tires are still rotating and pointing in the same direction of travel (or in a corner, the car is oversteering by approx 5-10 degrees of slip angle). Throwing a car sideways is yet again a good way to get yourself killed. when the wheels are locked and the car is not pointing in the same direction of travel, you have almost ZERO control of where the car is going to go. you're a projectile at that point. you can't turn the wheel and make it move. you can't hit the brakes and make it do anything. you might be able to hit the gas and make it change attitude slightly, but you're STILL not going to be able to sufficiently control the car.

take your rally driver comments and throw them aside. They simply don't apply to the real world. rally racing is almost ALWAYS done in a slide and tires don't count.. they do it halfway to set up the car into the corner, and they often have enough power to skid and accelerate faster than they can brake, turn, then accelerate. this isn't the case with a street car, nor is it desired for ANY situation driving on the street. you are yet again taking obscure and illegal driving techniques and presenting them as fact, which they are truely not. (In the US, you would be stopped and ticketed if you skidded through a corner. more than likely you would be immediately jailed if you did it in an urban area around other people.)

 

And that's why I chose Matt93SE to complete my drum to disc brake swap! Great reading, but I probably won't be able to throw any of it out during my next brake converstation...

 

hey mike, what kind of headlights are those?
-------------------------------------------------------------------------------------
let's see, one page about whether the poor guy should do a rear disk swap, and two pages of b!tching/arguing about brakes/brake theory...I'd say this thread is officially out of hand!!!

 

- I bet you do it randomly. Charts are bs without careful tests backing.
- Yes, World Rally champion is wrong again in car handling. lol. I am sorry for him, he must be ashamed...
- Facts 1-8 still stand

Yes, some of the racing things are as u said; pls cool down and find out: I dont question your expertise. Still, you try to play saddam like jeff and hinder questionin, givin out facts.

Your story doesnt belong to the issue of why generally [not Gene-Rally!] rear calipers rust first... or is rear caliper swap necessary to a family car...

Spin zone warning.

 

I don't think it's necessary, but I've always heard that modern disc technology helps you stop better then drums from decades ago. Who wouldn't want to improve stopping distance?

 

Issue of how to stop your car, avert deadly collision:

The Rally Championships keep their drivin schools. For the bullies here to laugh at, (laughing is good for heart), I pick the best one, with this even average joe may survive, NON ABS:

When you find your speed is way too high, road blocked, hit brakes as hard as u can. While brakes are locked, rotate steering wheel max left/or/right. Just before smash, release brakes. U vehicle jumps to direction wheels point. This dramatically eats kinetic energy, reducing possible damage. I've seen once how this even gives a chance to escape unscatched from certain death.

The Rally Champ is right in his spin the car -trick. Still, on public road, I cannot imagine granma doing this with her station wagon... So in my mind, giving this concept for the public as a general rule as he did, is not appropiate. U really need to know u vehicle before trying it out (on closed circ).

 

Wiking, my big issue with your statements are that you mention truly unorthodox forms of racing/driving in your descriptions and try to fit them into real-life sitations. You come from ice and dirt racing, and throwing the car sideways is fine there.
in road racing and general street driving, it's exactly the opposite- ESPECIALLY given the audience we're looking at. throwing the car sideways is the LAST thing anyone would want to do on the street. you have almost zero control of the car at that point, and if you DO get stopped before you hit something- or turn to avoid it- the guy behind you in his big lumbering SUV is just going to plow over you and kill you anyway. Rally driving may be fine on dirt, snow, gravel, etc but it's a good way to get yourself killed on the street. Just don't do it.
You also said the car stops faster in a complete skid, which is simply not true. static (sticking) coefficient of friction for rubber on concrete is stated in every engineering handbook I can find as 0.5-1.2, while kinetic friciton (sliding) is only 0.5-0.8. Thus you will stop roughly 50% FASTER if the wheels continue rolling and do not skid against the concrete. your arguement about throwing the car into a sideways skid was just disproven by the physics you try to hide behind.


As I've said a half dozen times now about the rear caliper issue.... the rear calipers rust and sieze because of the low pad wear rates. when the pads don't wear much, the sliders don't move much. when the sliders don't move much, they tend to freeze up.
Why are they so much smaller than the fronts?
For daily driving, even the tiny rear brakes are sufficient up front.. the brake system just doesn't get that hot.
for higher speed driving and harder braking, the fronts begin to do dramatically more work. the rears do incrementally less the harder you brake. they still do proportionally increase their work as you brake harder, but the fronts do more by approx a factor of 2.5. at full-lock, that comes out to about 80% front.
so when you're driving around town and your brakes never get above 250F or so, the rears do roughly 35-40% of the work.
when you get to the track or are in an emergency situation, the rears do between 20 and 35%, depending on how hard you're braking.

refer to the stoptech article I linked earlier. the best braking and shortest distances were noted with a slightly larger than stock brake setup on the rear (or dialing down the fronts just a tad, depending on the situation). also look at the rotor temperatures. even the stock brakes had some pretty hefty rear temperatures in the back. that tells me the rears are doing quite a bit of work. If you're like, I'll be glad to find the exact rotor mass of front and rear, then do the temp rise calculations on it to figure exactly how much energy was absorbed with both front and rear rotors on one of their published 100-0mph stops. then when you see the rears doing approx 35-40% of the work, will you stop trying to say that the rears do nothing on a street car?

 

Good points Matt , this is way more interesting than my physics lectures. but just to add to the kinetic friction vs. static friction discussion i found this example in my physics book. http://web.ics.purdue.edu/~jtdubach/...0friction.html
i know that they have the front and rear tires braking at the same rate but since the forces are summed that doesnt really matter. more than anything this just shows the difference between Sf and Kf.

 

Interesting, so like why does BMW's 330i decide to use bigger rotors in the rear, when most cars have it the other way around? Is brake bias reversed?

 

I'm not a big fan of the new 330 series.

But to answer the question, no, reversed brake bias is a very bad thing.

They probably chose to use larger brakes in the rear to make more effective use of the handbrake.

 

Wiking is correct in pretty much everything he says, but his topics are in very specialized forms of driving that generally dont pertain to the discussion of the best possible braking. ceteris paribus.

Matt, if you actually choose to read what wiking was saying, he was talking about averting a life and death crash, not trying to stop the best. I don't know which of you was more off topic.

Braking 101:
-Pick the brakes with the largest possible surface area for your application, larger or more calipers are not always the way to go, surface area is most important always.
-Cross drilled are a definite no-no.
-Be sure you break-in your pads and rotors before use, and make sure you brake heavily on a consistant basis to keep your pads and rotors mated together correctly. Edit: This applies to all cars with disc brakes, espically street cars.

All the rest of the info is contained in my previous posts.

 

If you see the braking performance of sports cars now days, it approaches supercar times of just a few years ago. Instead of makers being so conservative in their rear bias, makers are now putting more bias towards the rear to achieve good braking performance. But you cannot run too much rear bias. Because if the rears lock before the fronts, you stand a good chance at spinning the car around. Even though makers are using larger rear rotors than before, the bias is not changed that much more. They are just using diff size caliper pistons and using computers to control the braking. So they can achieve great brake performance w/o the danger of pre-locking the rears early.

 

As said above, most of his information is 99% INcorrect for the street and he is trying to talk like it is the proper way to drive on the street. It's simply not.. Throwing the car into a skid actually increases stopping distances due to less friction. it's also VERY unsafe because 99.5% of the drivers out there have zero experience controlling the car in a skid, and you lose almost all steering and directional ability. In a 'life and death crash' the last thing you want to do is lose steering control of the vehicle. steering AROUND the wreck is the best option. stopping before you get to it is the second best thing. skidding to a halt beside it and possibly blocking the path for any other oncoming traffic is the lowest thing on my list of smart things to do.

obscure forms of racing (like ice racing and rally) use those techniques just fine, but usually only to make the car rotate while braking and set it up for a corner, NOT to avoid an object in the middle of the course and veer off in the wrong direction- likely off the roadway and causing more damage to the car and increasing the hazard for others coming up behind you.

 

Just because the rotors are larger diameter doesn't necesarily mean the system is biased more towards the rear. you also have to factor in the piston sizes on both ends and brake proportioning valve output pressures.