No ABS- help

[OptionZero]

After several near-death incidents on the freeway where wheels locked up after I was forced to slam on the brakes, the lack of ABS on my s14 has become far too obvious to me. The tires lock up, the car keeps going, and when you are skidding you have very little control, and no where to go with traffic all around you. In the wet on a freeway, this problem is compounded.
Does anyone have tips on braking technique to avoid lockup? I know the goal is to modulate braking force just like ABS would, but are there methods to this madness? This goes beyond simply performance on the track to safety on street/roads.
Any practice techniques/info is appreciated, and i will certainly find time and empty space to learn better braking. Going fast is only half of the equation, after al.

[mrmephistopheles]

it's about knowing your tires & how much grip they have.
if you know when your tires are on the edge of losing their grip (skidding), you can control your braking. You need to learn how to not panic brake (slam the brake pedal through the floor) and learn how to emergency brake (push the pedal down till the tires are near their slipping point, and use the handbrake to help slow the rear wheels more effectively)
Using the handbrake is a good way to slow yourself down quickly, but again, it's about knowing your tires. If you crank up on the handbrake and lock your tires, you'll spin!

[crioten]

pretty much pump pump pump the brake pedal, just like when stoping in te snow/ice...the key is not to panic, but that is sometimes hard

all ya gotta do is lift off the pedal once the wheels start to lock up, then press it down again

-glen

[aznpoopy]

dude i know where you are coming from. i also have a non-abs 240sx. modulating the brakes is something that has to come naturally. if you have to think about it, you're probably eating the other guys bumper already. the first time i locked up my tires i had no clue what to do. afterwards, i read up on non-abs brakes. i imagined in my head what i would do if the brakes locked up, apply, release, apply release. after trying low speed braking in parking lots a bit, i realized you can actually feel the limit of ur brake. i dunno. its like, i just know when they are going to lock up.

this practice all proved very useful. my girlfriend was in the passenger seat giving me directions when we were looking for this autozone. i was going about 50mph going around a blind left curve in a 2 lane road. as soon as we clear the turn there are 3 cars there waiting to make a left turn! it was one of those -u need to live there to know- kind of intersections. i slammed on the brakes and they locked up almost immediately. before i could think my foot came off the brake and back on. i stopped maybe a foot behind the car in front of me.

call it whatever you will... instinct, learned from practice, road experience... but it all came together. so my advice to you is... take your car to a big parking lot. take it up to 50 and try to stop as fast as you can. do it over and over until u brake so hard the brakes lock up. you should develop a feel for it. its alot like cornering actually, now that i think about it. u just know when your tires will slip. same with ur brakes. once u get that down u have to train your foot to release just before its about to lock up. that you need to do before you think. if u need to think about it, its too slow (unless u have alot of stopping distance). other then that, for freeway driving; drive in a slower lane and/or give the guy more distance. don't forget u can pull to the shoulder in a near-miss accident. that gives u bit more distance to stop (and the guy behind you too).

[mrmephistopheles]

also, the MOST IMPORTANT aspect of your braking system is your tires, bar none. I don't care if you have a Brembo F50 brake setup and Hawk HP++++++++ pads with 13" rotors, if you have shitty made in tijuana 145/65r16 tires, you're not stopping worth a damn.
Good treaded sticky wide tires will reduce your 60-0 time better than anything besides ABS. Also, running wide tires on skinny rims isn't the best thing to do, so appropriately sized rims for the tires are optimal.

[LonelyDoridori]

Good tires will make a world of difference. Also seat time at autocross or drift events will give you a good idea of where your car's limits are.

[max power]

To make this more dramatic....

I was coming up over a hill and as soon as the hill cleared there was a traffic pile up. Hmm, 'what the hell do I do' I think to myself, while slamming the brakes (natural reaction). This car had a sloppy clutch so i was able to jam it into second and gain some track. It could have been worse...

http://www.shift240.com/IMG_0036.JPG

I was spoiled by ABS on my car. This thing was not abs equipped and had mushi wooshy, worn out all-seasons in the front.

[OptionZero]

I was on FireStone Firehawks (stock size), in the rain.
In the future, i'll definitely have two wheel packages for dry/wet season, thinking of Falken Azenis in the dry, Yokohama ES100 in the rain...but when i get money to do that, i'll definitely be researching in the future.

Thanks for the advice guys, time to look for an empty lot in Davis.

[nokeone]

you could always just slow down...:rolleyes:

i don't understand the need to play speed racer on city streets or highways...

yes, some incidents are unavoidable...but for the most part people just drive too fast...

[OptionZero]

Flow of traffic....just following the flow of traffic...

[nokeone]

Originally posted by OptionZero
Flow of traffic....just following the flow of traffic...

obviously too close...:p

[KiDyNomiTe]

Oh boy, can't wait for Chicago winters :D. But at least I got some Blizzaks.

Learning your breaking point is pretty easy. This is my first car I have had with no ABS, so I am learning. Easiest way I find is do it in the rain, I come home from work late and practice before a red light occasionally. Doing it in the rain will allow you to get the feel of when your car locks up, but of course it happens a lot quicker than in dry weather.

Plus just before you can sort of feel your tires skidding just a tiny bit.

Practice makes perfect.

[mbmbmb23]

For an emergency high speed "slowdown", learn to downshift rev-match so that your RPM's will jump to around 5k as you let off the clutch...while you are heavily braking (but not locking them up). This also can work if you are skidding on ice/snow...but you have to pick the appropriate gear according to your speed.

Learn to pump the brakes, it will regain traction when skidding....just make sure you keep the wheels pointed forward when you release the brake "pumps".

Also...learn to brake-swerve onto the shoulder of the road if you are approaching someones bumper too rapidly to completely stop without hitting them. Do NOT swerve into an open lane (left lane swerving to the right lane, or vice versa).


-m

[OptionZero]

yeah, the swerving into a shoulder is pretty reflexive for me already.
One of the incidents was my fault, it was a late lane change because of poor directions from my directions, i shouldn't have done it.
The others involved speeding civics that decided to cut me off.
I hate civics.

[aznpoopy]

Originally posted by mbmbmb23
For an emergency high speed "slowdown", learn to downshift rev-match so that your RPM's will jump to around 5k as you let off the clutch...while you are heavily braking (but not locking them up).

only in a straight line, imo. done improperly or without the proper feel, the car will just spin out totally, and often, uncontrollably.

case in point: when i was first going from my fwd to rwd 240sx. weather = rain, slick rear tires. brake + doubleclutching from 3 to 2. going pretty slow (25mph?). left hand turn. as soon as the engine brake kicked in (smoothly i might add), the rear end of the car just totally spun around. it was slow speed, so i only spun 90 degrees. thank god nobody was around me. this is when i realized i needed to be a much more technical driver to drive a rwd properly.

to do this in a turn you need to have a pretty keen sense of the cars balance. its almost like a limit trail braking technique. forget about doing it when you're swerving, you will totally unbalance the car... remember your brakes are balanced at a certain ratio, changing that ratio (braking more on the rears with engine braking) will affect the dynamics of the car.

[mbmbmb23]

Originally posted by aznpoopy
only in a straight line, imo. done improperly or without the proper feel, the car will just spin out totally, and often, uncontrollably.



True....I wouldnt try to revmatch+downshift when going fast if you are turning at all.

Also, if your car's rear end isnt firmly planted, I wouldn't try it either. I used to speed thru an intersection (going to work) and immediately turn right into the parking lot. Only problem is that entering the intersection it would dip, level off, then dip again upon exiting the intersection. The car's rear end would get squirrly if you let off the clutch too quickly while downshifting as the pavement changed height....especially in the rain.



-m

[aznpoopy]

hehe i think the revmatch downshift is one of those ff to fr initiations for everyone making the jump. its great in ff, rarely if ever does it destabilize the car. first time u do it in fr, ur toast! wish someone had warned ME before lol.

anyway just wanted to make sure optionzero stayed safe... seems like a nice guy; props for asking a serious question about driving without worrying about how people would view it.

[OptionZero]

Its amazing what you can learn when you just ask.

...

and have no pride:p

[TurDz]

It's funny, I've gotten into the habit of looking pretty far ahead of me and braking much earlier. I used to have a 5-speed Maxima...good brake pads, but the rotors and calipers were way too small for that kind of car. I had Potenza RE730s, they rarely lost traction unless I really, really pushed it.

Compared to the Maxima, the 240 brakes like a dream. That's why I'm not really complaining about braking performance....yet. Hopefully you don't get into another situation like that again Jon.

Since it's raining all weekend, why don't we go out to some empty parking lots and play around? get a feel for your car at it's traction limits.

[OptionZero]

Sorry, dude, goin back to SF this weekend. One grandpa's birthday, the other's in the hospital:bash: :hammer:
I'll be back sunday.

[sykikchimp]

Looking farther ahead is the #1 thing you should work on. I mean, WAY far ahead. You should NEVER be looking at the pavement. EVER. It's not going anywhere. So why look at it? the stuff you need to be worried about is about 5-6ft ABOVE the pavement. Tell yourself all the time "Look UP!, Look OUT, Look AROUND" Make sure you widen you visual field. Take in EVERYTHING you can see. Not just the 6 inches in front of your face. When doing this correctly, you should be able to tell what color the bums shirt is on the side of the road while going around the on ramp onto the freeway. If your vision is wide enough, ALL of your mirrors will be in view WITHOUT moving your head OR your eyes at all.

You should NEVER use engine braking or the ebrake to slow the car (unless your normal brakes have malfunctioned of course). Engine's are too accelerate, BRAKES are for stopping. Let them do what they are designed to do.

There was an engineer somewhere that spent DAYS calculating brake bias in your car. There is no reason to ever use your Handbrake, or engine to slow you. You'll just loose control of the car, and die.

All of your tires have a very specific amount of grip they can provide in any specific direction.

Think about this. You are threshold braking. you are at 99% of your braking traction available, MOST of the weigth in your car has shifted over the front tires, and your rear tires have almost no traction available. Suddenly you decide that engine braking may slow you down faster. Now the engine is also trying to slow the car along with the brakes in the rear where there is NO traction, and you just went to 120% of available traction and are now about to slide into a WALL/Light post/fence/other car.. whatever.

In order to fully understand this you need to comprehend the difference b/w "Slip" and "Slide"

Visualize your tires contact patch. It's (for simplicities sake) made up of an about 5"x5" section. probably 15 or so actual seperate tread blocks. Each tread block has thousands of seperate rubber particles. The road is NOT smooth. lots of little bumps, and edges.

slip is when some of particles are grabbing, and some are not. Often these particles can be pulled in several different directions. Maximum braking is found at about 5% slip. You still have total control of the car in a slip situation.

Slide is when ALL particles have lost connection with the road, and are simply floating over the surface. When sliding, you have NO control.

Also please read this:
http://www.geocities.com/prohibition_us/friction.html
on the friction circle.

Luckily you can "Sense" these small increase's in slip by detecting steering vibrations, and resistance changes, and you can actually feel it through the seat of the car. Often the tires will also make noise BEFORE breaking away (indicating slip).

For OPTIMUM braking: Sit upright in the seat with as much of your back touching the seat back as possible. Your but should be in the corner of the seat. Seat belt should be tight.(this all increases feel for the car).. CLUTCH IN, Steering wheel STRAIGHT, Brake hard SMOOTHLY, if you feel tires slipping, release pressure approx. 5%. NOT A LOT. just BARELY ease off the pedal, and get right back in. Everything must be smooth. I didn't say slow, just smooth. you CAN be smooth and fast.

PRACTICE, PRACTICE, PRACTICE. In ALL situation. When it's raining, when it's dry, going up hills, going over hills, going down hills, going around corners.. ALL of these situations will change the amount of available traction you have, and will all require a little different touch.

If you want to get better at braking, and driving in general, hit the track. Go to some auto-xes, or track events. Get someone to ride with you (important), and tell you what your doing wrong. People are not natural born drivers. Driving is a very specific skill set that requires many, many tools to be effective. Practicing with someone in the passenger seat critiquing you is the best, and fastest way to get more tools.

[aznpoopy]

correct me if i'm wrong.

slip = tires screech
slide = tire groan ... like a really horrid deep low kinda sound

also i think everything is just a technique. use it how you will. to unilaterally write off engine braking is to take away one tool you might use in some *racing* situation. a handbrake drift could save ur butt if you entered the turn too fast or at the wrong angle. but i do agree with you in that you should NOT use it in emergency situations on the road.

There was an engineer somewhere that spent DAYS calculating brake bias in your car.

i'd like to hear what you have to say about people doing brake 'upgrades' and the like then. wouldn't this mean replacing rotors with ones designed for improved performance may actually hinder your cars braking ability at the limit? i want to hear your opinion on this sykik. got into arguments about this before with no firm conclusion. :bow:

[sykikchimp]

Tire slip is usually a slight hum, to a fairly loud howl. Understand that this will be TOTALLY different for every tire. Even different sizes with the same compound will react differently. Some tires like a rain tire will make a lot of noise, and allow for a lot of slip, while some tires make almost no noise at all, and allow for very little slip like race slicks.

you are 100% correct, they are tools, but they are tools designed for very specific situations. We are talking about the basic priciples on how to stop in a straight line with no obstacles. You have to master that, before you can truley utilize the other tools available.

Brake upgrades of any kind could easily hinder braking. Replacing rotors would likely not change it. The rotors themselves have very little to do with actual braking bias. They all have similar surface friction characteristics no matter what they are. Changing Pads or calipers would have a much greater effect on brake bias than changing rotors. I think the main reason the 300zx brakes work so well when you utilize both front, and rear calipers AND the 300zx MC is b/c the 300zx has a similar weight distribution, and thereby similar weight transfer characteristics.

What most people do on track to adjust brake bias is just buy different pads. Need more rear brake bias? Get a pad with a higher friction coefficient. Same goes for the front. Getting a proper brake bias so that you use equal percentage of traction available from all 4 tires any time you brake is a very difficult thing to determine. Not nearly as easy as loose, or tight for cornering traction. Without very sophisticated logging equipment, it is usually a hit or miss situation. With a brake proportioning valve and a lot of test runs, you can get pretty close.

edit - grammer.. f*in grammer is killing me today..

[aznpoopy]

learn something new everyday. arigatou man! :bow:

[OptionZero]

As a broke college student, upgrading to Z brakes is but a distant future, so for now technique is all i can improve upon, hardware later. Technique>hardware anyways.

thanks, that was a great write up.
Pin this anyone?

[mistaanime]

damm that seems crazy..now im hella worried..hehi have a 92 240sx base model..do i have ABS?

[OptionZero]

I'm guess no...but on the S13, weren't ABS/LSD offered as separate options? Were these options available on an S13?

Just take the car to an empty place, slam on the brakes at 40+mph, and see if you feel the ABS-pulsing sensation.

[sykikchimp]

you can tell if you have abs if you have an orange "ABS" light on your gauge panel.

[mistaanime]

bump i guess I dun have..I have 2 extra lights but doesn't say ABS anywhere..oh well..abs is a good thing to have?

[KyoLo]

I don't know if it's the common sense that everybody knows or forgot to mention for the first part. When you know you're spinning out, push the CLUTCH FIRST(IMPORTANT)~~~~ , then you can pump pump pump your brake(not all the way down)to let it slow down. I learnt it when i first went to track, i was taught to do this for my own safety and for others as a newbie. But it's for track when there's basically nothing to hit on both sides tho.
I once spun out on a 20~25mph turn 2nd gear because of a bump on the turn ,and it's raining...i got back the control with the push of clutch and counter-steering(no brake)....it just got back automatically...no car on the coming way..(phew, LUCKY).

[mistaanime]

heh yea..i'd hate to mess up that piece of work..nice. car heh

[old_s13]

I cannot believe the stuff I hear written in this thread. Maybe this is why people always THINK having items like TEIN coilovers and BREMBO brakes makes the driver, it makes NOTHING.

Point in hand is that regardless if you had Brembo brakes OR stock, your car wouldnt have stopped any quicker with YOU behind the wheel, buddy. Why? Because of two simple things:
1) Tire quality
2) Driver quality

If you dont want to change your driving habits, atleast do yourself the favor and get yourself some good tires. Tires have the final say as to how quick a car stops, without sticky tires expect to lockup your brakes with ease.

Second of all, if you had some skills you would do what a few people said:
1) Module your brakes
2) Leave more space and be more aware of your surroundings

#2 is the most important, but atleast when you're in the situation, KNOW what to do! I am sure your driving style is acceptable when needing to stop in the dry while going straight. As soon as a turn comes up, a good percentage of that braking effects the INSIDE front wheel.. this is why that wheel is so easy to lockup, and this is why you should never ever brake in the turns (unless you absolutely need to and can feel the car).

All rain is doing is exaggerating things. Nokeone had the best advice out of everyone here. If you want to learn, practice in a parking lot while driving in the rain.. that will make locking up your tires MUCH easier while also saving whatever life your crappy tires have. In the meantime, leave more space and be more aware of whats going on.

Brakes are very much the same concept as a clutch: do you JAB your clutch when you are trying to be smooth? NO, because you will peel out. Same reason you dont jab your brakes, you want things to be smooth. You apply pressure quickly, smoothly, with a good firm feel. ONCE you start to feel the steering get loose, you'll probably also hear your tires start to skid -- wallah, thats when you ease off and then reapply.. but we're only talking about lifting you're foot maybe 1" high and then re-appling. The word PUMP is used incorrectly, this is not the old days of drum brakes and you dont have brake lines full of air where you need to PUMP them, you just need to let off a tiny bit and then firmly but carefully re-apply.

The other things that make no sense, clutch brake -- pointless, why are you going to try to teach someone who doesnt know how to walk, how to run? Using the clutch while driving is mostly good for dry conditions and even then, I only use it when performance driving simply because you want to be in the powerband and want to control the balance/momentum of the car. In panic situations, you focus on braking.. and even then, there have been times where I forgot to push the clutch in -- your concentration should be FULLY on braking.

Pulling up the e-brake? Garbage, completely pointless. Your master cylinder is responsible for the brake biasing, pulling up the e-brake does nothing other than fuck with your balancing, which YOU my friend, dont need. You need to focus on braking, let the MC do what its designed to do. For people with JUST the 300Z front brake upgrade that still run stock MC and stock rear calipers, your rear brakes are barely working anyway.. so thats your problem for not setting up your car correctly. Once you install the FULL 300Z front, rear, and MC.. THEN your car is back to proper specs. Unless you take the time to get a proportioning valve and re-configure your brake bias values.. your car is improprly setup. I would never suggest touching the ebrake while emergency braking. Now that I have 300Z rears, what is the point? Is the DRUM e-brake supposed to work better than the 2-piston rear caliper which has biased pressure from the MC? Everything is properly setup, dont touch the e-brake unless you want PROBLEMS.

Things like having your stereo LOW or OFF are most important. Being aware of your surroundings are most important. Driving SLOWER is most important. You dont drive with the FLOW of traffic, you drive with at speeds that are SAFE for you. When my car has new tires, I drive 90 on the freeway because I am happy knowing my car rocks and things are setup nice.. I sometimes drive faster. When my car is setup ALL WRONG like it is now, where my front tires are ass-bald, I drive REAL slow and dont even bother doing things like going on the freeway. YOU are responsible for knowing your car.

Sidenote: Not having power steering makes feeling your car even easier. When my brakes lockup, the steering feel is COMPLETELY ovbious, 10-fold then when I had power steering. Not having PS makes knowing your car MUCH MUCH easier.. for those of you who always ask why I dont have PS.

The key here is practice practice practice, get some nice tires.. and practice practice practice. Be more aware. I would say this is a stupid thread, but anytime someone asks for advice that doesnt require spending cash is a good thread.

- Mike

[sykikchimp]

"In a spin, both feet in!" (cluth and brake)

this is really one of those saying they teach newbies on track to try to minimize the trouble they get into. It works.

ABS is a good thing to have, but not necessary. Just learn how to threshold brake, and you'll be more than prepared.