Jay481985 Posted June 21, 2006 Share Posted June 21, 2006 actually drwho, you want weight shifting as per panick braking. When the weight transfers to the front while heavy braking it is better as it puts pressure on the front wheels which means the tire will grip harder making it thus brake better. Rear brakes do very little of the braking. First of all, if anyone ever "panics" in a car they deserve to crash. And the problem with that logic is you are ignoring the effect of shock rebound and the physics of friction. Shifting the weight to the front tires doesn't improve braking by putting more weight on the front tires because it is also taking weight off the rear tires. The car weighs N pounds and friction is a linear correlation to a vehicles weight and is not affected by surface area. No matter where the weight is distributed there is the same maximum friction potential - which means the car will stop just as fast regardless of which tires have the weight on them. What you really want to do with evasive manuvering is keep the car stable - which means keeping the suspension out of rebound and controlling the momentum of the car. Mashing the brakes compresses the front suspension very far and will be compounded when the gear lag catches up (when you hit the brake too fast). brake torque good for the transmission??? no..... Everytime your car sits still with the engine running the brake torque is engaged. It is designed to brake torque all the time. Sure, dragging itself isn't good for the car, but the way to cause as little damage as possible involves a fully reved brake torque as it prevents gears from slamming into each other and minimizes tire spin. It also happens to be faster too... Dodge has a very good driving school that should be a part of drivers ed where they go over all of this stuff. It'll also lower your insurance costs too. Oh boy..... where to start...... Brake torque is not applied when you are stopped and have your foot on the brakes. That would destroy you car and destroy your transmission and destroy your engine all at the same time. Try that method in a manual car and watch how fast you brake the clutch or worse the transmission. Go put your foot on the brake and gas with the clutch not engaged and rev it up there. Watch as you hear something tear apart and you have smoke coming from the clutch as it burns up. Without the torque convertor acting like a clutch in an automatic you will not move. The torque convertor allows the transmission to slip the force of teh engine while it is stopped First of all, if anyone ever "panics" in a car they deserve to crash. And the problem with that logic is you are ignoring the effect of shock rebound and the physics of friction. Shifting the weight to the front tires doesn't improve braking by putting more weight on the front tires because it is also taking weight off the rear tires. The car weighs N pounds and friction is a linear correlation to a vehicles weight and is not affected by surface area. No matter where the weight is distributed there is the same maximum friction potential - which means the car will stop just as fast regardless of which tires have the weight on them. Next, Panic Braking is a term used in the industry, it does not mean panicked person. Oh please, I am sure you never had a near miss experience that you never had the nerves scared straight? Yes I know that the weight of the car is shifted cause you take it off the rear. Hence why the brakes on the rear of every car is smaller in brake pads and less powerful. Actually in 9.99/ 10 cars sold in the world the brakes in the front are always more powerful than the breaks in the rear to cause a predicatably understeer as opposed to having brakes that are the same power, you never ever have brakes more powerful in the rear, that cause oversteer which is alot more unpredictable. What friction are you talking about there? friction of the brakes? or surface friction? No matter where the weight is distributed there is the same maximum friction potential - which means the car will stop just as fast regardless of which tires have the weight on them. this needs to be explained by you further. I think you are going by absolute physics from a book thinking that there is nothing like suspensions, more than two vectors, etc. I think you are thinking of a computer model that shows force x and force y without any other force vectors. With that notion, front wheel drive should behave just like rear wheel drive. Even though RWD is much more prefered on any race condition other than rally. When a RWD car accelerates the fact that the weight of the momentary acceleration shifts the weight to the rear of the car enhances traction that will in turn have more grip to reduce the wheelspin and put more power on the road. Notice there are not any stock 400 horsepower frontwheel drive cars? That is because FWD when accelerating have a. torquesteer, b. wheelspin, c. wheelhop, d. massive uncontrollable burnouts. etc etc etc. Remember again that the car suspension has to do alot with it, if we did have a Fred Flinstone car then no there would technically be no difference. What you really want to do with evasive manuvering is keep the car stable - which means keeping the suspension out of rebound and controlling the momentum of the car. Mashing the brakes compresses the front suspension very far and will be compounded when the gear lag catches up (when you hit the brake too fast). First you should always disengage the gear while braking. It is not good and you will hurt the engine in the long run and gear lag happens when the engine stops quicker then the transmission that is still engaged to the wheels. The engine can slow down alot quicker than the transmission hence when you stop with the car still in gear the engine will need to catch up to the wheels again hence the lurch. Yeah yeah keep the car stable, lotus had that idea in the 1970 in the indy event. Yes you can keep the car stable but you must know that that is a sports car, No one not even the hardcore drivers will drive a fully tuned sports car meant for true racing as their daily drive. There was a funny thing about UK people trading in their evos to get sti because their *** could not bare the suspension anymore [] Having a fully stable car is one thing having a car that absorbs every bump, crack, etc is another. Its called I like to have feeling in my spine when I step out of the car TYVM. Since its a fact that cars will be inherintly unstable, even racecars in extreme manuevers, you must therefor account for those instability problems and work to try and maximize the ability of the car in the particular environment. 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Jay481985 Posted June 21, 2006 Share Posted June 21, 2006 sorry DP Quote Link to comment Share on other sites More sharing options...
DrWho Posted June 21, 2006 Share Posted June 21, 2006 Jay, you keep talking about different irrelevant things all the time and assuming my perspective...I don't ever like to rely on my own experiences as I've only been on this Earth for 22 years. Everything I mentioned was discussed in driving schools where they have a crap load more experience... And I think you need to take a look at how the stall torque converter works and why it is installed in cars with automatic transmissions (which is what we're talking about). Automatics don't disengage when you hit the brake and the gear lag to which I'm referring is the engine's momentum pushing the car forward when you instantly slam on the brakes too soon after accelerating (ala 2 foot driving). And the stall torque converter doesn't disengage the second you hit the gas pedal - for example, my old monte carlo idled at 400 RPM and stalled up to 1500 RPM. It is no different to hit the gas from a stop and start moving before the RPM hits 1500 RPM than it is to hold the brake and prevent movement until 1500RPM. Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted June 21, 2006 Share Posted June 21, 2006 automatics allow for slippage to prevent damage. As with relying on one's own experience, its great to learn from others but one day it should be your time to give answers. Quote Link to comment Share on other sites More sharing options...
maxg Posted June 21, 2006 Share Posted June 21, 2006 Left foot braking - why? The Version from the other side of the pond. Well first off - to disagree with almost all of you - there is almost no benefit in an automatic car - only in a manual!!! Here is how it started (to the best of my knowledge): During early 70's the world rallying championship was dominated by the "Fying Finns". They had discovered(?) that you can get better performance out of your car by braking with the left foot whilst crashing the gears (i.e. no use of the clutch at all - other than for starting off). Basically to go from 2nd to 3rd you can pull the car out of gear and time the revs as they fall to snick third. If you do that well there is no way of telling you didnt use the clutch. Any of you with a manual can try this without doing the left foot braking manoevre as it doesnt apply here - you are increasing speed and therefore climbing the gears. I only mention this process as it is relatively easy to achieve. Going, for example, from 3rd to 2nd gear, however, needs a bit more skill. Whilst braking with the left foot you knock the car out of third and blip the throttle (accelerator) allowing you to crash into second gear. This is where the Finns gained the maximum advantage. With practice you can cut the change down times by about a huge amount and your car is always in "drive" thereby maintaining better control. As you release the brake pressure you are immediately propelled forwards as the throttle is already despressed. In those days cars only had 4 gears - so the biggest ratio swap was from 4th to 2nd - this was also the hardest to do properly. Get it right, however, and the benefit whilst racing was enormous. How do I know all of this? Back in the day (in my late teens) I was a rally co-driver with a friend who had a very hot rally car at the time (230 bhp Sunbeem Lotus if anyone has a clue what that was). We spend a happy day practicing this very manoevre - most of which was spent thanking God for the 6 point harnesses that kept my nose from the windscreen when the driver hit the brakes too hard. Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted June 21, 2006 Share Posted June 21, 2006 max, you did not do heel and toe? and as your method, yes its very quick but get it wrong in a corner and thank god really for eht 6 point harness and not just the nose. Quote Link to comment Share on other sites More sharing options...
maxg Posted June 21, 2006 Share Posted June 21, 2006 max, you did not do heel and toe? and as your method, yes its very quick but get it wrong in a corner and thank god really for eht 6 point harness and not just the nose. Jay, Many do heel and toe - even now - but we found that there was ultimately less control trying to do 2 things with a single foot. I guess it is whatever works for you - but at the time it was the Finnish way or no finish!! Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted June 21, 2006 Share Posted June 21, 2006 max, you did not do heel and toe? and as your method, yes its very quick but get it wrong in a corner and thank god really for eht 6 point harness and not just the nose. Jay, Many do heel and toe - even now - but we found that there was ultimately less control trying to do 2 things with a single foot. I guess it is whatever works for you - but at the time it was the Finnish way or no finish!! [] oops I got terms mixed up I mean doublt declutch. But the gear change without a clutch is risky but if your a great driver, its easy. Quote Link to comment Share on other sites More sharing options...
efzauner Posted June 22, 2006 Share Posted June 22, 2006 Dated a girl in HS who did it. Never really noticed until she did hit both the gas and break at the same time. Could see how you would find that annoying. BTW buy him a 6-speed manual corvette, not a five speed. Didn't many Audi drivers do that while in reverse? Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted June 22, 2006 Share Posted June 22, 2006 A 5 speed Corvette, or Porsche 911 will cure that........... I can't find a 6 sp. C4 vette...... keep a look out for a 90-96 black stick model for me ...ok ...??? R U serious??? I do know of a couple..................... Black, 90-96, for sure , Mr. oldbuckster, Please ......[] Quote Link to comment Share on other sites More sharing options...
oldbuckster Posted June 22, 2006 Share Posted June 22, 2006 DUKE, consider it Done..........[] Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted June 22, 2006 Share Posted June 22, 2006 $$$$$$$$$$$$$$...........[] Thank You ....!! i shoulda bought the black 6sp. '88 i looked at 10 years ago... my L-98 auto coupe is kinda boring now........... ........................................................................that i'm used to taking 30 mph corners at 80 mph Damn... cain't get them big tires to even squeal .... Quote Link to comment Share on other sites More sharing options...
seti Posted June 22, 2006 Share Posted June 22, 2006 DO NOT SCARE THESE 2 FOOTED DRIVERS WHILE THEY ARE BEHIND THE WHEEL OK so I just went to pick up some coffee after reading this thread and since traffic was light decided to try two footed driving [:^)]............My neck hurts......[:$] Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted June 22, 2006 Share Posted June 22, 2006 I usually run with both feet Quote Link to comment Share on other sites More sharing options...
Klipschguy Posted June 22, 2006 Share Posted June 22, 2006 Interesting discussion. Just 2 more cents... I just can't help myself. When a driver is confronted with a split second emergency situation stop, a drivers foot needs to be OFF the gas pedal. During a split second stop to avoid an accident, a two footed driver will have the dangerous tendency to push the gas with his right foot and the brake with the left - not good. Citing ideal racing techniques has little to do with "Oh my gosh! That child ran right in front of my car!!!" On the track, in a more controlled environment, kids don't run in front of cars. Also on the track, one is absolutely focused on operating the car and its slightest feedback. Daily driving, even good daily driving is not so focused as racing. To further illustrate, notice that we have widespread antilock brakes because people have the less-than-ideal tendency to "lock 'em up" during emergency accident avoidance situation. During an emergency stop people don't normally say to themselves "huh, refecting back on my race training, I will modulate the brakes impending lock-up for optimal stopping distance." No. They just nail the brakes and pray. (Hopefully without one foot on the gas and the other on the brake.) Quote Link to comment Share on other sites More sharing options...
r.cherry Posted June 22, 2006 Share Posted June 22, 2006 i use both techniques, sometimes due to the vehicle, other times due to my right leg being a bit funky from a sporting accident in my youth. i find it preposterous to imply that someone braking with their left foot is somehow driving in an inferior manor. there are so many things being done poorly by by so many people while driving, that which foot they use to brake with doesn't make the radar screen with my bytch list[] Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted June 22, 2006 Share Posted June 22, 2006 During a split second stop to avoid an accident, a two footed driver will have the dangerous tendency to push the gas with his right foot and the brake with the left - not good. Also alot of people have the tendancy using one foot to press on the gas because their feet act like a deer in front of headlights, they think that their foot is on the brake but its not [] Citing ideal racing techniques has little to do with "Oh my gosh! That child ran right in front of my car!!!" On the track, in a more controlled environment, kids don't run in front of cars. Also on the track, one is absolutely focused on operating the car and its slightest feedback. Daily driving, even good daily driving is not so focused as racing. To further illustrate, notice that we have widespread antilock brakes because people have the less-than-ideal tendency to "lock 'em up" during emergency accident avoidance situation. During an emergency stop people don't normally say to themselves "huh, refecting back on my race training, I will modulate the brakes impending lock-up for optimal stopping distance." No. They just nail the brakes and pray. (Hopefully without one foot on the gas and the other on the brake.) Actually its been proven that most drivers do better locking their wheels up then to have abs. Most people never realized how or what abs is, just that they have it and its supposed to do something. Then when they need it, guess what they go WTF my car is breaking, cause the gears are pulsing the brakes that most people actually let go of the brakes and hit the object at a faster speed then if they had just locked their tires up. Its a double edged sword. Those that know how to use it will stop faster and benefit, those that have no clue tend to have a worse accident. Quote Link to comment Share on other sites More sharing options...
meagain Posted June 22, 2006 Author Share Posted June 22, 2006 And how do you use/not use your ABS 'right'? ??? In my car - there's no options. I had a bad ABS episode recently. My first near accident in a zillion years. I hit the brakes. Darned abs kicked on as if I was on ice... did the pulse thing... It seemed like it took forever to stop that car. I still feel I could have stopped better without the abs giving me all the leeway. Yes, I might have made a skid mark, but my gut says I could have stopped quicker had they been disabled. Quote Link to comment Share on other sites More sharing options...
Klipschguy Posted June 22, 2006 Share Posted June 22, 2006 Hey guys, I'm not trying to cast stones. One of my best friends used to be a two footed driver for years (until he got a manual) and I have always considered him an excellent driver - including accident avoidance. Your points are certainly valid and are dancing around the issue "there is no substitute for skill through experience." As far as ABS, it is a good idea to try it out to see what it feels like. When I teach my children to drive it will be with one foot for the gas and brake. Some simulated panic stops will also be part of the training. BTW, thank you for pointing out the "pulsating pedal" deal - that is a real concern requiring a little education. The list of bad driving habits is endless, some much worse than others, and we all have to deal with it. Anyway, back to Klipsch speakers where drivers of all types are welcome. Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted June 22, 2006 Share Posted June 22, 2006 And how do you use/not use your ABS 'right'? ??? In my car - there's no options. I had a bad ABS episode recently. My first near accident in a zillion years. I hit the brakes. Darned abs kicked on as if I was on ice... did the pulse thing... It seemed like it took forever to stop that car. I still feel I could have stopped better without the abs giving me all the leeway. Yes, I might have made a skid mark, but my gut says I could have stopped quicker had they been disabled. I know it seems longer and probably is. But the fact that a car is equiped with abs does not mean a shorter stop. It means it is a non locking stop which means that you atleast have some control of the car as opposed to just sliding into whatever. ABS will still have skidmarks too [] just short repetative ones. The one thing with ABS girls and guys is the fact that if you have it on your car press down as hard as you can and let the abs handle everything. Do not let up, most people do and hence a longer stop. Mercedes Benz now has a brake assist that detects how fast the pedal was pressed and then activates full brake even if you lessen up as most do when they hear the clang and shake of the car as the abs engages. Cars without it you should learn the pumping brake method. Also if the car has abs and you pump it you actually disable the abs effects, which is necessary sometimes on things like ice when you need whatever traction there is, your skidding anyways....... Also if you want to learn or teach your kids panic braking methods, please in an empty parking lot with lots of room and try to do it on a day that the rain just stopped but the ground is still wet to not damage the tires. Oh Meagain, if you had locked your wheel you probably would have skided into the thing. What happens when you lock a wheel is essentially what happens to butter in a hot skillet or ice skates on ice. The friction makes the rubber on the tire melt and you essentially glide on a thin layer of rubber making those skid marks. You do not want to do that as first your cars is not not touching the road anymore (like hydroplaning) and second if you do not hit anything you're gonna have a terrible bald spot or a flat spot on your tire that will tell you when it goes flap flap flap as you drive. I love how in car races sometimes to get into the corner faster to beat someone out they go in to fast and deep, have to lock their tires (race cars do not have abs as its banned) and then lose out anyways and have to pit and get a new set of tires. Any more car questions Meagain? I am sorta a car nut to and realize mathematical world and real life experience. Heck I am going to go to another audimeet this Sunday to Pennsylvania, some state park. Quote Link to comment Share on other sites More sharing options...
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