I've coasted down many hills in my life... i've yet to lose control of my car.
The only time I didn't coast down a hill was down a mountain... It really depends where you coast at... if you coast down a steep but yet short hill... thats fine.
A long hill... im abit fidgety about it. I drive a porsche boxter and do not entirely trust the brakes... because if those fails... im screwed.
So both are you are right... And both of you are wrong.
And why the need for accelerating? When you have to make an emergency manuver... aren't you supposed to use braking and steering? Atleast thats what I was taught.... and what you'd go read in any manual.
Emergency manoeuvres require the driver to have full control of their vehicle, which includes the ability to control steering, braking, and throttle. If you coast, you lose the ability to control the throttle, and as a result your ability to recover from a skid or utilise engine braking to reduce speed, is lost.
If your vehicle is in motion, you should be in gear.
Let's say you are coasting down a hill when you spot a kid on a skateboard cruising down the side of the road. Being an observant and defensive driver, you take appropriate measures to reduce speed to accommodate this hazard. If your vehicle is in neutral, then this means you are relying on brakes only; or if you have to put the car into gear, you lose both time and attention because of this extra task. On the other hand, a competent advanced driver whose car was in gear when going down this hill will be able to use engine braking to modulate speed as well as the brakes, without any loss of time or attention, while in full control of the vehicle at all times, ready to respond to any unexpected changes (such as the kid falling off his skateboard into your path).
Good defensive driving practices are not just for driving under normal conditions. Their rationale is built on being prepared for the worst case scenario.
That example is nonsense. If the kid falls off into your path then you either evade if it's too close or you do an emergency brake. When doing an emergency brake, you push both the clutch and brake pedal fully, disconnecting the engine anyway, so in that case it doesn't matter whether you're in gear or not.
If your attentive slowing down due to the existing hazard is accomplished via engine and foot brake or foot brake only is completely irrelevant.
Bingo! If you aren't mashing both feet down and feel the need for "control" in that you think you are going to downshift through the gears utilizing engine braking, you are not concentrating on stopping as quickly as possible and are not going to stop as quickly as possible.
With the talk of leaving it in gear when stopped in case another vehicle is barreling down the road behind you, either you are driving in traffic or you are not driving in traffic. In the case of driving in traffic, the chance that you are the first car sitting is very slim. There will be other cars in front of you, thus there is no where to accelerate too. In the case of driving with no traffic, the chance that another vehicle is bearing down on you from behind is much slimmer, and also, it means that you probably aren't going to be stopped very long and will be in gear anyways.
So this entire discussion is really a waste of time. So, leave it in gear when going downhill as if you put it in neutral, by the bottom of the hill you will be doing 100 mph if not, or putting unreasonable wear and heat into your brakes. Take it out of gear when sitting at a stop in traffic because there's nothing you can do anyways with cars stopped along with you all around. And finally, leave it in gear when not in traffic because you aren't going to be stopped for long anyways with no traffic.
Samjh, if I see a car skidding out of control infront of me, my natural reaction is to hit the throttle.... No thats not my natural reaction, my reaction is to brake or manuver around it. If theres no way to possibly avoid an accident i'll try and slow down to the slowest speed possible. In an accident that cannot be avoided using the throttle would only make matters worse im afraid.
It would take me way less than a second to put my car into gear, thats both hands on the steering wheel and foot away from the clutch. (Which while I coast I have my foot on the clutch and stick the whole time.)
To be honest, I must ask you where you learned to drive.
It's great to conserve gas down that hill, but if it's a long hill with a couple of twists, it's probably best to stay in gear. But it's just a long straight steep hill, i'll just get up to 85-90 sometimes 95mph and consider putting back into gear.
I never mentioned hitting the throttle. If you have the car in gear, the engine will assist in your braking. You will slow down considerably faster if you have the engine in gear, than if your car is in neutral or you smash your clutch immediately. This is part of utilising your throttle to maximise control of your car.
That "less than a second" can mean the difference between hitting something and stopping a few inches short.
I would think twice about travelling down any public road at 95mph unless it is somewhere like an autobahn.
It matters. I say again, your engine helps you to brake. The difference may seem insignificant when posted on a forum like this, but practical experience says otherwise.
I will start this off on the beginning topic and work the flaming from there.
It is more economical to use higher RPM and less throttle. If any of you have done ECU programming you would obviously know that. The more load that is applied to the engine the more FUEL and less ignition advance is applied.
Perfect example: Car is supercharged.
Going up the hill in lets say 3rd gear doing lets call it 3500 rpm, at that RPM the engine is happy to maintain the speed without major throttle input (lets call it 20% throttle).
Now, for the same car going up the same hill in high gear at lets say 1200 rpm, the engine is not happy doing that low of RPM so you apply throttle to compensate for the lack of power, well guess what you are pushing that pedal down quite a lot more (lets call it 40% for the hell of it) well, you are screwing yourself, power enrich cut in at 35% throttle and you are dumping lots of fuel in now!
(I know, N/A power enrich is at around 80-90% throttle in fairly modern cars)
Slipping cars into neutral going down hills all depends on the car and the hill. You can do whatever pleases you. On steep mountain roads I do one up on you turkeys! I leave the car in gear AND turn the ignition off, Power brakes work, power steering works, speedometer works (*cough*in some cars). I would not suggest turning the ignition back on while still in gear with the engine rotating as your muffler may go boom boom.
Still I see no point of slipping a modern car with fuel cutoff into neutral going down hills
If your car does not decelerate when you let off it is probably made in japan, or you are in america and the car has an automatic.
I have been messing around with tuning cars and it is up to the tune as to if your car barely slows down when you let off or if you let off and your face impacts the steering wheel.
Now the freakin guy who said holding his clutch in is a great alternative to slipping the car into neutral will NEVER be allowed near any of my cars and should be shot.
Go ahead force that crank into the front engine bearing, dig the deepest rut into that crankshaft as you can! Take out every rod and main bearing, that's right keep going until the thing starts knocking! You think I am kidding? Think again.
Hahaha, all so true! I have been in a situation where if I reacted half a second later to some idiot in a Lexus that panic stopped right there in front of me of me, the world would have had one less annoying Lexus with those blinding junk headlights. (I was in a large pickup truck loaded with one heavy load of iron cargo)
I beg to differ. You should try my heater! My brakes do work very well too but so does the engine. Only thing that has gone wrong is my A/C relay and the previous owner neglected to change the timing belt...
I probably missed a couple points which I am sure someone will point out in the near future.
How can you question how others drive when you're near as makes no difference hitting 100MPH on public roads? That is just ****ing stupid in the highest order. More so as you just said you leave your hand on the gear stick, which means you're trying to control a tonne and a bit with one hand while rattling down a hill at those speeds.
You are an utter tool and should have your licence taken off you.
A. Apply for provisional licence - allowed to drive with an experienced driver in the passenger seat.
B. Take lessons of some form.
C. Take Theory test, which includes
i. A one hour mulitple choice exam with 50 questions, pass mark is 43.
ii. A hazard awareness test where you're scored on your ability to judge 15 potential hazards before they actually happen in 14 clips of simulated drives on real roads. Maiximum marks is 75, pass is 44 marks.
You have to pass both parts at the same sitting, to gain your theory test.
Theory pass gives you two years to pass your practical test.
D. Practical test. Involves 40-60minute drive on real roads, (though not motorways), including two standard reversing manouvers; eyesight test, and vehicle knowlege test (e.g. how to conduct a tyre wear test, oil level/tyre pressure/steering/ABS/Brake tests).
That last one... was completely fake. It was to show that someone like you has to be right and will be right. I knew exactly someone like you would try and pick it apart, without even me giving details.
And what right do you have to assume if I have a license? I love how you just assume everything. Jumping headlong and having to be right.
I love this part "when you're near as makes no difference hitting 100MPH on public roads?" first off where did I say that? Or are you just trying to exagerate and make things look worse for me? Where did I say public roads? And where did I say I was going 100 mph?
And I questioned him where he learned to drive, which could have been a negative comment... but you took it upon yourself to make it into one.
Sir/Ma'am, I waited for someone patiently like you.
If you were waiting for something like that, I might suggest you get a job as you're wasting your life.
I say near as makes no difference because when you cream into an object it really will be. The end result is the same.
Questioning where someone gained a qualification means that you doubt that creditability of that institution and that if they tried to gain said qualification elsewhere they would have failed.
The rest of it, to me, sounds more like you peddling your story in an attempt to hide the fact you're a ****wit.
But that is just my view on this event. Good talk.
That wasn't really to the point, was it? More of a reaction, rather than a reply. It's not my discussion, but from an outsider's point of view, you're losing. Calling people names isn't a valid debating method either.
In your attempt to prove that you were smarter than me, you failed.
"If you were waiting for something like that, I might suggest you get a job as you're wasting your life." - P5YcHoM4N
What makes it different for you? Clearly when you posted that first post, that was to make me look like a fool. You were waiting for my reaction, that is what I got from it, ONLY it backfired.
"I say near as makes no difference because when you cream into an object it really will be. The end result is the same." - P5YcHoM4N
Yet again, am I driving in a desert with no objects around or am I driving around abunch of trees? I didn't give details, so what right does that give you to go ahead and contemplate? How is the end result the same? 5 mph faster will obviously not be the same.
"Questioning where someone gained a qualification means that you doubt that creditability of that institution and that if they tried to gain said qualification elsewhere they would have failed." - P5YcHoM4N
Maybe I just wanted to know where he learned from? Am I not allowed to be curious?
"The rest of it, to me, sounds more like you peddling your story in an attempt to hide the fact you're a ****wit." - P5YcHoM4N
Why call me names? I have no clue what that means but whatever. I'm not trying to hide anything but rather expose you're a fool and a troll on these forums.
All safety issues aside, its moronic to go down a hill in neutral for this single reason:
Going downhill in neutral uses gas.
Going while engine braking uses _NO_ gas. zero. zilch.nada.
The weight and inertia of the car is pushing the wheels, and the ECU just turns off ALL fuel to the engine. You will be driving for free!
What eats fuel is your right foot, so higher revs, less throttle. The less you push the accelerator down, the better.
To add, engine idle rpm provides just the minimum of oil pressure. Idle oil pressure isn't spec'd for a moving engine that is subject to cornering forces. There is a safety margin of course, but to argue that neutral causes less engine wear is plain ridiculous.
Another thing is weight transfer, no matter if one acellerates or decellerates, an engine that is in the proper gear will allow for a smoother drive (Think rain, snow, ice, or on a track, potentially higher cornering speed).
Third thing point has already be discussed, brake temperature and wear are greatly reduced by letting the engine do most of the job (which, unlike brakes, has a purposely made water and/or oil cooler to get rid of the heat and doesn't have mechanical wear because it's only compressing and expanding air)
:jawdrop: BS much?
For one you can put about any car in neutral and fling it around a corner as hard as you can and you won't lose any oil pressure, modern oil pans have baffles to keep the oil in the lower portion of the pan where the pickup is. The oil passage ways in an engine do not care what g-forces are going on, as long as they are not blocked and the oil pickup is still in oil you will not lose oil pressure or flow around a corner.
The only time I have seen any oil pressure loss is going balls to the wall around a corner and sucking the oil pan dry, or the engine gets hot and the oil gets thinner and you will lose some pressure there.
For the second part of that quote, as long as the engine is cranking around there WILL be wear to one part or another.
An engine is always "compressing and expanding air" The only difference is when you add fuel it creates heat in the process. Either way, there is wear to your piston rings, bearings, oil pump gears, timing chain (and or belt), camshaft, lifters, etc.
I am not trying to pick fights here, I am just trying to get some facts straight.
What is the oil pressure of your car at an idle? My cars range from 55-80 PSI at an idle. That is the "minimum" sure but it is not anywhere even close to being a low pressure at an idle.
You don't need much oil pressure at idle. Most cars, when warn, sit at around 10 - 15psi. It's only really needed to overcome the centrifuging of the crankshaft drillings, and at idle there isn't much centrifuging going on (due to the low speed of the crank).
I've not said anything about losing oil pressure. My argument is that the oil pressure of an engine at idle rpm may not be enough to keep camshaft or crankshafts and the engine block from making contact and therefore causing what I consider real wear. Once any of these parts have touched and ripped away material, the process usually can't be stopped anymore.
It's certainly true that an engine has some wear from simply running. But have you ever seen broken engine that died from "normal" wear? Usually the car rusts away long before an engine that was properly treated starts to become a problem. (And if so, all it usually takes is a little honing and larger pistons, maybe new valves)
What I think I got wrong is that air gets compressed while engine braking. It's gets expanded in the step where the air fuel mix usually ignites. That should also produce some heat.
My bike engine has about 10-20psi in idle, depending on oil temp and viscosity, going up to 110psi at 10500rpm. I somehow doubt your car has that much oil pressure on idle, but it's a possibility to gear it that way and use a pressure sensitive valve to keep it in a sane range at full load.
Anyway, most modern engines have such low (may I say boring?) power/displacement values, and manufacturers make sure that even cold engines can take lots of abuse, so all this may be moot for them.
Yours is right when a stop becomes a wait put the handbrake on anf pop it out of gear.... about four seconds is a good rule of thumb. And all this from a driving instructor.
Beemer drivers can test this out. Drive down a hill in neutral at say 20 mph and the needle will move off the stop as fuel is needed to turn the engine over. Pop it into 4th 5th 6th and it moves back to 1,000,000 mpg
Also when I was driving in Italy recently I reset the fuel mpg at the top of the San Carlo pass. I then drove down (some 1500m altitude) and the average mpg didn't budge from 99.9 mpg for 20 minutes after hitting the flat.
Not such a simple answer, it is a combnation of tourque and power. Your throttle setting as well as your gear are dependent on the the power to tourque curve as supplied by your vehicle manufacture. One thing about modern cars / engine is that they almost never give you tourque information, althought, all automatic gearboxes need this information but normally get it from a vacume sensor.
Simple answer.... keep it centered in the power band, this is the area that the engine produces maximum tourque for minimum revs, and before anybody says it, yes this is a very simplistic answer but it does help most pepole that are new to the subject.
Long may the subject roll on.... as i am sure it will.
since my avrg raised from 9,3 l/100 km to 10,1 l/100 km now i try hardcore low rev
i never rev above 1800 rpm...that means a lot of shifting but if its worth it i dont care
usually cruising in the city at 50 kmh at 1400 rpm in fifth.
lets see if its any good.
