Driving in Neutral good or bad?

Karthik - Hi Everybody!!

I own hyundai Getz 1.3 Petrol, having a doubt on low warning lamp.  Need to know how much petrol in liters / How much KM can drive after getting low fuel warning lamp lights up.

Hi Karthik, There is about 6-7 litres of fuel in almost all cars after the first indication of low fuel.

However, I would caution you against testing it out personally, as when the fuel goes real low, the 'kachra' sundry debries lying on the bottom of the fuel tank can get sucked in the fuel line, and you may end up with worse trouble like engine misfiring or outright stalling, which could be really inconvenient if it happens in the middle of nowhere.

Keep it a practice to go back to your favorite fuel station and tank up right after you get your low fuel indication. The 6-7 litre reserve is also designed to keep it this way, as not many would need an indication for refuelling at about 100 km from the point where you run out of fuel.

Ravi:

For starters, I have already indicated that switching off the engine is an extreme action, not recommended to those who do not understand all of its consequences.

I do not understand how driving in neutral automatically results in overheating of brake pads. Driving in neutral does NOT mean driving with your leg on the brake pedal.

I have already indicated that DFCO suits better for driving down a mountain or a steep slope.

As far as following the owner's manual goes, I would like to know what your vehicle and its gear shift points as per owners manual are, and if you scrupulously (your word) follow those shift points. Would sure make interesting reading.

Gouri:

whether to coast in gear or neutral is a choice one makes, depending on the comfort level one has with coasting in neutral, and individual driving style. Aggressive drivers/riders are better off coasting in gear, and sedate drivers will do much better with coasting in neutral.

Nilesh:

When you switch off the engine, you are making a personal choice to save fuel at the cost of attention and focus on driving, to take care of contingencies like that. There are a few points on needs to pay real attention to, and it is a skill one acquires with practice. Safety is prime concern, and if your vehicle cuts off brake assist and power steering on engine switch-off, it is much better to stick to engine-on coasting.

A good strategy is to bump the engine ON right when you need the steering/brake assists. Brake assist is generally available to first two-three actuations after switch-off, before the vacuum dies out.

Nice said Ravi. However as far as the driving in neutral to save fuel is concerned, when your car is in neutral, it does consume a minimum fuel in idling or idle running of the engine. Now when you speed up your car to attain certain speed before going to neutral, you have already spent a lot of fuel just to speed up. But when you do not accelarate, or when you do not need to accelarate, not much fuel is used, as no additional work is done by the engine.

Driving in netural increases usage of brakes resulting in its overheating.  I do not want to save fuel at the cost of occupants' and other road-users' lives.  I learnt the alphabets of car driving in Austin A40, have driven extensively in Standard Herald, Fiat 1100D, HM Ambassador, Maruti Suzuki Omni, Maruti Suzuki Versa and now I own Fiat Linea.  I have been a careful, and hence, successful driver for more than 40 years without any accidents/endangering occupants' or other road-users' lives.  Yes, I do scrupulously follow the owners' handbook.  Period.

Thanks, adilip.  I never drive in neutral or with engine switched off.

Why exactly? Unless one is careless enough to accelerate to a speed not sustainable due to prevailing traffic, braking is not required. Driving in neutral cannot result in increased usage of brakes automatically. It simply conserves momentum to save energy, giving better FE.

I particularly asked about the gear shift points (in speed and RPM) as recommended in owners' handbook. This data is not practical in my car's case, so I do not follow it. I am sure it is similar in your car's case too, hence I asked for it.

And you skirted the question.

there are many fly overs in mumbai,and i have his guy in my class who has to cross 5 flyovers to come to college.He has this habbit of putting the car in neutral while coming down each flyover.i dont know how smart/foolish is to do such thing,always wondered about it.

Thanks Krishna!!

Can you please suggest your views on the usage of N2 gas for car tyres.

does this increase the performance / mileage or is there any draw back?

- Karthik

@Krishna,

IMO one should not drive in neutral (to save fuel or otherwise). Its better or safer to still let the engine control the car's motion. Another point is that in neutral as the engine's RPM drops, suppose the car is at some low speed but the gear position does not match that speed (it is still the same as it was when you put it into neutral) - what will happen once you put the car in gear then?

Regarding fuel saving, in neutral you still burn the minimum idling level fuel. However while coasting allowing the speed to come down with engine braking can save fuel depending on how much one allows the speed to come down - too much down you have to accelerate more to come up to speed. However if, say in 5th gear one is going at 60kmph, allowing engine braking to bring down the speed to 55kmph and maintaining that for some time and then gradually touching 60kmph (and repeating this cycle) will save some fuel. I do this all the time.

And on slopes let the engine control the speed - this is where most savings occur - depending on throttle position (if the RPM is above the throttle pos, the fuel will be cut off and if the RPM is lower, the engine will use some of the car's inertia - rather the natural acceleration due to gravity - to accelerate with a much milder throttle push than on a flat road)

Have a look at the relevant thread - it will help/guide.  Needless to add, discussion on the same, if any, may please be carried out in that thread.

I read this some where : Fuel consumption is less when the car coasts in top most gear (gear with overdrive) when compared to engine idling (car coasting in Neutral).

While on a long drive : Better be safe doing this (Coasting in Top most gear) rather than getting distracted to mantain high FE (periodical monitoring of speedo and shifting gears/switching on engine).

@Gouri

Driving your bike in top gear is safer than coasting in Neutral. Lord Krishna would second me on this, but I doubt about what Manus Krishna would post!