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How to get the Maximum Fuel Efficiency from Your Car

How to get the Maximum Fuel Efficiency from Your Car

How to get the Maxim..

  • 30 May 2016, 43254 Views

Roshun

Super Moderator

Member: 13 Oct, 2015

Total Posts: 2035

  • 30 May 2016, 11:45 am ( 1 Photo )
The one thing most people are obsessed about is fuel efficiency. "Kitna deti hai?" is probably the first or second question anyone asks about a car or a bike. The funny part is that ARAI - the agency that does the testing of every new car sold in India - does not specifically test for fuel efficiency. Instead, the claimed fuel efficiency figures that the agency puts out for a particular car, are a by product of its emissions testing of the car. And these ARAI figures are usually pretty good, bordering on unachievable for the average driver.
But what I'm putting down here are some driving tips to get the maximum fuel efficiency from your car - perhaps even bettering ARAI figures, without resorting to hypermiling techniques (a separate thread on that follows).
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GETTING THE MAXIMUM FUEL EFFICIENCY FROM YOUR DIESEL CAR
Diesel cars are inherently about 25 percent more fuel efficient than a petrol car with similar engine size, owing to the better torque, higher compression ratio and more energy in fuel (38.4 Mega Joules per litre) than petrol (34.8 MJ per litre). If you drive in the right manner, you can get significantly better fuel efficiency from a diesel than you can in a petrol car.
Use that torque
Diesel engines have pretty good torque at lower RPM. Most diesel's these days are turbocharged and produce their peak torque in a limited rev band, usually starting at about 1500 rpm and peaking out at just over 2200 rpm. Look for the torque figure in your car's specifications - if it says 200 Nm of torque between 1850-2200 rpm - that's the ideal rev band to drive the car in. Shift gears to keep the car within this band, don't rev beyond it. In this rev band on your tachometer, what is happening is that the car is producing maximum pulling power, while sipping minimum fuel.
Be gentle on the pedal
With a diesel engine, with excellent torque available from as low as 1500 rpm onwards, you really don't need to floor the pedal. Diesels usually have enough torque to move away from standstill without even touching the accelerator. Use only about 20 per cent of the pedal's travel for the necessary momentum. Don't push it all the way to the floor. Just by riding the torque wave as the revs climb, you can get your car moving while sipping the least possible amount of fuel.
Don't over rev the engine
There's no good in over-revving a diesel engine. In a diesel, getting the best efficiency is all about using the torque in the right way. Torque in a diesel engine rapidly drops beyond the specified rev band. Also the maximum horsepower (Bhp) also comes in much earlier in a diesel than in a petrol, so there is no joy really in revving the engine other than just creating a whole lot more pollution (And that's a really bad word these days). See: Ban on diesel vehicles over 2000 cc
Use engine braking instead of shifting to neutral
Diesel engines have a high compression ratio, which means that if you take your foot off the accelerator, you get much better engine braking. The other advantage of using engine braking (slowing down in gear) is that most engines have a "fuel overrun cut off", where the engine does not use any fuel on deceleration. If you shift to neutral while slowing down - you will not only be using fuel as the engine sips some fuel at idle - but you will also have more wear and tear on your brakes.
Don't ride the clutch
Diesel cars have pretty good torque, that help them crawl along in traffic without having to touch the accelerator pedal. But don't use half-clutch, as this will wear out the clutch plates. Instead, shift to first, wait for a second if needed to clear traffic and let the clutch in completely, once it's moving, let it crawl without touching the pedals. If you have to stop, press the clutch, shift to neutral. That way you will use the minimum amount of fuel, although these kind of bumper-to-bumper traffic conditions are the worst possible scenario for fuel efficiency.
Let the engine warm up
Diesel engines work best when they have reached their optimum running temperature, as diesel engines are compression ignition engines and depend on the heat generated in the cylinder to fire. When you start off, don't accelerate hard. Instead drive gently for the first 10 minutes or more (in cold weather). Trying to accelerate hard will just dump more fuel into the engine and result in a lot of wasted fuel. This is one of the reasons you should not use a diesel engine for very short trips just around the block.
STANDARD FUEL EFFICIENCY TIPS
* Reduce weight in the car. Don't carry around unnecessary junk in the trunk
* Keep the air filter clean, it helps the car breathe better
* Maintain the recommended tyre pressure. Check it regularly. Going up to 2 psi above recommended pressure is also safe, but may be a bit uncomfortable
* Accelerate gently, anticipate your stops and slow down gently. Minimum acceleration, gentle braking
* Drive at the optimum speed, in the highest possible gear for that speed
* Shift gears in the recommended RPM band
* Get the car serviced on time
* Reduce AC use if possible (but don't get too uncomfortable)
* On the highway, keep windows closed and use AC, as it reduces wind resistance, while AC use won't really increase fuel consumption too much at highway speeds
GETTING THE MAXIMUM FUEL EFFICIENCY FROM YOUR PETROL CAR
Squeezing maximum fuel efficiency out a petrol car is far more difficult than it is in a diesel car. The thing is petrol engines develop their peak torque at higher RPM and petrol itself is about 25 percent less efficient than diesel (see above). However, lately the advent of turbo-charged petrol engines has managed to solve some of these issues of lower torque, by increasing the compression ratio, making combustion more efficient. Also technologies such as direct injection petrol engines have also managed to improve fuel efficiency to quite an extent, along with reducing emissions.
Don't be in a hurry
It is tempting to floor the pedal and take off with a petrol car, given that they are far more free-revving compared to heavier diesel engines. But if you can, don't use more than 20 percent pedal input and move away gently, shifting gears quickly to keep it moving and at the minimum possible rpm for that road speed. Of course, you risk being honked at by a car behind for moving away too slowly in city traffic.
Don't wait for peak torque
Petrol engines (non-turbocharged ones) make their peak torque much higher in the RPM band compared to diesel engines. But you really don't have to wait for that torque. Lower down in the rev-band you still will get about 60 percent of the available torque, which is enough to move away. For example, most mid-size sedans with 1.5 litre or 1.6 litre petrol engines will have their peak torque beyond 4000 rpm. But you don't need to wait till that RPM to upshift. You can shift at about 2200 rpm and still get more than half the useable torque to move, except if you are in the hills, where you will need more torque to climb. Shifting early will help you burn less fuel.
Don't idle for too long
Unlike turbo-charged diesel engines, naturally aspirated petrol engines don't need a period of idling to cool off the turbocharger. Hence you can instantly switch the engine off when you don't need it, even at a traffic signal that is longer than 45 seconds. For shorter signals though, don't switch off the engine, as you would use more fuel re-starting the engine - the same amount of fuel almost as it would use in 30 seconds of idling.
Use engine braking, don't free wheel
Try to slow down in gear, by just taking your foot off the accelerator. This way, the fuel overrun cut off (all fuel injected cars nowadays have it) will cut off fuel to the engine. If you shift to neutral and go heavy on the brakes - you will not only increase brake pad wear and tear, but also use more fuel to keep the engine idling.
Take a load off the engine
Use the air-conditioning only when you really need it. When accelerating away from a traffic signal, switching off the AC compressor will help reduce load on the engine, until it gets to cruising speed. On the highway, keep the windows up and use the AC. Keeping the windows open would increase wind resistance and therefore fuel consumption, while the additional amount of fuel the AC would use at highway speeds is negligible.
Share any more fuel efficiency tips you have in this thread, and also let us know the best and worst mileage figures you have got with your cars.

Roshun

Super Moderator

Member: 13 Oct, 2015

Total Posts: 2035

  • 30 May 2016, 3:54 pm
I will start with posting the best and worst mileage figures on my cars. All figures are from tankful-to-tankful mileage calculations.
Mahindra Scorpio S10 4WD (2015): Best: 14.1 kmpl (with AC, highway run); Worst: 10.7 kmpl (bumper-to-bumper traffic mostly, with AC on very hot Delhi days)
Mahindra Scorpio DX CRDe 4WD (2006): Best: 12.8 kmpl (with AC, highway run); Worst: 9.6 kmpl (bumper-to-bumper traffic)
Maruti Wagon R LXi (2002): Best 17.1 kmpl (with AC, highway); Worst: 11.2 kmpl (bumper-to-bumper traffic, with AC)

MotuSid

Hot Hatcher

Member: 02 Nov, 2015

Total Posts: 319

  • 30 May 2016, 4:03 pm
Best and worst mileage figures of my car. Tankful-to-tankful mileage calculation:
Maruti Suzuki Zen LXi (2004)
Best:
25.84 kmpl (partially with A/C, minimal load, coming downhill for the most part and then highway run)
Worst: 5.47 kmpl (without A/C, full load, mixed traffic, very aggressive driving, tyre losing pressure)

NikilSJ

Moderator

Member: 02 Nov, 2015

Total Posts: 2354

  • 30 May 2016, 6:53 pm
Best and worst fuel efficiency figures of the Fiat Punto 1.3 Multijet (76PS)
Best: 24.3 kmpl (with AC, Chennai-Trichy-Madurai-Nagercoil-Trivandrum happily cruising at 90kmph)
Worst: 13.7 kmpl (with AC stop-go traffic in and around Chennai)
While I had the car for a short time in Chennai, I used to use half-clutch all the time inside the city inspite of knowing that it had enough shove to crawl even in second gear. I guess I'll have to get rid of the habit now. I also used to rev the engine till the peak torque kicked in inspite of knowing that it was unnecessary. Maybe that's why the fuel efficiency dropped so much inside the city.

CorsaVeloce

"Stage 3 Mod"

Member: 01 Dec, 2015

Total Posts: 1305

  • 8 Jun 2016, 11:50 am
Here are the best and worst fuel efficiency for some of my cars
2012 Skoda Laura 1.8 TSI
This is not really the car to discuss fuel efficiency, but for the sake of the argument, here are the figures.
Best : 18.7 kmpl (Highway drive to Karnal, Moderated accelerator input, A/C on)
Worst : 2.4 kmpl (Buddh International Circuit, track day. Nuff said!)
2016 Honda City 1.5 CVT
Best : 13.5 kmpl (Late night, Noida-Gurgaon round trip)
Worst : 8 kmpl (Greater Noida Expressway run)
2003 Hyundai Santro
Best : 16 kmpl
Worst : 9 kmpl
2009 Chevrolet Aveo U-VA

Never really understood this car, it was not all fun and extremely inefficient
Best : 10 kmpl
Worst : 6 kmpl

2005 Ford Ikon 1.3 Flair
Best : 12 kmpl
Worst : 7 kmpl

NikilSJ

Moderator

Member: 02 Nov, 2015

Total Posts: 2354

  • 8 Jun 2016, 11:57 am
CorsaVeloce I think it is time to take your Laura to a de-addiction centre as it has got a drinking problem. Does it smoke a lot as well?
You had the Aveo U-VA? Why would anyone bother buying that car. I would put it in the list of the worst cars ever to be sold in the country

JijoMalayil

Moderator

Member: 02 Nov, 2015

Total Posts: 2293

  • 8 Jun 2016, 1:20 pm
So, I recently bought a 2010 Ritz Diesel which had done about 74,000 kilometres.
In the 2-3 months of owning it, covered close to 7000 kilometres.
The best FE figure, Delhi - Mcleodganj - Delhi
24.5 km/l - Included hilly terrains, absolute straight highways and with two people on board (with the AC on)
Worst FE figure acheived, Delhi - Gurgaon - Delhi office runs (Peak office hours)
15 km/l - Stop & go traffic most of the time (with the AC on).

Akshat Pokhriya..

First Gear

Member: 02 Apr, 2016

Total Posts: 94

  • 8 Jun 2016, 2:44 pm
I think I might be a bit out of place on this one but, well here it goes
Car: 2002 Skoda Octavia 1.9TDI Ambiente. All figures with AC on
Best FE: 32kmpl: Highway drive Hyderabad to Bangalore
Worst FE: 10kmpl: Ghat sections with completely broken roads.

NikilSJ

Moderator

Member: 02 Nov, 2015

Total Posts: 2354

  • 8 Jun 2016, 2:52 pm
Woah! Akshat Pokhriyal how did you manage to get 32kmpl! Were you pushing the car or actually driving it

CorsaVeloce

"Stage 3 Mod"

Member: 01 Dec, 2015

Total Posts: 1305

  • 8 Jun 2016, 2:55 pm
Akshat Pokhriyal. WOW! And once again, WOW!!
Getting 32kmpl from that 1.9 Liter motor is surely a feat. Were you by any chance hypermiling? If you were, please tell me how were you moderating the throttle as I could use some of that advice on my 100-km daily commute.
konarktyagi, read that? Does your '110' ever come close to these figures? I doubt.

JijoMalayil

Moderator

Member: 02 Nov, 2015

Total Posts: 2293

  • 8 Jun 2016, 2:57 pm
Akshat Pokhriyal
How did you calculate FE? Is it the average FE shown on the MID or the good old tank-full to tank full method?

Akshat Pokhriya..

First Gear

Member: 02 Apr, 2016

Total Posts: 94

  • 8 Jun 2016, 3:06 pm
JijoMalayil
CorsaVeloce
NikilSJ
I know, 32 was a bit of surprise for me as well. No hypermiling, it was the first time I had gone for a road trip. I was with my girlfriend who didn't trust my driving skills then. Most of the highway driving was in 5th gear at around 70kmph, that keeps the engine at around 1400rpm.
The way I calculated it was the old full tank measure. My car's MID is a bit too optimistic. It was showing 2.4 to 2.5 litres/100 km. I knew that couldn't be true :P

CorsaVeloce

"Stage 3 Mod"

Member: 01 Dec, 2015

Total Posts: 1305

  • 8 Jun 2016, 3:23 pm
Akshat Pokhriyal
Thats great man. You will be part of the Skoda Book Of Records, if there was one.
And by the old tank method, im guessing it was tankfull to tankfull right? By my calculation, thats close to 1400 kms on a single tank. Amazing.
Being a Petrol Octavia Mk2 owner, these figures are a dream. Max I do on a full tank is no more than 450 kms

Akshat Pokhriya..

First Gear

Member: 02 Apr, 2016

Total Posts: 94

  • 8 Jun 2016, 3:28 pm
CorsaVeloce It was tank full to tank full. But I hadn't used up even half the tank when I reached, so I had to just do a simple kms/fuel calculation. On my car, a 1000+ kms on single tank is normal for me now. And it does 120-140kmph with ease. For it's time, when it was launched way back in 2001, it was really one hell of a car.

NikilSJ

Moderator

Member: 02 Nov, 2015

Total Posts: 2354

  • 8 Jun 2016, 3:53 pm
Akshat Pokhriyal I still like the older Octavia. It had a tank-like build quality and looked mean in darker shades. My school-time girlfriend's dad owned one and I used to swoon everytime he used to drop her at school. Maybe that's why I liked her in the first place
When the Octavia Combi RS came, I tried to convinc my dad to get one. But he just kept saying it was too big for the garage. I still love the Combi version and everytime I see one, I get a neck ache. Although it's unlikely, I wish Skoda would do something risky like that again and bring the new Octavia's estate version.

Akshat Pokhriya..

First Gear

Member: 02 Apr, 2016

Total Posts: 94

  • 8 Jun 2016, 7:25 pm
Highly unlikely Skoda would do that. Estates aren't very popular in India yet. Even a used Octavia Combi is very very rare in our market. Once you have owned a car like Octavia, it's difficult to switch to another car. It just doesn't feel as good. You get addicted to the comfort, the performance, the experience overall.

MotuSid

Hot Hatcher

Member: 02 Nov, 2015

Total Posts: 319

  • 13 Jun 2016, 9:36 am ( 1 Photo )
Akshat Pokhriyal, NikilSJ, CorsaVeloce, I think I know how to ensure estates sell in high numbers in India. Slap some black plastic cladding, faux skid plates, raise their ride-height by itsy-bitsy bits, slap on some tasteful looking chrome elements (the most difficult part, this will be), give a catchy macho tagline, advertise them as all-conquering, lots of equipment. Oh and also have a 'delete all this crap' option and 'add the important stuff' option for enthusiasts. Everyone goes home happy. Example below

NikilSJ

Moderator

Member: 02 Nov, 2015

Total Posts: 2354

  • 13 Jun 2016, 10:30 am
MotuSid that should work I guess. I remeber seeing the Audi A6 Allroad at the Auto Expo this year and boy did I go weak in my knees. Loved the black cladding and large wheels. I'm pretty sure it'd be capable on trails and mud since it has got quattro and all. Would love to see this launched here in India.

maheshy1

First Gear

Member: 05 Feb, 2016

Total Posts: 8

  • 30 Jun 2016, 2:23 pm
Beat DSL
Best 27
Worst 23
I think I have the Best Worst FE figure. After all, I drive 90% highway with a consistent cruise speed of 80-85. If that fourth cylinder still existed, I'd have been able to cruise at 100.

NikilSJ

Moderator

Member: 02 Nov, 2015

Total Posts: 2354

  • 30 Jun 2016, 2:48 pm
Maheshy1 wow. A worst fuel efficiency figure of 23kmpl! That's incredible.
Chevrolet quotes a fuel efficincy figure of 25.44kmpl with the diesel Beat. Looks like you managed to beat that figure quite easily.
How does it do in the city though? I have seen some Beat diesels here and there and one thing I've noticed is that it's not as loud as say the Mulitjet/DDiS from Fiat and Maruti or the i-DTEC from Honda. Is it refined in the cty?

kaiserketkar

Moderator

Member: 26 Oct, 2015

Total Posts: 403

  • 30 Jun 2016, 6:30 pm
"Originally posted by maheshy1"
Beat DSL
Best 27
Worst 23
I think I have the Best Worst FE figure. After all, I drive 90% highway with a consistent cruise speed of 80-85. If that fourth cylinder still existed, I'd have been able to cruise at 100.
Akshat and Mahesh, those are really awesome figures! Cheers!

maheshy1

First Gear

Member: 05 Feb, 2016

Total Posts: 8

  • 28 Jul 2016, 11:23 am ( 1 Photo )
NikilSJ
Don't know. I mostly drive on highways. Never driven extensively in city. I hope I never have to deal with that. The clutch is heavy and the first gear is too short and makes 1metre jumps jerky.
Here's a fun fact:
I saw the MID of the Datsun Go+ showed 195km as Distance To Empty (DTE). After driving it for 101km, it showed, 204km on the DTE screen.
After 300km, it showed 40km on the DTE display.

My 350km run also included 1hr of crawling in traffic.

Fourth Div