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How I achieved 23.6 km/l on my 2015 Maruti Swift petrol

9th December 2021, 15:07 by Rahul Nagaraj

Prior to this, the best fuel efficiency figure I had managed to get was 19 km/l.

BHPian Crow recently shared this with other enthusiasts.

This is the story of how I extracted an insane fuel efficiency of 23.6km/l over a distance of 830 km on my 2015 Maruti Swift ZXI (petrol). It also includes some fun things I did in Vadodara, so if you came here for fuel efficiency tips, you should definitely stay for the "things to do" section.

Stopped the car just to take a picture of the MID.

Quick index:

The pandemic has made me realize that it's better to hit my bucket list items sooner rather than later, and a solo long drive has always been something I intended to do. There were many ideas such as driving to Gir Forest, South India, MP, etc, but I had a commitment to honour. One of my closest friends lives in Vadodara and we'd been planning to go check out multiple cafes in Surat for a while. Apparently, the coffee culture in Surat is really picking up, and he wanted to show me around.

I'm not really a coffee person myself, but I figured why not try this new thing out? So it was decided that I'd be heading towards Vadodara for sure and maybe a stop for the cafes at Surat on the way back. Sadly I saw a thick blanket of smog around Surat bypass while going to Vadodara and we both decided to cancel that leg of the trip immediately. Maybe it'll happen in the summer!

The problem with starting very early is that popular hangouts, like McDonald's Surat and Hotel Ahura in Talasari, aren't open!

That's when I got the next brainwave and asked my friend if he'll come to Delhi with me to check out some things I've been missing a lot from the national capital. My friend, being the sport that he is, agreed immediately. My next question: "Why don't we drive to Delhi?" was met with a long silence and eventual denial. He wasn't up for that long a drive, so we finalized the plan — I drive solo from Mumbai to Vadodara, park the car at his house, and we drive to Delhi.

The Delhi trip was amazing in its own way, but details of that are for another thread. In this thread, I'm going to focus on my drive to Vadodara and back, and the fun things I did there. I visited the best cafe I've ever visited in my life. I met an amazing D-BHPian. And I drove an absolute beast of a car there (more on this in a different thread).

I had full faith in my ability to reach Vadodara without issues in my Maruti Swift ZXI (2015). The car has done almost 31,000km in six years, and 16,000 of those have been done in the last two years (including six months of running zero km due to the lockdown). I've driven almost exclusively on the highways in this time. However, I've never driven solo for that long, so I wasn't sure if I'd be able to stay awake for eight hours during this drive. That's when I got an idea—why not try a hypermiling run to Vadodara?

I've been massively inspired by D-BHPian @PrasannaDhana's threads and I asked him how he got 26 km/l from a Kwid. He pointed me to one of his posts, which had some useful tips. I've quoted it below for quick reference.

These are the simple measures I implement while driving the Storme:
Gradual acceleration and deceleration. Very very rarely does the rev needle go up fast (I used to floor my Ciaz all the time and still get 18 km/l )
Being in the highest gear possible without lugging the engine. Luckily Storme Varicor 400 has great drivability. You can stay at 1000 rpm and still see good progress with a dab on the accelerator
Anticipating braking. When there is slow-moving traffic or an obstacle, say 200 meters away, I take my foot off the gas pedal and coast it till that spot.
Coasting when possible. Especially on downward slopes. The 2+ tonne kerb weight of the Storme aids in maintaining the momentum downhill. You will be surprised to know that I have done over 1.5 km without any accelerator input coming from a large over the bridge.
Maintaining optimal highway speeds. Specifically 80-100 km/h, mostly 90 km/h
Proper tyre pressure. 32 psi recommended for low load driving. I maintain 33 psi
AC set to eco mode. Storme has an extremely powerful ac (like all Tatas). I use the ac in Eco mode which itself is sufficient. If I have rear passengers, I use the rear ac or else it's just the front AC in eco mode at blower level 1.
No idling unnecessarily. No short trips (<5km) unnecessarily.

With this knowledge at hand, I knew that it was possible to extract more mileage from my Swift. I've never really bothered with tankful measurements — the MID's accuracy is good enough for me. The maximum fuel efficiency I've ever got on my petrol Swift is 19.8km/l, on the way back from Rajasthan to Mumbai in 2019. On all recent drives, the best I've managed is 18.8km/l on the way back from Goa.

So off I went into this trip trying to see what I could do in terms of fuel efficiency. I started the journey at 0420 hours (really!) on November 23, 2021, and navigated past the usual road closures and other detours on the Western Express Highway in Mumbai.

In no time I was already past the dreaded Vasai Creek bridge near Hotel Fountain and that's when my Swift's mediocre headlights made it hard to go faster than 60-70km/h. There are no lane markings in this part of the road, for a few km, so I was going really slowly. By the time I reached the stretch with lane markings, my MID was already at almost 19km/l!

I assumed it was the lower temperatures coupled with lower weight in the car that got it up so fast and though it really can't get better than this.

So, I used the following methods to see if my car can get better fuel efficiency:

Completely let go of my ego. Never react to any drivers with poor road manners and move aside for anyone who wants to overtake, even if that person is in a vastly inferior vehicle.
Befriend anticipatory braking, absolutely no sudden brakes as much as possible.
Maintain steady speeds between 75 and 90km/h.
Try to follow sedately driven cars at a safe distance to reduce wind resistance.
Accelerate and decelerate gradually, always!
Use the recommended tyre pressure for your vehicle and tyre size. It's 29psi on my Swift ZXI, but I filled it to 30psi for the trip.

Other conditions were in my favour too:

An early start combined with winter meant lower temperatures throughout the drive, which is better for fuel-efficiency.
Driving on excellent tar roads on the NH48 ensures better grip, less road noise, and makes it easier to control the car for me.
With just one person in the car, the weight was as low as it could be. Even my luggage was under 15kg total.

All these things combined to make the average fuel efficiency number on the MID rise gradually. Over a distance of 410km from my home to my friend's home, the number rose to a staggering 23.6km/l!!! I never thought that it was possible to extract almost 24km/l from a petrol car on a long highway run, but that's what happened. I reached Vadodara with less than half a tank of fuel consumed, which is frankly quite insane!

The 2015 Swift ZXI has a 42-litre fuel tank if I remember correctly, so by my calculations, I used around 34 litres to reach Vadodara and get back home. A total trip distance of around 830km was done with some fuel to spare! (Of course, I refilled the car before leaving Vadodara, I do not like taking chances with things like that.) If I'd had a longer trip planned, I could have driven another 180-odd km with some petrol still left in the tank. The total range of one fuel tank rises to over 1,000km with this kind of sedate driving. I've never heard of petrol car drivers reporting these numbers in my limited experience. The stories I've heard are all from diesel car owners who report crazy numbers north of 22km/l fairly regularly.

Here are some useful stats for the trip.

Mumbai to Vadodara:

Distance: 430km
Average fuel efficiency (at the end of the trip): 23.3km/l
Top speed: Roughly 95km/h
Start time: 0420 hours
Arrival time: 1120 hours
Total time (including breaks): 7 hours
Average speed: 61.7km/h

The MID before leaving Mumbai.

The MID at the end of the first leg of the trip.

Vadodara to Mumbai:

Distance: 430km
Average fuel efficiency (at the end of the trip): 23.2km/l
Top speed: Roughly 100km/h
Start time: 0440 hours
Arrival time: 1205 hours
Total time (including breaks): 7.5 hours
Average speed: 57.3km/h

The MID before leaving Vadodara.

The MID after reaching Mumbai.

Mumbai traffic and some difficult driving conditions didn't allow me to be as disciplined as I was on the return leg. It was pouring for about 60% of the journey and spray from other vehicles, combined with poor road manners from heavy vehicles made it hard to avoid braking. Yet I managed a maximum of 23.4km/l on this leg.

I am very, very proud of this achievement. I never really thought of myself as a great driver with amazing skills. I always feel that Team-BHP has people who are so, so much more knowledgeable and experienced than I am. Just to be able to do something noteworthy gives me an immense sense of satisfaction. If I can do this, pretty much anyone can. Now just give me a light diesel car and watch as I hit 30km/l on it for sure!

Continue reading BHPian Crow's hypermiling journey for more insights, comments and information.

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