I like how you test what people says and things that are REALLY interesting. Few channels does this nice content

Great test! As a hardcore hypermiler, I love to see these fuel efficiency testing videos. What I found is that how you accelerate matters much less than what you do after you accelerate, but I have gotten my best tanks by a small margin accelerating at a moderate rate and shifting at around 2000-2500 RPM. At least on gas engines, efficiency tends to be best at a medium-low RPM and a medium-high load. If you would like to see a visual example of this, look at some BSFC charts. Too little load and/or too much RPM and pumping losses and frictional losses make the engine less efficient; too much load and the ECU commands a rich air/fuel ratio and the engine becomes less efficient because unburned fuel is wasted out the exhaust. How you slow down matters much more. Remember that every time you press the brake pedal, you are basically turning your expensive fuel into brake dust and heat. Letting off the gas really early for stop signs, red lights, turns, etc, and leaving a lot of distance in front of you in traffic so very little or preferably no braking is required is where most drivers will see their biggest gains without getting into drastic car mods or more extreme driving techniques like pulse and glide or engine off coasting.

When you accelerate very gently, you are spending more of the time at a lower speed and therefore reducing aerodynamic drag losses. Even though you hit the same top speed of 50mph, your average speed is lower with the gentle acceleration. I would like to see a test with different acceleration rates where you stop accelerating at the speed where the car gets its best gas mileage.

My mother and grandfather both have near-identical cars (same engine, same mileage - 170k), and they both drive similar roads, and yet my grandfather gets about 20% more MPG than my mother. For years I've been saying it's because she's the type of driver to get to the speed limit as fast as possible, then brake at the last possible minute, whereas my grandfather drives 'properly'. Her reason for that driving style is that she was taught to drive right next to the motorway, and we have a load of country roads where you really have to accelerate when you pull out of a junction. I can kinda see that being a valid reason, but there's no need to drive like that everywhere!

If the constant speed phase is much larger than the video, the difference becomes negligible, it seems. Since we have a short run on the video, it becomes more pronounced. This was a great video, answering a question that I had myself. Now I know that, at least in urban driving, there's absolutely no reason to get "spirited" while driving, since the constant speed phases are very short, and acceleration/deceleration takes much of the total runtime. On a highway I'll be pleased to accelerate faster to merge, knowing that it won't hurt my MPGs that much.

Passed my test today with 3 minors and your videos were a massive help in achieving something i've been putting off for years. Thank you! :)

I would love if you put all the results in a spreadsheet to compare them at the same time, that would be incredible! Thank you for the awesome video!

The tests, the explanation, the info for us and eu drivers, the camera's... this gotta be the most complete youtube video I've seen in a good while. Thanks!

I love you for putting the results in all different units. I always hate it when I have to open a new tab mid video just to keep track of the mpg -> L/100km ratio

I think the big reason for your results is the turbocharge. Most turbocharges have peak torque earlier, in the 1500~2000 range, which means you get more work and power delivered earlier. In an aspirated engine, peak torque is usually reached over the 5000 RPM limit.

Exactly what I have been debating so far. Why are you always in my head? Jokes aside, thanks for the video! You've been a great resource for my manual transmission journey here in the US.

No exaggeration, you are actually doing the nation a service with these videos 👍😂. Teaching people (for FREE!) on how to save money in times like this! Proper quality contentas always👌

Great video idea. Looking forward to watching this in full!

Love the video. I would bet that the reason Full throttle and half throttle were that high was because you stayed in 1st for so long. 1st destroys your mileage. In my own tests, the best option between speed/mileage was 1st until 2k then 2nd to 35mph. The goal with 1st was to get into "Turbo range" for second. Also no need to full throttle 1st, it's wasteful. All in all, your results match my experience. Cheers for the dope channel, your manual control is top notch.

Respect, man, for doing this videos with your engine fully up to temperature! Love to see carguys taking care of their rides! 💪❤️🚗

I thoroughly enjoy these tests, thanks for making them!

Would be interesting to see this in a small naturally aspirated petrol engine, as they tend to accelerate sluggishly in revs under 4000

Passed my test first time today! Just wanted to say a massive thanks Richard, your videos have helped so much during my learner driver journey and they would make concepts so much more easier to understand when watching before lessons and leading up to the test day. Keep up the brilliant work and all your effort in videos is very much appreciated :)

Hi, I passed my test today!! Thank you so much for your videos I don’t know what I would have done without them!!

Fantastic adherence to methodology and I love that you worked so hard to control as many variables as you could! I do fear one thing may have been overlooked though: built-in fuel efficiency indicators on vehicles are notoriously inaccurate from vehicle to vehicle - especially over extremely short durations. They rely on pre-ordained formulas built into the ECU logic based on RPM, requested torque which is a fudged guess from the ECU anyways, fuel pressure or manifold pressure, and - this is the kicker: throttle position. While they may work better over long trip durations (error averages out) and certain vehicles may be more accurate than others (Nissan & Hyundai are notoriously bad, whilst Subaru and Mazda seem to be slightly better), you'd be better off testing this either with longer test cycles and direct measurement of fuel before and after, or in a lab. Still, subscribed. I love your dedication to clear and succinct presentation of info!

Hi Conquer, passed my test today with 1 minor, and your videos made all the difference thank you, p.s will continue to watch them

I’m so glad you did the full throttle/short shift run. That’s how I drive, and a few of my friends who drive v8’s

Just passed first time with 3 minors, thank you so much your videos have been a massive help ! ! !

This is what I thought about and wanted to test for months! Thanks for testing!

Great experiment, and I was happy to see the theory play out in practice that low RPM and high load results in good economy. One of the things that irks me about cars with automatic transmissions but without electronic throttle control is that you can't really drive them this way: when you open the throttle it will also prefer a lower gear because it thinks you want more power. Still, I do like the way the CVT in my car generally allows decent acceleration to urban road speeds without the engine speed rising above 1500 RPM.

Passed my first test today with 7 faults lol. Your video helped me a lot. Thanks!

These short runs are most relevant to in-city driving, where you're doing accelerations from a stop quite often. This is valuable information.

I passed my test today! I have never commented before, but I couldn't have done it without your videos, so I needed to say thank you. Thank you! Xx

There has to be a balance between engine RPM and efficiency, which is offset by time spent at lower speeds and offset by drag coefficient at higher speeds. Really interesting video and well thought out, thank you for sharing

The theoretical numbers behind engine efficiency is in BSFC (Brake Specific Fuel Consumption). It's basically a 3D plot of engine RPM (X-axis) vs throttle position or torque (Y-axis), and on the "Z-axis" is the amount of fuel needed to generate a certain amount of energy (kWh or MJ). Less fuel is obviously better. For many engines, this is somewhere within the peak torque band at a decent -but not quite full- throttle load. Now I don't think many people would use "exactly 80%" throttle to get their best fuel economy, so it's not really realistic way of driving (unless manufacturers would make 80% the new 100% lol). But it is entirely true that petrol/diesel engines only get "more efficient" at higher speeds. The better fuel economy is just in the speed and losses involved..

I just passed my driving test first time this morning I thought I'd come here and thank you for your content it definitely contributed to my pass, Thank you!

Learned a lot in this video thank you very much bro you are doing a great job keep it up

I think for the slowing down part, the efficiency not comes with decelerating slowly, instead cutting throttle early. As long as you let the throttle off, it should change a lot if you're slowing down quickly or not. Lift and coast is the key.

Very interesting video, makes me want to do my own tests. One thing to note here is that you are changing gears at different RPM's for each throttle level. Doing tests where you shift up at the same RPM, while changing the throttle amount may show different results. In order to complete it you could even do the same for other RPM levels. That being said, on its own it is already interesting to see the difference between an aggressive driving style (more throttle, shifting later) and a relaxed driving style (less throttle, shifting earlier) is already a good real world test

Really happy to see the half throttle one getting those big gains, I don't know why but I've been doing that all the time lately. A proper financial decision by accident!

I passed my driving test today😁😁been watcing your channel for almost a year now. I will still continue to watch your channel, to become even better at driving : )

The only logic I can think of is the reduced pumping losses when your throttle body is wide open. But that alone does not make high acceleration efficient. Wheel slip (much of which cannot be felt), high RPM (more heat loss and less efficient combustion), and the likelihood of running into some kind of obstacle requiring braking sooner (aka, over-metering fuel for given conditions) all make accelerating quickly nowhere near as efficient as gradual, linear acceleration. Love your content!

As others have mentioned, a lot of turbocharged engines need a rich air-fuel mixture when the engine is under boost to keep detonation at bay. At the same time, I have my reserves trying the high throttle, low RPM shift on a turbocharged engine, given the risk of low-speed pre-ignition(LSPI). One info that would be nice to see is the intake manifold absolute pressure(IMAP), or more simply, just how much boost/vacuum the engine is under. Half throttle might be okay for a layman's understanding, but for more technical folks that know every car has different throttle mapping nowadays(sometimes changing the driving mode will change the mapping within the same car), it's a bit too general. Is half throttle putting the engine in lighter boost, no boost/vacuum(almost simulating full throttle in a comparable NA engine of the same displacement), or a slight vacuum? People with an OBD scan gauge can use this info to their advantage. Then there is the elephant in the room: you are reading the estimate in the gauge cluster. Now I understand that it's unrealistic to fill up after every run and longer drives would introduce more variables to throw the test off, but realize those things are sometimes pretty wonky. The one in my Camaro for example can be anywhere between -2%~12% better compared to the actual fuel efficiency(using miles driven and fuel filled up from the receipt). It tends to be 10% better than the estimate but that's not always the case. Mazda ones are typically a bit more trustworthy in my experience, but those also sometimes show worse efficiency in the gauge cluster than the actual mileage. Oh well, I don't really drive for economy myself for the most part. My fun car with a stick shift is a V8 so I drive for smiles per gallon, and my other beater is an old automatic. I do somewhat aim for slightly better economy for it but other times, I let my silly side take over and let VTEC kick in, yo.

past my driving test yesterday - some of your videos helped! :D

Brilliant video! Thank you so much for answering the question I had :)

I think the idea behind smooth acceleration is most important in cities when you're starting and stopping a lot. Going from 50 to 0 burns twice as much fuel as going from 25 to 0. Going slower overall rather than going right to the limit every time you move saves fuel, you're just going to waste it all anyway when you hit the brakes and turn that precious energy into heat.

Solid video! My whole driving style is based around driving it eco, but at the same time not being a grandma on the road. I still drive the speed limit and try to set an example, however I rarely accelerate slow, even if it might cost me a bit extra fuel. And I am not talking about driving it like I am racing either. Starting off a traffic light or stop sign I accelerate half throttle and change at around 2500-3000 RPM (maybe 3500 if I am feeling a bit rowdy) and go trough gears 1-3 and just accelerate to the speed limit (50km/h) and just drop it into 4th gear, rarely into fifth if I am driving on a wide and straight boulevard. My reasons being: 1. I don't want to feel like a snail around people and angering them (I've driven behind people which hold me in 1st gear for a solid 10 seconds and and the car jerks around it's a bad experience) 2. I like the sound that the cone filter makes when I press the pedal half way trough so it brings me pleasure when I drive around instead of it being a chore. 3. My throttle is cable driven so I get most of my torque with 1/2 throttle or even 1/3 throttle, compared to drive by wire. 4. I am hoping it reduces pumping losses and helps me get up to speed quicker and try to have good brake specific fuel consumption so I have more time to cruise. 5. It's a 98 civic with a small 1.4 liter N/A engine. Although I messed around with it and modified it it still feels in it's happy zone above 1500-2000 rpm, bellow that you feel like it's dragging it's feet. Hence why I rarely let it fall bellow 1,5k. If I dip bellow that I simply rev match and downshift. Small turbo cars or cars with bigger displacement that have good low end torque allow you to accelerate easier on lower revs, but small N/A engines lack that so you need to rev them a bit more to bring them to life. With all that being said most of my slowing down is focused on anticipation and letting the engine slow down on it's own if you are nearing a red light for example and there is traffic ahead. Even if you accelerate gently and don't speed to much, most of you economy is lost when you overuse the brakes. Hence why I was getting good economy before even when I was pushing it around (Around 5.2/5.3 L to 100km with most of my trips being 80-85% rural driving and 15-20% urban driving give or take). All in all it's really the best of both worlds. With moderate throttle and anticipation you still make the driving experience fun and engaging while maintaining good economy + the added benefit of reducing the risk of people behind you getting impatient and doing reckless overtakes and all that. You can't escape them completely, cause some people will always be "in a hurry" but it reduces those encounters quite a bit. Cheers!

Thanks for converting the numbers to different units.

I really like how you adjust fuel consumption to all types of measure

The one where you accelerated briskly to 3,000 RPM seems to be the best of both worlds. Economy was decent, and you may be able to merge onto a highway if the slip road is one of the longer ones. But, as said in the comments, it doesn't make that big of a difference in the big picture, so obviously safety over fuel economy, and a bit more progress as a bonus.

Very interesting findings, gentle is the way to go, but not very fun :P I really do wonder how a diesel would fare here. Not sure if this particular engine does it, but some (maybe they all do it, not sure?) turbo petrols at high loads (full throttle) and low rpm tend to run rich to prevent knock. No such thing in a diesel, since it can basically run on fumes without worrying about knock and air/fuel ratios, so I wonder if there would be more of a benefit of hard acceleration (70-80% throttle seems to be the general rule of thumb on some TDI forums i've read) and shifting at let's say 3000 or wherever the peak torque ends and not redline at 4500.

Nice video! Ive been asking myself this question already a lot of time :D

@Conquer Driving ,ur videos really helped me learning to drive and I passed 1st time with 3 minors 2 weeks ago and to be honest my instructor didn't teach me the things u mention in ur videos, thanks for the videos. 👍😁

It would be interesting to do the test with a NA engine. I think the torque from the turbo is doing god's work here :)

The run where you changed up late but didn't accelerate hard sounds to me pretty similar to people who just won't press the gas pedal more than a certain amount, so going up hills they stay in low gears for a really long time because they don't want to give it more throttle to get up to speed.

Thanks very much for this. I'm actually amazed by my Mazda 3 2016 that gets 8.4 L/100km with fairly gentle driving with slightly aggressive episodes here and there. Not ridiculing your video though, not at all, but it's thanks to this that I can appreciate my car even more, so thank you genuinely.

Another awesome video that'll help us save some fuel specially when its cost is rising each day.

Turbochargers are inherently less efficient at higher boost (at least for gas) so i'd be interested to see how a non-turbod car would fare

Given how close the results are between normal and hard acceleration on a turbo engine I feel like an NA engine might actually do notably better as a result of not needing nearly as rich an AFR for cooling.

Hi Richard! Great vid as always :)

Great video, well done. There are so many other variables to this to make it fully comprehensive. I find if you use medium acceleration and idle (no acceleration) as much as possible, it gives the best economy. Up hill driving uses a lot more fuel compared to down hill using very little.

Being a family man and driving in Bengaluru, I'm criticized for slow acceleration. Earlier I'd claim it was because I love my family and accelerating slowly gives me better control over a chaotic sutuation (bikes + cars+ autos swarming all over when the lights turn green. Now I can say it helps with fuel economy 😀

Amazing test, thank you for all the detail. The only info I was missing is the time it took to do the distance, not just reaching 50mph. (though I guess one can measure it from the video 😄)

One thing to consider that is harder to test as rigidly as done with this video: When I accelerate hard(er) I reach my cruise speed faster than accelerating softly, that means I can go for a slower cruise speed while keeping the same average speed as the softer acceleration. Combining that with the high-throttle, early shifting approach, which gave a good balance between economy and accleration in your test, might still be the way to go.

Something that genuinely works especially on older cars is to drive very conservatively on a daily basis with an occasional thrash to help clean out the engines carbon. My old VR5 bora was averaging 28mpg and after a 4 hour hard thrash on a day out with a convoy group (with a double shot of engine cleaner) I was then averaging 34mpg.

Remember that naturally aspirated engines are happier at high load low RPM than a turbo car

It would be interesting to see how naturally aspirated cars would compare in this test. I wonder if the results would be different considering turbo petrol's run richer under hard acceleration yet support the engine better (more fuel efficient) at low loads.

Passed today with 4 faults. THANK YOU SO MUCH FOR EVERYTHING.

1. In all cases, you need to burn the chemical energy required to reach the kinetic energy level of your intended cruise speed. Right off the start, it doesn't matter much if you derate 2. If you derate from peak power to peak efficieny, you will save some gas as the friction losses inside the engine are lower for a few seconds. You will often be a nuissence to traffic though. 3. Your average speed may decrease, but then it's more efficient to reach the same avergage speed with a lower cruise setting and a quick acceleration. That said, in order to drive fuel efficient: - lower your cruise speed (especially on roads where it is easy to pass) - don't use the friction brakes, retain as much kinetic energy as possible when maneuvering (- don't open the windows as it will induce drag) (- turn off unneccessary subsystems in your car) (- don't load stuff in your car you don't need) (- turn off the engine when you don't need it) If you want to modify stuff: - go for energy efficient tires (you have a conflict of goals as these offer less traction) - inflate your tires to the high end - use low viscosity motor oil, but it has to be approved by the car manufacturer for your climate If you buy a car, go for a long one if you need space. The more surface area you put against the wind, the more your fuel burn will be.

I have an idea why this is happening, not sure tho. The experiment you conducted shows that gentle accelaration is the way to go for turbocharged petrol cars. And i say that is expected since almost all turbocharged cars put their max torque around 1500-2000 rpm band. But lets say you are driving a naturally aspirated car which most of the give their max torque around 4000-4500 rpm, it is best to full throttle and reach that RPM band. After reaching desired speed, you can drive at normal rpm's.

75% engine load @1,800-2,500rpm is the target for me during acceleration. My car is a 1L 3 cylinder Aygo though so it's pretty slow at 75% load in that rev range... I get Around 72mpg.

Passed today with about 15 hours of lessons these videos helped so much lol

Breaking is a big fuel consumer too for the energy spent to get up to speed only to lose it again to the heat generated by the breaks, lifting early does save gas. Gently accelerating and decelerating is the answer to an efficient and comfortable drive. Looking ahead of the car and a 360 situation awareness helps as well.

Short answer: no Long answer: if you want it to, who knows. A jaaaaaaaag is by all means less economical than a SEAT Leon…

I think you misunderstood. Your engine is most effecient at full throttle AND LOW RPM. Shift at 2k and you'll see the difference.

Yo. You literally taught me how to drive manual transmission. Thanks mate

Ive always been gentle with accelerating and braking not so much for fuel economy but just to take it easy on the engines. Does yield great mpg results because of it!

Who in their right mind believes that logic? Acceleration uses the most gas so driving with the throttle wide open will use significantly more gas than doing gentle accelerations. Braking only wastes gas if you're constantly braking to slow down then to accelerate immediately after braking

I've been driving on an automatic licence for the past 15 years and today I took a test in my grandad's old (S reg!) Manual Renault Mégane... I've had no lessons and my only tuition has been practicing occasionally and watching these videos... I passed with four minors despite having a nightmare in the car park where the examiner announced "you're holding up traffic" - I decided to exit the car park and re enter then proceeded to stall on the monouver!!! - without these vids I'd have either of had a meltdown or continued to reverse where I was forcing the one behind to reverse - you're literally the only reason I passed today... Thank you so much!!!

Fuel burned accelerating is justified, but economy in my opinion comes from stopping. When you accelerate you convert liquid dinosaurs into kinetic energy, so economy depends on how you use that kinetic energy. While stopping you can let it dissipate in justified air, rolling, engine resistance and so on, or your dissipate it in your brakes.. I would like to see the test where you reset computer at 50 mph, drive for a while and make an emergency stop at defined spot. Then try resetting, coasting to 20 mph then apply brakes to stop at the same spot. And third run try downshifting and braking with engine till 20 mph and then apply brakes. Most efficient will be downshifting. This driving style could be harder to master in real life conditions, but I get manufacturers claimed range on all cars I ever have driven. Thanks for the great video! 👍👍

thanks for confirming my theory. been driving professionally for 3 years, had debate with other drivers which driving style uses the least fuel. i think I can say I won the debate with this video. i drive gently, but I still get to the destination on time. that's what matters anyway, being on time.

I figured as much but never took the time to whip out the pen and paper, good job. I regularly get 30-31 mpg highway with my 02 C230 Kompressor. Ill cruise around 90mph no problem, I let anyone else drive and its usually 24mpg (on the same trip)and they overall go just a bit slower at cruise, but really stomp throttle immediately after deceleration. Their reasoning always was that it used less fuel and could not be convinced otherwise. Theres also something to be said about listening to your transmission, some people really make the tqc work harder than it needs to lol. Glad to know I'm not crazy.

This was a surprising result to me, as my driving instructor here in Finland (almost 15 years ago) taught to us that the most fuel efficient way to accelerate is to reach your target speed as fast as possible (safely and reasonably) and then start cruising. I always thought it sounded a bit weird considering the high RPM:s but nevertheless believed my instructors word. One thing that popped to my mind was that maybe this was true back in the days when cars had carburetors in them? As my instructor was quite an old man he could've had outdated views on this subject. Thanks for the video, cheers and have a great day!

I hate it when how I think things are is shattered by a youtuber. good video, thanks for taking the time for the experiment

i passed first time yesterday with 0 driving faults thanks to your vidoes!

Nice heel and toe and 13:56 bud. Love seeing good driving techniques. Nice vid btw. earned a sub

I can tell this channel has useful content

Tnx for your videos. ,👊 really helpful . 🙂

Really interesting test. Thanks a lot for for doing a video and sharing. How about repeating it in at stop light scenario? You could check how many cars manage cross an intersection when the light is green and compare to idle consumption for those not making it at lower accelerations.

Thanks for confirming what I always believed! I am curious if the results remain consistent on a slight incline?

Gentle acceleration (RPMs 1.4-1.6k) with top speeds of 45-50mph on my commute (22mi) have been averaging 40-44mpg (US) in 2019 mitsubishi outlander 2.4L CVT. Glad to see some testing like this. It is not practical all the time (i.e. inclement weather, heavy traffic, etc.) but I think it is worth it in the long run.

Love the choice of music in the Kia onboard

Very nicely done. I'm left with the question of the efficiency of your baseline, normal shift points on a daily commute for this test. Sort of a control, a balance between fuel savings, comfortable ride and sound, and going ahead and getting there.

For me, giving about half throttle and changing up quickly does the ticket, to be honest. It is a naturally aspirated 1.4 from ages ago, mind you. 1.4 16V from a Skoda Fabia. The catalogue fuel consumption states that I'd be getting around 6.6l/100km in mixed driving. But I regularly get around 5.7-5.8l. It might be cuz I like to engine break a lot.. I mean A LOT. I grew a habit of going down from fifth to third and just using the engine to do most of the braking if I know I'll stop eventually. Or going downhill. Still. 1.4 TSI is rather sensitive to your driving style, so the results from the "hard acceleration, but quick gear changes" could be somewhat varied. And just going to add to the praise. You're helping me be even more economical with your videos. Learned a lot from you, so thanks a lot :D

For anyone interested, I have a 2016 Honda CR-V with the i-DTEC diesel engine and AWD. I've found the most economical way to drive it is to accelerate not too slowly, but somewhere in between that and briskly. The auto gearbox seems to choose the gears effectively and it's most economical at around 50mph where on a continuous run, it'll do well over 50mpg.

omg youtube, stop recommending great channels, I DON'T HAVE ANYMORE TIME TO WATCH! GJ man!

I had fun with this video, but this is a very complicated issue and I don't think it can be covered in a few minutes. but hey entertainment is the aim here so good job. :)

full throttle using less fuel used to work for carberatored cars as there was nothing there to adjust the fuel/air mixture. The modern ECU adjusts the fuel/air mixture based on driver input to give either better economy or better performance(less economical).

Thanks for the video and for converting to metric units! Although, how precise and reliable do you reckon this average calculated by the car is? (genuine question)

Thank you so much for your videos just passed my test today with 1 minor

as a hybrid owner for quite some time, I can very much confirm your suspicions. Accelerating at high speeds and stopping last minute tanks your mpg. In a hybrid taking your time and slowing far ahead of time is massively beneficial to your mileage.

Very interesting video, thank you! It would be also interesting to see a video with a similar test with a car that has CVT, as it does not have "gears".

This was really interesting. Thank you for this. Have you tried to skip gears?

That was good. Well done.

Definitely need to do this in an NA car. At the low RPMs the turbo is not spoiling much and you're not dumping in extra fuel for power and cooling to prevent knock. Turbos ruin fuel efficiency. I expect it would be closer in an NA car.