Can Fast Acceleration Save Fuel?
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- čas přidán 7. 06. 2024
- Many people have told me that accelerating gently doesn't save much fuel because it takes longer to get up to speed and the engine is less efficient when it's doing less work. So in this video I compare 6 different methods of acceleration and gear changes to find out which is the most economical and whether accelerating gently actually saves fuel.
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00:00 Why could it be possible?
00:55 The car
01:23 The tests
02:03 Full throttle
03:52 Half throttle
06:18 Gentle throttle
07:40 Different cars
09:36 Full throttle change up early
11:14 Gentle throttle change up late
12:26 Very gentle throttle
13:52 Results
15:09 Another video
15:34 Outro
I like how you test what people says and things that are REALLY interesting. Few channels does this nice content
Agreed. These are questions that really need answers
Few channels do* this
@@kerimking82 you're right, my bad
So he makes a video about people asking stupid questions. Interesting.
he need 16 minutes which i can tell you in 1 comment: yes, he have a greater consumption if he accelerates more, BUT he need more time. time is money, not fuel. drive efficient and not as slow as you can. everyone have less time in their life as they think!
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.
Hypermiling much more fun than speeding , it certainly makes you concentrate 😉.
It sounds like you're a good driver, I would be a happy passenger in your car.
The BSFC varies between engine types, engines with forced induction tend to perform best at lower rpms compared to naturally aspirated ones, and the same goes with 2 valve per cylider cars vs 4 valve. But general rule of thumb (BSFC charts for every engine are hard to come by) is to use RPMs close to peak torque (eg. peak torque is at 3000 so you should use 2500-3500rpm) under generous throttle (but not with pedal to the metal), and as always go straight to highest possible gear when done accelerating. Hypermiling is one of my favourite activities on long trips, but what you said is 100% true - the worst thing that you can do is braking. I'm able to go between 100-150 kilometers without using the brake pedal just by observing the road before me and acting accordingly. There is also the factor of gravity and potential energy, pulse and glide is not the best technique when being in normal traffic, but can do wonders when used correctly on a road with a lot of uphill/downhill combinations.
@@jakubm1187Great points. I wish BSFC charts were published by manufacturers, it would sure make life easier for us hypermilers. I wonder how true the theory that maximum efficiency occurs at peak torque RPM is on higher revving engines. Both of my cars make peak torque at around 5K RPM, but I can't imagine that shifting so late could be most efficient way to accelerate. As for pulse and glide, it certainly has its place. I have found it to be very effective on hilly roads (obviously not on hills so steep you will pick up too much speed on the way down). I have heard of good results using pulse and glide on longer highway trips instead of maintaining a constant speed, which makes sense especially if the top gear is short. With a tall geared transmission that has the engine cruising at barely above idle anyways, I'm sure pulse and glide wouldn't be as beneficial as with shorter gearing since frictional losses and pumping losses would be less anyways.
Interesting. I'm not exactly hypermiling right now (115 kph on highway, 70 average) but for now I can reach huge distances with driving relatively quick that driving behind me becomes no burden. I usually shift at 2200 RPM which is pretty much the middle of what you stated. My 13 year old Ford Mondeo TDCI on average can manage 1300km (or over 800 miles) if I keep doing this.
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!
I sold my father in law's car. I drove it myself for a week. 1.4 na engine.
Checked the BC when I collected it, drove some 500 miles.
Result: 72% better mileage.
Ah... excuses excuses... Just because something is a habit, it doesn't mean you can't break that habit. Discipline of the mind and all that
@@233kosta it's very difficult after a certain age. Neuroplasticity goes down. You'll realize when you get there.
@@shadmansudipto7287 Yeh, I've observed that. I've also observed octogenarians who are as sharp as they come. A lot of it will come down to how much use that brain sees, and I plan to keep mine as active as I can
I hate it when people stop abruptly past the stop sign or start to speed up before I can even pass the sign. You never know if they are actually going to stop in time & I'm always ready to swerve away from the vehicle if they don't stop but that's not always an option with oncoming traffic.
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.
Compared to in-engine losses, drag doesn't become a problem until about 50-55mph. V^2 and all that. You'd notice it comparing cruise speeds over long distances, but not in this case.
Apart from this test mixing two variable changes together (throttle position & RPM at which he shifts), the true comparison would be which combination of acceleration and top speed gets you to the goal in the same time (ie, faster acceleration would be combined with a slightly lower top speed).
according to the law of conservation of momentum (force = mass * acceleration) the car's mass remains constant, while the acceleration changes. this means that force is directly proportional to the acceleration. having a larger acceleration will require a greater force, which in turn uses more fuel for the acceleration.
@@totallynotkacper7629 Yeh, but your total momentum change in both cases is identical. As is the total added kinetic energy. The answer lies in the engineering, not the kinematics.
@@totallynotkacper7629 faster acceleration requires a greater force for the duration of the acceleration, but that duration is smaller compared to a slower acceleration, so it should cancel each other out
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! :)
That's fantastic news, thank you for watching and congratulations on passing!
what were your 3 minors? And were you nervous during the exams?
What kind of sadistic society has you take your driving test with three kids in the back?
@@peterjohnson9438 😭
@@peterjohnson9438 What were you smoking awhile ago 😂
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.
That's very true.
Well to be fair, it's an acceleration efficiency test so obviously the more of the test not being acceleration will ruin any differences
@@tommik4872 Exactly. As this video shows, the way you accelerate just isn't all that critical when it comes to overall fuel efficiency. If he accelerated then cruised for 10 miles, any differences in efficiency as a result of how he accelerated would never be seen due to normal run to run variance and wouldn't be as conclusive. The way he did this test was perfect IMO since he needed to keep all the tests the same distance while still leaving enough room for the very slow acceleration test.
I drive in bumper to bumper traffic in my 1.5 tsi engine and get a fuel economy of 6-7 kmpl when using fast accelerations and 8-9 kmpl when gently accelerating and braking (over 15-20 kms), so yeah, the difference isnt negligible in bad traffic/ roads
we test how we accelerate, not how much the car will consume if it is on the cruise control, of course they would consume the same 🤷♂️
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 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!
Great video idea. Looking forward to watching this in full!
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
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.
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
That's fantastic to hear, thank you for watching and congratulations on passing!
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.
Just passed first time with 3 minors, thank you so much your videos have been a massive help ! ! !
That's fantastic news, thank you for watching and congratulations on passing!
What you mean you had your first time with 3 minors? 🤨🤨🤨🤨
“first time with 3 minors”
Hi, I passed my test today!! Thank you so much for your videos I don’t know what I would have done without them!!
That's fantastic to hear, thank you for watching and congratulations on passing!
Respect, man, for doing this videos with your engine fully up to temperature! Love to see carguys taking care of their rides! 💪❤️🚗
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 :)
That's great to hear! Thank you for watching and congratulations on passing!
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👌
Which nation in particular?
@@MrArmorcat pretty much every
I thoroughly enjoy these tests, thanks for making them!
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
That's fantastic news! Thank you for watching and congratulations on passing!
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.
Passed my first test today with 7 faults lol. Your video helped me a lot. Thanks!
That's great to hear, thank you for watching and congratulations on passing.
This is what I thought about and wanted to test for months! Thanks for testing!
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
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.
Most autos have a manual mode these days, no?
I hate that about automatics. Almost no hypermiling is possible in them.
@@233kosta these days. But most people don't buy new cars, but 10-15 years old cars, because they're like £1500
Oh no why did you but a cvt?
@@daniel27560 Haha, fair question! My friend was selling it and it was extremely cheap. :) TBH, I remember being curious about CVT drivetrains in high school, purely from a technical perspective, but I'd be the first to admit that they're not very exciting to drive.
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
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 : )
That's fantastic news! Thank you for watching and congratulations on passing!
past my driving test yesterday - some of your videos helped! :D
That's really great to hear! Thank you for watching and congratulations on passing!
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!
Yeah, was gonna say similar. I thought he had some sophisticated fuel-dripping rig set up, but instead relying on the car's own built-in computer, which is constantly estimating the future as much as the past. As such it's just spitting out pre-written data. On the bright side, this is data directly from the car maker, on the downside, car makers lie about their product's mileage all the time, so... *shrug It's good to see the actual testing anyway, as there's no reason for the makers to lie about which method works best for fuel economy. I suspect the whole issue is more about weak engines pushed hard, rather than a strong engine working gently, as it's obvious a strong engine will use less fuel when it's not working so hard. My own experience with economy crap-boxes is they use as much fuel as a better car, cos I have to hammer the things much harder to drive like a normal human.
@@bigglyguy8429 the only real truth is going to the pump and seeing how many miles covered. (Although is this this really the truth? You need the same fuel click off point in each pump. Also, just like your speedometer reads a slightly higher speed, does your odometer read slightly shorter miles? I don't know.)
@@TimpBizkit Well I know for the fun of it I've been driving my stage-4 tuned Hilux Vigo turbodiesel off-road beast of a machine more gently... and people keep driving around me and seem to think they're winning a race! Normally I just drive away from traffic. I didn't realize people were so weird..
I was wondering how accurate the fuel consumption figures were at different RPM points. If the fuel consumption figure underreads at lower revs then the results will be skewed towards low acceleration giving the best results. Without knowing how the fuel consumption is worked out this may or may not be a good experiment. I read a news item in the past month that a couple of different sets of experiments found that accelerating at about 66% of maximum acceleration was the best way (wrt lower fuel consumption) to get up to speed quickly and into top gear. This is an example of the usual mixed messaging that can be found on the internet, same question two different answers.
Yeah, there's no way that thing was good enough to do a test like this. There are so many things that could be causing it to report better efficiency when he accelerates slower, and worse efficiency when faster, and in reality it could be the opposite
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
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 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!
That's fantastic news! Thank you for watching and congratulations on passing!
Would be interesting to see this in a small naturally aspirated petrol engine, as they tend to accelerate sluggishly in revs under 4000
Difference would be bigger in favor of higher rpms as the maximum torque is often around 4k instead of 1.5-4k like in turbo cars
@@anders2821 for my car itts 5krpm...so should i rev up to that in second gear and then use 5th gear ? is that more efficient ?
i face the same challenge
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.
Learned a lot in this video thank you very much bro you are doing a great job keep it up
Brilliant video! Thank you so much for answering the question I had :)
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!
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..
A lot of manufacturers actually put an efficiency ‘bump’ in their accelerator pedals nowadays where it feels like it stops at about 80%, but you can push past it to 100%.
Not sure if it’s a Renault/Nissan thing but my work van has it & it seems like a really good idea.
Nice video! Ive been asking myself this question already a lot of time :D
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!
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.
AEM sells a great AFR and boost gauge (failsafe) and I have one on my turbocharged car. I think it would be most efficient to give it about 70% throttle and change at 2500-3500 RPM depending on your car while being smooth with the throttle movements, making sure not to lug your engine or run rich AFR. I could do this but my car's MPG readout updates quite slowly and it would be hard. I haven't tested with this car but my previous car's MPG estimate was spot on, albeit with slightly larger tires than stock. V8 honda? 1st gen NSX?
"smiles per gallon" is exactly how I drive my car on a twisty B road in England. Its only a 148bhp Focus but its fun when let loose. Who cares about economy when youre having fun!
@@CrazyInWeston I wish there were fun roads near me, there's a road with 1 good and 1 decent corner near me. Little elevation change = few curves. I love Texas but I have not found any fun roads that I can safely/legally go fast enough to have fun on.
@@johnhunter7244 Prob why on the worlds "greatest driving roads" Jeremy Clarkson said it wont be in the USA because "everybody does 5mph" he also saw said it wont be Australia because "its full of Spiders" and not Africa "because everyone rides an ox" or the Middle east cos "the Americans will shoot you"
The instrument cluster reading is generally quite accurate. Its accuracy is by product of the ECU needing to very precisely meter fuel into the engine to ensure target AFR and emissions compliance.
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.
Actually, going from 0 to 50 is significantly more energy usage than 0 to 25. In fact, it's at least 75% more, even if there wasn't drag or friction involved.
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.
Thanks for converting the numbers to different units.
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.
In my experience diesels tend to be more economical in higher gears as long as the gear isn't too high. I may test this in the future though.
@@ConquerDriving yeah disel works great at 5-6th gear about 2k rpm u can get about 4.5 L/100km with 1.6 enengine but lower speeds take a lot off fuel at city driving,specially with higher rpm
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 :)
I would like to test an NA car also.
@@ConquerDriving I would like to see the difference too. My brother and I both have Ford Fiestas with direct injection and 5 speed manuals and 15 inch wheels. Mine has the turbo 3 cylinder but my brother has the NA 4 cylinder. He has far less torque down low so his gears are far shorter than mine. My economy should be better during acceleration as I can keep my engine speed lower but on the highway economy is almost the same even though his cruising rpm is higher. Would be interesting to see just how much turbo vs NA engines vary across a range of engine and driving speeds.
Actually a further distinction needs to be made: a small turbo does indeed increase torque at low RPM, whereas at high RPM it has to open the waste gates (which removes much of the efficiency benefit). So this favours a low-RPM driving style. At high RPM it's hardly different from an NA engine - in fact rather less efficient, because the engine itself will generally use a lower compression ratio.
By contrast, a large turbo doesn't even spool up at low RPM, which ruins both torque and efficiency. This is one reason powerfully turbocharged sports cars can't be efficient even when driven at low speed. However, a small engine with comparatively big turbo can actually be quite efficient, even at high RPM - while being completely useless at low RPM.
@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. 👍😁
That's really great to hear, thank you for watching and congratulations on passing!
Hi Richard! Great vid as always :)
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!
Awesome, i also have '98 Civic with 1.4 L engine, 90 hp. Sports exhaust and DIY air box so it's pretty loud :D
Love driving to and from work.
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.
Going up hills I kind of just floor it most of the time to get up to speed then let off and coast up the rest of the hill with the momentum
@@gotworc that could be another interesting comparison of fuel usage : most efficient way to go up a steep hill.
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!!!
It's amazing to hear the videos have helped you, thank you for watching and congratulations on passing!
@@ConquerDriving as a follow up I went onto pass my cat C today (that was the reason I was doing the manual car licence as it'll cover both now) - your videos helped me again today as its all the same really 😀😀😀
Another awesome video that'll help us save some fuel specially when its cost is rising each day.
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.
I think so too.
so how do i properly drive a non turbo engine ?
@@marvin2678 depends on your definition of properly.
IMO fuel economy is the least important thing to cater your driving style to. I would drive either engine mostly the same. Don't rev too high while the engine is cold. Once it reaches operating temperature, you should not be afraid of getting near the redline on acceleration. This does not hurt the engine and in fact helps keep it clean.
Modern manual cars will tell you to upshift too much, too soon, for fuel economy and emissions reasons. Automatics just plain force this on you. But this can get you into lugging the engine and bad throttle response situations. Don't hesite to downshift when you expect to load the engine soon, even just a bit. It'll greatly increase the general feeling of driveability of the vehicle. Both turbo and non-turbo engines have an operating RPM from which upwards they will start to feel responsive. This is where you want to be when you start to accelerate or climb a hill. Only lower engine RPM by upshifting AFTER you reach low load and constant cruising speed. This point will vary from engine to engine, turbo or no turbo. Try to find this point for yourself by accelerating in, say, 3rd gear from low speed to redline. Somewhere along they way, like maybe 2000 RPM for example, the engine will start to feel and sound "happy".
The only real difference in feel between turbo and non turbo engines is how and when the engine transitions from unhappy to happy.
Getting back to fuel consumption tho, the turbo engine will use more fuel in the happy area, despite being physically smaller than a non-turbo engine with the same horsepower output because it uses extra fuel for cooling of the combustion mixture. The non-turbo engine will use more fuel in the unhappy area because it has more internal friction. I have a personal preference for the latter because I drive a lot in the happy area. Non-turbo engines also just feel and sound better to me.
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.
The run where he floored it and changed gears early, I think he got hood mileage because you spend a decent bit of that time in neutral shifting 5 times. Regardless it’s not healthy for the engine to be flooring it under 2k, especially turbo charged ones. Mine throws misfire codes the moment I get into boost under 4k if not fully heated lol.
@@kunfupandarofl yeah, true. It would lug the engine, wouldn't it.
Passed today with about 15 hours of lessons these videos helped so much lol
Wow, that's not many lessons at all. Congratulations on passing!
omg youtube, stop recommending great channels, I DON'T HAVE ANYMORE TIME TO WATCH! GJ man!
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 😄)
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
I'm interested too.
I drove a 1.4L Clio for a few years before getting my 1.4L TSI Ibiza, coincidentally it looks like it has the same engine as Richard’s Leon in this video.
From my experience, the slower (non turbo) Clio was much more forgiving on full throttle. I could spend a good portion of the journey giving it all she had (which wasn’t much) and not have to think twice about the MPG which usually came out around 39-45. It never strayed away from this figure regardless of how much or little I tried to drive efficiently. I guess you could say the “spikes” in consumption were smoother.
The Ibiza on the other hand varies much more. A gentle drive can see me around 48-55 MPG. A faster drive could drop the MPG right down to 38 which is a huge difference.
I’ve found the turbo engine to be more fuel-efficient but *only* when I wanted it to be. By comparison it drinks a lot faster when you want that extra performance.
@@joshuatk59 What's the difference in power? did you factor in braking? If you are driving faster and braking from higher Vmax then you are also gonna put more energy in to heat.
Skoda Fabia 1.6 16V (77kW) non-turbo petrol.... I work in town 18 kilometers from where I live, there are 6 villages on my way to work stuck together with just few km between each of them...
I can get around 5.8-6,1l/km riding 50km/h in 4th gear (around 2000 RPM), giving it full gas after leaving the village shifting into neutral at 80km/h or 100km/h (a bit over but my tacho reads +5km/h) and cruising into another village....
I can get around 6.1-6.7l/km riding the same speeds, getting feet off the gas and leaving it in the gear (I have my spots to ease off and to get around 55-60km/h entering the village (city speed limit is 50 +-10%) but not being in the neutral literally half the time... Accelerating to around 70-75km/h and shifting into the 5th at around 2500ish RPM and being a bit gentle on the throttle accelerating all the time...
And by the way, look at that... the car in video suggests you to shift into the next gear at around 1800RPM, which just looks silly in car with TURBO.... jesus
@@joshuatk59 turbo engines have always been more thursty in the town traffic compared to NA engines, but in comparison the turbocharged engines have a nicer power delivery and better economy if you drive smoothly
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.
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!
Carburettors were even less efficient at low loads than modern engines, so in the past that may have been true.
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.
I am interested too.
I have an eighteen year old, SLK 350. Sport returns a better MPG than comfort mode. I've not tested as exact as this but slow speed destroys my MPG. I'll experiment more at a later date,
@@JohnPaulFoster I'm not sure myself about the sport/comfort thing. I'm not surprised you get bad mpg showing slower/ in traffic etc because you've got a big 3.5l V6. Bigger engines like yours would be at their most efficient in top gear on the motorway, with alot less of a penalty for going 70+ mph compared to smaller NA engines. A bigger engine doesn't have to work/ rev as hard for faster cruising. Due to its size it will burn more fuel in the slower regime because the extra capacity is largely wasted.
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 😀
Accelerating gently not only helps with fuel economy, but it also increases the engine lifespan. It has many benefits but accelerating too slowly can be a problem. It can cause the traffic flow on the road to slow down and may also cause clutch wear and tear if you hold it down for too long (especially partially).
Just please don't be one of those guys accelerating so slow on the ramp that they merging into the highway at 50kph its not safe for you or the people around you.
I really like how you adjust fuel consumption to all types of measure
Passed today with 4 faults. THANK YOU SO MUCH FOR EVERYTHING.
That's fantastic news! Congratulations on passing!
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.
Interesting this makes lots of sene
Well, that explains a lot! I have a 2020 Toyota Corolla hatchback with a 2.0 liter NA engine. I've noticed that I get far better gas mileage when I really get the engine revving before I change up a gear. Like, 4,000 rpm, as you mentioned (with the exception of 1st gear, I change up into 2nd as soon as I can). My car's normal rpm is 2,500 or so. If I change up at 3,000 rpm, I get fewer mpg versus waiting till I reach 3,500 or 4,000. I had long been wondering why I get better mpg when I accelerate more aggressively, and now I know why!
I would like to test an NA engine, but as I understand it, wide open throttle at low RPM in an NA engine will have a higher efficiency as there are less pumping loses and the fuel mixture will be less rich than a turbo.
Baseless claim
Remember that naturally aspirated engines are happier at high load low RPM than a turbo car
Yo. You literally taught me how to drive manual transmission. Thanks mate
I can tell this channel has useful content
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.
Goddamn, with a petrol engine? Thats awesome MPG
@@BasedMan Light car, really small modern engine. That's the recipe.
For that MPG result, is that In town, combined or motorway?
I accelerate quite gently but still acceptable on roads and change at the earliest point possible (usually 1800-2000rpm) get about 55-60mpg in town (where you constantly accelerate and slow down) in my 1.4 turbo diesel hatchback.
@@squeakers27 my commute is around 75% A roads and 25% city. I'm rarely ever out during rush hour though. Funnily enough though I get around 80mpg in city driving and 70mpg on A roads (at ~50mph). My partner has a 1.9 diesel Skoda Octavia and I find it gets opposite results, about 50mpg in the city and around 75mpg on A/M roads.
My best ever full tank was this year around the time of that 40°c heatwave at 79.1mpg (it did 494 miles and used 28.4L). I was taking it steady though as the cooling system on the car was struggling to keep up when ever I used the throttle. It was probably unnecessary really as the fan never kicked in anyway but I did see allot of broken down cars on the drive to work that day!
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 hate it when how I think things are is shattered by a youtuber. good video, thanks for taking the time for the experiment
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. :)
I think you misunderstood. Your engine is most effecient at full throttle AND LOW RPM. Shift at 2k and you'll see the difference.
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
Well the idea is that since acceleration uses a lot of gas, you want to be doing it for as short duration as possible, while taking advantage of the efficient bands of the engine, so high load, low rpm - around peak torque. My theory is that this engine ran rich to prevent knock when he was full throttle and shifting at 2k, and there would be more advantage in a diesel, where knock isn't a problem
@@EndstyleGG that would work for a tuned engine or high performance car from the factory. Most of us that drive the grocery getters won't have any advantage to doing hard accelerations cause those are mapped to just dump fuel to keep up with the rpms since the injectors are small.
@@Kisame663 cars tend to be most efficient at around 50-55 mph.
The reason people think it is better to accelerate faster is because you would be at the most efficient speed for longer on the same piece of road.
they are actually correct to an extent but can overestimate how fast they should accelerate.
hence the purpose of the video.
@@alfaruuto5182 that I can agree with, but it's wild to me to think people believe hard accelerations make any kind of sense outside of race applications when you're trying to save gas with these bonkers gas prices.
Probably if you accelerate like 5 times slower than "very gentle" run youd probably get worse economy, but again maybe and no one will ever do this, so slow acceleration is the key.
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.
Tnx for your videos. ,👊 really helpful . 🙂
Nice heel and toe and 13:56 bud. Love seeing good driving techniques. Nice vid btw. earned a sub
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.
i passed first time yesterday with 0 driving faults thanks to your vidoes!
That's fantastic news, thank you for watching and congratulations on passing!
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
naturally aspirated engines benefit from more throttle at lower rpms, since theres no turbo to hurt the economy by forcing a bunch of air into the engine.
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.
That was good. Well done.
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.
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.
Very useful video. Make more of these fuel saving test videos.
A question...
What is the most efficient minimum and maximum speed in top gear in normal highway condition?
My car gets it's best economy between 30-40mph. But this is too slow for the highway. Generally, lower highway speeds are more economical, but you still need to be fast enough to be safe.
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!
Thanks for confirming what I always believed! I am curious if the results remain consistent on a slight incline?
I would love to see the results of the same tests but using an automatic with a traditional torque converter. I've heard that torque convertors work more effectively as the RPMs rise and also most efficient once you achieve the clutch lock-up which only happens after the car thrust load has reduced back down. On a standard transmission, you always have clutch locked (while in each gear) but in automatic there is a lot of “slippage“ between the turbine and impeller at lower RPMs. Testing a modern CVT (like Honda's) would be interesting too. My gut wants to say a moderately strong acceleration would yield best MPG because the TC would get spinning faster and lock-up would happen sooner.
Thank you so much for your videos just passed my test today with 1 minor
That's great to hear! Thank you for watching and congratulations on passing!
Love the choice of music in the Kia onboard
This was really interesting. Thank you for this. Have you tried to skip gears?
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".
That was definitely an interesting video. One thing for anyone who was saying that accelerating harder should have resulted in the same/better fuel economy, because ICEs are more efficient at higher loads - That may be true in theory, but in practice I think there are two things that you’ll find will cause worse economy at higher throttle. The first is called transient throttle enrichment - it’s a part of the ECU programming that adds extra fuel when the position of the throttle changes rapidly (as would happen during a gear change in a manual transmission car). Adding extra fuel will worsen fuel economy somewhat, but it keeps the engine from running lean and potentially detonating. The second is that at higher loads, engine tunes tend to target a richer AFR or
engines are more efficient at higher loads, as long as you dont get to the fuel enrichment range
newer cars use numerous techniques to decrease the efficiency gap between high and low loads
a good example on this is the egr valve, putting some exhaust gasses back in the cylinder means you dont need to throttle the air intake as much, which means less pumping losses, which in turn gives better low load efficiency
however, there are numerous reasons why accelerating hard and then cruising is worse than gentle acceleration
an obvious one is getting up to speed faster and then cruising results in more aerodynamic losses
one that is not as obvious though, is the efficiency thing. high load (at low rpm) is indeed more efficient, but when cruising you are under very low and inefficient load. gently accelerating is more efficient than cruising because you stay on a medium load. if you look at a bsfc chart and find 3 points that represent these 3 scenarios, running a few calculations will show you that whole story
Would be interesting to compare different methods that have the same total trip duration: accelerate fast(ish) and cruise at a lower speed or accelerate slowly and cruise at a higher speed. And all that for as realistic a trip as possible: several accelerations and decelerations etc.
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.
plus the strain on components in the vehicle and safety
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)
I have tested it over more than 600 fill ups using fuelly. It usually under reads by 1-3 mpg. As in I get better real economy than it says.
Good video, interesting. I drive a VW TDI with a 6 speed manual. I often use 3/4 throttle when accelerating and but keep my rpm down. Always figured it's good for a diesel to work a little hard and get some boost. Diesel will have slightly different efficiency curves.
Which app are you using for the test you are doing for your car?? Btw I’ve learnt a lot from your contents
Fun and interesting video :D
Helpful, thanks! I go up to power band, shift, repeat, 5th (or 6th, if it's there). So 1, 2, 6th. I'm in 6th as soon as I hit 25 and then barely above idle keeps me coasting. I feel like that does something for fuel savings vs staying in a lower gear at 2500 like most stick people I know like to do