Why Small Turbo Engines Are Not Efficient

Why Don't Small Turbo Engines Get Good Gas Mileage? (Real World)
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In attempts to improve fuel economy, many companies are choosing to downsize and turbocharge engines. These small turbo engines tout the power of larger engines, but with much better fuel efficiency. You may notice however, your real world fuel economy may not always match up with the EPA numbers provided on the vehicle's monroney sticker.
Why is this? Well while downsized turbos do have many advantages, such as less moving parts, less weight, better packaging, lower frictional losses, and lower pumping losses, once the vehicles start to get into boost, that efficiency can be significantly lower. This video will discuss fuel enrichment and why it's necessary for high boost engines in order for them to run reliably.
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[@233kosta]

People forget - your right foot is connected to a valve. That valve drains your wallet ;)

[@MFizzle777]

You mean that valve is then connected to your wallet!

[@MrFister84]

@@MFizzle777 Oh shut up.

[@leezhenxiang4146]

i smell the foot where it is burning the notes TT

[@keithgenegallo6675]

This aged like fine wine. 😭

[@sigmamale4147]

Agree, i can go through liters in ten minutes or 1 hour depending on how heavy it is lol

[@tokinGLX]

3:37 "as you floor it" well there is your problem right there. if you want fuel efficiency, why would you ever floor it, n/a or boosted?

[@joeyhayes3137]

Spool noises make me happy...

[@dmytrosednev9867]

Some people buy cars, especially performance models to floor them. These type of people never cared about the fuel economy. Bureaucrats told the car manufacturers to lower fuel economy across the fleet. They decided to cheat. They created these small turbo engines to trick the test and lied to us about their fuel economy. We ended up with inferior product in terms of fuel economy (for the way we drive), decreased reliability, and worse dynamic characteristics (in a way or lag). Environment loses out too. My 2l turbo from 2020 in a smaller car has about the same fuel consumption as my 2003 3.5l V6 in a larger car. Go figure.

[@stealthg35infiniti94]

@@dmytrosednev9867 Agree with you...Now some manufacturers want to put a 4 cylinder turbo in a full size pickup truck...It will very hard not to bury your foot pedal when loaded...I guarantee turbo replacement will be very common before 120K miles in these over taxed vehicles...The fuel savings money if any, will be negated by the expensive repair...

[@441meatloaf]

Why wouldn't you floor it? When manufacturers like Honda put small engines like 1.5L turbo you need to floor it to get the power and passing power you need on the highways.......

[@pharaongaming8617]

@@441meatloaf well that's the thing, if you want to get the best fuel economy you drive very very carefully and slowly

[@teop7887]

My Alfa Giulia has the 2.0 turbo, and if I don't push it, the mileage is amazing. It really comes down to driver input.

[@juconkey420]

Had a Kia Optima turbo was getting around 31 in town. That's it you drive for economy and they deliver.

[@teop7887]

@ True, but there are plenty of FI vehicles, from Saabs to Volvos, petrol and diesel alike, that have achieved long odometer readings. By mileage however, I believe they meant consumption, not longevity. Cheers 👍

[@BluntEversmoke]

@@teop7887 Saab turbos break down constantly.

[@teop7887]

@@BluntEversmoke I know, but I didn't say all, I said many have managed to pull that long. Cheers 👍

[@nthgth]

And for some reason you don't think you'd see the same benefits from a modern V-6?

[@SpaceCadet4Jesus]

There's only ONE reason why my turbocharged 4 cylinder gets bad gas mileage.... REASON: It's because my foot's in it so far that the fan is clipping my toenails..

[@davidelliott5843]

An that's because its gutless ;)

[@ryansims9331]

You might want to trim your toenails.

[@ACERASPIRE1]

You're so cool Space cadet

[@campkira]

Don't had that problem with v6 or v8..... it is fine if you try to cruise on high way but yet again a Bugatti can cruise on the highway.... less power mean more rev and breaking and more rev.... while I just shipped down a few gear..

[@stevenjalopnik1342]

Yes you are correct. HOWEVER... let’s look at the 718 Boxster for example. The previous gen was a 6 cylinder and the new one is a turbo 4. They promise the same power from the new one with better economy. Perfect right? The problem is however that power is when the car is on boost however the fuel economy numbers are when the car has not hit boost. So you either have better economy or more power but not both. Therefore a turbo 4 is not a replacement for a na 6

[@Kraigmire]

I always looked at turbo'd engines as having the smaller displacement when driven softly and a larger displacement when driven hard. Therefore, you will only get good fuel economy when you drive very easily, but you have the option of way more power when you want it. You just have to sacrifice that fuel economy when you want power. Kind of like cylinder deactivation, only more reliable.

[@siraff4461]

Apart from that smaller displacement being tied to lower compression or retarded ignition. Basically you have no power until it's on boost. It would make more sense to have the larger engine and turbo that to the same power level so it can run higher static compression and less boost.

[@goodmandiad2713]

I had (2) 2.0 Direct injection turbo engines, one in a Forester XT the other in a Sky redline. Both rated at about 250-260 HP. My 13' Accord with a 3.5L V6 (rated at 278 HP) and variable displacement was faster and got better fuel economy. The Accord ran on 3cyl when that is all you needed. Problem with a turbo is you are always into the turbo and asking more air and fuel to get moving and stay at highway speeds. If you paid attention to the whole video they reason for these turbo engines is not really fuel efficiency but to get the EPA numbers higher. That does not translate to real world fuel economy. Ask anyone with an eco boost Ford Pickup. The Accord with cylinder deactivation is 100% reliable. before 13' there were issues, especially on vehicles where people didn't step on it so much. Even in the older ones people easily got 200K if the changed the oil regularly.

[@TheNerd]

@Si Raff small turbo engines start boosting at like 1300/1400 revs... there is no safe "no boost" range cause if you drive it below boost you are going to damage your engine

[@siraff4461]

unheardNerd Go on then - what damage will it do if you drive off boost? This should be good.

[@TheNerd]

he did a very long video about this. driving in low revs. i dont remeber the name

[@sruijc5250]

so.......what you’re telling me....is that they *ARE efficient* , but idiots keep flooring it while expecting to get 40mpg.

[@paulanderson79]

Exactly. No point buying a highly fuel efficient car and then driving it for performance. Unless we want to drive impossibly slowly then it makes more sense to buy a car that suits your needs and preferred driving style.

[@Boz1211111]

People dont have knowledge or patience.

[@spawnof200]

get a motorbike, you CAN floor them and still get 40mpg

[@Boz1211111]

@druss999 true. i am trying to drive as efficient as i can and most people find that laughable... when i calculate savings its a different story, though im not really sacraficing driving pleasure, efficient driving is my thing lol

[@thePavuk]

No, problem is that EU won't allow to make different motors so now you have 1 liter in cars where was 1.6-2.0 liter. Except some rare 2.0, biggest engines is 1.5 3cylinder.

[@MartinA-xh9ck]

A turbo engine is great power when you kick it and eco when you don´t. Its that simple

[@MMizie]

Which mean if I dont push the gas too much I can save more fuel?

[@unrealisticgoals]

@@MMizie if you dont push the gas at all you save all the fuel, amazin right?

[@rickeydriskill1096]

You have eco or boost. You cant have both.

[@Buzzzardtolife]

Carlos Soriano Q

[@stephenpowstinger733]

Some say the flat torque curve means a turbo is less exhilarating to floor it. And a little boring to drive.

[@LegacyIvyTerascale]

in short : you're Jeremy Clarkson , or James May

[@alessandromontalto823]

seems legit.

[@christianbro2]

Hammond doesnt count because hes crashed the car?

[@firdauszainudin7118]

hybrid of those two

[@GrockleTD]

@@christianbro2 he's very good at coming to a quick and sudden stop

[@wadimek116]

​@@GrockleTD Which is not very economical if you think about it

[@humanperson900]

"You dont want that many cylinders" *laughs in Italian*

[@jammi__]

Yeah, the Italians drive mostly in small Fiats with tiny powerless engines and always did. I think you meant *laughs in top 1%-er*

[@arunkumar-ok4pm]

@@jammi__ I think he was referring to the Lamborghini

[@dantevito1193]

*laughs in bugatti*

[@beezanteeum]

@@dantevito1193 Bugatti is French, not Italian

[@dantevito1193]

@@beezanteeum i know, i'm just saying that bugatti has a lot of cylinders Just ignore my old comment

[@EvanMoon]

The answer is more stickers

[@guerrillaradio9953]

lmfao.....

[@mr.357mag4]

Evan Moon And the flame paint job

[@TheRealChilly]

"This sticker added 5hp"

[@boonvang708]

I started putting racing stickers on my computer i havent noticed a difference at all.

[@1barnet1]

The answer is water ethanol injection. Just look up the german BF109 late variants.

[@notmirelnam248]

You mean to say that when my engine is making more power, it's also using more fuel? Say it ain't so!

[@remissiveslave]

It's not so

[@topkek7003]

not necessarily, compression ratios play a pretty big part. two engines can be using the same air fuel ratio at the same displacement, and provided the fuel can handle it, the engine with higher compression will make more power while using the same amount of fuel.

[@christianbro2]

Its efficiency what we are talking about. If you accelerate little with a smaller turbocharged engine it is going to consume less than a naturally aspirated engine. If you accelerate more, it is going to consume more. Consumption tests are done when accelerating little, while in the real world, you may accelerate more, so consumption is higher than its rating, or higher than the former N/A engine.

[@marcuscook5145]

Not always, but if the extra power comes from forcing more air at once, then yes... because more air always requires more fuel to keep the same A/F ratio. You can make more power and gain efficiency by adding compression or reducing friction. You can also improve breathing, which while not cramming more air per stroke, does shift the powerband into higher revs... since you have to rev higher to make the power afforded by the airflow, you have more strokes.... so you still use more air (and fuel) overall if you want to take advantage of the power gains.

[@rupunzel6299]

Not quite so simple as richer fuel mixture and retarding ignition timing to prevent pre-ignition (aka Detonation). Combustion chamber shape and piston top shape, detonation sensing, intake air temperatures and LOTs more factor into how good any turbocharged engine could be. To overly simplify turbo engines are less fuel efficient due to the need to enrich intake mixture does not factor in or account for how some manufactures have addressed these innate problems with turbo engines. Example: Saab-Scania's B234 & B204 turbo engines have a static compression rating of 9.2 to 1 and they achieve good fuel economy with balanced shafts (which consume power increasing fuel consumption). This is done by using a well designed pent roof cylinder head combustion chamber and a domed down piston top and intake/exhaust gas flow pattern control. These basic designed in factors work to prevent detonation with and without turbo boost. The more complete burn due to the afore mentioned design elements in the engine work to help the intake charge burn more complete which extracts more energy per intake charge, lowering emissions and resisting the potential for pre-ignition aka Detonation. To monitor pre-ignition at each cylinder burn cycle, Saab uses in cylinder ionic sensing of the burn in process via the spark plugs. Before and after the intake charge is ignited by the spark plug, the spark plug becomes a sensor to detect pre-ignition and alters when the spark plug is fired as needed, per intake cycle, per cylinder. To address intake charge temperature rise due to air compression by the turbo an intercooler is used to reduce the heat of the intake air. Intake air to the intake manifold is monitored for air temperature and air density. Both are figured and LOTs more factors are figured into the amount of fuel to be injected per cylinder. These factors work in conjunction with the ionic pre-ignition system using the spark plugs. The Saab-Scania turbo engine management system IS one of the most sophisticated out into production with with many technical features that are not recognized, appreciated or understood. Beyond Saab-Scania's turbo engine management system, the B234 & B204 engines are built really tough, durable and very strong to withstand the increase in torque of a turbo engine. It is also why a stock B234/B204 can be up boosted to 450 lb/ft of torque as delivered. Forged chrome-moly steel cranks with nitrided bearing surfaces, Forged chrome-moly steel con-rods, forged aluminum alloy pistons specifically designed for turbo engine duty made by Mahle with oil jets and additional oil cooling features. Stout main bearing and bottom end design, good coolant flow design to move the larger amount of heat produce by a turbo charged engine, oil cooler with thermostat to reduce the oil's operating temperature.... These are just a few technical reasons why Saab-Scania was able to produce a reliable-very durable turbo engine with good fuel efficiency for a given power requirement. These same turbo engines also features low emissions. Turbocharged engines are essentially a two stage pump system that recovers some of the heat energy that would have been lost via the exhaust to increase overall engine efficiency. The added plus of a turbocharge, lower exhaust noise due to conversion of that pulsed energy into rotational forces to drive the turbine.

[@johnferguson7235]

Not everyone drives at sea level. Turbocharging makes a huge difference when driving at higher altitudes. For the vast majority of the time, the engine is operating at only a limited throttle opening. Sure, if you smash down on the gas pedal all the time, your fuel mileage will decrease. The advantage of the turbo is that the extra power is there when you need it; entering onto a freeway or climbing steep grades or over-taking slower vehicles. You must factor in the effect of the intercooler in any discussion on engine efficiency.

[@stephenpowstinger733]

The air forces realized in WW II that superchargers ( turbos cousin) increased high altitude hp.

[@LunarStrike]

@@user-zv8qg1co4z I never had a time where my lancer es n/a 120hp engine had me wishing to have more hp to get on a freeway ramp lmao. And on my 18 wrx if I go above 10% foot pedal then rip fuel economy

[@theJ4ZZ]

All the Coloradans raise their hands 😝

[@SkylineFinesse]

@@LunarStrike mine could do burnouts in 2nd-3rd. Beast of a car for what it was

[@Explorerman1293]

All I heard was V8s are more efficient and I should drive my turbo car fast for better mileage. Don't correct me, this is the world I want to live in.

[@kunalsing8164]

Danny Daskalakis That’s my world as well

[@daszieher]

I like your world, which is why I have the best of both ends described by you: turbo-six :D

[@jamesavery6671]

Larger engines just make the power easier. Don't need all the turbos, cooling lines etc just to make 400 horse with a v8

[@Playboysmurf1]

Is your world Venezuela ?

[@MrCarguy2]

Playboysmurf in Venezuela there are no cars to start with

[@shapshooter7769]

In the case of extremely high boost pressures, I remember seeing twin-fuel systems being implemented. Check out the Ronin Exige, which uses a separate methanol system that is injected into the engine after reaching a certain boost threshold. The methanol increases the octane rating of the gas being burned, at the expense and complexity of two fuel systems in a single car.

[@yesok3379]

Love your videos sir. Facts supported with evidence. So rare and very much appreciated. PLEASE keep it up!

[@panther105]

When my Firefly Turbo kicks in around 3000 rpm, it feels like an extra cylinder just started firing. My 3 cylinder, 1 litre suddenly becomes a fire breathing 1300. Hold onto your hats....!!!

[@EngineeringExplained]

Stay safe out there!

[@panther105]

It's too slow and fun to drive it recklessly. No airbags in 1991..... Easy to work on....but a death trap any way you look at it. Just incredibly cheap to drive to work.

[@Dockhead]

i see these engines being used in the new fiestas etc in the UK and really wanting to know are they really as effective and powerful as a 4 cyl engine with near enough same HP or even less, there is a fiesta ST model not sure on exact name of model, but its sports a 140hp 3 cyl turbo engine and im just amazed that old 6's didnt make that much more before.

[@anthonywebber2211]

panther105 i had a non turbo Geo Metro, and every two weeks was a massive $35 fill up lol, i now have a 2005 Chevrolet Colorado and $40 is only half a tank now

[@conman1395]

pescod96 look at Carwow's comparison between the 3 cylinder and 4 cylinder Fiesta ST

[@FlatPlaneCranky]

This makes perfect sense. My 2017 GT Mustang gets 26 mpg on road trips. My Kia Optima gets 28 mpg on the same trip. You can guess which vehicle I prefer when I go!🏎

[@daos3300]

nice! would love to see more on superchargers. tons of available info on turbos, comparatively very little on blowers.

[@josemanuelruiz2036]

I recently saw a video made by Jason Camissa on this subject that left me with more questions than answers. You just clarified everything. Beautiful explanation. Thanks!!

[@jaredhoats1846]

I'm a proud owner of a 2018 Civic Si with the 1.5 L turbo that's pushing 20.6 psi from the factory. I get well over 30mpg under normal circumstances because I don't rev the crap out of it like some people do. They complain the mileage is bad; yeah it's gonna be bad when you're hammering the throttle all the time. These cars were built for the instances where you need power, but most of the time you want to save fuel. They're not supposed to be efficient when you're hammering on them

[@SoldMyHat]

I have an 18 si as well. I get better than advertised on the hwy. If I keep my foot out of it, very hard lol, I can get 40-42 mpg

[@yurrr7511]

I get over 41 with my 2012 Altima, and its rated at 32 hwy. my city mpg sucks tho lmaoo

[@rareginger2113]

18 Civic Hatch, hammer the throttle when taking off, slowly decelerate after getting about 5 over, barely hold speed with very light pressure on the gas pedal : 34-37 mpg city Same car, eco mode on, give as much throttle as I can while keeping a full green eco bar, 5 over to decelerate the maintain same as before : 42-43 mpg city 43-47 highway I only use Shell Premium

[@rareginger2113]

It's an EX Cvt 18 hatch (1.5L Turbo)

[@gwcrispi]

I'm going to buy one after the refresh. I'm going to hammer the throttle all the time. Who cares about mileage... Good thing I can afford all of the fuel I will be burning! ;) Great car.

[@mkkm945]

I owned a Suzuki with a Fiat sourced 1248 cc 4-cyl diesel. Really small engine. 75 horsepower and 143 ft lb torque. I used to joke that my fuel economy numbers were directly related to my mood. During my 3 yrs of ownership, I recorded anywhere between 30 mpg and 62 mpg which almost entirely depended on how I was feeling and how calm I was driving. That engine was stunningly efficient at, say, 2000 rpm cruising in 5th gear. Push a little to overtake someone and it would be the exact opposite. I think that means that a good/sensitive driver will be able to get good gas mileage if he/she is paying attention but the average joe may struggle to replicate EPA.

[@chir0pter]

Great video! It'd be interesting also to see how say an LS motor stacks up against a DOHC V8. It's interesting to compare how the E92 M3s compare to the Corvettes of the same era in terms of mileage, for example.

[@rdlytle65]

Love your videos. Always informative!

[@johnny-bracer6515]

Very well explained Jason. As usual. That's why I've been a subscriber to your channel for so long. Bravo chap! Keep up the good work

[@mattdagger1480]

I’m surprised you didn’t mention the option of higher octane fuels to help reduce knock. Typically the factory turbo cars use a specific type of programming or ecu tuning called “adaptive octane logic” so the computer can tell how high of octane the fuel it’s using is. Most of the factory turbo cars tend to “recommend 91/93 octane” for this reason. Basically it allows you to use 87 if you want but once the adaptive octane logic sees the fuel is crap it can set a lower cap on the engine timing. So let’s say you use 87 octane. The adaptive octane logic may set the limit of the timing to 12 degrees(advanced) well once you throw 93 in the tank and the sensors sample that fuel it will increase the limit of the timing from 12 degrees to lets say 20 degrees (advanced) resulting in more power out of the same calibration all while keeping the engine safe.

[@mikep490]

True and a lot depends on how heavy your foot is applied. With a light foot the tranny can shift before the turbo kicks in. This eleminates knocking and the need for high octane fuel. In this scenario, lower octane fuels can get the same MPG w/o spending that extra 10% per gallon. Regular gas ignites easier and burns quicker than premium which can improve MPG in some scenarios. For the lead foot driver, premium offers more power and better MPG but offset by the fuel's expense.

[@thresh-]

That's because higher octane gasoline doesn't actually affect fuel economy. That sales point is a scam. If that were true, all car manufacturers would design engines for that type of gas, and all gas stations would serve only that type of high octane gas.

[@mattdagger1480]

@@thresh-idk if I’d use that as a blanket statement for all cases. Especially since if your engine is knocking and the fuel system has to retard the timing to compensate for it. Then in that situation the higher octane would result in better fuel economy. It’s not as cut and dry as most people think who haven’t studied the modern fuel systems in the past 10-15 years honestly. No disrespect intended. People just assume cause they knew long ago it’s the same as it was. And fuel systems and the methods engineers use to control the fuel systems have drastically changed over the past few years.

[@mattdagger1480]

@@thresh- for someone like me a master tech of over 15 years to hear someone say higher octane dosnt affect fuel economy it just shows people like me you don’t understand Timing, long and short term fuel trims, what octane actually does and how it affects an engine, or how modern fuel system works. Again no disrespect. But when people say blanket statements like that it really shows the uneducated ignorance unfortunately

[@skaownz234]

@@thresh-Domestic car companies are lobbying for a unified 95 octane fuel. Makes sense since we have so much corn ethanol. Lower octane fuel has a little more enthalpy, but not being able to compress it as much is costly.

[@JayzBeerz]

Just bought a 2019 Sonata Limited 2.0T. Thanks for all your turbo videos.

[@LuisTrac]

Man thanks for all of this analysis and information!!! I truly appreciate it

[@jonniemactyler7929]

I've got a 2017 Honda Civic Hatchback. For life of that car so far, I have averaged 41-42mpg according to the in car mileage tracking computer. So probably a little less than that, but I would put it at about 40mpg based on when I actually did the math of mileage/gallons at fill-up. I drive 40 miles per day and mostly on the highway going to work & back. Even when I've been driving around town (stop & go) and sitting in fast food drive through lines a lot, my mileage hasn't shown below 36mpg. I don't remember filling up where the computer showed less than 40mpg. Basically if you aren't getting 35+mpg in the current model turbocharged Civics, then it is your driving to blame. Most perceived gas mileage problems in vehicles are the fault of the driver.

[@monkeymind3067]

It is Japanese HONDA

[@Encryptus1]

I have a Geo that does 52mpg... 😂

[@M1911Guy]

My 2016 Jeep renegade and my 2017 Kia both did better than sticker. The Jeep was right at sticker until it cleared 7000 miles if I stayed in it. The KIA did 27 in the city with me playing around and using sport mode. Normal city was 29. The Jeep was also the 6 speed manual so that helped since they are notoriously bad on MPG. Nice video, looking forward to the Mazda.

[@davidperry4013]

I usually prefer Naturally aspirated engines but, twin turbo 3.0 V6s are quite nice.

[@kevinc2332]

Turbo lag is a killer though

[@fracturedrealitygaming1326]

I’ve got a 2012 Chevy Cruze with the 1.4L I4 Turbo, and I’m completely turning this thing into a project car. I’ve got a wrecked ‘15 Cruze LTZ with the rear axle disc setup that I’m stealing for my Cruze, and I found a ‘13 eco that caught fire and was totaled out I’m gonna be cannabalizing the frame and splice welding pieces into mine to elongate the engine bay so it can accommodate a 2JZ engine with a twin turbo setup. And it’s thanks to watching your channel, among others, that I’ve been able to realize i can make this happen! Yours just taught me the how it all works at it’s base so that i can understand how my vision can come to life. So thank you man

[@Remenschneider]

Knock is not the only reason for having to use a rich mixture, exhaust gas temperature is also really important. Water cooled integrated exhaust manifolds really help increasing the lambda = 1 operating range. Current Miller Cycle engines like the EA888 Gen 3b can even run stochiometric in their whole operating range. Also, this video really should have had a bsfc diagram in it to show why smaller engines (higher internal pressure) are more efficient at partial load.

[@impulsivetravelerguy2448]

I have a 2017 Ford Focus with the 1.0L Ecoboost. When putting a load on it, it's a pooch until you get the RPMs up. Where it is great is open highway driving where you can set the cruise control. I'm a travel blogger who travels by car through North America and the 1.0 is great in terms of fuel economy. I regularly exceed the 40mpg EPA estimate. My best is 52.4mpg when I drove from Winnipeg to Thunder Bay on a 2 lane 90kmh (55mph) highway. Even in Texas I still get 40-45 maintaining 75-80mph. For my circumstances, it works great. I do see it not being as good for more city stop and go driving or if I actually had to pull something. I also gave it a run for its money when I had to drive the hills of Duluth, MN from a dead stop at a stop and go light.

[@stealthg35infiniti94]

Really enjoyed the Geek explanation...Keep them coming!

[@starryvoyage]

Free education time !!! Thx for making another great vid!

[@rnreajr9184]

I have a small (1.4 liter) turbocharged engine in my car. I have never gotten the mileage that I thought I should be getting, and this video helps a bit to understand why this is. The real blow that I got was when my car was in the body shop for a month (let's just say that it was the busy season, and that's all I have to say about that). I had a rental car that was a larger sedan with a V6, and it got better mileage than my smaller car. I still miss that rental car...

[@estuardo2985]

yeah, you have to drive like "that annoying slow person" to get those rates.

[@Kristian-oj7qy]

Stay out of boost and your gas mileage will be good 🤷🏻‍♂️ (really hard to do sometimes)

[@mitch9521]

hard to do when it makes 9ft.lbs of torque without boost.

[@AlanTheBeast100]

Hook up an OBD to it (if you don't have a gauge) and monitor. Even in cruise there will be some boost - and that's okay - just means you're getting energy out of the exhaust flow to make the small displacement engine behave bigger. Lighter engine=fuel savings.

[@kurtsaenz4048]

Kris91790 Very true. Really difficult when the turbos start spoiling at 1,700 rpm though, but it saves gas.

[@yourbabyboyfriendonlyme2485]

@@AlanTheBeast100 Well I know OBD2 stats suck. The O2 sensor just sucks at its job(to freaking slow). Plus on some vehicles they have the o2 sensor behind the cat ALSO. SO WHAT IS THE SECOND CAT TELLING THE FIRST O2 SENSOR TO DO? DON'T SAY IT JUST TELLS THE ECU THAT THE CAT IS WORKING! When Pee my brain tells me that i'm peeing (1st o2 sensor) , If when i'm peeing my pee is black (2nd o2 sensor) brain says WTF!!! WHAT DO I DO! It freaking does something.

[@AlanTheBeast100]

@@yourbabyboyfriendonlyme2485 I'm not saying it's a substitute for a proper boost gauge, but it does indicate the MP albeit with a slight lag. (I have Bluedriver with an iPhone and it's quite good in this regard - other readers may be better or worse). The important thing here of course is not the OBD-II - it's that turbo on a small engine means more energy extracted for the fuel burned. That's the main point.

[@g1981c]

good video. what i like about Toyota hybrid system is that no matter how hard i drive it fuel economy stays good. it's really incredible - the combination of naturally aspirated engine and regenerative braking makes for a system that pretty much doesn't care what your right foot is doing - it always returns the same good fuel economy. of course some people may dislike the feeling and sound of an e-CVT but to have responsiveness of a V6 with over 40 mpg in real world driving - i'll take it.

[@Kaz-ct3vd]

I was very impressed with ford focus and its 1L 3cyl turbo, easily got 45mpg. It has a very low torque range so you could run it below 2k rpm and it still pulled nicely. I didnt get it for performance though, wasnt as peppy as a normal 2L.

[@DS-TRUCKS]

Also keep in mind how people drive turbocharged vehicles. When you're driving a big V8 you have to drive slow to get any decent kind of mileage. Where most people who drive turbo cars always have their foot down... Who remembers the old days when you could literally watch the gas needle move in a V8 truck?

[@otm646]

DonnaSean this is exactly the problem. These smaller turbocharged engines are usually dramatically more powerful than the naturally aspirated motors the owner was previously driving. Thus the driver accelerates significantly faster than their old car ( horsepower requires fuel either way) and then complains about the economy.

[@timfox2344]

‘71 Olds Toronado ... 455cid, kick in the 4 barrel over 70mph and just watch the gauge drop 1/10 every few seconds

[@lildeena1]

I just rented a Kia Soul that did that from full tank to a half a tank Driving 80 on a short 80 mile trip. Watched the needle move.

[@johnoehrlein8379]

70 Chevelle 396 ss w/cowl, yup it def was a race, those were the days

[@youkofoxy]

see the gas needle move? that remember my first car, i kind fixed it... but the ECU was think the engine needed more gas. in fact the poor thing barely moved.

[@tempk490]

Interesting video. I have a 2017 Jetta with the 1.4 turbo. EPA Highway estimates are 40MPG; doing 65 mph I'll get 48+. I've been delighted with the gas mileage so far, however I'm not doing autocross or anything.

[@ManuJohn380]

Brandon M but Toyotas new 2.5L NA with 200hp is getting 45mpg at 75-80 mph in a much bigger car.

[@Iraqveteran-ke6qu]

Same here. It's been great to me.

[@jakegarrett8109]

What's funny is my 30 year old Mercedes gets better than "Highway EPA" while doing burnouts... I laugh at those ratings, so innacurate, I've never made that bad of fuel economy as they say.The diesel Merc makes 35-40 mpg driving wild, rated 27 from EPA My Mazda on the other hand is impossible to hit its rating (best was 19.2 MPG drafting a Semi for 150 mile run at 65mph in 6th, the EPA rating is not realistic). Normal in town is single digit, but who cares, its a rotary, drive it like you stole it!

[@Tonyx.yt.]

epa rating could be not so realistic but still much more realistic than current (soon replaced) european test... the worst one was a extremly small 850cc 2 cylinder car, official numbers said 56 mpg, real world town+countryside+highway is only 35 mpg...

[@flybyairplane3528]

Tony x the EPA tests, are done on a dyno, Indoors, no road bumps, no wind, and the fuel they use NOBODY can buy.

[@digitalbilly]

i learn alot form this channel... thankyou!!!

[@TheKingkingg]

Good day. We went on a road trip in our 2016 EX-T Civic with family of 4 and fully loaded trunk for a Trip from Timmins northern Ontario to Sault Ste Marie Ontario (557km) around Lake Superior with lots of hills. We got 690km on 1 tank before fueling up. So it cost $80 Canadian in fuel... that is amazing.

[@hackfreehvac]

It is more efficient to go with a turbo 4 over a V6 but the problem is the power, especially the very low RPM power of the Ford EcoBoost, is addicting and people have a hard time not putting their foot down from a dead stop. LOL

[@ericverster4069]

lol the 2.3s are wicked fun. 5.0 not too shabby either.

[@Hollywood49]

@@ericverster4069 I miss my 1.6 Fiesta ST. Always had power whenever you needed it, regardless of what gear you were in. Too bad the seats killed my back, otherwise I'd still have it.

[@jacobrohr5903]

lmao my moms Escape with the eco boost is fun as hell to drive. it’s quick at the low end

[@billydavison3134]

I'd personally take the duratech family of engines over any of the ecoboosts in terms of reliability.

[@thetechlibrarian]

I would take a good v6 over a turbo 4 any day

[@AlanTheBeast100]

I've had a Honda Accord 1.5L (turbo) for about 2 months. The mileage is phenomenal for this size car (which also delivers up to 192 hp / 192 ft-Lbs over a ridiculously flat "curve" if needed). Using the OBD port and monitoring the wastegate position and manifold pressure, it's easy to see when the turbo is active. And that is when needed to get performance. Thus the small displacement engine consumes as little fuel as needed when cruising and more when power is really needed. That said, at higher cruising speeds the wastegate does close, but only enough to get the power needed. In effect, that exhaust energy is being recycled to help the engine breathe enough for the power demand. So, the small engine will use as much air and fuel as a larger displacement engine _when needed_. Lighter engine= less mass = less fuel to accelerate. And the consumption numbers v. my previous Accord prove beyond a doubt that a small turbo engine is a happy and efficient engine. And, BTW, no knock with 87 octane as recommended by Honda.

[@benjaminturpin2749]

I used to have a modified jetta tdi diesel. That thing was awesome. No matter how hard a drive it. I never really got under 35-40mpg in town. On the highway 50-55 all day long.

[@nts0011]

Great explanation mate, thanks !!!

[@TheLeonardoRF]

Love this video finally answer my question about why i get better gas milage in a 2.5L L6 BMW than a 2.0T in a Tucson

[@jelanifane7530]

2.0 better gas 2.5 go fast

[@nissan2829]

Idk about all of that, but in my experience, keeping at a lower speed seems to do pretty well. I have a 2013 Ford escape with the 1.6 EcoBoost engine. Epa estimates it at 33 hwy mpg. I can achieve it if I keep it at 65-70. However in Texas most of our speed limits are 75 or hwy. If I run 75, it gets about 28. Well under the advertised amount.

[@kingsford6540]

This has to do with gear ratios, mostly. The beginning of your last gear is around 60mph, so under 70 you're still in the low revs

[@joecool4656]

@@kingsford6540 air resistance is also considerably higher

[@gototcm]

Keep in mind that the highway fuel efficiency ratings are due to the way cars are tested using a dynamometer and the the Highway schedule which is run at 60 mph, not 75 mph. Higher speeds means more drag (proportional to the square of the speed) resulting in lower mpg.

[@yonatanshenhav1208]

A great video. thank you for making it

[@lang9872]

Could gasoline with a high octane number minimize knock and also minimize the injection of fuel to cool the cylinder temperature? It sounds like fuel consumption could also be significantly reduced at full load at downsized turbocharged engines. What are your experiences?

[@ICYUNVM3]

I see this a bit on the 2018 wrx. I have to downshift going up hill to keep it out of boost to see any decent MPG . Gearing in that car always keeps boost at the ready. Good for hooning in the twisties not for road trips lol

[@TL1000S97]

Two things: 1) This is not only linked to "small" displacement engines with turbo. It is the same for any *gas* powered engine using a turbo. 2) This is only relevant for gas powered engine. Diesel-turbos is another discussion.

[@electrictroy2010]

It applies to turbo diesel too. More air is more diesel burned (and my 51 mpg Jetta TDI drops into the 30s) .

[@petarmiletic997]

​@@electrictroy2010 More air is more diesel burned, but more work is done so efficiency of the engine is the same or even better. Of course fuel consumption is NOT the same thing as efficiency. Exampe: drive at 70km/h, engine load and efficiency is lower, but the car itself is more efficient since there is less power wasted to overcome air resistance. Double the speed to 140km/h, the power required to overcome wind resistance increases 8 times!! (since air drag power increases with the cube of the speed). Far more energy is needed to travel the same distance so the car is less efficient BUT the engine is more heavily loaded and runs more efficiently. Fuel consumption increases even if the engine is more efficient. IE fuel consumption doubles, but the work done quadruples, so the efficiency increses. Another simple experiment, try pulling up a hill in 5th gear and then try the same hill at same speed, so the power required is the same, but in 3rd gear. In 3rd gear load is lower, there is less boost but it will burn more fuel to do the same work as the efficiency is lower. There is no efficiency penalty for high boost on diesels because diesels don't require full load enrichment. In a gasser full load enrichment helps prevent knock but also causes decreased fuel efficiency, so a gasser might even burn less fuel when you downshift for less boost uphill, which is practically never the case in a diesel

[@kennedy796]

Then explain how semi trucks can still average 6-8 mpg towing dry vans when 10 is the most they ever will do?

[@yourbabyboyfriendonlyme2485]

@Chris Russell Shhhh elect........ might learn something. Granted it is 4 grade stuff. I just wish they had . well telling would be telling. sorry

[@dieselgeezer18]

@@kennedy796 these engine are like huge 14L V8 engines. How do you expect a good milage from such a huge engine?

[@azizlenox]

Great explanation 👍🏼

[@lesliethilow3011]

Fantastic explanation professor!

[@jonkess2768]

I changed from a 1,4 litre four cylinder 90 PS to an 1 litre threezylindet engine with a turbocharger and 95 PS and i am down from 6,5 litre per 100 km to 5,5 litre per 100 km. For me thats a huge Deal because i save around 250 Euros a year.

[@satsumagt5284]

The biggest advantage of the smaller turbocharged engine is the low end torque, so that your new turbocharged car (might even be a Volkswagen) has more low end torque and can sustain lower revs at high speeds

[@Encryptus1]

I have an 993cm3 n/a from 1999 that does 4.6...

[@user-sz8qr3oc6q]

Pedro Pereira but how much hp does it have that’s the question

[@Encryptus1]

@@user-sz8qr3oc6q 56 bhp.

[@KarlAlfredRoemer]

My Polo 6N1 build 1996 1 Liter 4 cylinder Big Block needs 5 Liter\100 Km.

[@Wpjgdmtu]

For a little while I drove a '13 VW CC with a manual and a stage 1 93 tune to about 250whp. I was getting 28-30mpg combined and I could squeeze 36mpg on the highway. I think the real advantage to these turbo engines is you get all the fun while on boost and then when you're cruising on the highway off boost, it turns into a fuel sipper.

[@ilovetotri23]

Great explanation!

[@sgkountz3280]

Thank you for helping me understand why I'm getting 18 mpg in my A4.

[@beenusirimanne]

So short version: you get a small Turbocharged car to drive it sensibly for economy, and to have some power reserved for when you need it. I own a 2006 Land Rover Discovery 3 with a 2.7 litre diesel V6. On the Motorway doing 70 it happily gets above 37 Mpg, whereas in the city, it drops to around 27. The key is just how much you put your foot down; that thing pulls away hard once the turbo spools up, but then the Mpg goes out the window. Its all down to driver input and how you drive it. A good example of this is the race that Top Gear did with a BMW M3 and a Toyota Prius.

[@Ozaneee]

Diesel engine are more efficient than a gasoline engine

[@upsidedowndog1256]

My 85 Kawi 750 turbo motorcycle can get 45+ mpg steady state cruising at 75+ mph. Around town and under high boost that drops to about 7 mpg! Small price to pay for the fun though.

[@fournierdon2172]

Thanks for explaining what I have noticed with cars I have owned/own. My current vehicle (small turbo) gets poorer mileage than my previous model of the same car (larger non-turbo).

[@nigelclark7360]

That was really good very well explained.

[@TCPUDPATM]

Please confirm this on the topic of cooling with AFR: Adding fuel beyond the stoichiometric ratio 14.7:1 does not add any more heat because there is no more oxygen to burn the fuel with. It extracts heat from the engine when changes phase from liquid to gas (as described in the video), and exits the engine unburnt with thermal energy that leaves the engine cooler. Diesel engines also use this technique, the side effect of this can clearly be seen as soot exiting the exhaust as black smoke. So rolling coal = blowing raw fuel out the exhaust. Not very efficient.

[@matthewbehr5725]

Diesel engines don't use this technique. They are compression ignition and direct injection (in modern diesels) and therefore do not need to overfuel to avoid knock. Sometimes they will smoke a bit before the boost kicks in and cleans up.

[@TCPUDPATM]

I meant that they use over-fueling technique to keep EGT down, among other things. Not knock. Thanks for catching that. Can't have pre-detonation when there's nothing to detonate!

[@Trundle_fkr]

TCPUDPATM PORTS diesel's run lean. Over fueled the exhaust temperatures increase because of after burning during the scavenge cycle.

[@Bartonovich52]

Overfuelling cools the air and makes it more dense. This is why water injection is used in the same way even though it adds nothing for combustion-even on (especially on) turbine engines where there are also no knock considerations.

[@Trundle_fkr]

Turbines have extremely high exhaust temperatures and often use fresh air to cool perforated turbine blades. Excess fuel in a diesel is burned during the scavenging cycle causing high exhaust temps and burned valves.

[@Connor4x4]

Ecoboost engines at least in the trucks get worse mileage and can't tow as well as a typical v8. Ecoboost are only good on paper

[@ecoboostedfuze]

I’m struggling with the fuel economy with the 1.5L ecoboost in my fusion. If I’m going for fuel efficiency I have to barely use any throttle lol.

[@Godlyhank]

Using a suzuki baleno 1.0 RS (112hp one) here in UK. I can confirm torque and power crossover is very volatile if you are heavy footed...however. if you know your pedal and maintain some patience you can find that very small sweet spot that allows very very high efficiency on the road in it. Basically where the turbo wastegate is cranked open the tinyest amount to allow the increase in torque without the near 2x hp jump.

[@WiekingderViking]

You kick “serious anatomy!” I continue to be impressed. AND you give a darn.

[@amp888]

It's an interesting discussion, but it's missing real-world data. The lower displacement turbo engines are less efficient in specific conditions, but you haven't presented any data about how often those conditions are actually encountered, in average driving situations for average drivers. For example, do most people spend most time driving in stop-go traffic (inner cities or congested roads) and constant speed (highway), with low throttle percentage?

[@Lazerecho]

amp888 look at this guy critical thinking! Just like the "mpg" is based off a specific test, and if you aren't driving that test at the same altitude/temperature why should you get the same results?

[@slanahesh]

I think his point is more towards the performance oriented driver, who may be considering a lower volume engine as a way of having their cake and eating it too. In normal day to day driving you don't usually floor the throttle very often.

[@amp888]

Sure, but that doesn't support the video's title. Perhaps "When Small Turbo Engines Are Not Efficient" would have been more appropriate.

[@neptronix]

That's a good point, my dude

[@peterm3861]

I think so, too. The video is not wrong but as always you can't speak generally. I'm sure Jason knows exactly what is going on and he also didn't say that the shown scenario is the case in every situation. But yeah, your video title would be a bit better for sure. I think he could have mentioned the words "downsizing" and "right sizing" since that is the topic here.

[@adamgoebel3551]

I'd like to see your thoughts on the 2019 civic si with the stock turbo!

[@Intrepid175a]

I worked for a Lincoln/Mercury dealer back in the very early 80's. In my three years there, we sold one Mercury Capri with the 2.3L turbo four. It was a nice little car but the owner brought it back to us several times complaining about lousy fuel economy. We checked it out each time and it returned proper gas mileage when we were driving it so there was nothing we could do. We talked to her several times and could never figure out what her problem was when she finally said it. "My salesman said I could have V8 performance AND 4-cylinder gas mileage!" Ok, "now" this makes sense. The service manager resisted the temptation to tell her that her salesman lied through his teeth to her and simply said he was mistaken. She could have V8 performance OR 4-cylinder gas mileage but not both at the same time. She didn't like that answer and we were never able to satisfy her on this issue.

[@otterspooptoo]

Nice video!

[@alimzia1]

Does this also lead to the emission of unburnt fuel at higher loads when more fuel is injected for the cooling effect?

[@Mgoblagulkablong]

Finally someone talks about this! Here in europe all we got the last decade were tiny 1.0l - 1.5l (mostly 1.0) turbo engines, because the official fuel economy numbers were measured by a method called NEFZ, which was pure protectionism of the europeans thanks to lobbying. In that test only 5 hp were used on average. So turbo engines did not use their turbo at all in the fuel economy testing and the official fuel economy mostly depended on how small the engine was, the smaller the better. In real driving these cars depend completely on the turbocharger to make power and use at least 30% and up to 50 % more fuel than the official numbers say and their emissions became much more toxic than 20 years ago (and they were allowed to emit 10 times more and a much more dangerous kind of particles than diesels, extremely harmful to the human body). You americans don't know how lucky you are that you have EPA, best fuel economy testing on the world.

[@slanahesh]

exactly, those tiny 1L engines suck so bad.

[@philipph3421]

Mgoblagulkablong sorry, but I want to see your sources. I highly doubt that the stated numbers in your comment are true. It is true that the recharging of the battery, applying duct tape to the gaps, changing camber and toe, having higher pressure in the tire, lowering weight by removing additional stuff, and tuning the ECU to maximise efficiency is allowed within the NEFZ, but with an additional error of 4% the difference of the date isn't that high. The cycle is a standardised on with 66% of city driving and 33% of highway. It includes the coldstart and even fuel and temperature and air pressure are standardised. The resistance (rolling and air) is mesured and applied to the dyno on the forehand. The thing is that every vehicle runs through that cycle to be able to compared. But in the real wold the variables do change more. And especially the position of your right foot, if you know what I mean. The thing is that speed and throttle position do matter more in the real world through air resistance at high speeds and the lamda value and thus the enrichment of the mixture. And it is obvious that if it's floored that it's neither efficient nor clean, because what you are doing is solely asking for acceleration. If you want to achieve the bumbers stated you need to shift early, slightly touch the accelerator pedal and use the same things the manufacturers do. But it is possible to achieve good numbers close to the ones mesured in the real wolrd. F.E. the Honda Jazz is stated with 5.3 l/100km. I achieved 5.5 myself. And this while the battery was charging and haven't used duct tape. Nobody said that it is easy to achieve the numbers, but nor impossible. In the USA the cycle is not that efficiency focused. This results in numbers closer to the ones achieved by most of the users. Both cycles are there for a reason and NEFZ gives the manufacturer the ability to let the engine mork in it's most efficient way. This is not the most realistic but it shows what the engine can do. But when asking for power the car has to deliver. It's the same thing with BMW and the "Deutsche Umwelthilfe" who tried to sue them for manipulation of the diesel because when the car was floored or reached high rpm (so there was asked for power) the EGR valve closed. That's becaue they we're asking for power and therefore fuel needs to be burned with fresh air. It's obvious that EGR needs to be closed in this scenario. And it's obvious that if you use the accelerator pedal and ask for some power that fuel needs to be burned. The emissions do mostly are clead out by the cat. But they depend on how you get the fuel in the car. Having a look on the emission classes I belive that most new cars are much cleaner than before.

[@Tonyx.yt.]

agree... european test is totaly fake, 0-50 km/h in 27 seconds... WTF that's why smaller is the engine, higher is the difference between official and real world consumption... my car has a small 4 cylinder naturaly aspirated engine and despite claiming worst consumption than tiny 3 cylinder turbo, in real world has better consumption, yes it lacks of torque but who cares, just drop a gear.

[@nokobz2624]

@@philipph3421 'herzig' nice jew name. Don't believe him, this jew was born with a snake's tongue like all of them are and never stops spitting outr lies and confsion to the gentile slaves....

[@paultasker7788]

I had 1.4tsi and it did 45mpg average. The worst I ever got was 40mpg and best 52. Gave it back at end of finance deal. Only Kept our other car a 1.6 naturally aspirated does 35mpg in same conditions. The turbo is a lot faster yet more economical. Not as economical as promised but still very decent for a mid sized petrol car. Before that had 1.2tsi and that did 43 with 38 worst and 60 best. So that could do more in right conditions but on average did less. Makes me wonder if 1.4 is about the sweet spot. I test drove a 1.0 turbo and most of the time was only in mid 30s economy.

[@8__D]

This is a good explanation of why fords eco boost had valve carbonization issues when used under load. The rich air fuel mixture used to cool the combustion space resulted in incomplete combustion allowing soot to build up on the exhaust valve and eventually ruining the valve and it’s seat

[@dr.williambrice24]

Excellent explanation...I trick my small turbo with friction modifiers and anit-carbon such as PEA....over 10,000mi. I actually am beating the EPA numbers with decent loads and pretty spirited driving.

[@MaikEletrica]

Nice explanation! Thanks

[@JohnnyAmerique]

Got a 2017 GTI. If I drive it conservatively, it gets fantastic fuel economy, around 30/36. However, if you even begin to open it up, that drops dramatically - even routinely getting into boost range a bit cuts the fuel economy in half or more. Overall though, it’s a fantastic engine: The power is there when you want it, and for the 90% of the time you don’t, it’s as economical as a Civic.

[@xXlURMOMlXx]

Tyler Brown damn I get like 25-27 max driving normally 😅

[@johnferguson7235]

Exactly, if you drive like a mature adult, the turbo doesn't cause any dramatic decrease in fuel economy.

[@sykokilla77]

Word love my 1.8 Passat. 40 hwy 33city

[@xXlURMOMlXx]

John Ferguson I’m under 2k rpm 85% of the time! I don’t even use more than half pedal often bc I’ll be far over the speed limit at that point, even stock!

[@marco1173]

"25-27 max driving normally" You're not driving it "normally", trust me. Those engines are so eager to rev it's easy to overdo it. I love my 1.8T but I know I could be getting better MPG if only I could bring myself to ease off on the gas pedal a little bit. It's pretty much impossible for me, though lol

[@AnalisandoSampa]

Nice video. In Brazil (and South America market) car manufacturers are all downsizing the engines. Many models now are 1.0 to 1.5 liter turbocharged. Our petrol already contains 25% of ethanol and then a higher octane, and they can also run with pure alcohol.

[@RockStarCrisis1]

My 2019 Jetta with a manual seems to do better mileage wise than expected with a 1.4L Turbo. Rated at 40 mpg on the highway, I've done a 45 mpg trip, recorded by the cars computer. Still fast enough to punch it on the highway as well, doing zero to sixty in about 8 seconds.

[@jaredgates4310]

Wow so basically when you are driving under normal highway conditions turbo 4 cylinders get great fuel milage but when you floor it to make boost/horsepower they make bad fuel mileage.... Surprise!

[@MaliciousSRT]

A 2.0L @ 14.7psi boost is now a 4.0L. Its really just displacement on demand, going down the highway its a 2.0L again, but when you pass its back to a 4.0L.

[@justinjones5281]

SP392 not exactly but first comment worth giving a thumbs up

[@MaliciousSRT]

close enough ;)

[@siraff4461]

The big difference being flow rates, intake air temps and active vs static compression but you're not all that far off.

[@kurtperdew2391]

There is no replacement for displacement.

[@goodmandiad2713]

I had (2) 2.0 Direct injection turbo engines, one in a Forester XT the other in a Sky redline. Both rated at about 250-260 HP. My 13' Accord with a 3.5L V6 (rated at 278 HP) and variable displacement was faster and got better fuel economy. The Accord ran on 3cyl when that is all you needed. Problem with a turbo is you are always into the turbo and asking more air and fuel to get moving and stay at highway speeds. If you paid attention to the whole video they reason for these turbo engines is not really fuel efficiency but to get the EPA numbers higher. That does not translate to real world fuel economy. Ask anyone with an eco boost Ford Pickup.

[@junkitlow]

I had a short trip with Audi A3 1.4tsfi and actually it is quite efficient though. There will be slight turbo lag but once get up the power is quite decent.

[@cop2506]

You are my favorite nerd! I learn so much from you lol

[@Ricardo_C]

I didnt buy a twin turbo 3.5 ecoboost for mpg , I bought it for power !

[@rogerk6180]

Ricardo Chavez high five! Boost is for fun, not economics. Got best of both worlds, v8 with a turbo on either side of it. Like driving a rocketship!

[@rangerrick1859]

If you buy it for power then buy the V8. The most reliable engine in the f150. Then you do not need to worry about the turbocharged headache of an engine in the future when it wears out

[@dj_paultuk7052]

Just to say, Saabs never suffered from knock. Or at least they prevented Knock. They Developed APC in 1986. (Automatic Performance Control). They used the spark plugs as a sensor and detected the onset of knock from the ionisation within the combustion chamber. If knock was about to occur, then timing would be adjusted. And/Or, boost levels reduced. This meant it effectively detected the Octane of the fuel. Better quality of fuel = more power. A Saab 9000 Aero has standard compression ratio. And yet with 98 Octane RON fuel, it can run 1.4 BAR (24 PSI) boost pressure with no knock. Giving a max of 310bhp from its 2.3L 4cyl. Ford are only just getting to that now with the Focus ST and RS.

[@Bartonovich52]

No SAAB 9000was getting 310 hp stock... and modified it wouldn’t have lasted as long as newer cars.

[@eaglefat9398]

Most OBD1 and Every OBD2 car i've ever worked on had a knock sensor which is basically just a microphone on the engine block, you can pop the hood while the engine is running and give the engine a light tap with a wrench and you will hear the idle drop because the ECU will pull timing, All ECU's do is advance timing until it senses knock then retards timing back down until it stops thus getting the best ignition timing possible. Nothing special or new.

[@buggs9950]

"No SAAB 9000was getting 310 hp *stock*..." Did he say stock? No he didn't.

[@flybyairplane3528]

Paul Taylor too bad GM killed the SAAB.

[@dj_paultuk7052]

Yes @ 310bhp the B234R is at Stage3. My point is, a stock engine will run at 1.4 Bar boost with no Knock when using higher quality fuel. FYI: The above is a just a remap. A B234R can be taken to 500bhp on a completely stock engine. They are fully forged from the factory so dont need to be touched. ALL Stock hardware goes to 310bhp. Then you just change the turbo and injectors and head for 500.

[@jayson657]

When I was leasing a turbo was fine. Now that I own, can’t go wrong with a nice large displacement natural aspirated engine. Mazda 2.5 L Skyactiv 4 cylinder here.

[@mgbond]

Hi, love your videos. I wonder if you could give a bit of advice. I have a 2.5 V6 duretech engine and I need to get more air into it. The plan is to fit the 3.0 duretech engine heads along with inlet manifold. The question is that the dome in the 3.0 head will be larger than the 2.5 cylinder. The gasket used will be the 3.0 so that will line up with the edges of the dome. My concern is this effective lip that will be created from the cylinder being of a smaller dia then the head dome. Do u think this will cause an issue. Plan to run 500bhp and around 1.2-1.3 bar. Look forward to your advice.

[@radude131]

Can you do a video on gasoline direct injection, and how they prevent knock with this method in turbo engines? Should reduce the need to spray extra fuel for cooling the cylinder.

[@peterm3861]

I am pretty sure there is a video about that. And you are correct, the reduction of knock whilst raising the compression ratio and not spraying tons of fuel for cooling is the main reason of gasoline direct injection. But they raise the compression ratio so much that they still have to spray more fuel under high load and rpm scenarios...

[@dexterjsullen]

That's why I drive a twin turbo v12

[@vladlelcu5316]

Dexter Sullen 'TRUTH' what do you drive?

[@dexterjsullen]

Vlad Lelcu sl600

[@SoI_Badguy]

So... You mean biturbo?

[@Rickcrazy100]

sorry bud but I don't think your sl600 has a biturbo v12...maybe a N/A v12...but zero turbos on that old crap

[@SalvadorSTMZ]

This comment makes no sense. Same exact problem happens in any turbo fed engine, whether sequential or twin or single turbo v12 or v6. Problem is manufacturers are pushing engines to do more with less volume.

[@michaeleverson3801]

My Mk 7 GTI once returned an impressive 42 mpg driving from Bend, Oregon to Portland, Oregon. Mostly fast-ish, sweeping roads, a decent amount of climbing, and I was stuck in, "stop/start, slow to a crawl" traffic for a good 10 miles. I didn't think it was real...but it was.

[@jivantakirstenpillay6128]

Nice explanation here. Anyways on the topic of small displacement turbo engines, I wanted to more regarding the Downpipe sizing, is larger better ? The reason I ask is my car has a 42mm stock DP and I upgraded to 63mm so almost 50% larger and although the power figures increased nicely to around 15% with the addition of a stage 1 tune, the car seems rather flat under load in the higher gears around 2k rpm. In stock form the response is instant. Even the stage 1 file could not improve this 'Flat spot'. Could it be the upgraded downpipe is too large or is there an optimum ratio when upgrading downpipes, eg. 10-20% larger ? I have also heard many suggest smaller turbo engines require some degree of back pressure to maintain nice torque figures and yet most disagree. Would love to know more, before either doing a revision on the tuning file or changing the downpipe. Thank.

[@mlok4216]

That white board in 4K lookes awesome! I have 1080p, just joking =) Great vids!

[@Trades46]

If you drive like a street racer and punch the throttle all the time, the boost is always on = bad fuel economy. I manage to get 6.5L/100km average on a 200hp 2.0T engine all the time on a small hatchback, so not impossible.

[@rogerk6180]

Trades46 i do 19,5 liters per 100km average. Wooha lol.

[@KevBoy3D]

That is really good for 200bhp, you do mostly highway driving?

[@Trades46]

About 80% highway I would say yes.

[@al3oqab128]

I average 7.5l/100 km on my 1.2 TSI 110 hp ahahaha

[@martins5176]

6,5l/100km city driving, 6l highway, 12/15 track (1.5t chatch)

[@BabyBugBug]

They are extremely efficient. My Jetta gets 42-48 mpg on the highway depending on how fast I drive. In the city it is around 30 mpg. The car goes from 0-60 in about 8.5 seconds. I couldn’t be happier with it. The only problem with the TSI engine is that I will have to get a carbon cleaning in about 60k miles to keep it in top shape.

[@namesdom]

I got a 2020 Honda Accord with the 1.5 liter turbo. Makes almost 200 horsepower yet it still gets about 42 mpg on the highway

[@bloqk16]

Turbo is nice to have when the vehicle is still under factory warranty. But once the expense of engine repairs becomes out-of-pocket for the owner/driver, watch out!

[@pauld.b7129]

Well the turbo itself is a wear part... But besides that not really. The pistons, rods cams etc are fine, unless those fail" your all good. Ive seen volvo turbo with 300k+ miles that never had an issue.

[@turboseize]

My car (with a turbocharged, downsized petrol engine) is out of warranty since about 32 years. The car has tons of problems - the electrical wiring is disintegrating, the body is rusting badly, and there have been issues with the drivetrain. For example, after half a million kilometres I needed a new alternator, and shortly after that the gearbox had to be rebuilt. But the engine itself is bulletproof. Small turbocharged engines CAN and DO last. All it takes is an owner with a minimum degree of mechanical sympathy and who does not neglect maintenance.

[@bloqk16]

@Martin Rudolph . . . I'm impressed with the durability of your vehicle's engine, turbo, and alternator. The half-million kilometers for an alternator is astounding, as here in the US, the average life expectancy I've had was around 161,000 kilometers when it needs replacing.

[@jammi__]

@@bloqk16 Simply stop buying American cars then. Here in Finland, we judge them as having roughly Soviet style build quality. Get Japanese or German instead, but avoid the Chrysler era Mercedes-Benz.

[@zipper978]

Modern turbos are very reliable. It’s old turbo designs that were not as reliable. Keep in mind semi trucks are turbo diesels with 300,000 miles or more

[@DaPepster]

ANY engine with forced induction will be less efficient when under boost when compared to operating it during low idle and cruising conditions.

[@MsSashbar]

It would be interesting to hear a review about the relatively new VW 1.5 EVO TSI engine that uses MIller cycle. Does M.c. help to avoid knocks and using an enriched mix?

[@altaloma7789]

Nice video, very understandable. Not sure if it's been mentioned, but the decrease in efficiency translates out to unburned fuel/oxygen in the exhaust, as well as fuel washing on the cylinder walls and pistons. This becomes carbon buildup, which translates out to another knock source. There just doesn't seem to be a way to win. In addition, the exhaust continues to burn on it's way to the turbo, which is an impediment in the exhaust system. The exhaust continues to expand, jazzing up the turbo on it's way out. It also translates to higher temperatures within the catalytic converter and exhaust. In other words, the whole system is getting worked harder. This converts to more wear over time, and will shorten the life of the engines. If long life and reliability are important, which apparently isn't a problem for the manufacturers but is for the customer, the long term outlook will be that old used car engines will be disposed of rather than being rebuilt. Chrysler, and Shelby's, grand experiment with turbocharged engines back in the 90's made their cars effectively disposable after a few years.