5 Reasons You Shouldn't Buy A Turbocharged Car

hello everyone and welcome we are sitting inside of the Lexus RCF track Edition and it has a 5.0 liter naturally aspirated v8 engine and you know not that long ago naturally aspirated was pretty much the norm and turbocharged stars were the rare ones the crazy powerful ones the ones that were cool and today that's kind of flipped we're moving towards downsized turbo chargers and now these big naturally aspirated engines are becoming the more rare ones and there's kind of an allure to them because of that and so in this video we're gonna be talking about five reasons why perhaps you shouldn't be buying that turbocharged car perhaps you should be looking at a naturally aspirated engine because there are some real advantages to naturally aspirated engines and there's some real disadvantages to turbocharged cars and so starting off we're going to talk about throttle response and of course you know turbo lag is gonna be mentioned here but that's not my main point my main point is with throttle response with your throttle mapping you know if you were to think about what is my torque that I'm putting down on the ground and where is my foot on that throttle pedal as far as how much acceleration have I asked for you want a nice linear relationship between those two so you get exactly what you asked for and in a naturally aspirated engine like we have right here that's much more easy to modulate with the turbocharged car basically you're waiting for that turbo to spool up and then you've got some control there but there's kind of this gap in that throttle pedal where you go okay I don't have turbo boost right here and above this I do and so you know I've driven cars for example Subaru WRX we're at 50% throttle it's capable of full boost and at that point it's like well why isn't throttle pedal even there it's basically just acting as an on/off switch instead of actually allowing you to modulate how much torque you want to the ground and so that's what's really nice about the way surely aspirated engines work is that you don't have to wait for that boost and you know speaking of that boost a lot of people say well you know it's kind of cool to have that turbo lag you kind of wait for it you wait for and then bam you're hit with all that torque and that's cool and my counter would be a delay is never a good thing would you want a delay in your steering response no of course not what you want to delay and your braking no of course not that'd be incredibly dangerous would you want a delay in shifting gears no you want it to happen when you want this is America I want it and I want it now and that's how we should want our power we should want it when we ask where it enough two seconds after and so there's my rant on turbo lag it's unfortunate that it exists and you know modern cars are doing a good job of shifting that torque curve so the turbo spools up more faster which leads us to point number two which is the torque curve now this is something modern turbos are actually very good at is getting a nice flat torque curve with a naturally aspirated engine you're never going to have a perfectly flat torque curve there's pretty much it's going to be a peak and that torque curve where your engine is just getting the most air in it and it's making the most power most torque at that peak of the torque curve and so you know looking at a turbocharged engine you might think well it's great that it has this long flat torque curve and yes that's true but the downside is before that flat curve and after that flat curve is where things kind of fall apart so before it you're waiting for that turbocharger to spool up you basically got no torque and let's say you've got you know a 2.5 liter engine with 15 psi boost well it's going to behave like a 5 liter engine at full boost but until you get to full boost it's going to behave like you know a 2.5 liter engine and so you don't get that torque on the low end and it you do you're sacrificing your top and so you're designing that turbo what do you want you want a lot of power do you want a lot of response and I think manufacturers have taken the correct idea lately and that they try to give it response over peak power because response feels better than just having a really high horsepower engine but only at the very top of that torque curve the problem with this though is that that torque will really noticeably die off once you get into those higher rpm and so versus a naturally aspirated engine when you get up into those higher rpm it just keeps pulling and you know there's a joy to that it's nice to be able to have power wherever you are in the RPM band rather than waiting for that turbo to spool up and then not letting it die off once you get up into the top end now our third point is reliability versus cost because I'm not going to claim that a turbocharged engine is less reliable than a naturally aspirated engine it very well could be the thing is it takes more money to make it that way because it has to be built more robust than a naturally aspirated engine you can get away with less with a naturally aspirated engine because the internal pressures are less so you know let's say you're putting 15 psi in an engine that's twice as much air if everything's going really well then a naturally aspirated engine in each cylinder and so your pressures are going to be dramatically higher and your temperatures are going to be dramatically higher so you know if inside an engine with a naturally aspirated engine you might be getting a thousand psi peak pressure within those cylinders a turbocharged engine could be 2,000 psi a turbo diesel could be 3,000 psi and that's why you see turbo Diesel's as such expensive engines they're an expensive option because they have to be built very robust in order to handle those insane pressures that they see on top of that is the heat so you know the critical aspect in making sure you don't have where within your engine is of course the oil and making sure you have proper oil flow and oil everywhere in between your metal on metal contact areas and so with a turbocharged engine this oil is exposed to significantly higher temperatures versus a naturally aspirated engine because you've got those higher pressures which result in higher temperatures within those cylinders and then also the turbo itself gets extremely hot it's cooled and lubricated with oil so oil is passing through and going across that turbo shaft between the impeller and the turbine and so that oil is being exposed to very high heat especially also when you shut your core off and then that oil is just sitting there on that hot turbo shaft and just cooking and so the oil has a much more difficult time taking care of a turbocharged engine versus a naturally aspirated engine simply because of the temperatures and the demands placed on that oil so that's another big advantage to naturally aspirated engines is not having quite as much heat for the oil to have to deal with our fourth point is efficiency and you know downsize turbochargers are the new norm and the whole purpose is to improve fuel economy now that doesn't necessarily mean that everything about a downsized turbo is more efficient yes smaller engines will tend to use less fuel than larger engines or our disadvantages to slapping a turbo on it one of them being because of course that turbocharger is adding pressure within the cylinder you have to use a lower compression ratio so that you don't run into knock and damage the engine well there's a direct correlation between what is your compression ratio and what is your thermal efficiency and so by reducing that compression ratio you get less efficiency and naturally aspirated engines are able to get away with significantly higher compression ratios and as a result they're able to operate at efficient ranges now on top of this of course with that downsized turbo if you want power that means you've got to spool up that turbocharger now one of the problems with this is fuel enrichment and so the problem is that you know you have all this heat and pressure because you've put all this air in and you're trying to burn all this fuel up and so as a result it's a very hot environment and hot environments are conducive for engine knock and engine knock will destroy your engine eventually so you want to avoid it well how do you reduce the temperatures within that cylinder well you dump in more fuel that's great it protects your engine using that really rich air fuel mixture but the downside of course is that your fuel economy goes out the window and so with a turbocharged engine you know think about how much throttle are you giving it and what's your air fuel ratio those turbocharged engines are gonna have to dip into rich or air/fuel ratios earlier and on top of that at wide open throttle they're probably going to be slightly more rich versus a naturally aspirated engine as well so on that upper end of your power band you know where you're really asking for full full power from your engine your turbocharger is not going to be that efficient because it's got to run such a rich air fuel mixture in order to protect the engine and finally point number five and this one is subjective but with some objective reasons is sound and so you know there are three reasons why a turbocharged engine may not sound as great as a nice naturally aspirated 5.0 liter v8 like we're in right now and you know the first one of those is where is the location of that turbo well it's it's between the engine and the atmosphere so your tailpipe and so because that turbos sitting between your engine which is shouting out this incredible noise that turbocharger is trying to take all of that energy that's coming out of the engine and pull it up and turn it into useful energy to add boost so instead of trying to make all kinds of noise that turbos trying to take that noise away and make it useful so that's a disappointment now there's of course those turbo noises the you know what whatever it may be the blow-off valves there's added value there's noise from the turbo but you're pulling away noise from the engine so that's kind of the disappointing thing about turbochargers versus a naturally aspirated engine the other thing because you know turbochargers allow for significantly more horsepower well they tend to mean you use a smaller engine smaller engines just simply don't put out as much bark and then you have less cylinders and so having less cylinders means you're firing interval has a longer delay between it so when you have all these firing the cylinders firing back-to-back really close together it sounds really cool that's why v12 just sounds so amazing v8 sound wonderful it's having all of those firing intervals happen really close to one another rather than spreading them out like with a you know 4 cylinder engine so a v8 versus a 4 cylinder engine you're firing twice as often at whatever rpm you're at and so you get that really beautiful naturally aspirated and yeah it's just it's hard to argue against it it just sounds beautiful it makes you smile and I guess this thing's beeping at me because I need to shift but anyways I'm trying to listen to the engine so I'm a fan of this Lexus RCF track edition they've been some serious weight savings on it over 170 pounds saved they've done so by adding carbon fiber on it they've taken out over 48 pounds of unsprung rotational inertia part of that using carbon ceramic brakes which is nice to see they've got a titanium muffler so they're taking out some weight from this thing and it's a it's a cool ride sounds good at the VA you know 472 horsepower so you know it's not crazy fast but 0-60 under 4 seconds so it's good I mean it's a it's a fun car so I've been enjoying it and naturally aspirated engines there's a special place in my heart for my I do love these v8 and and the bark that goes along with it so thank you all so much for watching if you have any questions or comments of course feel free to leave them below

Channel: Engineering Explained

Views: 1,051,522

Rating: 4.7840014 out of 5

Keywords: v8 engine, turbo, turbocharged, supercharged, turbo engine, twin turbo, don't buy this car, used car, new car, naturally aspirated engine, NA V8, V8 vs I4, engine sound, fuel efficiency, engineering, torque curve, throttle response, reliability, cost, engine reliability, don't buy a turbo, how it works, engineering explained

Id: m2qExaEwn0g

Length: 11min 30sec (690 seconds)

Published: Wed Sep 25 2019