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When you say they have "gone turbo" that only means some of their engines are turbos. My 2017 F150 5.0 Coyote V8 for example is not turbo, and has 385 horsepower. The base Escape has a non-turbo engine. Most manufacturers are the same, some turbos but not all.
Exactly. Camry is another good example. Unlike its rival the Accord which is all-turbo, both the Camry mills rely on size, not spin.
it's because of emissions regulations and higher mpg checkmark
Emissions are mostly a function of fuel burned. Conversion of fuel into horsepower is now much the same with any engine modality, because of universal improvements in engine-management, fuel-injection, intake manifold design, and so forth. A larger displacement naturally-aspirated engine, and a turbocharged engine of a smaller displacement, will have essentially the same environmental footprint, if they have comparable torque-curves. The difference is that the larger engine will have more motoring-losses (the cost of spinning its own crankshaft), and possibly higher weight. But the turbo engine needs turbo plumbing – much of which is heavy cast-iron parts. So, I am not convinced that the smaller turbocharged engine offers weight-savings or packaging-savings. What it does offer, is flexibility for the manufacturer: a naturally-aspirated, lower performance-version… and a higher-performance version with turbo, using the same block. It also potentially offers advantages to aftermarket tuners.
Quote:
Originally Posted by Katana49
...When Mercedes had their awesome 6.2 liter NA engine in their 63 AMG models, it was great. ..But now, the top engine switched to a 4 liter twin turbo engine. This is even smaller than the 4.7 liter twin turbo engine that used to be the basis for the 550 models.
Quote:
Originally Posted by Ziggy100
I don’t like the trend either (with performance cars anyway), but they don’t have lag anymore like in the old days. I honestly can’t tell there’s a turbo anymore other than the sound.
My question would be, as these engines have downsized in displacement, have they also downsized in weight? From a vehicle-engineering viewpoint, neither the displacement nor the number of cylinders matters. What matters is the fuel efficiency, the power-delivery, the weight and external size of the engine.
Driving the nearly latest-model (2014) BMW 340i, the turbo lag is distinctly noticeable, and very annoying. There’s hesitation, then a rise in power, and finally it pulls like the proverbial freight-train.
Emissions are mostly a function of fuel burned. Conversion of fuel into horsepower is now much the same with any engine modality, because of universal improvements in engine-management, fuel-injection, intake manifold design, and so forth. A larger displacement naturally-aspirated engine, and a turbocharged engine of a smaller displacement, will have essentially the same environmental footprint, if they have comparable torque-curves. The difference is that the larger engine will have more motoring-losses (the cost of spinning its own crankshaft), and possibly higher weight. But the turbo engine needs turbo plumbing – much of which is heavy cast-iron parts. So, I am not convinced that the smaller turbocharged engine offers weight-savings or packaging-savings. What it does offer, is flexibility for the manufacturer: a naturally-aspirated, lower performance-version… and a higher-performance version with turbo, using the same block. It also potentially offers advantages to aftermarket tuners.
My question would be, as these engines have downsized in displacement, have they also downsized in weight? From a vehicle-engineering viewpoint, neither the displacement nor the number of cylinders matters. What matters is the fuel efficiency, the power-delivery, the weight and external size of the engine.
Driving the nearly latest-model (2014) BMW 340i, the turbo lag is distinctly noticeable, and very annoying. There’s hesitation, then a rise in power, and finally it pulls like the proverbial freight-train.
It is more efficient otherwise they wouldn’t bother using them. The weight is probably close to half the weight. Plumbing is negligible. On mine, the pipes before the turbo are plastic, the turbo itself is integrated with the exhaust manifold/catalytic converter, and there is a short pipe from turbo to manifold. The block and pistons however are half the size.
At full throttle, a turbo 4cyl will pull in more fuel and air, but as soon as it backs off WOT, the air and fuel is cut in half and the volumetric efficiency of the cylinder is better utilized.
Location: East of Seattle since 1992, 615' Elevation, Zone 8b - originally from SF Bay Area
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Quote:
Originally Posted by Ziggy100
When car manufacturers claim to offer a lot of electrics, what it usually boils down to is offering either a PHEV or EV option alongside the ICE versions, not replacing all their lineups exclusively with EVs. 40% of the population lives in an apartment and won’t have a place to charge their car.
Correct, and they have yet to come up with an electric that will tow a 10,000 lb travel trailer and go 700 miles on a tank of gas (when not towing!) like my F150 V8 with 36 gallon tank. They may come up with a hybrid pickup soon, though.
I've had a 2.0 turbo for 9 years now (in 3 different VW's), and absolutely love them.
I drove turbos for 14 years. They were tuned for 91 octane and were dogs if somebody put 87 octane fuel in the tank on me. The price spread between 87 and 91 octane went from 20 cents in 2000 to 50 cents+ now. The car I'm driving now, a key criteria was "must burn 87 octane". There are low boost turbos that run just fine on 87 that are fine but I'm done buying hightest gas.
My ideal car would be an AWD plug-in electric hybrid wagon with a low boost turbo. You get the 6 second 0 to 60 mph time, the superb around town fuel economy for the first mile or two, and good highway fuel economy.
Correct, and they have yet to come up with an electric that will tow a 10,000 lb travel trailer and go 700 miles on a tank of gas (when not towing!) like my F150 V8 with 36 gallon tank. They may come up with a hybrid pickup soon, though.
My ideal car would be an AWD plug-in electric hybrid wagon with a low boost turbo. You get the 6 second 0 to 60 mph time, the superb around town fuel economy for the first mile or two, and good highway fuel economy.
My question would be, as these engines have downsized in displacement, have they also downsized in weight? From a vehicle-engineering viewpoint, neither the displacement nor the number of cylinders matters. What matters is the fuel efficiency, the power-delivery, the weight and external size of the engine.
They have decreased in weight, but you are wrong to say that neither displacement or number of cylinders matters. An inline 6 and a V12 engine are the smoothest engines because they are inherently balanced. That means less rotating mass as manufacturers don't have to build harmonic/crank shaft balancers to compensate, which is also less efficient.
As far as displacement goes, you can't beat physics. A 4 liter turbo engine will simply not be able to make the same amount of horsepower and torque that a 5.5 liter turbo engine car, with boost pressures etc, being equal. An internal combustion engine is just a glorified air pump, the more air you can push through a motor, the more power you are able to make. Since I like sports cars and high horsepower vehicles, I'm not a fan of using a smaller turbocharged powerplant in all cases, especially like my Mercedes example. People aren't buying the AMG versions of their cars for fuel economy.
You can get a lot of horsepower out of a turbo 4 liter (the new 911 GT2 RS has a 700hp, 550 lbft torque 3.8 liter engine after all) but from a simple tune, I can get 700hp and 850 lbft of torque out of my Mercedes ML63 with a 5.5 liter. It's capable of even more, but the drivetrain can't handle any more power than that.
Admittedly, I'm in a small demographic of car buyers who want the highest performance version of a car, and then want even more from aftermarket solutions. So this downsizing trend will probably continue to happen, so long as the end result is that the performance keeps increasing from the previous models.
Smoothness and other NVH considerations have their own importance, but are a side-issue as regards efficiency. Not all 4-cyl or V6 engines have balance shafts. The old standby 90-degree pushrod V8 not only has no balance-shafts, but has been refined by the aftermarket to substantially reduce rotating mass… billet crankshafts with scalloped counterweights, and that sort of thing.
I too am a fan of larger displacement, especially when said displacement is possible by maximizing bore and stroke, within a given external block envelope. Many smaller-displacement engines take exactly the opposite approach, with cast-iron blocks and thick cylinder walls; small displacement, but [relatively] high weight. This can potentially allow aftermarket tuners to increase boost-pressure without worrying about cylinder sealing or block integrity, the next weak-link being likely the rod bolts or the main caps.
My point wasn’t to argue for one or another approach to building horsepower, but to ask whether indeed the trend toward lower displacement and forced-induction on the whole manages to save weight. Towards that end, I’ve been stymied in trying to find actual engine-weight numbers. Take for example BMW, in going from naturally-aspirated inline-6 (3.0L), to turbo 4-cyl (2.0L). How do these engines compare in weight? Not trying to push an agenda here… I’m just curious.
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