As engines continue to downsize and become smaller, though that trend may have reached a peak, we are seeing forced induction take the place of displacement as a way to deliver similar gusto with greater fuel economy.
Pick one of many long-time General Motors vehicles and you will likely notice it offers a turbocharged four-cylinder engine these days, likely replacing a V6 engine. But, sometimes, turbos don’t always fulfill their job to the fullest.
The Detroit News spoke with David Amodeo, a senior manager at J.D. Power, regarding the trend of turbocharging, and consumers aren’t always thrilled with the ownership experience.
Specifically, in regards to fuel economy, drivers aren’t seeing the lofty numbers promised by the window sticker.
“The caveat is that on the EPA’s test cycle, these engines look fantastic from a fuel efficiency standpoint for the window stickers, but some consumers are saying, my fuel economy is horrible, because they have to sink their foot into it more because the engine has to work harder to generate that power,” Amodeo said.
But, Amodeo doesn’t see the trend fading anytime soon.
“You can get the same horsepower, and you can get really good driving characteristics out of a much smaller engine. This is going to become more and more commonplace, and I don’t expect that growth to slow down. We’re going to see turbos in all sorts of applications.”
In last year’s J.D. Power dependability study, which combs through data from 2013 model year vehicles over a three-year period, turbos had nearly 30 percent more complaints than non-turbos. Consumer Reports has also often found turbocharged engines don’t meet their expected fuel economy estimates.
However, in the J.D. Power 2016 Initial Quality Study, which composes 90 days of ownership, turbos did not have more complaints than non-turbos. Amodeo said this could indicate manufacturers have cleared the hurdle of delivering real-world fuel economy with boosted engines.
It boils down to how the driver is operating the vehicle. The EPA is gentle in testing, meaning the engine is sipping fuel. But, as we all know, we’re not always the most gentle drivers in real life.
Comments
I’ve been happy with the performance and MPG of my LE2 1.4L, but it’s pairing with the 6 speed automatic leaves a lot to be desired. Bouncy shifting, odd turbo lag when cold and shifting patterns. The 6 speed in our older cruze is the same. Smooth is definitely not something I’d class it as. That same transmission when paired to an NA has a much more pleasant driving dynamic. I average close to 40MPG with more highway than city, and when I need some power, it’s there. There’s also the question of long term reliability, I don’t foresee heavily boosted engines lasting longer than their NA counterparts. I certainly wouldn’t mind seeing some V6 engines come back into play on larger models, but an i4T does the job well on smaller cars.
I have the 1.6 sidi LWC engine in my 2015 opel insignia, 6T45 automatic transmission, I have the same problem… Bouncy shifting, odd turbo lag. There s also the question about Turbo and direct injection engine long term reliability
A 48-volt mild-hybrid module like the system being developed by Johnson Controls could be a viable replacement to turbochargers used by small engines as instead of the turbocharger kicking in; you get the power of 75-100 horsepower instantly from an electric motor as you can get performance without the sacrifice of fuel mileage as there’s no additional stress put on the gas powered motor.
I think the disconnect in real world fuel economy is even more pronounced when the turbo engine is undersized. My 2015 Sonic RS is rated 32 Hwy. My 93 mile daily round trip commute contains 84 miles of highway. Setting the cruise at 72 mph I’m lucky to average over 29mpg. When I first got it I would set the cruise at 78mph and get about 26mpg.
My previous car was a 2001 Grand Prix GT with the NA 3800 rated at 29 mpg. Setting the cruise at 78-80 mph, I would repeatedly get 25mpg.
So, a heavier car with a larger ( and older tech) engine achieved roughly the same gas mileage as a 700lb lighter car with a turbo engine having less than half the displacement. Plus, the GP had much better acceleration.
GM could do much better if they marketed the cylinder deactivation better. A 3.6 V-6 running on 3 cylinders is a 1.8 liter with the torque of a 3.6L at its disposal (No need to wait for a turbo to spool up).
Also, a 1.4L turbo @ 15psi of boost is ingesting the same fuel rate as a 2.8L NA motor. If you have to get into the boost to move the car, it’s not much more efficient.
CAFE first came in when the federal speed limit was 55 and I think that all the standards were set then …. and I think for consistency that’ still the case, so powertrains are tuned to maximize fuel economy at that speed…..not real world for many consumers though. Many high MPG models have severe mileage drop offs at high speeds — and not just GM
The laws of aerodynamics are the same on each vehicle. I had a 2013 cruze mt6 1.4 turbo, if I did 55-65 I could easily outdo the EPA estimate and routinely had 45+mpgs. Now, same vehicle, add 10 mph and hit 75 on the interstate, MPGs would drop to upper 30’s. This isn’t crazy, its wind drag. Your sonic is not quite as aerodynamic as the cruze but I bet if you did the 93 mile commute at 60mph, you would get EPA estimate or more.
I found GM had a snorkel on the end of the air intake, assuming this was for noise, I took it off and adjusted the gaps on the plugs slightly, and the turbo lag reduced significantly. The 1.4t was very adequate for the cruze/sonic cars but could benefit from a twin scroll type turbo like what is on the 2.0l LTG’s in the Caddy ATS, very smooth compared to the 1.4 single scroll-er.
I understand the wind drag issue and I know that I could get the EPA rating at a lower speed to mimic their testing. In comparison to my previous car, I was still expecting a bigger bump in mileage given my ’01 GP had more than twice the motor, had 600+more lbs to push and a larger frontal area that pushed more wind than the Sonic. The Cd of the two a likely comparable, so I was still surprised that the Sonic doesn’t do better. It feels underpowered for me, which is a shame that GM couldn’t have given a better factory tune to help instead of lowering the final drive. I may have to look into the snorkel and plug gaps. Thanks for the tip!
Kinda like the old 301 Turbo Trans Am’s. Wasn’t all bad, just wasn’t very good.
Well this is another thing you need to use a complete thought of the market to get why.
Yes smaller engines and turbo generally get better MPG with more power in normal driving.
But the other big factor is the engine size tax regulations globally. GM and most other MFG are not just making single market engines much anymore unless they are tied to a large volume product like a Pick up Truck.
Some markets charge a higher tax with the displacement of the engine and that is why some of out engines are the size they are for some segments.
Now also most turbo engine do get pretty good MPG. My 2.0 Turbo gets much higher than the GM numbers and I do not drive it easy.
The odd thing was I added the GM Performance tune and picked up 1-2 MPG. I asked an engineer if I was making a mistake or was it true. He said it was an unintended side effect they were happy to see.
He explained that the more torque gets the vehicle up to speed faster and then you lift off the gas and it saves fuel. Most people do no understand when off the throttle DI engine use no fuel unlike port injection that still receives some fuel.
To get better DI fuel mileage you just need to make sure you are off the gas all the way when coasting.
Yes like any engine if driven hard you can and will use more gas. That is a no brainer but you also do not need to floor most modern turbo engines to get anywhere like in the past either.
“But the other big factor is the engine size tax regulations globally. GM and most other MFG are not just making single market engines much anymore unless they are tied to a large volume product like a Pick up Truck.”
This is why I wish some of the manufacturers (mainly GM) would push for a revision to the engine size regulations. Maybe regulate based on a formula for specific air consumption/RPM. GM could argue that their cylinder deactivation allows a larger engine to behave like a smaller engine. simply the converse of a smaller turbo engine behaving like a larger NA engine. They could use the real world information of their full size pick-ups compared to Ford’s eco-boost. The new GM V-8’s with the DoD tech get as good economy as the Ford’s boosted V-6’s in real world conditions. Maybe this wouldn’t work globally, but they have an opportunity right now with the current US administration.
Plus one.
The problem is everyone has a standard they want but not all agree. So while they have a common with they do not agree on the standard they all want.
To change it someone will lose a lot of development money into what they have already done if they don’t get their way.
Global standards are kind of like world peace. Something we all want but not everyone can agree with.
im not sold on the long term reliability of the turbos. i have a 2.2 ecotech with 280k miles that still gets 34mpg. do u think that turbo will last 300k?
Lynn, I hope your post was made tongue in cheek. You are the definition of long term reliability. 280,000 is a crap ton of miles! More than 99% of people will ever put on a vehicle.