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Discussion Starter · #1 ·
So I was talking with my brother last night (Senior Ford Tech) and we swung around to the subject of downsized turbo engines and what he had to say was interesting to me...

He said the Turbos will absolutely give you a great gas mileage if you drive like an old lady, but once you get into it all your efficiency gains are tossed out the window.

When they say the smaller motor will make the power of the bigger motor they're not lying, but what they don't tell you is when your smaller motor is making the same power as the larger motor its using the same if not more fuel to do so...

We were talking in the context of Ecoboost 4 cylinders replacing V6's but it applies to any downsized turbo IMO
 

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I think that honestly holds true to ANY small engine... i've wrung out my civics in the past just to see how bad of mileage i could get... 17mpg.... and that coming from the same 8th gen coupe that netted me 42mpg on a trip to pittsburgh from columbus.

edit* any engine period... people just don't expect as much from larger engines in terms of mpg
 

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Discussion Starter · #3 ·
I think that honestly holds true to ANY small engine... i've wrung out my civics in the past just to see how bad of mileage i could get... 17mpg.... and that coming from the same 8th gen coupe that netted me 42mpg on a trip to pittsburgh from columbus.

edit* any engine period... people just don't expect as much from larger engines in terms of mpg
yea but if you drive a larger engine like an old lady it will return STUNNING mileage.

TBH most cars don't get their advertised econ because of the driver behind the wheel. Which gets exacerbated by the turbo engines, high boost=high fuel consumption. and most people don't drive like old ladys...

steady state is whats great for fuel econ.

but my brother and I were talking in the context of using a 4 cylinder where a 6 should be. If the motor can't do it without the turbo stay away is what he had to say, its just working like a dog

(this doesn't really apply to the Civic TBH, its just an interesting conversation in general IMO)
 

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I think that honestly holds true to ANY small engine... i've wrung out my civics in the past just to see how bad of mileage i could get... 17mpg.... and that coming from the same 8th gen coupe that netted me 42mpg on a trip to pittsburgh from columbus.

edit* any engine period... people just don't expect as much from larger engines in terms of mpg
Agree with you completely. That being said, the gang at Motor Trend got really good real world MPG and they are not known for taking it easy on their loaner cars.
 

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Agree with you completely. That being said, the gang at Motor Trend got really good real world MPG and they are not known for taking it easy on their loaner cars.
That's true they did... and yea, you have to imagine they weren't easy on the car either... and their tester hasnt even hit breakin point which easily ups the mileage 5mpg or more.
 

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I do wonder what it's going to return under real world semi-spirited driving?
I'd say motortrends estimates are probably a good guess on that one... you can expect them to have driven the car pretty spiritedly, without breakin period they got around 31-33mpg which isn't bad at all before break in period... .
 

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Turbos are a mixed bag. They are efficient when you want them to be. But you have to be off the boost. CVT will mitigate some of this. But ultimately if you mash the pedal, expect a 25-35% drop in efficiency (or more).
 

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I think one of the main reasons why Honda went with a 1.5 liter and such a small turbo is to get that quick spool and allow the car to feel powerful from the torque it'll give. It will be hard to be out of boost with such a small turbo but the mpg's look promising but then again, how often do we get the advertised mpg anyway? Add a turbo to the mix and those numbers might even be lower especially on spirited drives. For me, I just trust that Honda is good on fuel efficiency and the power part, I'll take care of myself. I do have a few plans to free up some power on the turbo motor that hopefully will not hurt the mpg too much.
 

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I'll be watching the reliability and maintainability of this new motor. Things like heat soaking in summer heat, coking of oil lines and the turbo, cooling of the engine in warm weather, ability to maintain the AC running in high temps, and the electronics of the power train. I'm hoping that Honda learned from the mistakes of predecessors and has designed a motor that runs as well as the r18a it is replacing. I'm not saying this will be a bad motor, but I'm still going to give this power train some maturation time before I open my checkbook. As for mileage, I get 44 to 46 mpg out of an EPA rating of 39 on the highway. Should be a POC to get 48+ out of this new power train.
 

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So you have to learn a new driving technique with a turbo to save gas. You have to learn a new driving technique to get the best gas mileage from a hybrid too. You have to learn a new driving technique to go as far as possible on a charge with a battery electric car.
 

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Alright, while I understand the concerns I think they are way overblown with the newer generation of engines. I drive a small turbo now, a Fiat 1.4 liter with 160hp and 170tq. Rated 28 city and 34 highway and for me with mixed driving and mostly city I'm getting 31-33mpg. I'm not easy on the boost either, not ragging it and not grandma either and the car lives with sport mode enabled and traction control off. I'm over two years in with no issues at all of any type and I'd like to think that Honda is a large step up from Fiat!

Also, never noticed real heat soak issues (can tell more power on cool days though, the cool days recently are even more fun than usual!) and my Abarth has a massively overcomplex dual intercooler piping mess too. Also has an electric motor that kicks on when you shut off the car that circulates water and cools the turbo down correctly as needed (mine runs most of the time on shutdown). Mileage has literally never been an issue for me with a small engine and large turbo. This car has only 101hp in non-turbo guise so the turbo is pretty sizable! I see boost up there at 18 PSI or more in my car yet my mileage is great, I expect the Honda will do just fine. This seems to be a pretty mild tune on the Honda setup for mileage and not HP and Tq so I think it will be great.

The Fiats might have other issues but the little turbo engines have been very well regarded and there are no widespread issues of any type engine related really.
 

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Alright, while I understand the concerns I think they are way overblown with the newer generation of engines. I drive a small turbo now, a Fiat 1.4 liter with 160hp and 170tq. Rated 28 city and 34 highway and for me with mixed driving and mostly city I'm getting 31-33mpg. I'm not easy on the boost either, not ragging it and not grandma either and the car lives with sport mode enabled and traction control off. I'm over two years in with no issues at all of any type and I'd like to think that Honda is a large step up from Fiat!

Also, never noticed real heat soak issues (can tell more power on cool days though, the cool days recently are even more fun than usual!) and my Abarth has a massively overcomplex dual intercooler piping mess too. Also has an electric motor that kicks on when you shut off the car that circulates water and cools the turbo down correctly as needed (mine runs most of the time on shutdown). Mileage has literally never been an issue for me with a small engine and large turbo. This car has only 101hp in non-turbo guise so the turbo is pretty sizable! I see boost up there at 18 PSI or more in my car yet my mileage is great, I expect the Honda will do just fine. This seems to be a pretty mild tune on the Honda setup for mileage and not HP and Tq so I think it will be great.

The Fiats might have other issues but the little turbo engines have been very well regarded and there are no widespread issues of any type engine related really.
I think it's the american auto makers honestly... european cars have been integrating turbos for a while and their refinement of the process certainly shows looking at the great mileage of cars like your Fiat, VW Golf/GTI etc... I think the americans just need to do more homework on their turbos.

I'm positive honda has done that homework (hence taking so long to jump on the turbo bandwagon)... so i'm not really concerned that honda has found the good mix of power and fuel consumption.
 

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I think one of the main reasons why Honda went with a 1.5 liter and such a small turbo is to get that quick spool and allow the car to feel powerful from the torque it'll give. It will be hard to be out of boost with such a small turbo but the mpg's look promising but then again, how often do we get the advertised mpg anyway? Add a turbo to the mix and those numbers might even be lower especially on spirited drives. For me, I just trust that Honda is good on fuel efficiency and the power part, I'll take care of myself. I do have a few plans to free up some power on the turbo motor that hopefully will not hurt the mpg too much.
http://paultan.org/2015/10/19/2016-...litre-vtec-turbo-engine-and-cvt-transmission/

The more powerful 1.5 litre turbocharged engine gets its fair degree of separation from the base engine, with the obvious being the inclusion of a turbocharger – in this case, a Mono scroll turbo system with an electric wastegate and intercooler. This allows for turbo boost to be built up with relatively small throttle openings and low rpm. Direct injection is also part of the turbo unit’s specifications, featuring a computer-controlled system with multi-hold fuel injectors, which allow for a compression ratio of 10.6:1. Smaller M12 spark plugs are installed instead of the common M14 ones as well.
 

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Normally aspirated engines that are rated at say, 150hp and 155ft lbs of torque at 5800 rpm, means that you have to wring the engine to 5800 to get that power. A well designed turbo engine will start to make good power in the 2500 rpm range. Last month I tested a Ford Fiesta ST with the 1.6 turbo, and that thing was a blast! The only reason I don't have one in my driveway is that I'm not confident of Fords reliability compared to Honda's.
 

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Not familiar with these engines...

Turbos are a mixed bag. They are efficient when you want them to be. But you have to be off the boost. CVT will mitigate some of this. But ultimately if you mash the pedal, expect a 25-35% drop in efficiency (or more).
So the boost is like a blower or super charger?
 
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