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Does having turbo really mean better fuel effiency?


Ahgong
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I think TC engines more fuel efficient in stop-start traffic, due to their higher torque across a larger rev range. I take this to mean you can accelerate faster while still keeping revs low, which works out to lesser fuel used. Please let me know if my thinking is wrong, not really a car guy...

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Totally agree with this bro!

TC car does not translate into more fuel efficient due to the need to maintain 15:1 air to fuel ratio for all petrol engine.

So more air (compressed), more fuel. The only saving is the design of powertrain - engine and gear and minor adjustment to drag-coefficiency..etc. In fact, I suspect low rpm does not equate lower fuel use if the gear is not correctly engaged. You can't put into 5/6th gear at very low speed as the ECU may be dumping more fuel into the cylinder. 

 

Diesel engine is the real efficient one... Go read more on why from the internet and you will know why.

 

My view is yes, but not the way sellers make it out to be.   Becoz no matter what, cannot escape.  If you force more air into an engine, e.g., force the amount of air that normally goes into a 2.0 NA into a 1.4 w TC, ....air to fuel ratio will still apply.  

 

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Used to drive the older 2 liter Subbie GT, 245 bhp turbo and unmodded..

Only managed to do 8km/l on a near 90% highway.

Start-stop traffic and picking up kids and groceries... Around 6-7km. Pump petrol until sian...

 

Same here. Best I could average with a very light light foot and RON98 was 9.5km/l. Drive a bit more enthusiastically and/or plenty of multi-storey car park visits and it will be 7km/l. Now switched to Ah Pek turbo W212 E250. 211 bhp and 350Nm torque. Pump RON95, and still averaging 10.5 km/l. With more highway driving, average 12.5km/l. 

 

So yes, turbo charging does improve fuel efficiency. But together with variable cam timing to maximize efficiency. The Subbie old fashioned engine TC without variable valve timing was drinking at any revs.

 

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Turbocharged

Its the AWD thats affecting your fuel efficiency not turbo , the Type Rs and GTIs oso getting abt 10km/L,Subbies are known for their terrible fuel economy no tks to their AWD

 

oh ya.. AWD 'helps' ..  it's been some years already.  [:p]

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Was chatting with a fellow brother and we were arguing about how having turbo will contribute to FC.

I was on the camp that having turbo, FC friendliness will only be achieved if the required gear-ratio vs RPM is achieved.

He was on the camp that turbo is FC friendly regardless, only the max BHP is the difference at the correct gear-ratio vs RPM.

 

so, just to generate some chit chat. i am bored. share your views.[/17953 ]

 

Typically.... Turbo = More shiok = Heavier right foot = Higher FC.

 

For my case, light or heavy foot oso 10km/l. No diff.

Edited by Jellandross
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Wait for 2.3L 350bhp, 440 nm torque. Awd coming soon hehe

 

 

Adding on to ts qn, how about high compression smaller cc vs normal compression bigger cc ?

 

Fc v drivability. Eg. Mz new engines all at 13/14 compressi N ratio vs normal cars at 10/11?

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Depends on the tuning.

 

It can be tuned for more power and so use more fuel

 

or tune for economy so use less fuel.

 

Also depend on the rev range.

 

Start stop use more fuel cos no boost

 

as the exhaust gas still lagging

 

but on the highway at a constant high speed

 

then very economical as the exhaust gas

 

is used to force more air into the engine.

 

More oxygen means more power so less

 

fuel needed to maintain high speed.

 

:D

 

 

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ok for those who is has been misguided by turbo information in the past,

 

turbos do not increase fuel economy

 

that being said, turbos increase torque (and thus horsepower) from the increase in intake air, hence more fuel can be burnt in the chamber.

 

what increases fuel economy is the downsized engine that is being used. essentially, if you compare a 1.6L NA and 3L NA, you will definitely say the 1.6L got more fuel economy right? that's because the engine is running at higher rpm (means about 3000++rpm) more often, so it is more fuel efficient.

 

add a turbo to the 1.6L, now you can run even more torque at the same 3000++rpm, so you get about the same torque as 3L NA. but the increase in torque does not come free. you still need more fuel to get more power. so if you use 100hp, you will still spend at least 100hp worth of fuel no matter if you use turbo or not. (of course, going back to above paragraph, 100hp on 1.6L NA engine will run at higher efficiency than 3L NA, so that's why 1.6L is better fuel economy)

 

 

Turbo increases performance. downsized engine increase fuel economy. 

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Naturally aspirated, air intake from surrounding, not powered/aided by turbocharger.

 

thanks for the inform. learn something new today!  :grin:

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Wait for 2.3L 350bhp, 440 nm torque. Awd coming soon hehe

 

 

Adding on to ts qn, how about high compression smaller cc vs normal compression bigger cc ?

 

Fc v drivability. Eg. Mz new engines all at 13/14 compressi N ratio vs normal cars at 10/11?

 

that formed the second half of our argument.

 

smaller cc engines with higher power output due to coupling with the TC. paper stats has shown that the FC is better and power out put is similar or better than NA engines of higher cc.

both of us have never drove a newer TC car before. and given my limited experience with a old school turbo car, i can't agree with my buddy.  :=B:

ok for those who is has been misguided by turbo information in the past,

 

turbos do not increase fuel economy

 

that being said, turbos increase torque (and thus horsepower) from the increase in intake air, hence more fuel can be burnt in the chamber.

 

what increases fuel economy is the downsized engine that is being used. essentially, if you compare a 1.6L NA and 3L NA, you will definitely say the 1.6L got more fuel economy right? that's because the engine is running at higher rpm (means about 3000++rpm) more often, so it is more fuel efficient.

 

add a turbo to the 1.6L, now you can run even more torque at the same 3000++rpm, so you get about the same torque as 3L NA. but the increase in torque does not come free. you still need more fuel to get more power. so if you use 100hp, you will still spend at least 100hp worth of fuel no matter if you use turbo or not. (of course, going back to above paragraph, 100hp on 1.6L NA engine will run at higher efficiency than 3L NA, so that's why 1.6L is better fuel economy)

 

 

Turbo increases performance. downsized engine increase fuel economy. 

 

that was what i argued too. it is the coupling of the lower tier engine with the TC that makes up for the better FC stats.

i kinda like that idea too. lower cc car with higher power output with lower FC as compared to the similar 1.6L car we are familiar with.

 

so far, not many models are made liddat rite?

i only know of the VW and the Nissan SUV. 

any fellow enthusiast driving such cars? can share your experience?

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On highway and low load, air to fuel ratio is altered to it will go into lean mode. less fuel will be injected thus there is saving in fuel but this does not mean lean mode can be used always as it will cause detonation (if i remember) which can damage the engine. ECU is smart to alter all these which is designed by automotive engineer. Lean mode, rich mode... depends on car load

 

But on highway, as the speed increases, piston will find the resistance becoming negligible to overcome but the drag resistance increases... that is why as car increases in speed, so does fuel usage to over the drag at an exponential way.

 

Turbo does not improve fuel efficiency, that is my take. But turbo on small engine will definitely save on road tax... and if engine+turbo is tuned for fuel efficiency, then it will of course be better than high power turbo engine. 

 

Look at ford 1L ecoboost, i read it is not fuel efficient. just my thought.

 

Depends on the tuning.

 

It can be tuned for more power and so use more fuel

 

or tune for economy so use less fuel.

 

Also depend on the rev range.

 

Start stop use more fuel cos no boost

 

as the exhaust gas still lagging

 

but on the highway at a constant high speed

 

then very economical as the exhaust gas

 

is used to force more air into the engine.

 

More oxygen means more power so less

 

fuel needed to maintain high speed.

 

:D

 

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2.0t consume more fuel than 2.5 NA under similar driving conditions 

 

so smaller engine turbo doesn't mean better fuel efficiency than bigger engine NA

 

 

 

 

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