Does turbo charging improve FC?

[Expertz]

say if i turbo charged my 2L to attain the same power as a 2.4L, will my 2L consume less fuel than a 2.4L if the driving patterns are the same?

 

also if my 2L does 8km/l at 180km/h, if i added a bolt on turbo kit, will the car get better FC at 180km/h?

and if i added a small turbo into my car, how much gain will i be able to get if i don't intend to change anything else?

 

not that i intend to add a turbo into my car, but wondering if turbo technology can help improve FC

[Emperor]

  On 5/5/2011 at 1:41 PM, Expertz said:

say if i turbo charged my 2L to attain the same power as a 2.4L, will my 2L consume less fuel than a 2.4L if the driving patterns are the same?

 

also if my 2L does 8km/l at 180km/h, if i added a bolt on turbo kit, will the car get better FC at 180km/h?

and if i added a small turbo into my car, how much gain will i be able to get if i don't intend to change anything else?

 

not that i intend to add a turbo into my car, but wondering if turbo technology can help improve FC

 

Seriously, Turbo charging was originally intended to improve efficiency as well as power. A small turbo would in fact, improve your fuel consumption...

 

This is the simplified version. I could get technical, but that would require a full page explaination that includes technical drawings......

[Chpeck]

Wonder why Mit Evo 2.0 Turbo is such a drinker. Maybe small or light pressure turbo do help but not those huge or high pressure ones.

[Mona-vie]

Yes, Turbo does improve FC if its a small turbo and running under low boost.

 

Try reading up on dynamic compression. A turbo can actually increase the dynamic compression (the actual compression ratio when engine is running), and hence boost efficience. Technically, higher compression is more desirable because you can extract more energy from the combustion. eg. a 10:1 vs 12:1 compresison, the 12:1 compresison will have better power buring the same amount of petrol vs 10:1.

 

So a turbo does similar things. Eg, when your piston moves down and suck 100ml of air and then compress till the volume becomes 10ml. So the compression is 10:1. Now, the turbo pushes in extra 20ml of air, so your piston will have 120ml instead of 100ml. Then when it compresses, its still becomes 10ml. The ratio increases to 12:1. You may need a little more petrol to burn that extra 20ml of air but you will get alot more power. Hence more efficient. Of course, things are more complicated than that but its just a simple analogy.

 

So when are Turbo cars becoming fuel guzzler? thats when you run high boost like 1 bar or higher. The biggest problem faced by turbo cars is pinging. When you have more air and compresses it, pinging is prone to occur. So what can you do? Dump in more petrol. We know the optimum ratio is like 14.7:1, but in order to prevent pinging, turbo cars run 12:1 or even lower like 10-11:1 A/F ratio. Having so much petrol actually causes lost of power. But its done to prevent pinging. Of course another is lower static compression of the engines. Cars like Evo WRX runs only 8.5-9:1 compression. Much lower than 10-10.5:1 compared to lightly TC cars.

 

You want to run high compression + high boost + good FC? It can be done actually. But its too expensive you cannot use regular petrol. Having to be well above RON100 petrol. Racing gas is EXPENSIVE!!

Edited May 5, 2011 by Mona-vie

[John112]

just get high ratio na car eg. mark x

[Tanly]

Actually it's the 4WD thats a drinker more than the fact that it's turbochharged. You need double to torque to power the 4 wheels rather than a normal 2 wheel drive.

 

  On 5/5/2011 at 2:06 PM, Chpeck said:

Wonder why Mit Evo 2.0 Turbo is such a drinker. Maybe small or light pressure turbo do help but not those huge or high pressure ones.

 

[Limxiaoming]

Wow bro, you could not have put it better.

Expert

[Mona-vie]

  On 5/5/2011 at 2:57 PM, Tanly said:

Actually it's the 4WD thats a drinker more than the fact that it's turbochharged. You need double to torque to power the 4 wheels rather than a normal 2 wheel drive.

 

Its not true lar. You need more power because of mechanical losses thru differentials and transmission. Thats why 4WD sucks more power compared to 2WD.

[Mona-vie]

  On 5/5/2011 at 2:38 PM, John112 said:

just get high ratio na car eg. mark x

 

Wah Mark X is expensive and its 2.5L.......COE and road tax + insurance... ahem.....

 

At least a 1.4L TC or 1.6L TC much cheaper.

 

Btw, talking about high comp na engines, they are mostly direct injection. Its a big problem with clogging of intake valves though. With conventional engines, the injectors clean the intake valves but not the case for DI engines. Junk and crap stuff build up on the valves over time and very troublesome and need $$$ to remove.

 

I remembered seeing a photo of a Porsche engine having junk built up on the valve and the person have to remove the whole head to clean the valves.

[Chpeck]

  On 5/5/2011 at 3:10 PM, Limxiaoming said:

Wow bro, you could not have put it better.

Expert

 

I second that. So well explained in merely 330 words! The only thing I know about turbo is that the insurance premium is much higher.

[Tanly]

Err it's a well known fact that draggy all wheel 4X4 drive saps power in favor of more tractiion, the additional differential loss is minimal compared to the power needed to power the additional axle/2 wheels.

 

4wd is the real fuel guzzler rather than turbocharged cars, as turbocharged cars are more fuel efficient if you drive the same way and not floor the pedal more excessively than u normally do or your NA ride.

 

Can safely say that a 1.6 Subaru TS wold be more fuel efficient & powerful if it's a 1.6L 2WD turbocharged unit rather than an NA 4wd unit.

Most of the power loss goes to powering the additional 2 wheels while a small part is lost thru the rear differential.

 

For everyday driving or efficiency I would say turbocharging is the way to go and not 4WD. Anyway having 4WD in urban roads is redundent.

 

 

 

  On 5/5/2011 at 3:10 PM, Mona-vie said:

Its not true lar. You need more power because of mechanical losses thru differentials and transmission. Thats why 4WD sucks more power compared to 2WD.

Edited May 5, 2011 by Tanly

[Expertz]

  On 5/5/2011 at 2:25 PM, Mona-vie said:

So a turbo does similar things. Eg, when your piston moves down and suck 100ml of air and then compress till the volume becomes 10ml. So the compression is 10:1. Now, the turbo pushes in extra 20ml of air, so your piston will have 120ml instead of 100ml. Then when it compresses, its still becomes 10ml. The ratio increases to 12:1. You may need a little more petrol to burn that extra 20ml of air but you will get alot more power. Hence more efficient. Of course, things are more complicated than that but its just a simple analogy.

 

would this still hold true if i'm driving normally? so i won't be using all that much power so the turbo boost doesn't come on at all most of the time as my car will be constantly below 2k rpm

 

also won't this extra add fug up your ecu? afterall the ecu calculates on the fly how much petrol is needed to burn the air

if you forced in extra air and there isn't enough fuel to burn up that air, won't there be ignition issues which will result in a loss of power instead?

Edited May 5, 2011 by Expertz

[Expertz]

  On 5/5/2011 at 3:16 PM, Mona-vie said:

At least a 1.4L TC or 1.6L TC much cheaper.

 

1.4TC VWs post really great fuel economy, i'm wondering if their results are reached by driving really slowly and not activating the turbo so the cars are running strictly on 1.4L engine only, or does that turbo help

 

thus a 1.4TC will drink lesser fuel than a 1.4L given the exact same driving conditions

[Joseph22]

  On 5/5/2011 at 3:39 PM, Chpeck said:

I second that. So well explained in merely 330 words! The only thing I know about turbo is that the insurance premium is much higher.

high meh?

 

turbo car like Golf TSI, Citron Thb all lower interest than my NA car leh

[Joseph22]

  On 5/5/2011 at 4:06 PM, Expertz said:

1.4TC VWs post really great fuel economy, i'm wondering if their results are reached by driving really slowly and not activating the turbo so the cars are running strictly on 1.4L engine only, or does that turbo help

 

thus a 1.4TC will drink lesser fuel than a 1.4L given the exact same driving conditions

 

 

you teach me how to drive that car without turbo when the turbo activate at 1.5 or was it 1.7K onwards

 

the car have good FC because its can rev low to reach normal driving speed.

Edited May 5, 2011 by Joseph22

[Tanly]

From my experience definately a 1.4TC would give better fuel consumption under the same driving conditions and even if you drive bit more aggresively it would get about the same or just slightly below the average fuel consumption of an equivelent NA 1.4 unit.

 

  On 5/5/2011 at 4:06 PM, Expertz said:

1.4TC VWs post really great fuel economy, i'm wondering if their results are reached by driving really slowly and not activating the turbo so the cars are running strictly on 1.4L engine only, or does that turbo help

 

thus a 1.4TC will drink lesser fuel than a 1.4L given the exact same driving conditions

 

[John112]

i think to save fuel is to rev to mid torque range & drop to cruise at 80-90kmh asap,

 

[Iambored]

Well I think AWD is not redundant because it would be beneficial to people who are not comfortable with driving on wet days. AWD provides more grip so chances of spinning out are lesser than a FF or FR. In addition certain sports cars such as the Porsche, Lambos, GTRs are AWD to provide extra grip. Sure you hardly have places to race in SG but nevertheless the grip is there. I personally prefer FR cars becos of better turning through narrow spaces and u-turns.

 

Now back to the topic about FC, I think in terms of fuel consumption, it depends on many different factors such as the weight of the car, size of the rims, etc. Having a turbo may not necessarily improve the FC but keep it constant. Well if you're talking about 1.6l turbo or 1.8l turbo. But then again it wasn't always this way, I remember at one point of time in the year 2000, the Audi A6 had a 1.8l turbo version but the fuel consumption was extremely high and the car was rather noisy. I'm not too sure why that was the case, I don't think it's still is a problem. I know that the saab 9-5 is turbo charged and has very high fuel consumption due to the heavy front of the car. So like i've said before, FC is affected by lots of factors. In addition if you plan to add an aftermarket turbo you should make sure you car's engine can be turbocharged in the first place. By the way an aftermarket turbo is illegal so do think twice before trying to add a turbo charger to your car.