Does Turbo effect gas milage??

[AVOturboworld]

Turbochargers are viewed as gaining MPG by the manufacturers because they don't compare the same motor n/a vs. turbocharged variant, they are viewed that way because they compare the turbocharged version vs. a n/a motor making the same hp as the turbo motor.

Say, for instance, a manufacturer wants a 250hp motor in a car. They have a choice of a small (1.8~2.0 liter) turbocharged motor vs. a larger (3.0-3.6) liter V6. Which of the two is going to produce the power more efficiently, all other factors (gearing, etc) aside? The smaller turbo motor. That's what you are seeing throughout the industry for quite a time, and for a reason.

Point blank, more hp = more fuel. A turbocharged vehicle can still get high mpg figures, though, because when it's at a steady state cruise, it doesn't need to be in boost to maintain speed. On the other hand, if instead you used a larger n/a motor with the same power (and same gearing), it *would* return less gas mileage in that steady state cruising.

[ziggz501]

Originally Posted by AVOturboworld

Turbochargers are viewed as gaining MPG by the manufacturers because they don't compare the same motor n/a vs. turbocharged variant, they are viewed that way because they compare the turbocharged version vs. a n/a motor making the same hp as the turbo motor.

Say, for instance, a manufacturer wants a 250hp motor in a car. They have a choice of a small (1.8~2.0 liter) turbocharged motor vs. a larger (3.0-3.6) liter V6. Which of the two is going to produce the power more efficiently, all other factors (gearing, etc) aside? The smaller turbo motor. That's what you are seeing throughout the industry for quite a time, and for a reason.

Point blank, more hp = more fuel. A turbocharged vehicle can still get high mpg figures, though, because when it's at a steady state cruise, it doesn't need to be in boost to maintain speed. On the other hand, if instead you used a larger n/a motor with the same power (and same gearing), it *would* return less gas mileage in that steady state cruising.

couldn't have said it better. that's why i referred people to Focus. It is the perfect example for a modern production car. Look at Ford's n/a engines, then look at their ecoboost version. The n/a variants only push 160hp, but the mpg is great at about 32~ combined, while the ecoboost version gets only 26 combined, but on the other hand also pushes 252hp. Tap into that power and I doubt you get anywhere near 26mpg though...

MPG figures are all created by driving a car mildly, and that's why manufacturers like turbos. Drive it mildly, and you can get decent mpgs... The same goes for n/a motors. If you drive it like you stole it, then your milage is going to go down. Like I said earlier, the motor has to have the correct amount of fuel for the amount of air it brings in. More air = more fuel. You cannot add air and not fuel unless you want to melt metal.

[Gixxersixxerman]

Originally Posted by ziggz501

Like I said earlier, the motor has to have the correct amount of fuel for the amount of air it brings in. More air = more fuel. You cannot add air and not fuel unless you want to melt metal.

I agree to a certain point.. I added a intake and exhaust, it flows more air, there fore using more fuel to keep the same A/F ratio, but I've gained almost 3 mpg constantly for a 38-39 mpg highway and 33 or so city, because the engine breathes easier and more efficient it doesn't have to use that energy needed to suck the air in and push the air out.. An engine is by all accounts a big air pump.. Pumping air in and pumping air out.. The easier you make it, the more fuel efficient it is.. I agree that there is a point to where your adding more then what is considered efficient.. 20lbs of boost needs a fuel requirement to support it.. But unless I misread two people on here have boosted the car and picked up a little mileage... I wouldn't, I drove a turbo MX6 and was constantly 10 mpg or more less then the owner, becaus I couldn't keep it off boost to hear that whine and blow off valve..

[industrial]

Originally Posted by ziggz501

couldn't have said it better. that's why i referred people to Focus. It is the perfect example for a modern production car. Look at Ford's n/a engines, then look at their ecoboost version. The n/a variants only push 160hp, but the mpg is great at about 32~ combined, while the ecoboost version gets only 26 combined, but on the other hand also pushes 252hp. Tap into that power and I doubt you get anywhere near 26mpg though...

MPG figures are all created by driving a car mildly, and that's why manufacturers like turbos. Drive it mildly, and you can get decent mpgs... The same goes for n/a motors. If you drive it like you stole it, then your milage is going to go down. Like I said earlier, the motor has to have the correct amount of fuel for the amount of air it brings in. More air = more fuel. You cannot add air and not fuel unless you want to melt metal.

Oh Christ. The ecoboost on the ST is for performance. You can't compare the ST to the normal focus. The ST makes some 100hp/130lb-ft more! Not even close to a valid comparison. If the ST was designed by ford to be an economy turbo car, it would rock something like a the turbo Cruze, a 1.4t making the same power as the standard car but with better fuel economy.

Stop looking at performance cars with turbos and look at normal cars like the Cruze, Golf, Escape, F-150, etc. The turbos on these cars are spooled at insanely low rpms to help what would be a fairly inadequate engine move the car around town. Like AVO said, try comparing normal commuter cars that make the same power NA and turbo and look at the fuel efficiency numbers.

Turbos let you use smaller engines to improve economy in economy cars. Turbos also let you get large engine performance from smaller engines. It's all in what the system is designed for.

[Huehuecoyotl]

didnt car and driver test focus st real world at some 21mpg?

[ziggz501]

Originally Posted by industrial

Oh Christ. The ecoboost on the ST is for performance. You can't compare the ST to the normal focus. The ST makes some 100hp/130lb-ft more! Not even close to a valid comparison. If the ST was designed by ford to be an economy turbo car, it would rock something like a the turbo Cruze, a 1.4t making the same power as the standard car but with better fuel economy.

Stop looking at performance cars with turbos and look at normal cars like the Cruze, Golf, Escape, F-150, etc. The turbos on these cars are spooled at insanely low rpms to help what would be a fairly inadequate engine move the car around town. Like AVO said, try comparing normal commuter cars that make the same power NA and turbo and look at the fuel efficiency numbers.

Turbos let you use smaller engines to improve economy in economy cars. Turbos also let you get large engine performance from smaller engines. It's all in what the system is designed for.

firstly, you basically just made your own point invalid by using those cars... find me an engine the same size, with a turbo attached to it getting better mileage.

secondly, the escape and f-150 ecoboost versions get worse milage than the larger displacement n/a versions.

thirdly, golf has a turbo model called the gti, which is performance oriented like the focus st. I hope you aren't comparing TDI to gas. That's a different type of fuel burning. You can't say that the regular golf gets 33 mpg and the tdi gets 40, so the turbo is causing better milage. its an entirely different combustion process.

fourthly, yes the cruze 1.4L does get like 1-2 mpgs better than the larger 1.8L n/a engine. wow, you found one car out of 100s of turbo models out there. you know what else has a 1.4L engine and gets great milage? the old honda HF models... less grunt, but yeah 50mpgs.

what i would like to see is someone take an engine, any engine. strap a turbo on it, and make it improve the fuel economy of that engine. its perfectly obvious that a turbo makes the engine pound for pound more efficient, but it isn't going to boost fuel economy of the engine. as i've already stated, the manufacturers are strapping turbos to the cars because they create a big bump in the hp numbers with only a slight ding to fuel economy, but if you actually step on the gas and spool that turbo, u might as well poor your gas onto the street.

with the recent increase of direct injection vehicles, its much easier for car manufactures to use a turbo, because the risk of detonation is nullified. they have the ability to lean out the AFR quite a bit, yes, but it still has to have fuel to avoid melting the cylinders. and the turbo adds quite a bit more air, so you need quite a bit more fuel, lean or not.

[industrial]

Originally Posted by ziggz501

firstly, you basically just made your own point invalid by using those cars... find me an engine the same size, with a turbo attached to it getting better mileage.

secondly, the escape and f-150 ecoboost versions get worse milage than the larger displacement n/a versions.

thirdly, golf has a turbo model called the gti, which is performance oriented like the focus st. I hope you aren't comparing TDI to gas. That's a different type of fuel burning. You can't say that the regular golf gets 33 mpg and the tdi gets 40, so the turbo is causing better milage. its an entirely different combustion process.

fourthly, yes the cruze 1.4L does get like 1-2 mpgs better than the larger 1.8L n/a engine. wow, you found one car out of 100s of turbo models out there. you know what else has a 1.4L engine and gets great milage? the old honda HF models... less grunt, but yeah 50mpgs.

what i would like to see is someone take an engine, any engine. strap a turbo on it, and make it improve the fuel economy of that engine. its perfectly obvious that a turbo makes the engine pound for pound more efficient, but it isn't going to boost fuel economy of the engine. as i've already stated, the manufacturers are strapping turbos to the cars because they create a big bump in the hp numbers with only a slight ding to fuel economy, but if you actually step on the gas and spool that turbo, u might as well poor your gas onto the street.

with the recent increase of direct injection vehicles, its much easier for car manufactures to use a turbo, because the risk of detonation is nullified. they have the ability to lean out the AFR quite a bit, yes, but it still has to have fuel to avoid melting the cylinders. and the turbo adds quite a bit more air, so you need quite a bit more fuel, lean or not.

I'll make this easy for you. Compare engines of the same output, not displacement or cylinders. Why do you think it's ok to compare a 160hp engine with a 252hp engine and think your conclusion that turbos aren't efficient is valid? How is that a valid comparison?

Don't compare the v6 F-150 with the Ecoboost F-150. Look at the power and torque. Compare the 5.0 v8 and the ecoboost. The 5.0 v8 makes 360hp and 380lb-ft of torque and gets 15/21 mpg. The ecoboost v6 makes 365hp and 420lb-ft of torque and gets 16/22 mpg. Because of the mountain of early torque on the ecoboost, alot of people think it's more powerful than the top of the line 6.2 v8. Look it up. This is a valid comparison. Compare the output, not the displacement.

Look at the lowest two motors available on the Escape. One is a NA 2.5L I4 which makes 168hp and 170lb-ft of torque and gets 22/31 mpg. The comparable turbo model is 1.6L I4 which makes 178hp and 184lb-ft of torque and gets 23/33 mpg. What you are doing is comparing the base 2.5L NA motor to the high end 2.0 ecoboost. What you are missing is that the 2.0 ecoboost makes +70hp & +100lb-ft of torque. Why would you make that comparison when there is a comparable turbo model?

If you don't get it by now, you'll never get it. Understand now?

[ziggz501]

Originally Posted by industrial

I'll make this easy for you. Compare engines of the same output, not displacement or cylinders. Why do you think it's ok to compare a 160hp engine with a 252hp engine and think your conclusion that turbos aren't efficient is valid? How is that a valid comparison?

Don't compare the v6 F-150 with the Ecoboost F-150. Look at the power and torque. Compare the 5.0 v8 and the ecoboost. The 5.0 v8 makes 360hp and 380lb-ft of torque and gets 15/21 mpg. The ecoboost v6 makes 365hp and 420lb-ft of torque and gets 16/22 mpg. Because of the mountain of early torque on the ecoboost, alot of people think it's more powerful than the top of the line 6.2 v8. Look it up. This is a valid comparison. Compare the output, not the displacement.

Look at the lowest two motors available on the Escape. One is a NA 2.5L I4 which makes 168hp and 170lb-ft of torque and gets 22/31 mpg. The comparable turbo model is 1.6L I4 which makes 178hp and 184lb-ft of torque and gets 23/33 mpg. What you are doing is comparing the base 2.5L NA motor to the high end 2.0 ecoboost. What you are missing is that the 2.0 ecoboost makes +70hp & +100lb-ft of torque. Why would you make that comparison when there is a comparable turbo model?

If you don't get it by now, you'll never get it. Understand now?

i already said that turbos are more efficient way of making power, or did you misread my last post. the entire point of this thread is whether or not adding a turbo to an engine improves/decreases fuel economy. simple answer: NO. does the added power offset the the fuel consumed, simple answer: YES. more detailed answer: as long as you don't romp on it because AFR still has to be considered once that turbo spools up.

You will NEVER add more air to an engine and get better fuel economy on the engine if you aren't forcing air into it. AFR, if you don't get it by now, you'll never get it. Understand now?

[industrial]

Originally Posted by ziggz501

i already said that turbos are more efficient way of making power, or did you misread my last post. the entire point of this thread is whether or not adding a turbo to an engine improves/decreases fuel economy. simple answer: NO. does the added power offset the the fuel consumed, simple answer: YES. more detailed answer: as long as you don't romp on it because AFR still has to be considered once that turbo spools up.

You will NEVER add more air to an engine and get better fuel economy on the engine if you aren't forcing air into it. AFR, if you don't get it by now, you'll never get it. Understand now?

You want to improve the fuel efficiency by strapping on a turbo? No problem. I already mentioned how earlier in this thread. Get lower compression pistons, destroke the motor and run a tiny little turbo in the meat of it's efficiency range. You'll lots of great usable power from 2k-5k and the car will choke up top. Not what you want in a sports car really. You need to end up making around the same HP as stock for the comparison to be valid. Why anyone would spend $10,000 for a 2-3mpg improvement I don't know. This is why you never see an aftermarket economy turbo kit, only turbos for people wanting to make more power. Economy turbos are best left to the manufacturers.

[Synack]

I know AVO mentioned this but I would like to reiterate;

You CAN get better MPG by adding a turbo to an N/A motor, but only in the cruising RPM's where the turbo isn't really spooling at all. In this range your tune won't be compensating the extra air (because there won't really be much extra air) by adding more fuel because the turbo isn't spooling. So your highway MPG's should be better if you have a good tune. But if you don't know this already, here it is again, once a turbo starts spooling your tune makes sure that more fuel is being consumed to compensate the extra air, so in turn you will get WORSE gas mileage.

So if you REALLY want to maximize your cars usefulness, drive low RPM's and lightfooted when you want max MPG's, because any more than that then you will be getting worse and worse gas mileage.

This is why I love turbo's, they go fast when you put the hammer down; and they get awesome mileage when you're taking real easy.

[usptwins]

With power comes fuel cost. You can't add more air without adding more fuel. Plain and simple.

[himbo]

Originally Posted by usptwins

With power comes fuel cost. You can't add more air without adding more fuel. Plain and simple.

You're not always using that power though. When you do, yes a lot more fuel gets dumped to compensate for the added air. F1 is moving to downsized motors that are turbo for better fuel economy.

In general though most tunes for aftermarket turbos are optimized for power rather than fuel efficiency. My advice to the OP is to just get a tune, to improve mpgs and free more power...

[Synack]

Originally Posted by himbo

You're not always using that power though. When you do, yes a lot more fuel gets dumped to compensate for the added air. F1 is moving to downsized motors that are turbo for better fuel economy.

In general though most tunes for aftermarket turbos are optimized for power rather than fuel efficiency. My advice to the OP is to just get a tune, to improve mpgs and free more power...

I asked my tuner to crank out the power when the foot is slammed, and sip on gas when partial throttle. It's not impossible to tune for it.

[Godzilla35]

two words... boost controller.