Does Turbo effect gas milage??

[Tansey86]

I think you are looking for Fast,Reliable,Cheap. Pick two.

[industrial]

Originally Posted by McDeLtA_T

Turbos increase your fuel economy drastically. I am an engineer with years of experience designing propulsion systems for ships. Every engine is fitted with a turbo to recovrr the waste heat from the exhaust and basically transfer the wasted energy back into your engine by increasing your cylinder air density by bumping the pressure up. You can tune it for efficiency and add an intercooler to further increase your air density for better combustion. Inter coolers are used to cool the air to again to increase air density so your combustion is improved. It all about density , pressure and temperature. Also, the more your engine is loaded the more efficient it runs.

Sent from my GT-P3113 using Tapatalk 2

I don't think anyone here will be adding a turbo to be more efficient. That would involve what, low compression pistons and a tiny snail so you can make the same HP more efficiently? Spend 10k to get 5mpg better?

[serialk11r]

Originally Posted by McDeLtA_T

Turbos increase your fuel economy drastically. I am an engineer with years of experience designing propulsion systems for ships. Every engine is fitted with a turbo to recovrr the waste heat from the exhaust and basically transfer the wasted energy back into your engine by increasing your cylinder air density by bumping the pressure up. You can tune it for efficiency and add an intercooler to further increase your air density for better combustion. Inter coolers are used to cool the air to again to increase air density so your combustion is improved. It all about density , pressure and temperature. Also, the more your engine is loaded the more efficient it runs.

Sent from my GT-P3113 using Tapatalk 2

Uh, diesel engines are not the same as gasoline engines.

The more your engine is loaded the more efficient it runs, but a turbo only increases load when you want full power or because it's a restriction in the exhaust that needs more power to pump exhaust past. Adding a turbo to a gasoline drivetrain doesn't increase efficiency in most cases.

[McDeLtA_T]

Originally Posted by serialk11r

Uh, diesel engines are not the same as gasoline engines.

The more your engine is loaded the more efficient it runs, but a turbo only increases load when you want full power or because it's a restriction in the exhaust that needs more power to pump exhaust past. Adding a turbo to a gasoline drivetrain doesn't increase efficiency in most cases.

A turbo does not increase load, load is basically a brake acting on your engine like a hill when compared to flat ground. Most people think of load as functions of MAP, MAF, TEMP and RPM, this is more of system resistance. Load is more of an external driver. Never said diesel engine is the same as a gas engine. However, the principle is the same with respect to increasing energy whether its ignited by pressure or spark. You are effectively taking the wasted energy from your exhaust gasses to drive air, and pressure into your cylinders.

On the propulsion systems I have designed for ships, both gas and diesel propulsion always have dual turbos to increase efficiency by increasing the engine performance without having to increase the engine size, this is the driver for efficiency. The problem with efficiency on a car is the fuel mapping and the gearing. Like I was saying before your car has to be tuned correctly to maximize efficiency, as in running leaner. This can be done safely, but if not done correctly can lead to decreasing your longevity of your motor from heat issues.

You also have to select the right turbo for your car. If the OP is questioning if a turbo affects your gas mileage, the answer is yes. You can significantly increase your gas mileage with the correct size turbo and associated ancillary systems. Mostly your decrease in your mpg comes from your foot.



This curve is typical of a curve you will find for many compressor/turbine like applications. From centrifugal pumps to turbochargers. When designing a system, obviously you want to aim your system within the middle of the efficiency lines by adjusting turbo mass flow and pressure ratios. If your boosting your car like crazy 15psi your going to be wayy off the charts on the efficiency rating for your turbo and it just won't be worth it. But if you design your system appropriately your can gain a modest 2-4 mpg with a good turbo application. You won't melt your engine, you won't eat more gas, IF you tune your MAF, IF you adjust your gearing to compensate for the added torque. you can expect good mpg gains.

If you drive the exact same, with a turbo and without a turbo you will gain more mpg with a turbo even though your putting in more fuel. You know why? One reason is volumetric efficiency. Adding a turbo can increasse the volumetric efficiency up to 30-60%. Second, the system is not linear, just because you think you add 2 times the volume of air and you add 2 times the fuel does not mean you get 2 times the pressure after ignition.. the pressure is not linear as it is an isentropic gas situation. and varies as a power.

If you want efficiency, yes you can increase your mpg with a turbo.
If you want performance only? Yes it decreases your mpg. Why? because your foot is ass ramming the gas peddle...

[McDeLtA_T]

It really depends what the OP is after, performance or fuel efficiency?

[ziggz501]

i'd like to see the turbo production engine that improves fuel economy. please show me because i chose the wrong car.

[McDeLtA_T]

Originally Posted by ziggz501

i'd like to see the turbo production engine that improves fuel economy. please show me because i chose the wrong car.

Some interesting turbo site wrt efficiency:


autospeed.com/cms/A_109931/article.html

caranddriver.com/columns/turbocharged-engines-to-the-rescue-why-it-will-be-different-this-time-around

fueleconomy.gov/feg/tech_engine_more.shtml

If you want a production engine that comes with a turbo to save you money check out these cool cars in the link below!!

autoguide.com/auto-news/2012/06/ten-turbocharged-vehicles-we-cant-wait-to-get-our-hands-on.html

[ft_sjo]

I think you guys are on drugs if you think having a turbine wheel in your exhaust with an exducer the size of a pea is going to improve fuel economy at ANY point.

[McDeLtA_T]

Originally Posted by ft_sjo

I think you guys are on drugs if you think having a turbine wheel in your exhaust with an exducer the size of a pea is going to improve fuel economy at ANY point.

I am on drugs, but seriously turbos do increase efficiency, they even help scavenge the cylinder of dirty exhaust!... all in the way they are chosen/set-up. I'm done on this thread.. can't .. do.. anymore...

every single engine I have ever seen on ships diesel or gas or heavy fuel oil (HFO) have all been turbo charged. Why may you might ask? because they save money on fuel, especially when they spend millions to fuel their ships for they're long voyages.

Another GREAT GREAT site to learn about engines and all that cool stuff is: (its not just about diesel, it has gas engines, turbines etc.)

http://www.dieselduck.net/machine/in...l#.UQTnRGfRJHU

Real Case Study:
http://www.allpar.com/fix/holler/slant-six-turbo.html


But look at this site: It's a really easy read on turbos and shows how they work with the benefits (and.. also talks about efficiency).

http://www.popularmechanics.com/cars/how-to/4306310

I personally am not going for efficiency, I will be buying a badass turbo to maximize speeding tickets not my mpg.

[Gixxersixxerman]

Thought that was fords whole thing with the Eco boost engines.. Smaller more fuel efficient turbo engines..

[djdnz]

Affect!!!

[industrial]

Originally Posted by ziggz501

i'd like to see the turbo production engine that improves fuel economy. please show me because i chose the wrong car.

Uh, they are everywhere. Ford's ecoboost engines are an example of this. Chevy's 1.4t and VW's tdi as well. Why do you think when you chip an ecoboost or 1.4t you can gain like +50%hp? They tuned these cars for efficiency, not speed. They are designed correctly with tiny little efficient turbines. On cars like the wrx or evo, the engine and turbo is designed for speed. Making excess power.

This conversation is stupid. If you install a turbo on this car, it's because you want to go faster. Going faster will cost you mpg. How much? Supermassive shared his experience. That's the only data in this thread. Everything else is pretty much speculation and garbage.

[Huehuecoyotl]

What a thread...

[ziggz501]

I think people are confusing fuel efficiency with power... Let me break it down for you.

Turbos are a great way to pull every ounce of power from the engine, and still put up those big mpg numbers. Reason? the turbo is not spooling in the everyday driving rev range. Simple as that. That is why manufacturers are turning to turbos to make power. It gives them a big horsepower number without sacrificing fuel as long as they tune it correctly. And the ecoboost engine does NOT get better gas mileage than the normal engine. Please see Ford Focus specs.

Also, TDI is a whole different beast. You can't compare gas to diesel. Just because you can get 40mpg out of a turbo diesel 2.0L Jetta, doesn't make it more fuel efficient. First of all, we're talking a gas/petrol here. Secondly, I promise you that the old non-turbo diesel VWs got better gas milage than their turbo variants. So please stop claiming that turbos IMPROVE fuel economy, because it is NOT true.

For those people that are putting turbos on their cars and getting better mileage, chances are you are just driving it better to avoid spooling the turbo in everyday driving situations, and effectively improving your gas milage by doing so...