Turbocharging helping gas mileage?

[Pu241]

Air density would have to increase in order for the temp to also rise. Apparently said metros defy the laws of physics, cool. I want one.

No laws broken or even bent!

I couldn't find a temp/pressure/density profile for air so this will have to do.

Depending upon how much the temp of the compressed air increases during compression the decrease in density due to the increase in temp can be offset by the increase in pressure. Even this can be improved upon by the use of an inter-cooler which will help reduce the temp of the compressed hot air and further increase its density.

http://www.engineeringtoolbox.com/air-temperature-pressure-density-d_771.html

[dlaske]

The Turbo, Engine and Exhaust items mentioned can all be debated individually, and most of you are fundamentally correct. But the vehicle has to be looked at more holistically and the people that mention driving style have hit on what has more effect than the bolt-on mod and more closely to the overall effect that some people are experiencing. I've had my share of small cars that should have been more fuel effecient, based on their weight, power and displacement. But, when the Driver or the transmission intentionally keeps the engine out of its peak efficiency areas of its power curve, you get bad performance and can actually make worse mileage when you think you are really saving.
Most modern incremental increases in today's cars are a combination of controlling that combustion tighter, but 6-12% increases are attributable to just the transmission improvements mated to those engines keeping them running in their peak efficiency range.
Shade-tree turbo swapper may just have pulled his motor into an effective match for the every-day driving style to offset the ocassional WOT moments where he wastes a few ml of fuel. The amount of time you stay around the peak efficiency to overcome the mass, friction and aerodynamics to get to a particular speed then the lowest level of power you can output to maintain the speed is vehicle efficiency. If the throttle position was just that much higher and the sensors cooperated in keeping his fuel flow lower even with the O2 sensor calling for more from the air increase, it usually happens.

I'll have to dig up the study that BMW did when debating a 7-speed automatic years ago; Best results overall went to the driver that went WOT to target speed and then slipped to 5th in the manual than anything they did to calibrate the 7-speed auto (NA, not turbo, sorry).

[resuwrecked]

No laws broken or even bent!

I couldn't find a temp/pressure/density profile for air so this will have to do.

Depending upon how much the temp of the compressed air increases during compression the decrease in density due to the increase in temp can be offset by the increase in pressure. Even this can be improved upon by the use of an inter-cooler which will help reduce the temp of the compressed hot air and further increase its density.

http://www.engineeringtoolbox.com/ai...ity-d_771.html

I spoke before I thought about that one. Good point. Be sure not to use an intercooler if your tcharging for economy! ha

[FB71]

I spoke before I thought about that one. Good point. Be sure not to use an intercooler if your tcharging for economy! ha

exactly!!

[FB71]

The Turbo, Engine and Exhaust items mentioned can all be debated individually, and most of you are fundamentally correct. But the vehicle has to be looked at more holistically and the people that mention driving style have hit on what has more effect than the bolt-on mod and more closely to the overall effect that some people are experiencing. I've had my share of small cars that should have been more fuel effecient, based on their weight, power and displacement. But, when the Driver or the transmission intentionally keeps the engine out of its peak efficiency areas of its power curve, you get bad performance and can actually make worse mileage when you think you are really saving.
Most modern incremental increases in today's cars are a combination of controlling that combustion tighter, but 6-12% increases are attributable to just the transmission improvements mated to those engines keeping them running in their peak efficiency range.
Shade-tree turbo swapper may just have pulled his motor into an effective match for the every-day driving style to offset the ocassional WOT moments where he wastes a few ml of fuel. The amount of time you stay around the peak efficiency to overcome the mass, friction and aerodynamics to get to a particular speed then the lowest level of power you can output to maintain the speed is vehicle efficiency. If the throttle position was just that much higher and the sensors cooperated in keeping his fuel flow lower even with the O2 sensor calling for more from the air increase, it usually happens.

I'll have to dig up the study that BMW did when debating a 7-speed automatic years ago; Best results overall went to the driver that went WOT to target speed and then slipped to 5th in the manual than anything they did to calibrate the 7-speed auto (NA, not turbo, sorry).

you are correct. this is basically what I was eluding to.