Turbo Efficiency
 

Why do turbo'd cars do so much less MPG? are they naturally less efficient than there NA counterparts. Obviously they are more powerfull and have the ability to burn more fuel if driven fast but if driven at the same speed as a similar engine sized NA car shouldnt thay do about the same MPG.

Steve

The biggest reason most turbo'd cars get less gas mileage is because of the foot pressing the accelerator. When you are not on the boost the car should for the most part consume about the same amount of fuel as an NA car. I had a VW GTi 1.8t. The car got about 32-34mpg at 75-80mph. Granted the newer turbo'd cars are much more efficient in terms of engine management and even higher compression for better combustion.

I suppose low compression ratios may make the engine less efficient when off boost.

I agree, most of the reason the MPG is low is driver discipline, or lack there of. I own one and it beggs to be driving at low rates of efficiency. Outside of that, the low compression rate will adversly effect the engines relative ability to generate power. I try not to measure my driving experiences in dollars.