Turbochargers are Exhaust Driven Air Pumps

Auto manufacturers are obsessed with 2L Turbo engines, now in more than 700 different cars. Did I mention that I am like Jalopnic, obsessed with technology & cars. Jalopnik | Obsessed With The Culture Of Cars

Make the engines smaller. Where 6.7L naturally aspirated engines once were, now we have 2.7L Turbo with direct injection from Ford. Where 4L engines were, the 2L turbo engine emerges. Toyota even turbo direct injected a 3 cylinder 1.6L in the GR Corolla for 300 HP out power, holly banana pants, that's amazing. 

2L inline 4-cylinder engine consider a darling in engineering with 500cc of swept area that the piston & rings slide up & down through. The goal of engine designers to get more power out of the fuel. In principle this would increase thermal efficiency, but they waste fuel to keep combustion temperature low & to play nice with the ECU & catalytic converter & exhaust emissions, but also by running slightly rich fuel air ratios that can prevent detonation or valve pinging at higher engine loads like when you're passing on the highway & shove the accelerated all the way down with your foot. 

By turbo charging, the naturally aspirated 2L goes from 160 HP to as much as 700 HP. Above 350 HP requires advanced dry sump lubrication, intercoolers, oil jets under the piston skirts, titanium valves, hydraulic valve variability control, variable ignition, & direct injection of gasoline with an addition set of port injectors to keep the valve seats clean and to maximize boosted performance fueling under full load or maximum output or full acceleration :) Using E85 with flex-fuel like ECU mapping variability control, power output can be further enhanced. Higher ethanol blends have much better performance because they are intrinsically higher octane, like a race fuel. 

There exists small hobby weak blend nitromethane fueled engines that make 3HP out of 27cc of displacement. Thats over 700HP per liter, like F1 engines. Nitro motors use 4X more fuel or are not fuel efficient for that amount of power. The 16% nitromethane + methanol & synthetic oil fuel is also not clean burning & releases and oily gummy mist in the exhaust. 

Top fuel dragsters pushrod V8 use 90 nitromethane & 10% methanol fuel. They can go 330 MPH within 1000 ft, less than 1/4 mile. The top fuel dragsters engines make 11,000 HP but are opened up & cleaned & checked after a few runs for safety. They are so high performance that these engines sometimes explode, so some parts of the engine are now strapped down with safety straps to keep shrapnel from an engine explosion from hurting anyone nearby. 

This is why virtually no power generators use small nitromethane engines. These little hobby car nitro motors are also 2 strokes so engine life only a few hundred hours max. A well-made Toyota 2JZ liquid cooled 4 stroke gasoline engine operates for 10,000+ hours by comparison, as long as the engine oil changed regularly & other basic maintenance performed. 

The 4.0L 1UZ engine in the 1989-1995 model year Lexus LS400 the most reliable engine ever made, though that means 10MPG city in the real world. Back then gasoline was less than $1/ gal in the USA. The 1NZ-FXE in the 04-09 Prius a 4 banger 1.5L of exceptional durability. The 2ZR-FX in Meg's 3rd Gen. Prius & my newer Corolla Hybrid are 1.8L of Atkinson exceptionally high thermal efficiency & very reliable. Toyota has a history of selling fuel efficient, long last, reliable engines, better than Honda, better than anyone else. 

Other than Toyota, most automobile transmissions are crap & wear out in less than 100,000 mi & cost $4000-$10000 to change, rather to pay a mechanic to change out the broken transmission. Some HD diesel trucks have long lasting Allison transmissions but get poor fuel economy. The diesel Bluebird School bus I drive gets 5.6 MPG using diesel in the variable gate Turbocharged Cummins inline 6 engine, typically used in class 8 trucks. It also weighs nearly 40,000 pounds. 

That means a 4000 lb. passenger car should get 10x better economy or 56 MPG if the power to efficiency & mass scaling was linear. VW did sell TDI vehicles that get over 50 MPG when driven gently. TDI stands for turbo-diesel injection. I really like the 1.9L 88 VW diesel TDI engine, and the TDI Jetta that it powered back in 2003. It was a strong contender on the list that included the 2nd Gen Prius which I ended up going with because it does not have a transmission. The HSD or hybrid synergy drive system in Toyota Hybrids is far more reliably that even the best manual transmissions.