Saabs supercharged SVO engine (2001) gets 30% BETTER MPG than naturally aspirated engine.

NOW WHY THE F--K DOESN'T GM DO THIS WITH THEIR FLEX-FUEL CARS (E85 has higher octane rating than high test gas) WHICH WOULD WORK EVEN BETTER WITH HIGHER OCTANE E85!

PEOPLE COULD BE GETTING 30% BETTER MILEAGE WITH E85 FLEX-FUEL CARS!

SHIT GM, NO FUCKING WONDER YOU'RE IN TROUBLE. WHY DON'T YOU MAKE A REAL EFFORT? MAYBE YOU WOULDN'T BE IN THE TROUBLE YOUR IN TODAY IF YOU HAD MADE A REAL EFFORT BEFORE. SHIT. NO WONDER FORD IS KICKING YOUR ASS!

(and GM HAD a supercharged Cobalt engine available as an option -- BUT NOT ON FLEX FUEL VEHICLES!!)


http://www.enginebuildermag.com/Article/2321/saabx2019s_unique_engine_concept_provides_variable_compression.aspx

Saab reports the SVC concept reduces the fuel consumption of a conventional naturally aspirated engine by up to 30%.

Wikipedia says, at the moment:

"The SVC project was shelved by General Motors, when it took over Saab Automobile, due to cost."

A moving cylinder head could be quite an engineering problem. It'd be interesting to know what difference they thought it'd make to manufacturing cost, and reliability.

about supercharging or turbocharging producing more power from the same cu in. and allowing downsizing. The result is you can get equal power from a smaller mill and mileage equal to or better than the larger naturally aspirated engine.

with ethanol (E85) having an octane rating of 113 you can use more boost and higher effective compression - and thus more power per cu in.

GM knows this but doesn't want to make the effort - probably because there are so few E85 pumps available. Still, I think they could offer it as an optional engine on FFVs. The fuel sensor could set timing and boost so you could optimize for the octane.

Burning a fuel under compression means the octane rating is very important. I'd take a higher octane fuel any day over a lesser one IF I had an engine that can take advantage of it.

Alcohols have less energy then gasoline and diesel. High performance vehicles, those with high compression or supercharged need higher octane to prevent preignition. The higher octane of E85 will allow the turbocharged engine to run it OK but to get the same performance MPG goes down.

There ain't no free lunch!

With higher octane fuel (E85 = 113 octane) You can use higher compression and get more power per cu in. MOre power means more "work". and work is what were interested in.

YOu can downsize a supercharged or turbocharged engine and get better mileage than a similar powered naturally aspirated engine of larger size.

http://ateupwithmotor.com/terms-and-definitions/technology/78-turbocharging-and-supercharging.html

" a supercharged engine tends to consume less fuel in day-to-day driving than a larger displacement, normally aspirated engine of similar power. For example, a 2.0L turbocharged four-cylinder engine with 240 hp will be somewhat less thirsty than a 240-hp 3.5L normally aspirated V6 engine, at least in normal driving. "

Now if you "put your foot in it" all the time your mileage will suffer but of course the same would happen with the naturally aspirated heavier engine too.

Premium made with ethanol should cost less than regular not more.

(or for that matter superchargers) push more air into an engine, permitting more fuel to be burned.

Burning more fuel generates the greater horsepower.

Naturally aspirated 4 stroke engines benefit from charging by an increase in volumetric efficiency. This results obviously in more power for a given sized engine. This translates to a smaller engine for a given size power requirement. Turbos are more efficient than engine driven superchargers but have a less flat performance curve.

The problem with turbocharged cars is the fact that the engines have to work over an extremely wide power range. Turbochargers, by the fact that they are exhaust driven, only begin to function at high power levels where there is sufficient energy going out the exhaust pipe.

Going to a smaller engine means less cooling losses and less friction loss. This then is the primary benefit of turbo charging thus resulting in better fuel economy.

Then there is the issue of the fuel. The higher the combustion temperature, the greater the thermal efficiency as well.