[DML] Re: Carb vs FI

["content22207" <brobertson@xxxxxxxxxxxx>]

Auto manufacturers also switched en mass to EFI because any manufacturer still using carbs would have been crucified in the popular press (same crap I receive, only my bottom line doesn't hinge on negative press).

Carbs did continue to be used on holdover domestic models until 1991 (Jeep Wagoneer), and on fringe selling imports until 1992 (Subaru Justy).

Note that there is a world of difference between electronically controlled fuel injection and mechanical fuel injection. Mechanical injection (gasoline) never caught on outside Europe. No Japanese manufacturer ever used it. General Motors only used it as an option on the Corvette, and only for 7 years (1957-1965). American Motors studied Rochester's system intensely in the mid 1960's (squandering scarce development dollars in the process), but ultimately decided that it would place the company at a competitive disadvantage against carbureted models. 

Gasoline fuel injection does work acceptably well under electronic control. It is mechanically controlled fuel injection that was rejected by most of the world's manufacturers. One would think that, had mechanical fuel injection provided benefits over carburetion, at least one manufacturer would have introduced it for competitive advantage. Whatever you want to say about American manufacturers, the Japanese certainly were innovative enough in the 1970's and 1980's, and had deep enough pockets, to have done so. That the Japanese walked away from it speaks volumes, IMHO.

Trivia: Lambourghini did not use K-Jet on its European Countach's -- European Countach's had Weber carbs. European Countach's also had better performance numbers than North American imports.

Bill Robertson
#5939


--- In dmcnews@xxxxxxxxxxxxxxx, Bob Brandys <BobB@...> wrote:
>
> The statement that a carburated engine could not meet 1981 emission standards is wrong.   Way back then I was in charge of testing thousands of vehicles in the chicago area for emissions as a public service through the American Lung Association.
> 
> The 1981 emission standards were essentially the same as those implemented in 1975 which required the addition of a catalytic converter.   GM and other car makers met these emission standard with carburated engine as late as 1986.  90% of all emission in the EPA test methodology come from starting the engine when it is cold.  Quick heating cats solved this emission problem. Thermo reactors were even used by Mitsu and Chrys to speed up this heating process. 
> Ford put the cats right on the exhaust manifolds to achieve the same effect. 
> 
> Carburated engines can be as efficient as FI engines BUT it is a lot more work to get a carburator to do this. 
> 
> FI can be controlled with electronics to measure fuel delivery to easily compensate for the individual engine variations that occur in the manufacturing process.  However, carburators do not have this flexibility.   To achieve maximum fuel efficiency from a carb you need to put the car on a dyno and adjust the jets accordingly to get the maximum fuel economy.   This is a long and expensive task to do.  BUT IT CAN BE DONE. 
> 
> The best example I know of this is a friend who has a 1969 Camaro with a 501 and a Quadrajet.   He also works for a research company that tests additives for cars.  They have a dyno to test effects.  
> 
> Fortunately, he has free access to this dyno and the equipment to measure emissions and fuel consumption.  He spent almost a month of evenings dialing in his 501 to get maximum fuel economy.  
> 
> Did it work?   Well, he gets over 20 mpg at 60 mph.  I would say that works.  I don't know of any FI engine of this size that gets 
> anything close to this mileage.  
> 
> 
> The reality is that the choice to go to FI by the car makers was done to get better mileage and NOT to meet emissions.  
> 
> Bob
>




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