TheSamba.com :: View topic - Turbo diesel fucntion I understand, but turbo Gasser I dont

Thu Mar 04, 2004 8:33 am

i understand how a turbo in a diesel works, by compressing the are before it is pushed into the combustion chamber where it is them mixed with fuel. But how does a turbo on a gasser work when the fuel is mixed with the air before entering the combustion chamber? I tried a search using turbo function, but no luck.
thanks
lc

Thu Mar 04, 2004 8:41 am

Basically, both work on the same concept. its all about cramming as much air/fuel mixture into the combustion chamber as reasonably possible. the more you can cram in, the more power you make.
this is why you will always here things about porting and polishing heads, big carbs, etc. this is to make it easier to pull more air/fuel in on a conventional or naturally aspirated motor. with a turbo, you are forcing it in instead of sucking it in.

Edit.
after reading your post again, are you asking about mixing the fuel before it enters? in other words, such as pulling it out of a carb before the turbo instead of doing a fuel injection?
all still works the same, fuel mixed here or there.

Thu Mar 04, 2004 9:28 am

thanks for the reply. i guess what i am asking is, can you put the turbo before the carb, or after the carb. I always had this idea that a carburator needs to be open to the atmosphere to function properly. not true? and it just seems that if the air fuel mixture was sucked out of the carb and then crammed into the combustion chamber, that there would bee some sort of concentration of fuel on the fans in the turbo possible pre-combustion do to sparks etc... I have no background knowledge, this is just speculation. so thanks for your help.
lc

Thu Mar 04, 2004 9:59 am

actually, you can do either, carb before or after. if it is before or a draw through, just have to worry about the type of seal that is in the turbo.

as far as fuel going through the turbo, has never been shown to be a problem. i dont think it ever gets hot enough in the compressor to get to the flash point of gasoline. at least not at the boost levels most might try.

Fortunately, there should be no sparks or any thing like that in the compressor side of the turbo, or at least as long as the turbo is working proplerly.

I am currently running a draw through set up on my car. (carb is before the turbo) and i am hoping some time this year, that i might try and take some temperature measurments of the air after the turbo just to see. But at 10ish lbs of boost, i dont forsee seeing any thing much over 150'F or so.

if you are interested, there are a whole boat load of web pages on how turbos work, etc. such as
http://auto.howstuffworks.com/turbo.htm
http://www.turbofast.com.au/
hope that helps

Thu Mar 04, 2004 3:30 pm

cool. Thanks a bunch. that helped a bunch
lc