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Im looking into building an engine and making it very fuel efficient. Im not sure where to start though. Any input would be greatly appreciated. At first I thought about taking an engine from another vehicle and using that but then I decided to just build one myself. That way I can get a better understanding of how everything works together. What major parts would I need? How do I make it extremely fuel efficient? Is it difficult to build an electric/gasoline engine? Would it be more expensive to build a small engine or purchase an engine already assembled?



Like I said any input is appreciated. Thanks for your help. =]  

really... you want to start from scratch...  with a clean sheet of paper...

you need to calculate how much power you need.. and at what RPM....

whats really neat.. with the advent of CNC machines... and computer aided designs..  and some serious software...  you can really build a motor to suit your needs...       it's not cheep...  i am talking thousands of hours in front of a computer...  after hundreds of hours with a paper and pencil... then finding a bunch of manufacturers who can do it..


you might want to start at this blog...

http://www.sandyblogs.com/techconnect/2009/07/improving-internal-combustion-with-direct-injection.html

this it the current state of the art..  there is a ton of other stuff to read on that blog.. be sure to check the archives..


most people can take already built production engines and modify them... and the fuel systems ...

when you get around to finishing the design.. let me know.. i will point you in the direction of the hand full of manufacturers that are able to start with a solid chunk of aluminum... and come out with a finished engine..

there are multiple ways to even save weight in the engine.. and durability.. take a look at how kubota mounts their crankshaft in blocks and then bolts them into the aluminum block...    for superior for long lasting motors with ultra high compression..

i would really like to know if the direct injection system would be more efficient with no throttle blade so the engine pumps every cubic inch of air it can...  like most truck diesels...  or with a throttle blade... so the engine is run at a partial vacuum ...

i just cannot run the numbers in my head.. how much horsepower does it take to create the intake manifold vacuum...    how much in pumping losses will offset power used to create the intake manifold vacuum...

i wonder if that vacuum is what causes some motor when you shut them off to spin backwards...


you might want to join SAE.org...  and take their automotive magazine..    and have access to all of their articles on the automotive subject..  

w0w! lol. Thanks for the feedback. I appreciate it. You might want to break it down more barney style for me though. Im not very familiar with engine dynamics. So you pretty much lost me when you started talking about the vacuum. lol.

I've come to the decision that I wont be building one myself. Manufacturers spend tons of money engineering theirs so constructing one myself from scratch would be an expensive proposition. Not to mention very time consuming.

But, Im very interested in the software you mentioned. I'd love to get a chance to play with that. What is CNC machines?

And can I really come up with a design and then get a manufacturer to make it for me? That would be simply amazing.  

check out this set of pictures and the article...

http://www.carcraft.com/techarticles/ccrp_0803_524_chevy_small_block_engine/index.html
With a CNC machine you can make any size engine you want.


http://www.vetteweb.com/tech/vemp_0905_warhawk_engine_block_chevrolet_corvette/photo_02.html

http://www.vetteweb.com/tech/vemp_0905_warhawk_engine_block_chevrolet_corvette/index.html

http://www.hotrod.com/techarticles/engine/hrdp_0902_motown_ls_engine/index.html

here are some videos

http://www.youtube.com/watch?v=GU32Q6QXtWQ

there is a whole bunch more videos on the right frame...  

as for the software...  got a speedy PC>..???/  there are a bunch of them..  i am not into Computer aided design "CAD"  


http://www.google.com/search?hl=en&source=hp&q=CAD+software&aq=f&oq=&aqi=g10  

So which is better as far as power and fuel economy; 1.A turbocharged diesel engine with direct injection, or 2.A turbocharged gasoline engine with direct injection?  

lately..  the diesel...   but i have not had a chance to compare...

the reduction in fuel economy is do to the need to feed the cat enough fuel to maintain combustion to convert the NOX and NO to breathable air...