Engine Power Vs. Engine Displacement Vs. Engine Configuration

I have a question about engines. The other thread about turbos and engines inspired me to create this one. If there were six engines- 2.0 L I-4, I-6, V-6, V-8, Box 4, Box 6, all the same size would they all produce the same power or would some engines produce more due to the configuration? I was thinking the V-8 would create the most but then again because they're the same size the cylinders would shrink, thus limiting the amount of fuel used. Would fuel economy be also affected by these different engines?

Would the same thing happen for diesels as well?

[QUOTE=NSXType-R]I have a question about engines. The other thread about turbos and engines inspired me to create this one. If there were five engines- 2.0 L I-4, V-6, V-8, Box 4, Box 6, all the same size would they all produce the same power or would some engines produce more due to the configuration? I was thinking the V-8 would create the most but then again because they're the same size the cylinders would shrink, thus limiting the amount of fuel used. Would fuel economy be also affected by these different engines?[/QUOTE]
Too many variables. Depends on state of tune(air flow, cams etc), how high they rev ect.

You say all of the same size.....I think you should predefine the size and the required power, in order to make a certain vehicle move.

Like slicks said its way to hard to judge there are too many variables. I think this site will help you out though.
[url]http://www.autozine.org/technical_school/engine/smooth1.htm[/url]

Thanks guys. I was thinking that because they were the same displacement they should create the same power.

In my auto technology class in high school my teacher claimed that it was a more effecient design to have a lot of small cyliders than a few very big ones. His reasoning had something to do with the ratio between surface area and volume inside of the cylinders. He used a similar rationalization to explain why a hemispherical head was, in theory, better than a flat cylinder head.

But with a lot of small cylinders there would be more surface area which means it would be less thremodynamically effecient wouldn't it?

Surface area causes heat loss which equates to lost power

I understand with that reasoning used for Hemi's though. Hemi's are better than flats because hemi's have less surface area than a flat head would. Therefore they are more thermodynamically effecient.

It is easier to fit 4 valves in a flat head, which far outweighs the power gained from a hemi.

Actually, these goals are contradicting each other.
The best economy will be achieved with the I-4, whereas the most power will be achieved with the V8.

Less cylinders mean less friction losses, leading to a better mpg figure.

More cylinders mean less reciprocating mass, leading to more revving capability.

a 2L V8 will be able to rev much higher than a 2L 4 cylinder becasue the maximum accelration rate of the piston will be far less than the 4 cylinder engine because the piston will not have to travel as far.

[QUOTE=deffenbaugh03]But with a lot of small cylinders there would be more surface area which means it would be less thremodynamically effecient wouldn't it?

Surface area causes heat loss which equates to lost power

I understand with that reasoning used for Hemi's though. Hemi's are better than flats because hemi's have less surface area than a flat head would. Therefore they are more thermodynamically effecient.[/QUOTE]

It makes sense what you say about thermodynamic efficiency. I was always confused by his statement because it seemed to me that having more volume in the middle of the cylinder, far away from the walls, would allow a larger percentage of the fuel to be burned. It always confused me because this guy (my teacher) was incredibly knwoledgeable abut cars and I didn't think he would be likely to make a mistake like that. Maybe there is something I'm missing.

Alright. Say they theoretically they shared the same parts- injectors, intakes etc. (I know it's not possible since the crankshafts are already different but work with me here ;) ). Would they make the same power each or would their configurations lend some advantage?

I wonder why people voted for V8 when part of the poll question is "best gas mileage".... :rolleyes:

I voted for a V6 when I thought of how much power can be squeezed out of one and it sure have better gas mileage than V8. :p

i thing that the v-8 would be more powerful. if im not wrong i believe that the smaller the cylinder is the less likely detonation would occur. With that the v-8 could have the highest compression. As well as the highest revs. Not to sure about mileage

The V8 will be the fastest...just look at the F1's 2,4L V8....but offourse it will need the same style setup,,,,,,,,,,,,,,