Quick question concerning fuel and engines

[matchuk]

Just wondering for example just because a car has a 2 litre engine, it doenst mean that 2 litre capacity is used 100% right? it depends on the a certain area of rpm (power band) where it can fit most air efficiently and hence more fuel right?

just curious for example a 4th gen prelude h22a would use less fuel driving at low revs (esp with its steep powerband) opposed to like an auto 1.8 litre 05 civic which we also have at home

thanks

[trism]

aer you asking if the h22a can use less fuel than a 1.8?

it depends on teh age and condition of the engine, how you drive it, what fuel you use, heaps of things

you could have 2 2litre engines witht he same power and drive themn the exact same and one could use more fuel than the other

[string]

An engine is a big thirsty air-pump. The mechanism for limiting the air it receives is the THROTTLE - a large valve attached to your right foot.

A 2 litre engine will always pull in 2 litres of air. If it has to pull it through a tiny hole (let's say you only open the throttle valve a tiny bit) there's no way it will be at full atmospheric pressure: lower pressure = less oxygen = less fuel needed for adequate combustion.

The throttle controls the ammount of air that enters the engine, but the actual metering of fuel is calculated by the RPM of the engine, and the air pressure in the intake manifold (which is between the engine and the throttle, i.e. a reservoir of air at the pressure your right foot is describing).

Engine size and fuel consumption are not directly linked, there are many factors, including some determined by how the driver drives it. A heavier vehicle takes more energy to move around, which is where larger engines are normally fitted.

I don't believe a H22 in an EG civic would return as good day to day economy as it's standard 1.6L motor for example, but there's no reason it wouldn't be very close. a 4th gen prelude would consume far more due to the fact the engine has to lug around more mass.

[trism]

but compare say a k20 in a new integra type r and then a conversion into a, eg or ek, the converted car should get better fuel economy, due to less mass to haul

[string]

but compare say a k20 in a new integra type r and then a conversion into a, eg or ek, the converted car should get better fuel economy, due to less mass to haul

Better economy than the new Integra sure, but not necessarily better economy than a similar eg/ek with the stock 1.6L.

The best guide for fuel consumption is the total vehicle mass. An engine can have all the efficiency in the world, but it'll drink like a fish if it is bolted to a large load. Case in point: Camry 4cyl vs 6cyl. Similar economy figures but substantially different engines.

[tiksie]

An engine is a big thirsty air-pump. The mechanism for limiting the air it receives is the THROTTLE - a large valve attached to your right foot.

A 2 litre engine will always pull in 2 litres of air. If it has to pull it through a tiny hole (let's say you only open the throttle valve a tiny bit) there's no way it will be at full atmospheric pressure: lower pressure = less oxygen = less fuel needed for adequate combustion.

The throttle controls the ammount of air that enters the engine, but the actual metering of fuel is calculated by the RPM of the engine, and the air pressure in the intake manifold (which is between the engine and the throttle, i.e. a reservoir of air at the pressure your right foot is describing).

Engine size and fuel consumption are not directly linked, there are many factors, including some determined by how the driver drives it. A heavier vehicle takes more energy to move around, which is where larger engines are normally fitted.

I don't believe a H22 in an EG civic would return as good day to day economy as it's standard 1.6L motor for example, but there's no reason it wouldn't be very close. a 4th gen prelude would consume far more due to the fact the engine has to lug around more mass.

Accelerator attached to my foot ?!

What has this world become!!!!!!!!!!!!!

[matchuk]

k i should clear it up

for example

disregarding the engine condition, aging etc

imagine a b16a/b and just a normal 1.6 ek i think its a d16 something

both are 1.6 litre engines pulling similar mass

the normal ek engine has a less steep power curve so on normal road driving 2000-3000 rev range it would generate its peak torque or potentially power

now the b16b engine which is more racing tuned with its steep curve, driving at 2000-3000 rev wont be pulling that much torque or power

so the normal ek d series engine would use more fuel as theres more oxygen in the cylinders at that rev range yes?