just a thought, your opinions? (General engine discussion)
#1
01-25-2008, 08:31 PM
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just a thought, your opinions? (General engine discussion)
This is just a thought I had the other day....It all came about because I finally broke down and bought a new(er) fuel efficient car.
Its an 04 Focus...I got a CEL, pulled the codes and said something about the cat being inefficient. This was due to the fact I was running 87 octane, not premium.
So I filled her up with premium and I get significantly better mileage (duh i know the car was made for it)...but that got me to thinking....
people usually generalize high compression with high performance engines...but I remember a few years back as a mischevious teenager playing with fireworks I could light a mighty mite off in the palm of my hand with no ill effects....however if I closed my hand around it, well it wasnt pretty.
use the firecracker as the fuel, and my hand as the cylinder. Same amount of fuel, but the smaller the space it was condensed into the harder it blew up. S
So my thought is this: If you have an iron headed engine, bump the compression up to 10.5:1 and run premium fuel, will you gain the extra mileage because the engine is running more efficient to offset the extra cost of the higher octane fuel?
I get better mileage with premium in the focus than i do on 87 octane. Running premium I actually save money, even after paying the added cost. Again I know thats because its designed for premium, but the idea is there.
Whats your take on it?
Its an 04 Focus...I got a CEL, pulled the codes and said something about the cat being inefficient. This was due to the fact I was running 87 octane, not premium.
So I filled her up with premium and I get significantly better mileage (duh i know the car was made for it)...but that got me to thinking....
people usually generalize high compression with high performance engines...but I remember a few years back as a mischevious teenager playing with fireworks I could light a mighty mite off in the palm of my hand with no ill effects....however if I closed my hand around it, well it wasnt pretty.
use the firecracker as the fuel, and my hand as the cylinder. Same amount of fuel, but the smaller the space it was condensed into the harder it blew up. S
So my thought is this: If you have an iron headed engine, bump the compression up to 10.5:1 and run premium fuel, will you gain the extra mileage because the engine is running more efficient to offset the extra cost of the higher octane fuel?
I get better mileage with premium in the focus than i do on 87 octane. Running premium I actually save money, even after paying the added cost. Again I know thats because its designed for premium, but the idea is there.
Whats your take on it?
#2
01-25-2008, 09:57 PM
The EFI system in the Focus is designed to advance the timing to the edge of detonation, and higher octane fuel will permit more advance because it's harder to ignite. Now... the more advance you put on a motor the more torque it makes, and usually this results in improved milage because the motor doesn't have to rev as much to get around.